NATIONAL

TRANSPORTATION

SAFETY

BOARD

WASHINGTON, D.C. 20594

AIRCRAFT ACCIDENT REPORT

DESCENT BELOW VISUAL GLIDEPATH

AND COLLISION WITH TERRAIN

DELTA AIR LINES FLIGHT 554

MCDONNELL DOUGLAS MD-88, N914DL

LAGUARDIA AIRPORT, NEW YORK

OCTOBER 19, 1996

PB97-910403

NTSB/AAR-97/03

NYC97MA005

6785B
The National Transportation Safety Board is an independent Federal agency dedicated to

promoting aviation, railroad, highway, marine, pipeline, and hazardous materials safety.

Established in 1967, the agency is mandated by Congress through the Independent Safety

Board Act of 1974 to investigate transportation accidents, determine the probable causes of

the accidents, issue safety recommendations, study transportation safety issues, and evaluate

the safety effectiveness of government agencies involved in transportation. The Safety

Board makes public its actions and decisions through accident reports, safety studies, special

investigation reports, safety recommendations, and statistical reviews.

Information about available publications may be obtained by contacting:

National Transportation Safety Board

Public Inquiries Section, RE-51

490 L’Enfant Plaza, S.W.

Washington, D.C. 20594

(202)382-6735

(800)877-6799

Safety Board publications may be purchased, by individual copy or by subscription, from:

National Technical Information Service

5285 Port Royal Road

Springfield, Virginia 22161

(703)487-4600
NTSB/AAR-97/03 PB97-910403

NATIONAL TRANSPORTATION

SAFETY BOARD

WASHINGTON, D.C. 20594

AIRCRAFT ACCIDENT REPORT

DESCENT BELOW VISUAL GLIDEPATH

AND COLLISION WITH TERRAIN

DELTA AIR LINES FLIGHT 554

MCDONNELL DOUGLAS MD-88, N914DL

LAGUARDIA AIRPORT, NEW YORK

OCTOBER 19, 1996

Adopted: August 25, 1997

Notation 6785B

Abstract: This report explains the descent below visual glidepath and collision with terrain of

Delta Air Lines flight 554 at LaGuardia Airport on October 19, 1996. The safety issues in this

report focused on the possible hazards of monovision contact lenses, visual illusions encountered

during the approach, non-instantaneous vertical speed information, the weather conditions

encountered during the approach, the guidance in air carrier’s manuals regarding flightcrew

member duties, the stabilized approach criteria in air carrier’s manuals, emergency evacuation

procedures, special airport criteria and designation, and LaGuardia Airport issues/runway light

spacing. Safety recommendations concerning these issues were addressed to the Federal

Aviation Administration and to optometric associations.

iii

EXECUTIVE SUMMARY.........................................................................................................vii

1. FACTUAL INFORMATION.................................................................................................. 1

1.1 History of Flight ................................................................................................................... 1

1.2 Injuries to Persons ................................................................................................................ 8

1.3 Damage to Airplane.............................................................................................................. 8

1.4 Other Damage....................................................................................................................... 8

1.5 Personnel Information .......................................................................................................... 8

1.5.1 The Captain.................................................................................................................. 9

1.5.2 The First Officer......................................................................................................... 10

1.5.3 Flight Attendants........................................................................................................ 10

1.6 Aircraft Information............................................................................................................ 11

1.6.1 General........................................................................................................................ 11

1.6.2 Vertical Speed Information......................................................................................... 11

1.7 Meteorological Information................................................................................................ 11

1.7.1 Weather Information Provided to the Flightcrew by Delta........................................ 12

1.7.2 Runway Visual Range (RVR) Values....................................................................... 113

1.7.3 Windshear Information/Low Level Windshear Alert System (LLWAS) ................. 113

1.8 Aids to Navigation.............................................................................................................. 15

1.9 Communications................................................................................................................. 15

1.10 Airport Information .......................................................................................................... 15

1.10.1 Runway 13 Information ........................................................................................... 17

1.10.1.1 Runway 13 Runway Lights/Spacing ................................................................. 17

1.10.1.2 Runway 13 RVR Information ........................................................................... 18

1.10.1.3 Runway 13 VASI Information .......................................................................... 19

1.11 Flight Recorders ............................................................................................................... 20

1.11.1 CVR .......................................................................................................................... 20

1.11.2 FDR........................................................................................................................... 20
iv

1.11.2.1 FDR Information on Windshear........................................................................ 22

1.12 Wreckage and Impact Information ................................................................................... 23

1.13 Medical and Pathological Information ............................................................................. 24

1.14 Fire.................................................................................................................................... 24

1.15 Survival Aspects............................................................................................................... 24

1.15.1 Evacuation-related Information From CVR Transcript ............................................ 26

1.15.2 Crewmember Responsibilities During an Emergency Evacuation ........................... 27

1.15.2.1 Flightcrew Duties During an Emergency Evacuation ....................................... 27

1.15.2.2 Flight Attendant Duties During an Emergency Evacuation .............................. 28

1.15.3 Flight Attendant Actions/Decisionmaking During the Evacuation .......................... 29

1.15.3.1 Flight Attendant in Charge................................................................................ 29

1.15.3.2 Second Flight Attendant.................................................................................... 30

1.15.3.3 Third Flight Attendant....................................................................................... 31

1.15.4 Delta Flight Attendant Training................................................................................ 31

1.15.5 Previous Safety Board Recommendation—Flight Attendants’ Actions................... 31

1.16 Tests and Research ........................................................................................................... 32

1.17 Company/Flight Operations Information.......................................................................... 32

1.17.1 Delta’s Procedures and Guidance Regarding Flightcrew Responsibilities During

CAT I ILS Approach to Land .............................................................................................. 32

1.17.1.1 First Officer’s Actions During Approach to Land ............................................ 36

1.17.1.2 Delta’s Postaccident Actions Regarding PF/PNF Duties.................................. 36

1.17.2 Stabilized Approach Criteria..................................................................................... 37

1.17.2.1 Previous Safety Board/FAA Actions Regarding Stabilized Approaches.......... 39

1.17.2.2 Delta’s Actions Regarding Stabilized Approaches........................................... 41

1.17.3 Crew Resource Management (CRM) Training........................................................ 42

1.18 Additional Information ................................................................................................... . 43

1.18.1 FAA Oversight of Airman Medical Certification (Vision)..................................... . 43
v

1.18.1.1 Vision Requirements for Certification .............................................................. 44

1.18.1.2 Information/Guidance Available to AMEs and Optometrists........................... 46

1.18.2 Information on Monovision (MV) Contact Lenses.................................................. 47

1.18.2.1 The Captain’s Use of Monovision Contact Lenses........................................... 48

1.18.2.2 Captain’s Postaccident Vision Test Results...................................................... 49

1.18.2.3 General Aviation Accident Involving Monovision Contact Lenses.................. 50

1.18.2.4 Postaccident Delta Air Lines Actions Regarding MV Contact Lenses............. 51

1.18.3 Information on Visual Cues/Illusions ....................................................................... 51

1.18.4 Information Regarding Special Airports................................................................... 52

1.18.4.1 FAA Information Regarding Special Airports .................................................. 52

1.18.4.2 Delta’s Information Regarding Special Airports............................................... 54

2. ANALYSIS.............................................................................................................................. 55

2.1 General................................................................................................................................ 55

2.2 The Accident Scenario........................................................................................................ 56

2.2.1 The Approach and Descent......................................................................................... 56

2.2.2 The Landing ................................................................................................................ 58

2.3 Delta’s Flightcrew Procedures............................................................................................ 60

2.4 Availability of Information About the Hazards of Monovision Contact Lenses................ 61

2.5 Non-Instantaneous Vertical Speed Indicator (VSI) ............................................................ 62

2.6 Special Airport Designation ............................................................................................... 63

2.7 Flight and Cabin Crew Evacuation Actions ....................................................................... 64

2.8 CRM Issues......................................................................................................................... 65

2.9 Other LaGuardia Airport Issues.......................................................................................... 66

3. CONCLUSIONS .................................................................................................................... 67

3.1 Findings .............................................................................................................................. 67

3.2 Probable Cause ................................................................................................................... 70
vi

4. RECOMMENDATIONS....................................................................................................... 71

5. APPENDIXES ........................................................................................................................ 75

APPENDIX A—INVESTIGATION AND HEARING............................................................ 75

APPENDIX B—COCKPIT VOICE RECORDER TRANSCRIPT ....................................... 76

APPENDIX C—EXCERPT FROM FDR REPORT ............................................................. 127

APPENDIX D—MEDICAL/VISION INFORMATION....................................................... 128

APPENDIX E—WEATHER INFORMATION..................................................................... 148
vii

EXECUTIVE SUMMARY

About 1638 eastern daylight time, on October 19, 1996, a McDonnell Douglas

MD-88, N914DL, operated by Delta Air Lines, Inc., as flight 554, struck the approach light

structure and the end of the runway deck during the approach to land on runway 13 at the

LaGuardia Airport, in Flushing, New York. Flight 554 was being operated under the provisions

of 14 CFR Part 121, as a scheduled, domestic passenger flight from Atlanta, Georgia, to

Flushing. The flight departed the William B. Hartsfield International Airport at Atlanta, Georgia,

about 1441, with two flightcrew members, three flight attendants, and 58 passengers on board.

Three passengers reported minor injuries; no injuries were reported by the remaining 60

occupants. The airplane sustained substantial damage to the lower fuselage, wings (including

slats and flaps), main landing gear, and both engines. Instrument meteorological conditions

prevailed for the approach to runway 13; flight 554 was operating on an instrument flight rules

flight plan.

The National Transportation Safety Board determines that the probable cause of

this accident was the inability of the captain, because of his use of monovision contact lenses, to

overcome his misperception of the airplane’s position relative to the runway during the visual

portion of the approach. This misperception occurred because of visual illusions produced by the

approach over water in limited light conditions, the absence of visible ground features, the rain

and fog, and the irregular spacing of the runway lights.

Contributing to the accident was the lack of instantaneous vertical speed

information available to the pilot not flying, and the incomplete guidance available to

optometrists, aviation medical examiners, and pilots regarding the prescription of unapproved

monovision contact lenses for use by pilots.

The safety issues in this report focused on the possible hazards of monovision

contact lenses, visual illusions encountered during the approach, non-instantaneous vertical speed

information, the weather conditions encountered during the approach, the guidance in air

carrier’s manuals regarding flightcrew member duties, the stabilized approach criteria in air

carrier’s manuals, emergency evacuation procedures, special airport criteria and designation, and

LaGuardia Airport issues/runway light spacing.

Safety recommendations concerning these issues were addressed to the Federal

Aviation Administration and to optometric associations.

NATIONAL TRANSPORTATION SAFETY BOARD

WASHINGTON, D.C. 20594

AIRCRAFT ACCIDENT REPORT

DESCENT BELOW VISUAL GLIDEPATH AND COLLISION WITH TERRAIN

DELTA AIR LINES FLIGHT 554

MCDONNELL DOUGLAS MD-88, N914DL

LAGUARDIA AIRPORT, NEW YORK

OCTOBER 19, 1996

1. FACTUAL INFORMATION

1.1 History of Flight

About 1638 eastern daylight time,1 on October 19, 1996, a McDonnell Douglas

MD-88, N914DL, operated by Delta Air Lines, Inc., as flight 554, struck the approach light

structure and the end of the runway deck during the approach to land on runway 13 at the

LaGuardia Airport (LGA), in Flushing, New York. Flight 554 was being operated under the

provisions of Title 14 Code of Federal Regulations (CFR) Part 121, as a scheduled, domestic

passenger flight from Atlanta, Georgia, to Flushing. The flight departed the William B.

Hartsfield International Airport at Atlanta, Georgia, about 1441, with two flightcrew members,

three flight attendants, and 58 passengers on board. Three passengers reported minor injuries; no

injuries were reported by the remaining 60 occupants. The airplane sustained substantial damage

to the lower fuselage, wings (including slats and flaps), main landing gear, and both engines.

Instrument meteorological conditions (IMC) prevailed for the approach to runway 13; flight 554

was operating on an instrument flight rules (IFR) flight plan.

The accident occurred on the first leg of a scheduled three-leg trip for the MD-88

flightcrew. The pilots reported for duty at 1330 for the scheduled 1430 departure from Atlanta.

According to the pilots, they received a thorough preflight weather briefing2

 as they prepared to

depart. The weather briefing indicated that there was frontal activity in the New York area; the

pilots stated in postaccident interviews that they believed the weather conditions could result in a

bumpy flight or otherwise make for a more difficult approach at LaGuardia.

According to Delta dispatch records, the flight departed the gate at 1431 and took

off about 1441, with the captain performing the pilot flying (PF) duties during the trip to

LaGuardia. The pilots stated that the departure, climbout, and en route portions of the flight

 1

 Unless otherwise indicated, all times are eastern daylight time, based on a 24-hour

clock.

2

 For additional information concerning the weather information obtained by the

flightcrew, see section 1.7.1, “Weather Information Provided to the Flightcrew by Delta.”
2

proceeded uneventfully, although they experienced turbulence at their cruising altitude of flight

level (FL) 370.3 

The pilots stated that as they approached LaGuardia, they observed large areas of

precipitation on the airplane’s weather radar and encountered light-to-moderate turbulence and

strong winds during the arrival to the New York area. According to flight and cabin

crewmember statements, the captain had previously briefed the flight attendant in charge (FAIC)

that their descent in the New York area might be bumpy. The flight attendants indicated that at

the captain’s suggestion, they prepared the cabin for landing and were seated in their jumpseats

earlier than usual during the descent to land. 

As the airplane approached LaGuardia, the pilots received radar vectors for the

instrument landing system with distance measuring equipment (ILS DME) approach to runway

13.4 At 1611:57, the cockpit voice recorder (CVR) 5 recorded the captain commenting about the

3o offset of the localizer course6 as he began to brief the details of the ILS DME runway 13

approach. At 1612:39, New York air route traffic control center advised the pilots to contact

New York terminal radar approach control (TRACON); the first officer acknowledged and

complied with the instruction. At 1613:30, the captain finished the approach briefing, stating in

part, “glide slope’s unusable below two hundred feet...final approach course crosses runway

centerline and twenty-seven hundred and fifty-four feet from threshold... .”

The first officer initiated the descent checklist at 1616:39, during which the pilots

discussed the wind and rain conditions reported at LaGuardia with regard to their approach

airspeeds. They determined that 131 knots would be their target airspeed for final approach to

LaGuardia and completed the descent checklist. At 1617:32, the captain called for the approach

checklist. At 1632:11, the captain asked the first officer if the approach checklist was completed,

to which the first officer replied, “we’re both identified ... approach check’s complete.”

 3

 37,000 feet mean sea level (msl), based on an altimeter setting of 29.92 inches of

mercury (Hg).

4

 For additional information concerning the ILS approach to runway 13 at LaGuardia,

see section 1.10.1, “Runway 13 Information.”

5

 See appendix B for a transcript of the CVR.

6

 According to the instrument approach chart used by the pilots of Delta flight 554

during their approach to runway 13, the localizer heading (132o

) is offset 3o from the runway heading

(135o

); however, according to Federal Aviation Administration (FAA) personnel, the actual offset is 1.8o.

Additionally, the instrument approach chart contains the remark, “Final approach course crosses runway

centerline extended 2745 [feet] from [the runway] threshold.” The ILS DME runway 13 approach

contains a waiver for runway threshold crossing height. The FAA’s requirement for electronic

glideslope height at the point where it crosses the runway threshold is 45 feet; the threshold crossing

height of the ILS DME runway 13 glideslope was 44.1 feet. According to FAA personnel, a new

localizer for runway 13 should be commissioned by October 1997. The new localizer will not require

the 3o

 offset.
3

At 1633:28, the captain stated, “Still showing sixty-three knots [of wind] now.”

At 1633:33, New York TRACON stated, “Delta five fifty-four, turn left heading one three

zero...you’re three miles from LYMPS,7...maintain three thousand until LYMPS...cleared ILS

DME runway one three approach,” and the first officer acknowledged the clearance. At 1633:55,

the first officer stated, “Yeah, I guess the wind’s gonna blow us over [to the localizer course],”

and (at 1633:58) the captain responded, “I think you’re right.” (See figure 1 for a copy of the

instrument approach chart used by the pilots of Delta flight 554.)

According to the CVR and pilot statements, about 1635, the flightcrew intercepted

the localizer and glideslope and received air traffic control (ATC) instructions to contact

LaGuardia tower. At 1635:23, the LaGuardia air traffic control tower (ATCT) transmitted,

“Delta five five four, you’re number two, traffic to follow...two mile final, the wind now one

zero zero at one two...one departure prior to your arrival...braking action reported good by [a

737]...low level wind shear reported on final by [a 737]... .”8 Within the next 25 seconds, the

CVR recorded the captain calling for landing gear extension and the before-landing checklist. At

1636:18, as the flightcrew accomplished the before-landing checklist, LaGuardia ATCT advised,

“Runway one three RVR [runway visual range] touchdown three thousand...rollout two

thousand two hundred,” and the captain commented, “must be raining hard at the airport.” At

1636:25, the first officer announced, “Before landing check is complete...not cleared to land

yet.”

According to the pilots’ statements, as they began their descent from 3,000 feet on

the ILS DME approach to runway 13, the airplane was in the clouds, in what the pilots described

as light-to-moderate precipitation. The pilots indicated that although strong, gusty surface winds

and turbulence had been forecast for their arrival in the New York area, as they descended on the

approach to the runway, LaGuardia ATCT reported steady surface winds out of the east at less

than 15 knots, and the pilots reported that the turbulence lessened.

At 1636:46, the first officer called out “...a thousand feet above minimums,”9

 in

accordance with Delta’s procedural guidance.10 As the airplane continued to descend in the

clouds, the captain commented that the ceiling was lower than the 1,300 feet reported in the

automatic terminal information service (ATIS) recording.11

 7

 LYMPS is the initial radar fix for the ILS DME approach to runway 13 at LaGuardia

and is located 8.5 miles from the approach end of runway 13.

8

 According to ATC records, the most recent low level windshear report was reported by

a Boeing 737 (at 1543:05), about 55 minutes before the accident occurred.

9

 The decision height (DH) (“minimums”) for the ILS DME approach to runway 13 at

LGA is 250 feet above ground level (agl) (263 msl).

10 For additional information concerning procedural guidance contained in Delta’s flight

manuals, see section 1.17.1.

11 LaGuardia ATIS information “Delta” was obtained by the pilots before they contacted

New York TRACON (at 1612:52). For additional information on the weather, see section 1.7.
4

-—

I

JEPPESEN NEW YORK, NY ATIS Arrival 125.95 LA GUARDIA

New York Approach (R) 120.8

~

i 2000’ 11S DME Rwy 13

LA GUARDIA Tower 118.7 t 10C 108.5 s 121.7 MSA -. A VOR Apr. Elev. 22’

‘3” r

unusable

~;;~5~.

1 Loc Cra offset ~

Rwy centerline 135+ 1 —mMv—

#n

/1

1 YMPS D8. 9 JGDI ILS

or 8,5 RADAR FIX

40-s0

“5k

mu

509 ’

& & IGDI ILS

&

b17’

A 475’

7400 73-50 73.40 I

GARDE

~819YyD~+l* D5.6 IGOI :1S

GS1940’(/727’)

,?!fl?~:,:

I author izcdby ATC. i (1387’/1

3.3 I 1.2 I 3.4

MISSEDAPPROACH: Climb to 800’ then climbing LEFT turn to 2000’ direct

UR LOM and hold.

STRAIGHT-IN LANDING R WV 13 CIRCLE. TO-LAND

ILS LOC [GSeUt)

OA(H) 263 ‘(250,/ MDA(M) 620’(607’)

FULL RAIL or A15 WI MM W? RAIL o.f I AIS O“t ~: _ MDA(HJ

4 RVR 24 RvR 40 RVR 50 9Q

i w Y2 ., Y, ., I ~ 620’(s98’)-1 M24WYZ RVR 24 RvR 400ryt RVR 60

OrzY 0,114 I Y4 I 40 620’(598’)- 1 YJ

) RvR 400, y4 1 Y2 2 105 700’(678).2Y4

G“d spe,d.Kts 70 90 !00 120 [ 140 160

Gs —— 3.00” 378 485 ~39 b47 f 755 863

MAP ● , 00 4 IGD1 11$.,

GAR!>F ,“ MAP 5.2 4:27 ~j8 3:07 2:36[ 2:14 1:57

<ANGF5 6, ,3.,, *, @) JC*PC$EM SANOERSm. INC 19U7 199S A1t #lCMIS RESERVEO

I

Figure l—Instrument approach chart

(reproduced with the permission of Jeppeson Sanderson, Inc.)
5

At 1637:08, LaGuardia ATCT instructed a TWA airplane at LaGuardia, “TWA

eighty-six thirty, wind one zero zero at one two, runway one three cleared for takeoff, traffic [on]

three mile final runway one three.”12 The pilots of TWA 8630 acknowledged the takeoff

clearance and advised that they were “rolling,” and at 1637:22, LaGuardia ATCT cleared Delta

flight 554 to land. Two seconds after he acknowledged the landing clearance, the first officer

advised the captain that he was “starting to pick up some ground contact.”13

At 1637:29, the pilots of TWA 8630 indicated that they were rejecting the takeoff

and needed to turn off the runway. LaGuardia ATCT responded, “TWA eighty-six thirty, make

the first right turn, runway four two two...can you do that for me, sir?” then stated, “...if you

could expedite, traffic on a two mile final...prevent him from going around.”14 According to

CVR and pilot statement information, simultaneous with this transmission, the captain turned off

the autopilot and advised the first officer “I’ve got the jet” (indicating that he was taking manual

control of the airplane).

At 1637:41, one of the pilots of TWA 8630 stated, “TWA eighty-six thirty’s

turning off,” and LaGuardia ATCT responded, “Thank you very much...say the reason for the

abort, sir?” Five seconds later LaGuardia ATCT stated, “Just continue down the runway...make

the first right turn on taxiway golf...when you get a chance let me know the reason for the

abort.”15 At 1637:52, as the airplane descended through about 492 feet agl, flight 554’s CVR

recorded an expletive on the captain’s channel, and the airplane’s descent rate (calculated from

FDR data) shallowed briefly. During postaccident interviews, the captain stated that at the time

of the expletive comment he was concerned that they might have to perform a missed approach

because the TWA flight had aborted its takeoff, and he believed that it had not yet cleared the

runway.

At 1637:57, the CVR recorded the first officer’s callout—“two hundred above

[minimums].” Four seconds later the first officer advised the captain, “speed’s good, sink

[rate]’s good.” At 1638:07, the captain stated, “no contact yet.” According to the CVR, at

 12 According to FAA Order 7110.65, “Air Traffic Control,” controllers should, “Separate

a departing aircraft from an arriving aircraft on final approach by a minimum of 2 miles...this procedure

permits a departing aircraft to be released so long as an arriving aircraft is no closer than 2 miles from the

runway...at the time the departing aircraft commences [its] takeoff roll.” According to FDR data, Delta

flight 554 was located 3.28 miles from the threshold of runway 13 at 1637:08.

13 FDR data indicated that at this time the airplane was about 600 feet above minimums,

or 850 feet agl.

14 According to FAA Order 7110.65, “Air Traffic Control,” controllers should, “separate

an arriving aircraft from another aircraft using the same runway by ensuring that the arriving aircraft does

not cross the landing threshold until...the other aircraft...is clear of the runway.”

15 Postaccident interviews with ATC and the pilots of TWA 8630 indicated that at this

time, TWA 8630 had turned off of runway 13 at runway 22 and was taxiing to the southwest on runway

22 towards taxiway Golf.
6

1638:10, the first officer called out “one hundred above [minimums],” and at 1638:11, the

captain stated, “I got the (REIL [runway end identifier lights])...approach lights in sight.”

At 1638:13, the first officer advised the captain, “You’re getting a little bit

high...a little bit above [the] glide slope...approach lights, we’re left of course.” The FDR data

indicated that at 1638:13, the airplane was 1.39 dots high on the electronic glideslope and 0.39

dots left of the localizer, at 306 feet agl (319 msl). At 1638:18, LaGuardia ATCT stated, “You

are cleared to land, Delta five fifty-four,” and the first officer acknowledged the reissued landing

clearance. According to FDR data, at that time the autothrottle was disconnected and the captain

reduced power manually. At 1638:20.6, the CVR recorded the sound of the ground proximity

warning system (GPWS) announcing “minimums,” followed by, according to the CVR

transcript, a “sound similar to that of windshield wipers increasing to full speed.” About 1

second later, the captain restated that he had the approach lights in sight.

The captain began to reduce the engine power, and at 1638:25.6, the first officer

stated, “speed’s good” and then, about 1 second later, “sink’s seven hundred.”16 At 1638:30.1,

the captain stated, “I’ll get over there,” which he later explained referred to the airplane’s

alignment with the runway.17 One second later, the first officer stated, “a little bit slow, a little

slow.” According to postaccident interviews, the captain stated that the approach seemed normal

until about 4 to 5 seconds before the initial impact, when “all of a sudden, [the] aim point shifted

down into the lights.” About 1638:33, as the captain was adding power and pitching up, the first

officer stated, “Nose up,” and then at 1638:34.3, stated, “Nose up” again. At 1638:34.2 and

1638:35.7, the CVR recorded the sound of the GPWS “sink rate” warning,18 followed by sounds

of impact at 1638:36.5.

The airplane struck the approach light structure and the vertical edge of the

concrete runway deck, and then skidded approximately 2,700 feet down runway 13 on its lower

fuselage and nose landing gear before it came to a stop. (See figure 2 – an overhead photograph

of LaGuardia Airport, with runway 13 approach lights, the point of initial impact, and the point

where the airplane came to rest on runway 13 depicted.) The nose landing gear came to a stop on

the pavement, with the fuselage oriented on a 345o

 heading; the left wing extended towards the

runway centerline, and the right wing extended over the wet, grassy area next to the runway.

According to flight and cabin crewmember statements, after the airplane came to a stop, the

pilots began to assess the damage to the airplane and determine whether an emergency

evacuation was warranted, while the flight attendants picked up their interphone handsets and

awaited instructions. About 74 seconds after the airplane came to a stop (about 94 seconds after

 16 For additional vertical speed information, see sections 1.6.2, 1.11.2, 2.2, and 2.5.

17 The captain indicated that after he saw the approach lights, he made a right correction

to align the airplane with the runway; then the airplane drifted to the right, so he made a correction to the

left. The captain reported that he recalled a drift correction of about 10o

 during the final approach.

18 The warnings annunciated in accordance with the manufacturer’s specifications.
7

Figure 2—LaGuardia Airport, with runway 13 approach lights, the point of initial impact, and

the point where the airplane came to rest on runway 13 depicted
8

impact), the captain issued the emergency evacuation command19 after a non-revenue Delta pilot

and the FAIC reported that they smelled jet fuel fumes in the cabin. All aircraft occupants exited

through the left front door (L-1) slide.20

The accident occurred during daytime hours, at approximately 40o, 46 minutes, 94

seconds North latitude, and 73o, 52 minutes, 73 seconds West longitude.

1.2 Injuries to Persons

Injuries Flightcrew Cabin Crew Passengers Other Total

Fatal 0 0 0 0 0

Serious 0 0 0 0 0

Minor 0 0 3 0 3

None 2 3 55 0 60

Total 2 3 58 0 63

1.3 Damage to Airplane

The MD-88 received substantial damage to its lower fuselage, main landing gear,

slats, flaps, and both engines. The estimated cost to repair the airplane was about $14 million.

1.4 Other Damage

The metal runway approach light structure and the wooden catwalk that accessed

it were damaged when the airplane struck the approach light structure. The approach end of the

runway deck and the runway/pier support stanchions were also damaged. The estimated cost to

repair the damage to airport property was about $240,000.

1.5 Personnel Information

The flightcrew consisted of the captain and the first officer. The captain and the

first officer had been paired together as a crew on one previous occasion, in January 1996. Three

flight attendants were aboard the airplane.

 19 At 1640:10, the CVR recorded the captain’s evacuation command, “Ladies and

gentlemen, we’re going to evacuate the airplane...please follow the flight attendants instructions right

now.”

20 For additional information on the emergency evacuation, see section 1.15, “Survival

Aspects,” and 1.15.2, “Crewmember Responsibilities During an Emergency Evacuation.”
9

1.5.1 The Captain

The captain, age 48, was hired by Delta Air Lines on September 5, 1978. He held

an airline transport pilot (ATP) certificate with airplane multiengine land and instrument ratings,

a commercial pilot certificate with airplane single-engine land privileges, and MD-88 and Cessna

500 type ratings. The captain’s most recent first-class medical certificate was issued on

October 8, 1996, and contained the restriction, “Must have glasses available for near vision.” The

captain was wearing monovision (MV)21 contact lenses for vision correction when the accident

occurred. The captain’s vision and MV contact lenses are discussed further in sections 1.18.1,

“FAA Oversight of Airman Medical Certification (Vision),” and 1.18.2, “Information on

Monovision (MV) Contact Lenses.”

The captain had about 10 years of civilian and military flight experience before he

joined Delta Air Lines, including 3,320 total flight hours in military aircraft. He was upgraded to

a captain on the MD-88 in June 1990. His most recent proficiency check, which included crew

resource management (CRM) training, was completed on September 18, 1996, in the MD-88.

According to company records, at the time of the accident, the captain had accumulated 10,024

total flight hours, with about 3,756 hours as pilot-in-command in the MD-88.

The captain had been off duty for 3 days before the day of the accident. He

reported that during the 3 off-duty days, he performed routine activities at home and received

about 8 to 9 hours of sleep each night, which he indicated was a normal amount of sleep for him.

On the day of the accident, the captain was not scheduled to fly, but was available in reserve

status;22 he was called for flight 554 at 1145 and reported for duty in Atlanta about 1330. The

captain had landed at LaGuardia on numerous occasions; however, he had landed on runway 13

on only two occasions before the accident flight. Both of the previous approaches occurred in

visual meteorological conditions (VMC); the captain had not performed an instrument approach

to runway 13 before the day of the accident.

During postaccident interviews, the first officer described the captain as “quiet,”

“easy to get along with,” and “by the book, procedurally.” Two other first officers who had flown

with the captain before the accident described him in similar terms; they indicated that he made

first officers feel at ease and was open to criticism. A review of Delta’s personnel records for the

captain revealed no problems.

 21 MV contact lenses are prescribed by optometrists for patients who require both near

and distant vision correction and who would otherwise be considered candidates for bifocal glasses. MV

contact lenses apply distance vision correction to one eye, and near vision correction to the other eye.

According to the FAA’s “Guide for Aviation Medical Examiners,” MV contact lenses are not approved

for use by pilots when performing flight duties.

22 A pilot in reserve status is on standby duty for assignment to flights.
10

1.5.2 The First Officer

The first officer, age 38, was hired by Delta Air Lines on May 30, 1988. He held

an ATP certificate with airplane multiengine land and instrument ratings. He had commercial

pilot privileges for airplane single-engine land. His most recent first-class medical certificate

was issued on February 15, 1996, with no restrictions or limitations. The first officer’s vision did

not require the use of, nor was he using, corrective lenses or glasses when the accident occurred.

Before he joined Delta Air Lines, the first officer had approximately 6 years of

military flight experience in the U.S. Air Force. He began his career with Delta Air Lines as a

flight engineer on the Boeing 727 and performed flightcrew member duties in the L-1011 and

DC-9 aircraft before he transitioned to first officer on the MD-88 in November 1992. His most

recent proficiency check, which included CRM training, was completed on October 17, 1996, in

the MD-88. According to company records, the first officer had accumulated about 6,800 total

flight hours, with 2,220 hours in the MD-88, all as first officer.

The first officer had been off flight-line duty for 3 days before the day of the

accident; however, on October 16 and 17 he underwent 2 days of recurrent simulator training.

He reported that during the 3 days before the accident, he received about 71⁄2 hours of sleep each

night, which he indicated was a normal amount of sleep for him. On the day of the accident, he

reported for duty in Atlanta at about 1330. The first officer had never landed on runway 13 at

LaGuardia before the accident flight.

During postaccident interviews, the captain described the first officer as “very

competent” and “fun to be with.” The Safety Board interviewed another captain who had flown

with the first officer before the accident; the captain described the first officer as a “fine first

officer” who “did everything a captain would expect from a first officer and more.” A review of

Delta’s personnel records for the first officer revealed no problems.

1.5.3 Flight Attendants

The FAIC occupied the aft-facing jumpseat (adjacent to the L-1 door) in the

forward cabin at the time of the accident. She had more than 7 years of service with Delta and

had completed her most recent recurrent training before the accident on October 11, 1996. The

second flight attendant was seated in the forward-facing jumpseat on the left side of the airplane,

forward of the aft galley. She had almost 5 years of service with Delta and had completed her

most recent recurrent training before the accident in February 1996. The third flight attendant

was seated in the forward-facing rear cabin jumpseat. She had 5 years of service with Delta and

had completed her most recent recurrent training in September 1996. According to company

records, all three flight attendants had satisfactorily completed Delta’s initial flight attendant

training program and were qualified on the MD-88 aircraft.
11

1.6 Aircraft Information

1.6.1 General

N914DL, a McDonnell Douglas MD-88, serial number (SN) 49545, was operated

by Delta Air Lines, Inc. The airplane was purchased from the Douglas Aircraft Company and

was put into service as part of Delta’s fleet in June 1988. The airplane was powered by two Pratt

& Whitney JT8D-219 turbofan engines.

No noteworthy discrepancies were found in the maintenance log, and the pilots

did not note any maintenance irregularities before or during their flight from Atlanta to

LaGuardia.

At the time of the accident, the airplane had an estimated operating weight of

109,295 pounds. The maximum landing weight of this MD-88 was 130,000 pounds. The

estimated center of gravity was 15.6 percent of the mean aerodynamic chord, which was within

limits.

1.6.2 Vertical Speed Information

The accident airplane was equipped with a traffic advisory/vertical speed indicator

(TA/VSI), which displayed vertical speed information with a permitted lag time of up to 4

seconds. According to the manufacturer, the TA/VSI unit could be rewired to display real-time

(instantaneous) vertical speed information to the flightcrew if an inertial reference unit (IRU) was

installed in the airplane. Although Delta was replacing the altitude/heading reference systems

(AHRSs) with IRUs throughout the MD-88 fleet, at the time of the accident, the accident

airplane’s AHRS had not been replaced.

Several of the MD-88 check airmen and flight instructors interviewed during the

investigation stated that they believed that most Delta line pilots were unaware that the VSIs in

the MD-88 were not instantaneous.

1.7 Meteorological Information

According to the National Weather Service (NWS), on the day of the accident the

weather in the New York area was being influenced by a low pressure center located in central

New Jersey and a weak occluded front23 extending to the east and southeast from the low

pressure center; strong easterly winds and rain were noted to the north and northeast of the low

pressure center. The terminal forecast for LaGuardia, issued by the NWS forecast office in

Upton, New York, and valid at the time of the accident, predicted strong, gusty winds out of the

east, a 400-foot cloud ceiling, and visibility of 1 mile in moderate rain and mist.

 23 According to FAA weather publications, occluded fronts occur when a fast-moving

cold front catches up to a slow-moving warm front.
12

Although VMC prevailed when Delta flight 554 departed Atlanta, the flightcrew

stated that when the flight arrived in the New York area, it encountered the forecast IFR

conditions. The pilots obtained ATIS information “Delta” during their approach to LaGuardia. It

indicated winds out of 120o at 16 knots, visibility of 11⁄4 miles in heavy rain and mist, and an

overcast cloud layer at 1,300 feet. It also advised that the ILS DME approach was in use, with

airplanes landing and departing on runway 13.

Weather observations made at LaGuardia between 1627 and 1651 indicated a

broken cloud layer at 800 feet, visibility between 1⁄2 and 1 mile in heavy rain and fog or mist, and

easterly winds at 12 to 14 knots.

Automated surface weather observation system weather data obtained for the

period approximately 13 minutes before to 7 minutes after the accident indicated the following

conditions:

Time Winds Precipitation Visibility

1625 080o @ 17 knots Heavy rain 1 1⁄4 miles

1635 090o @ 11 knots Heavy rain 1⁄2 mile

1645 060o @ 16 knots Heavy rain 3⁄4 mile

The NWS Aviation Weather Center in Kansas City, Missouri, issued several

significant meteorological information advisories (SIGMETs)24 for turbulence in strong winds

and possible low level windshear, which were applicable for LaGuardia at the time of the

accident. Additionally, the NWS Aviation Weather Center in Kansas City, Missouri, issued

several airman’s meteorological information advisories (AIRMETs)25 for strong winds and

occasional IFR conditions, which were applicable for LaGuardia about the time of the accident.

Further, Delta’s meteorological staff issued an Airport Alert for moderate-to-severe turbulence,

strong, gusty surface winds, and possible low level windshear at LaGuardia around the time of

the accident. The SIGMETs, AIRMETs, and additional weather information are included in

appendix E.

1.7.1 Weather Information Provided to the Flightcrew by Delta

The pilots of flight 554 received a complete preflight weather briefing (prepared

by Delta’s meteorologists) with their flight release before departing from Atlanta. A review of

the weather information in the flight release paperwork revealed that it included terminal

forecasts, surface weather observations, and notices to airmen (NOTAMs) for the departure, en

 24 According to the Weather Service Operations Manual, a SIGMET advises of weather,

other than convective activity, potentially hazardous to all aircraft.

25 According to the Weather Service Operations Manual, an AIRMET advises of

weather, other than convective activity, that might be hazardous to single-engine and other light aircraft,

and VFR pilots. However, operators of large aircraft might also be concerned with these phenomena.
13

route, destination, and alternate airports, as well as pertinent weather alerts for those regions.

The flight release paperwork also included SIGMET Uniform 2 and Delta’s meteorological

staff’s Airport Alert (both for moderate-to-severe turbulence in strong winds), and the following

1251 LaGuardia hourly weather observation:

sky -- broken ceiling at 1,200 feet, broken cloud layer at 1,800 feet, overcast

at 2,200 feet; visibility -- 2 miles, in moderate rain, mist; temperature -- 16o

C; dew point -- 14o C; winds -- 080o at 23 knots, with gusts to 38 knots; and

altimeter setting -- 29.54 inches Hg. Remarks: peak wind -- 070o at 38 knots

occurred at 1247; tower visibility 2 1⁄2 miles; pressure falling rapidly.

The pilots also obtained an updated preflight weather briefing about 10 minutes

before they departed Atlanta. The briefing included the LaGuardia hourly weather observation

from 1351, which indicated winds out of the east, with wind speeds more moderate than the

previous hour’s observation. Records indicate that at 1511 and 1618, during the flight to

LaGuardia, the pilots requested and received updated weather information via their onboard

automatic communication and reporting system (ACARS).

1.7.2 Runway Visual Range (RVR)26 Values

Investigation revealed that the RVR was taken out of service sometime after the

accident because of a problem with the line that ran between the receiver and the computer,

where the RVR values were recorded.27 According to FAA airways facilities (AF) personnel,

this anomaly might have resulted in slight inaccuracies in the recorded RVR values.

The minimum RVR value estimated about 1637 was 2,800 feet. ATC records

indicate that at 1636, LaGuardia ATC advised traffic that runway 13 RVR at touchdown was

3,000 feet, while RVR during landing rollout was 2,200 feet.

Postaccident interviews with air traffic controllers revealed that they first

observed Delta flight 554 as it neared the runway threshold; the distance between the ATC tower

cab and the approach end of runway 13 is approximately 2,800 feet. According to the ILS DME

runway 13 instrument approach plate, the minimum RVR required for the approach is 2,400 feet.

1.7.3 Windshear Information/Low Level Windshear Alert System (LLWAS)

Examination of the ATC transcripts for the local control frequency revealed that

between 1525 and 1545, about an hour before the accident, there were numerous pilot reports of

 26 According to the Aeronautical Information Manual, RVR is the “range over which the

pilot of an aircraft on the [centerline] of a runway can see the runway surface markings or the lights

delineating the runway or identifying its [centerline].”

27 The method for determining RVR for runway 13 is discussed in section 1.10.1.2,

“Runway 13 RVR Information.”
14

windshear, and the flightcrews of four flights executed missed approaches while attempting to

land on runway 13. The ATC transcripts revealed that these missed approaches were attributed

to wind conditions. Examination of the LLWAS recorded data and ATC records indicated that

no LLWAS system alarms occurred between 1525 and 1545; however, wind gusts were recorded

during that time (peak gusts to 28 knots). Review of the ATC tapes did not reveal any pilot

comments regarding windshear between 1545 and the time of the accident.

Weather Surveillance Radar-88 Doppler (WSR-88D) is installed at the NWS

Forecast Office in Upton, New York, approximately 46 nautical miles east-southeast of

LaGuardia. The 1640 winds aloft estimates obtained from the WSR-88D velocity azimuth

display vertical wind profile revealed the following:

Height (agl) Wind Information

1,000 feet 083o @ 60 knots

2,000 feet 090o @ 65 knots

3,000 feet 105o

 @ 70 knots

4,000 feet 108o @ 70 knots

5,000 feet 109o @ 65 knots

A tape containing Doppler weather radar data from the Upton, New York, WSR88D around the time of the accident was obtained from the National Climatic Data Center. A

review of these data showed the presence of weather echoes along Delta flight 554’s approach to

runway 13. The weather echoes varied from moderate to very strong.28

A Phase II LLWAS was installed and operational at LaGuardia at the time of the

accident. The LLWAS system consisted of six wind sensors; one sensor was positioned near the

center of the airport, and the five remaining sensors were placed in locations surrounding the

airport. Information obtained from the LLWAS northwest wind sensor (sensor 6) data29 and

center field average (CFA [sensor 1]) wind data for 40 seconds about the time of the accident

indicated the following surface wind conditions:

Time Northwest Wind Sensor CFA Wind

1638:26 080o @ 14 knots 090o @ 13 knots

1638:36 080o @ 13 knots 090o @ 14 knots

1638:46 080o

 @ 14 knots 090o @ 14 knots

1638:56 080o @ 14 knots 090o @ 14 knots

1639:06 080o @ 15 knots 090o @ 14 knots

 28 For details of the review of the WSR-88D data, see appendix E.

29The northwest wind sensor is located about 5,468 feet northwest of the approach end of

runway 13.
15

Examination of the LLWAS recorded data indicated that no LLWAS system

alarms occurred between 1600:06 and 1649:56. Additionally, no wind gusts were recorded from

1600:06 through 1649:56.

After the accident, the FAA performed a site performance evaluation system of

the LLWAS archived data. The examination revealed that three of the six sensors (sensors 3, 4,

and 5) appeared to have problems. According to the FAA, the sensor problems might have

resulted in the system’s failure to detect existing windshears, or the system producing false

windshear warnings.

Postaccident discussions with FAA personnel revealed that they are “improving

and expanding” the existing LLWAS system at LaGuardia. They reported that the improved

LLWAS system will consist of eight new sensor sites replacing the present LLWAS sites, which

should be commissioned by November 1997.

1.8 Aids to Navigation

There were no known malfunctions with the aids to navigation involved in this

accident.

1.9 Communications

There were no known difficulties with internal or external communications.

1.10 Airport Information

LaGuardia Airport is located in Flushing, New York, and has an airport elevation

of 22 feet.30 The airport is served by runway 4/22, which is oriented north-northeast/southsouthwest and runway 13/31, which is oriented northwest/southeast. The runways are 7,000 feet

long and 150 feet wide, grooved paved surfaces, and constructed of asphalt and concrete. The

approach ends of runway 22 and runway 13 extend on an elevated deck above the Rikers

Channel portion of Flushing Bay. The extended portion of the runways is constructed of asphalt

and concrete laid out on steel piers, the approach end of which is covered by orange and white

plywood panels that extend vertically toward the water. Runways 22 and 13 are equipped with

approach lighting systems built on stanchions and accessible by catwalks, which extend farther

into the bay from the end of the runway deck. During postaccident interviews, the LaGuardia

airport manager stated that the airport “[does] a lot in a small area,31 [but we] feel the physical

constraints of its size.” Refer to figure 3, “Diagram of LaGuardia Airport.”

 30 The published touchdown zone elevation for runway 13 is 13 feet.

31 Airport records indicate that there are 337,087 flight operations at LaGuardia per year,

of which 316,287 are commercial flight operations.
$ I , I I , I I
17

LaGuardia is fully certificated under 14 CFR Part 139. According to the FAA

airports inspector with oversight responsibility for LaGuardia, the airport was in compliance with

FAA standards, and all past deficiencies had been corrected in a timely manner.

1.10.1 Runway 13 Information

According to ATC operational records, the average prevailing winds at LaGuardia

are northwesterly. Because the winds are generally out of the northwest, and because of other

operational considerations, runway 13 (the landing runway for Delta flight 554) is used less

frequently than the other runways. Runway 13 was equipped with high intensity runway lights

(HIRL), centerline lighting, REIL, medium intensity approach light system, runway alignment

indicator lights, and visual approach slope indicator (VASI) lights.

Runway 13 was serviced by an ILS DME instrument approach made up of six

components: glideslope, localizer, DME, approach lighting system, marker beacons, and

compass locators. The electronic glideslope is not usable below 200 feet agl because of signal

irregularities.32 According to FAA personnel, the ILS DME runway 13 DH, which is 250 feet agl

(263 feet msl), is 50 feet higher than the standard DH because the localizer course is offset from

the runway heading.

On the day after the accident, the FAA conducted an airborne operational check of

the ILS DME approach to runway 13. All components of the instrument approach and landing

system were determined to be capable of normal operation, with the electronic glideslope

restriction (unusable below 200 feet) in effect. As mentioned previously, a new localizer for

runway 13 should be commissioned by October 1997. The new localizer will not have an offset

course.

1.10.1.1 Runway 13 Runway Lights/Spacing

According to FAA Advisory Circular (AC) 150/5340-24, “Runway and Taxiway

Edge Lighting System,” a runway edge lighting system is a configuration of lights that defines

the lateral and longitudinal limits of the usable landing area. With regard to location and spacing

of runway lights, the AC states the following:

The longitudinal spacing of the lights should not exceed 200 feet (61 m) and

be located such that a line between light units on opposite sides of the runway

is perpendicular to the runway centerline. The lights should be spaced as

uniformly as possible with the threshold/runway end lights used as the starting

reference points. Where a runway is intersected by other runways or

taxiways, a semiflush light...should be installed to maintain the uniform

 32 According to the FAA, the signal irregularities are the result of the runway pier’s

location over the water, tidal changes/influences, and the metal content of the water.
18

spacing for HIRLs. For MIRLs [medium intensity runway lights] and LIRLs

[low intensity runway lights] a single elevated edge light should be installed

on the runway side opposite the intersection to avoid gaps in excess of 400

feet (122 m) where the matching of lights on opposite sides of the runway

cannot be maintained... .

Postaccident measurement of the runway light spacing on runway 13 revealed that

the runway lights were installed at irregular intervals, even where no other ground utilization

considerations (crossing runways, taxiways, etc.) existed. The runway light spacing distances

varied, with the most common distances between lights falling between 120 feet and 170 feet.33

1.10.1.2 Runway 13 RVR Information

Although LaGuardia has four runways that are usable for landing, the airport only

uses three RVR transmissometers (visibility sensors). The transmissometers are located at three

positions on the airport:

• The approach end of runway 04, aligned with runway 04.

• The approach end of runway 31, aligned with runway 31.

• The intersection of runway 13 and runway 22, aligned with runway 22.

According to the LaGuardia Tower standard operating procedures (SOPs),

because the runway 13 and runway 22 touchdown areas are close to each other, a common RVR

transmissometer services both runways. The shared RVR transmissometer is located about 1,500

feet from the approach end of runway 13. FAA AF personnel stated that the equipment is

correctly situated to record valid touchdown RVR readings for both runways. The LaGuardia

Tower SOP states, “To obtain an accurate RVR reading, the Runway 4-22 edge lights MUST BE

AT A STEP THREE SETTING OR GREATER. If the Runway 13-31 HIRLs are [at a setting]

equal [to] or greater than the Runway 4-22 HIRLs, then the Runway 13 RVR will display an

accurate reading.”

According to FAA Order 7110.65, “Air Traffic Control,” at the time of the

accident, the HIRLs for runways 13 and 22 should have been set on step 5, the runway 13 REILs

should have been set on step 3, and the runway 13 VASI lights should have been set on high

brightness. During postaccident interviews, the LaGuardia air traffic controllers stated that they

did not recall what light settings were in use at the time of the accident. However, according to

AF personnel, the LaGuardia HIRLs are connected to, and monitored by, a warning system. If

the runway 13 and runway 22 HIRLs are not on the same setting, a “fail” light and an aural

warning alarm will activate. The controllers did not indicate that an alarm had activated.

 33 Most airports have runway edge lights generally positioned at, or near, the maximum

200-foot intervals.
19

1.10.1.3 Runway 13 VASI Information

The VASI light system for runway 13 is a two-bar VASI system, which may be

used by pilots as a visual aid for maintaining an approximate 3o

 glidepath to the touchdown point

on the runway. The two-bar VASI system consists of two light boxes located on the left side of

the runway; the boxes are positioned on either side (downwind and upwind) of the touchdown

point.34 According to the pilots of flight 554, when the airplane descended below 200 feet agl and

the electronic glideslope was considered unusable, they were in visual conditions; however, they

did not observe either bar of the VASI lights during their descent to the runway. Postaccident

interviews with the pilots of the four airplanes that landed on runway 13 just before flight 554

revealed that none of them recalled observing the VASI lights during their approach/landing.

However, none of the pilots interviewed (including the flightcrew of flight 554) recalled

specifically seeking VASI light guidance during their approach to land.

According to LaGuardia facility records and interviews with ATC personnel, there

was no tower cab indication that the VASI lights were not operating normally at the time of the

accident. However, a note in the “Daily Record of Facility Operation,” FAA Form 7230-4,

indicated at 1730 (52 minutes after the accident), a “Power surge in the [tower, runway] 13

MALSR (medium intensity approach lighting system with runway alignment indicator lights) and

VASI [out of service].”35 The runway 13 VASI light system was inspected by AF personnel on

October 20, 1996. The inspection revealed that the VASI light bar angles and high brightness

 34 The electronic glideslope touchdown point is located about 985 feet from the approach

end of the runway deck. The downwind light box (closest to the landing airplane) and the upwind light

box are positioned about 650 feet and 1,550 feet from the approach end of the runway deck, respectively.

Each light box contains a set of white lights and a set of red lights, with the set of white lights over the

set of red lights. The visual glideslope guidance is indicated by the color of the lights in the two boxes

that is visible to a pilot on final approach for the runway, as follows:

• Red lights visible in both downwind and upwind light boxes = glideslope

lower than 3o

.

• White lights visible in both downwind and upwind light boxes = glideslope

higher than 3o

.

• White lights visible in downwind box, red lights visible in upwind box =

glideslope equals 3o

.

The Safety Board’s calculations based on the positions of the light boxes revealed that an

airplane on the ILS course at DH (250 feet agl) would be positioned 4,442 feet from the downwind light

box and 5,342 feet from the upwind light box; an airplane on the ILS course at 200 feet agl would be

positioned 3,486 feet from the downwind light box and 4,386 feet from the upwind light box.

35 Postaccident interviews with AF personnel revealed that the log indication of “power

surge” at 1730 was incorrect; a power “outage” occurred at 1730 because the “gear switch took on

water.” The gear switch is an electro-mechanical mechanism that monitors and controls the main airport

power supply; if one power source loses power, the gear switch selects an alternate airport power source.

According to a Daily Record of Facility Operation entry at 1831, “[AF personnel advised] that we were

on generator from [1730-1745] when we came back to normal power, also AF [advised] that extensive

damage was done to [runway 13 approach lights.]”
20

output current level were normal; however, the medium and low brightness output current levels

were below tolerance. According to FAA Order 7110.65, “Air Traffic Control,” VASI light

intensity is required to be set to high brightness during the hours of “daylight - sunrise to sunset.”

As noted previously, ATC personnel did not recall what light settings were in use when the

accident occurred.

1.11 Flight Recorders

A digital FDR and a CVR were installed in the airplane. The FDR was a

Lockheed Aircraft Service Company Model 209F, SN 4548, recorder, which recorded 68

parameters of airplane flight information in a digital format on 1⁄4-inch magnetic tape. The CVR

was a Fairchild Model A100, SN 2698. Both recorders were removed from the airplane and sent

to the Safety Board’s laboratory in Washington, D.C., for readout. The cases of both recorders

were intact and exhibited no evidence of damage or excessive wear.

1.11.1 CVR

The CVR recording consisted of four channels of audio information: the cockpit

area microphone (CAM), the captain’s position, the first officer’s position, and the flight

attendant intercom/public address (PA) system. Although the overall quality of the recording

was good, the CAM and crewmember channels, from which all crewmember conversation was

transcribed, were of excellent quality. A transcript was prepared of the final 30 minutes, 9

seconds of the recording. The transcript started approximately 27 minutes, 49 seconds before the

first sounds of impact occurred on the CVR. The recording ended after APU shutdown, with the

airplane stopped on runway 13.

1.11.2 FDR

Although the quality of the FDR data was good, the FDR experienced data loss

coincident with the highest recorded vertical acceleration forces (Gs) that occurred during the

airplane’s impact with the approach lights and runway pier. The Safety Board’s laboratory

retrieved portions of the lost data and developed a composite data set of the accident approach

and landing. A copy of the FDR data plot, with CVR excerpts overwritten, is included in

appendix C.

The FDR data indicated that as the airplane descended on the ILS DME approach

to runway 13, it was established on the electronic glideslope and localizer until it reached about

400 feet msl. As the airplane continued the approach from that point, it began to deviate above

the electronic glideslope and right of the localizer. FDR data indicated that between 1637:33 and

1638:11, the airplane went from .09 dots high on the glideslope to 1.3 dots high on the

glideslope. At 1638:20, the airplane was 1.43 dots high on the glideslope, and at 1638:28, when

the airplane descended through 200 feet agl, the airplane was about 1.66 dots above the

electronic glideslope. As discussed in section 1.10.1, from this point to the surface, the

electronic glideslope information was considered unusable. Excerpted FDR data from the last 63

seconds of the approach is included in Table 1.

22

According to FDR data and CVR information, between 1638:24 and 1638:28, the

engine pressure ratio (EPR) reduced from about 1.2 EPR to about 1.15 EPR as the first officer

stated, “speed’s good.” At 1638:26, when the first officer called a 700 feet per minute descent

rate, the airplane’s actual rate of descent, calculated from FDR data,36 was about 1,200 feet per

minute. At 1638:30.1 (when the captain stated, “I’ll get over there”), the FDR data indicated that

the airplane was descending through about 110 feet agl at a rate of descent of about 1,500 feet

per minute. The FDR data indicated that between 1638:24 and 1638:32, the elevator position

oscillated between about 2o nose up and 8o nose up, and the airspeed decreased from 131 knots to

about 126 knots. (About 1638:31, the first officer stated, “a little bit slow, a little slow.”)

The FDR data indicated that an increase in EPR and nose-up elevator position

began to occur about 1638:32; about 1638:33, as the engine power and pitch increased, the CVR

recorded the first officer stating “Nose up...nose up.” By 1638:33, the FDR data indicated that

the airplane was descending through about 75 feet agl at 1,800 feet per minute. At 1638:34, the

rate of descent began to decrease. At 1638:34.2 and 1638:35.7, the CVR recorded the sound of

the GPWS “sink rate” warning, followed by loss of FDR data at 1638:36.5, the moment of

impact.

1.11.2.1 FDR Information on Windshear

The horizontal wind encountered by Delta flight 554 during the approach to

runway 13 and estimated from FDR data indicated no sudden changes associated with windshear.

Postaccident examination of the windshear computer (WSC) from the accident airplane revealed

that the WSC was capable of detecting and annunciating windshear alerts. No commands were

recorded on the CVR regarding windshear during the final 1,000 feet of flight 554’s descent.

The Safety Board requested and received FDR data from three of the four flights

that preceded Delta flight 554 on the approach, and from the airplane that followed flight 554 on

the approach to runway 13. FDR data was received from Delta Air Lines flight 1215, a Boeing

727, which landed at LGA about 1630; Continental flight 1614, a Boeing 727, which landed at

LGA about 1633:07; USAir flight 212, a Boeing 737-300, which landed at LGA about 1634:53,

and United flight 1576, a Boeing 737-300 (this flight was at an altitude of about 1,780 feet

when—at 1639:08—ATC instructed the pilots to execute a missed approach after the accident).

Examination of the FDR data and pilot reports from these four flights revealed no evidence of

windshear encounters during the approach to runway 13.

 36 The FDR system installed on the accident airplane did not directly record the

airplane’s inertial vertical speed; however, the Safety Board calculated the airplane’s descent rate based

on the FDR data. References to the airplane’s actual rate of descent are based on these calculations.
23

1.12 Wreckage and Impact Information

Postaccident examination revealed damage to the approach light bars located 203

and 100 feet short of the approach end of the runway deck, the access catwalk structure, the edge

of the runway deck, the runway deck support structure, and six runway threshold lights. The

plywood on the vertical portion of the runway deck exhibited two main areas of impact damage;

both areas of damage extended from the upper surface to a point approximately 3 feet 9 inches

below the upper surface of the deck and were approximately 4 feet wide. The approximate

midpoints of the damaged areas were located 11 feet and 271⁄2 feet left of the extended runway

centerline.37 In addition, debris from the approach light structure and the access catwalk was

found embedded in the plywood at the end of the runway deck.

Witness and flightcrew statements indicated that the airplane touched down on its

nose landing gear and lower fuselage, slightly left of the extended runway centerline, and skidded

down the runway pavement. Postaccident examination revealed that both main landing gear had

separated from the airplane; although one main landing gear tire was located on airport property,

the remainder of the main landing gear was not recovered during the investigation.

Examination of runway 13 revealed faint scrape marks38 that started at the

approach end of the runway deck, left of the runway centerline. The scrape marks veered farther

left as they continued down the runway, to the point where the airplane came to rest,

approximately 2,700 feet from the approach end of the runway. The airplane came to a stop

facing north-northwest on runway 13, with the nosewheel about 99 feet left of the runway 13

centerline, and the right wing extended over the grass next to the runway. Airplane and approach

light structure debris was scattered along the wreckage path.

The right wing exhibited extensive damage to the leading edge, leading edge slats,

fuel tank, trailing edge flaps, wing-to-fuselage fairing, and landing and position lights. The

damage consisted of crush, dents, tears, and one puncture. Wood and fiberglass objects were

implanted in the leading edge of the wing structure, and stones were wedged in the trailing edge

flap components. Fuel leakage was noted and traced to a right wing fuel tank puncture; an

estimated 600 gallons of fuel leaked from the airplane's right wing as a result of the accident.

The left wing exhibited less extensive damage to the trailing edge flaps, wing-to-fuselage fairing,

and one leading edge slat.

Examination of the fuselage revealed extensive damage to underside antennae,

skin, stringers, frames, and longerons, increasing in severity in the aft direction. Landing gear

doors, the APU doors, and the lower surface of the tailcone were scraped and torn. Examination

of what remained of the main landing gear assemblies revealed that the main landing gear

 37 According to the Delta Air Lines MD-88 maintenance manual, section 06-10-00, pages

2 and 3, the distance between the midpoints of the main landing gear is 16.7 feet.

38 Scrapes/damage to the runway were minimal; according to airport personnel, the

runway was very wet, with areas of standing water when the accident occurred.
24

cylinders were fractured approximately 12 to 13 inches below the bottom surface of the wing.

Although both engines exhibited foreign object damage, damage to the right engine was more

severe. A diagonal buckle was located above the aft portion of the right engine pylon, the

exhaust case was fractured at the forward joint, and the right engine thrust reverser had separated

and was not recovered.

1.13 Medical and Pathological Information

Three passengers reported that they received minor injuries during the accident

and evacuation. Two passengers reported that they bumped their heads during the landing

touchdown and deceleration on the runway, and one passenger sustained a minor neck injury

during the emergency evacuation; the passenger with the neck injury was transported to a local

hospital, where she was treated and released the same day.

In accordance with 14 CFR Part 121 requirements, the flightcrew provided

postaccident toxicological samples for analysis. The samples were analyzed39 and found to be

negative for ethanol and other drugs of abuse. Toxicological samples were not requested or

received from the flight attendants or air traffic controllers.

1.14 Fire

No fire was associated with this accident.

1.15 Survival Aspects

Although no serious or fatal injuries occurred in this accident, the Safety Board

examined the flight and cabin crew decisions and procedures during the emergency evacuation.

The airplane was configured with 142 passenger seats, 58 of which were occupied on the

accident flight. Two floor-level exits were located in the forward cabin; four overwing exits

were located at seat rows 20 and 21; one floor-level exit was located in the aft galley, on the left

side of the cabin; and a tailcone exit was located at the rear of the cabin. According to the flight

attendants and dispatch documentation, most of the passengers were seated forward of the

overwing exits. All airplane occupants were evacuated safely through the forward left (L-1)

door. See figure 4 for an airplane diagram and seating chart.

 39 Toxicological analysis of the samples was conducted on October 22, 1996, at

MedExpress—National Laboratory Center, per Dr. William H. Whaley, Delta Air Lines, Atlanta,

Georgia.
25

Q 1st Flight Attendant ● a .

Main Passenger Entrance ~

L-1 + Gal~r

G1 G2 .

2 Overwing Exits

2nd Flight Attenda

Aft Galley door ~

L - 2

k

G 4

36

37

!

13 * Seating chart is based upon assigned

14 seating as listed on passenger manifest.

15 Actual passenger positions at time of

1* impact are unknown.

17

2 Overwing Exits

38w3a

 Lav 3rd Flight Attendant

~Aft Emergency Exit

Figure 4—Airplane diagram and seating chart
26

1.15.1 Evacuation-related Information From CVR Transcript

According to CVR information, the airplane came to a stop on the runway about

1638:56, about 20 seconds after the first sounds of impact were heard. The CVR recorded, in

part, the following comments pertaining to the emergency evacuation:

1639:06 (PA announcements attributed to the captain)—“Ladies and

gentlemen please remain seated at this time...please remain seated with your

seatbelts securely fastened please.”

1639:17 (Comment attributed to the first officer--CAM)—“We need to get out

of the airplane I think.”

1639:29 (Comments attributed to the captain--CAM)—“Let’s evacuate...well

hold, hold on a minute.”

1639:34 (Comment attributed to the FAIC--interphone)—“Stay away from

the back.”

1639:52 (Comment attributed to FO-ATC communications)—“Yes, we’re

gonna evacuate the airplane and...we’ll try and get everyone off the front of

the airplane on the...runway.”

(1640:01-1640:06—Unattributed comments--CAM—including “...smelling

fuel...” “we need to get out,” and “evacuate the airplane.”)

1640:10 (PA announcement attributed to captain)—“Ladies and gentlemen

we’re going to evacuate the airplane...please follow the flight attendants

instructions right now.”

1640:12 (Evacuation instructions attributed to FAIC)—“Release your

seatbelts, get up, get out...release your seatbelts, get up, get out...release your

seatbelts, get up, get out.”

1640:15 (Interphone comment attributed to a flight attendant in the aft

cabin)—“Do you want to go forward or backwards?”

1640:19 (Sound similar to door opening and slide inflating)

1640:39 (Interphone comment attributed to a flight attendant in the aft

cabin)—“Are we going out the back?”

1640:43 (Interphone comment attributed to a flight attendant in the aft

cabin)—“I’m wanting to know which way out.”
27

1640:48 (Interphone comment attributed to a flight attendant in the aft

cabin)—“Do you want to go forward?”

1640:50 (Interphone comment attributed to the first officer)—“Lets come

forward, yes come forward.”

During postaccident interviews, the FAIC stated that she did not recall making the

statement “Stay away from the back,” which was attributed to her in the CVR transcript.

Statements obtained from the FAIC and the first officer indicated that after the first officer left

his seat in the cockpit to assist with the evacuation, he instructed the FAIC to use the L-1 door

for the evacuation. That instruction was not audible to the aft flight attendants and was not

recorded on the CVR.

1.15.2 Crewmember Responsibilities During an Emergency Evacuation

1.15.2.1 Flightcrew Duties During an Emergency Evacuation

Emergency evacuation procedures for flightcrews, in Delta’s flight operations

manual (FOM),40 chapter 10, “Abnormal Operations,” page 10-14.2, state the following:

After a thorough evaluation, if an emergency evacuation is required, complete

the evacuation checklist and make the evacuation announcement:

“This is the Captain, Evacuate, Evacuate.”

• If an engine fire or other conditions make certain exits unusable,

state the direction of egress (i.e., Use the left side exits only).

• Some aircraft are equipped with an evacuation signal or horn

which can be used to give the evacuation command.

Remove all passengers to a point well clear of the aircraft, out of range of

possible fire or explosion.

Do not allow passengers to return to the aircraft until danger no longer exists.

On page 8, Delta’s MD-88/90 pilots operating manual (POM),41 under the

heading “Ditching/Evacuation,” outlines the following flightcrew duties and responsibilities

during an emergency evacuation:

 40 The FOM provides the policies, procedures, practices, instructions, and guidance for

Delta flight operations personnel to follow. It is supplemented by other Delta manuals and documents.

41 Each Delta pilot is issued a set of pilot’s manuals (the POM and the pilot’s reference

manual [PRM]). The POM contains procedures, techniques, and operations that establish the standard to

which pilots will be trained and by which the airplane should be operated. The PRM is designed as a

training manual, and an in-depth reference manual, and contains specific airplane information. The

information in both manuals complies with the FAA-approved airplane flight manual.
28

CAPTAIN

• Order evacuation.

• Proceed to forward cabin area.

• Assist in evacuating passengers as conditions dictate.

• Check that all persons have been evacuated, if possible.

• After exiting, assemble passengers away from the aircraft.

FIRST OFFICER

• Remove and carry ELT from crew closet.

• Assist in opening forward cabin door and assist in evacuation until able to

proceed to mid cabin.

• Proceed to mid cabin area.

• Assist in evacuating passengers as conditions dictate.

• Assist in assembling passengers away from the aircraft.

Examination and documentation of the cockpit switch positions was

accomplished on October 20, 1996; a review of the documentation revealed that all passenger

evacuation checklist items had been completed, except that the emergency light switch was

located in the “off” position.

1.15.2.2 Flight Attendant Duties During an Emergency Evacuation

Chapter 5, “Emergency Procedures,” of Delta Air Lines’ in-flight service on board

manual addresses flight attendant procedures during emergency evacuations on land and water.

The following excerpts from chapter 5 of the in-flight service on board manual, pages 5-20 to

5-24, address flight attendant procedures during evacuations on land:

The type of emergency dictates the means of communication to determine if

evacuation is necessary. Once determination is made to evacuate begin

evacuation commands. ...

Unanticipated Emergency

• Call the cockpit crew to coordinate evacuation (be prepared to provide

information such as structural damage, fire, etc.)

NOTE: Upon hearing an evacuation horn [or command]...,

evacuate without further communication from [the] cockpit.

(Emphasis added.)

• Give motivational commands

On land --
29

“Release seat belts! Get up! Get out!”

• Release seat belt, grab flashlight and proceed to nearest or designated exit.

Assess conditions

• Look for structural damage, fire or if exit is underwater or obstructed.

• Assess type of emergency.

Activate exit

• Quickly confirm armed status of exit.

• Open exit.

If exit or slide is not usable REDIRECT passengers to an alternate exit:

• Consider Time, Availability and Distance to redirect to a usable exit.

Evacuate—LAND

At a door

• Command first 2 passengers:

“You two, stay at the bottom! Help people off!”

• Command passengers: “Arms straight ahead” (all types of slides)

“Sit and slide!” (slides)

“Move away”

Continually assess conditions—LAND

• If passengers are waiting in line at any exit, consider redirecting to less

crowded exits.

• If passengers are piling at bottom of slide, temporarily halt evacuation.

The in-flight service on board manual also states that if a main landing gear

collapse/nose high situation occurs, the most desirable exits are low door and low window exits.

1.15.3 Flight Attendant Actions/Decisionmaking During the Evacuation

During postaccident interviews, the flight attendants were asked to describe their

actions, communications, and decisionmaking process during the evacuation procedure.

1.15.3.1 Flight Attendant in Charge

The FAIC, who was positioned in the forward cabin, stated that when the airplane

came to a stop on the runway, she picked up her interphone handset and waited for instructions.

She stated that moments later the flightcrew opened the cockpit door, and thereafter she

communicated with the pilots without using the interphone. The FAIC indicated that when she

heard the evacuation command, she opened the L-1 exit, pulled the manual slide inflation handle,

and began the evacuation. She stated that she recalled receiving verbal guidance from one or
30

both of the pilots to use only the L-1 door, but she did not recall specifically when or by whom

that guidance was given.

The FAIC indicated that the first officer stood near the cockpit door and assisted

her by attempting to calm the passengers during the evacuation. She stated that she instructed

two passengers to remain at the bottom of the slide to help, but they did not do so. She stated

that after four or five passengers “piled up” at the bottom of the slide, she slowed the pace of the

evacuation; shortly thereafter, firefighters and police officers began to assist at the bottom of the

slide, and there were no further problems with the evacuation. The FAIC indicated that when all

the passengers but one had been evacuated, she exited the airplane at a firefighter’s request; the

flightcrew remained behind to assist the remaining passenger out of the airplane.

1.15.3.2 Second Flight Attendant

The second flight attendant indicated that from the jumpseat she occupied

(forward of the aft galley, on the left side of the airplane), she was able to see outside during the

accident sequence by looking out a passenger window on the left side of the cabin. She reported

that she saw debris and heard “slushing sounds” during the impact sequence; then when the

airplane came to a stop, she picked up the interphone handset and waited for instructions. She

stated that she heard two PA announcements from the cockpit: the first was made seconds after

the airplane came to a stop and instructed passengers to remain seated, and the second PA

announcement, which was made about a minute after the first, ordered the evacuation. She stated

that sometime between the two announcements, she began to smell fumes, which she described

as a combination of burned motor oil and fuel fumes.

The second flight attendant stated that after she heard the captain’s evacuation

command she replaced the interphone handset, got up, and began to instruct passengers to move

forward to evacuate. During the evacuation process, the second flight attendant also obtained ice

from the aft galley for a passenger who had bumped her head. The second flight attendant

reported that she based her decision not to use the aft exits on the following information:

• Passenger seating positions—no passengers were seated behind her in the

cabin, about four passengers were located between her jumpseat and the

overwing exits, and the rest of the passengers were seated forward of the

overwing exits. She stated that “based on time and distance,” she believed

that it was “one third” faster to direct passengers to evacuate through the

forward exit.

• The debris and “slushing sounds” she observed during the accident sequence

led her to determine that the L-2 exit might be unsuitable for safe egress.

• A woman seated near the jumpseat occupied by the second flight attendant

had bumped her head as she stood up from her seat and was slow to

move/evacuate. The second flight attendant stated that she was concerned that

the woman might have been trampled if they had attempted to use the aft

exits.
31

1.15.3.3 Third Flight Attendant

According to the third flight attendant, she believed that she was somewhat

“displaced” during the accident sequence and evacuation because she was seated on the aft cabin

(tailcone) jumpseat and no passengers were seated in the rear of the cabin. She indicated that

when the airplane came to a stop, she picked up the interphone to listen for instructions. She

reported that when the captain commanded the evacuation the engines were no longer operating,

and she had no difficulty hearing the announcement over the PA system. She stated that as she

prepared to open the tailcone exit, the second flight attendant stopped her and indicated that they

were evacuating through the L-1 door only.

The third flight attendant left her position in the rear of the airplane and proceeded

forward to help the remaining passengers. She stated that as she moved forward in the airplane,

she began to smell fuel fumes. By the time she reached the middle of the coach section of the

cabin, most of the passengers had moved forward into the first-class section of the airplane,

toward the L-1 door. However, two passengers who were standing near the midsection of the

airplane appeared disoriented and were not moving forward toward the exit. The third flight

attendant indicated that she tried get the two remaining passengers to move forward quickly, but

the passengers did not respond. She reported that the first officer “was telling me to hurry

because there was extensive aircraft damage and potential for explosion.” When the first officer

moved aft to carry one of the passengers out of the airplane, the third flight attendant exited

through the L-1 door.

1.15.4 Delta Flight Attendant Training

According to Delta's Flight Attendant Training Manager, Delta's flight attendants

are instructed that every emergency situation is different and that flight attendants should follow

the evacuation guidelines outlined in the in-flight service on board manual, make an individual

assessment of the conditions, and use appropriate exits.

1.15.5 Previous Safety Board Recommendation—Flight Attendants’ Actions

A review of the Safety Board’s previous recommendations concerning flight

attendants’ actions during emergency evacuation procedures revealed that as a result of

information gathered in several accident investigations, on August 12, 1992, the Safety Board

issued Safety Recommendation A-92-077, which recommended the following to the FAA:

Require that flight attendants receive crew resource management training that

includes group exercises in order to improve crewmember coordination and

communication.

In response, the FAA revised AC 120-51B, “Crew Resource Management

Training,” to provide information concerning training that includes combined flight and cabin

crewmember exercises, and it published its final rule, “Air Carrier and Commercial Operator
32

Training Programs,” which requires that air carriers include CRM training for flight attendants in

their FAA-approved training program.

On July 15, 1996, based on the FAA’s actions, the Safety Board responded, in

part:

Because of the FAA’s...adequate general definition of a comprehensive CRM

program, the [Safety] Board classifies...A-92-077... “Closed—Acceptable

Action.” However, based on safety issues previously identified by the [Safety]

Board in its accident investigations, the [Safety] Board encourages the FAA to

provide additional guidance to air carriers about the importance of group

exercises involving both cockpit-cabin coordination and coordination among

the individual members of a flight attendant crew.

At the time of the accident, Delta pilots received 3 hours of CRM training during

the 2-day ground school portion of their annual recurrent training; the 3 hours consisted of a 2-

hour segment of joint flight and cabin crew CRM training and an additional 1-hour segment for

flightcrew members only.

1.16 Tests and Research

No additional tests and research were conducted in this accident.

1.17 Company/Flight Operations Information

At the time of the accident, Delta had approximately 68,000 employees and

operated 536 aircraft with more than 2,700 flights each day to 153 domestic and 51 foreign

destinations. Delta’s fleet included 52 Lockheed L-1011, 58 Boeing 767, 86 Boeing 757, 67

Boeing 737, 129 Boeing 727, 12 MD-11, 12 MD-90, and 120 MD-88 aircraft. Delta has

operated the MD-88 aircraft since December 1987.

1.17.1 Delta’s Procedures and Guidance Regarding Flightcrew Responsibilities

During CAT I ILS Approach to Land

During postaccident interviews, several Delta MD-88 check airmen/flight

instructors and the pilots of Delta flight 554 stated that Delta’s manuals did not contain detailed

guidance for pilot not flying (PNF) duties after visual contact with the runway environment is

established during a Category (CAT) I ILS approach. A review of Delta’s manuals supported

that comment; excerpts from Delta Air Lines’ FOM and the POM/PRM will be discussed in this

section.

Delta's FOM, chapter 7, "Normal Operations," addresses flightcrew duties and

responsibilities during normal flight operations, including instrument approaches. On page 7-46

(dated November 30, 1995), under the heading "Instrument Approach Procedures—General," the

FOM states the following:
33

Approach and landing should be planned to maintain minimum drag

configurations as long as possible, safety and conditions permitting, while still

meeting the stabilized approach requirements.

The aircraft should be stabilized on final approach in the landing configuration

at least 1,000 feet AFE [above field elevation] except where this conflicts with

nonprecision approach procedures.

Any abnormal condition, such as tail wind as evidenced by higher than normal

sink rate while maintaining glide slope and airspeed, should be verbalized.

If operable, both the Autopilot and Flight Director will be utilized for all ILS

approaches when the reported visibility is below RVR 4000 or 3⁄4 mile.

On page 7-48 (dated August 31, 1995), under the heading "Decision to Land," the

FOM states the following, in part:

During all instrument approaches, regardless of who is flying, the Captain

shall announce his decision to allow the aircraft to continue to a landing or to

execute a missed approach. This decision must be made no later than:

• CAT I Approaches—[Decision Altitude or Height/Missed Approach

Point] DA(H)/MAP

• CAT II ILS Approaches—DA(H)/RA

• CAT III ILS Approaches—AH/DH

The Captain will state, and the F/O will acknowledge (when operating to an

MDA or DH):

If and when visual reference is established with the runway

• "Approach lights in sight" or

• "Runway in sight"

Note: The "runway in sight" callout does not relieve the PF from the

responsibility to execute a missed approach if it would be unsafe to continue

to a landing.

If either visual reference is not established or a safe landing cannot be

accomplished in the touchdown zone

• "Missed approach"

Also, on page 7-48, under the heading "Descent Below DH/MDA," the FOM

states the following:
34

Upon reaching the DH/MDA, and at any time before the missed approach

point, the pilot may continue the approach below the DH or MDA and touch

down if meeting the conditions listed in the Airway Manual—Procedures

(Ops. Specs.).

On page 7-49 (dated June 30, 1996), under the heading "Crew Duties," the FOM

states the following, in part:

On each instrument approach the Captain shall ensure all requirements for the

approach are met. The duties below are the normal duties for all pilots,

however, the Captain may assign additional duties as required.

Pilot Flying (PF) Duties

• All Approaches

♦ Fly the aircraft.

♦ Conduct a suitable approach briefing.

♦ Conduct the approach as outlined in the POM.

♦ Crosscheck all instruments.

♦ After passing the final approach fix using the autopilot, the pilot

flying should follow through on the controls and be prepared to

immediately disengage the autopilot and autothrottles if

performance is not satisfactory.

• CAT I and CAT II

♦ Adjust scan pattern approaching MDA or DA(H)/RA to include

outside references.

♦ Primary duty continues to be accurate aircraft control

approaching DA(H) or MDA and maintaining MDA as

required.

♦ Either pilot may initially call "Runway in sight" (except CAT II).

♦ Autopilot may be disconnected when "runway in sight" is

established.

♦ The Captain must make the decision to continue or to execute a

missed approach.

♦ The PF will continue the approach or execute the missed approach.

♦ Refer to Airway Manual—Procedures (Ops. Specs.) section for

description of visual cues that allow operation below MDA or

DA(H)/RA.
35

Pilot Not Flying (PNF) Duties

• All Approaches

♦ Positively make all Standard Callouts.

♦ Crosscheck all instruments, both primary and raw data.

♦ Closely monitor flight instruments.

♦ Call attention to any flight path deviations, flags or

malfunctions. Any deviation from the published

approach should immediately be brought to the

attention of the PF.

♦ After establishing visual contact, the PNF must

continue to monitor the flight instruments through

the flare. Call out any significant deviation to

minimize the effects of possible visual illusions for

the PF.

♦ Monitor airspeed and sink rate through touchdown.

♦ After landing, F/O assists in runway and taxiway identification.

♦ If the approach cannot be continued, assist in execution of missed

approach.

♦ Pay particular attention to rotation, thrust, positive rate of climb,

airspeed, gear/flap retraction, and the missed approach procedure.

• CAT I

♦ Approaching DA(H), or MDA,

♦ Closely monitor flight instruments.

♦ Adjust scan to include outside references and verbalize

those observed.

Delta’s MD-88/90 POM, on pages 10-12 of the section entitled “Normal

Procedures,” states that during all CAT I ILS approaches, the PNF will make the following

callouts:

• First positive movement of localizer—“localizer alive”

• First positive movement of glide slope bar—“glide slope alive”

• At approximately 1000 feet above DH—“1,000 above, cleared to land,” or

“1,000 above, no landing clearance”

• Approaching DH—“200 above” and “100 above”

• At DH—“minimums”

At the time of the accident, the POM stated that at or before the DH, the PF will

call “Approach lights in sight,” “runway in sight,” or “missed approach,” and the PNF will

acknowledge that callout.
36

1.17.1.1 First Officer’s Actions During Approach to Land

During postaccident interviews, the first officer stated that from the time he made

the “one thousand above minimums” callout during the approach, he looked almost exclusively

at the instruments until the captain called out “approach lights in sight”; after which point the

first officer “glanced out a few times.” The first officer indicated that when he stated, “a little bit

high” and “above the glide slope” he was looking at the glideslope indicator on the instrument

panel; however, he believed that when he said “approach lights, we’re left of course,” he had

glanced outside. The first officer reported that he believed that the approach was a good, stable

approach—not rushed—until a few seconds before impact. However, about 3 seconds before

impact, he had the sensation that they would touch down short of the runway. He stated that at

that point, he looked outside the cockpit and saw the approach end of the runway. Information

obtained from the FDR, CVR, and flight and cabin crew statements indicate that the captain

applied power about the same time (1638:33) as the first officer called out “nose up.”

The first officer stated that because the guidance contained in Delta’s manuals

concerning the duties of the PNF during a CAT I ILS approach were “not real specific as [to]

what [the PNF] should be monitoring,” he followed his own personal procedures. He reported

that his personal practice after the PF established ground contact was to monitor the cockpit

instrumentation, provide the captain with information, and be ready to take over control of the

airplane if necessary. He indicated that he did not believe that he needed to take over control of

the airplane at any time during flight 554’s approach to runway 13; he stated, “as I said or

thought to do something, [the captain] was doing it. I don’t think I could have done much more.”

1.17.1.2 Delta’s Postaccident Actions Regarding PF/PNF Duties

As a result of this accident, Delta’s program managers discussed PNF duties and

landing callout requirements in several Joint Standards Meetings. The minutes from the

February 1997 meeting indicated that the program managers discussed the non-flying pilot’s

callout requirements in effect at other air carriers, which included the following:

• 1,000 feet agl

• 500 feet agl

• every 100 feet thereafter to 100 feet agl, then

• 50 feet agl

• 40 feet agl

• 30 feet agl

• 20 feet agl

• 10 feet agl

According to the minutes from that meeting, Delta’s program managers concluded

that their “...scan policy is adequately explained in [the proposed revision pages of the FOM

which do not contain such callout requirements]...we wanted the PNF to be aware of the outside
37

environment in the final phase of an approach/landing.” The minutes further indicated, “A

methodical approach to teaching our scan policy is needed.”

According to the minutes from the March 1997 Joint Standards Meeting, the

program managers agreed to revise the Maneuvers section of the FOM to reflect increased details

concerning PF and PNF scanning responsibilities during instrument approaches. The following

procedures are expected to be included in the revision, which is still in draft form:

Scan Policy:

• Approach scan policy is set to ensure someone is always focused on

airspeed, altitude and profile.

• Approach scan responsibilities for the PF and PNF are listed below.

• IN means primary responsibility is inside the aircraft.

• OUT means primary responsibility is outside the aircraft.

• The item inside the parenthesis ( ) means secondary responsibility.

 PF PNF

Runway Environment NOT in Sight IN (out) IN (out*)

Runway Environment in Sight OUT (in) IN (out)

• Except for CAT II and CAT III approaches.

1.17.2 Stabilized Approach Criteria

As mentioned previously, several Delta MD-88 check airmen/flight instructors

and the pilots of Delta flight 554 stated that Delta’s manuals did not contain a formal definition

of a stabilized approach, and that the only specific guidance concerning pilot actions during an

unstabilized approach was located in the windshear guidance section. A review of Delta’s flight

and pilot manuals supported their statement; although the word "stabilized" and the terms

"stabilized approach" and “unstabilized flightpath” appear several times, the manuals did not

define these terms, nor did they prescribe stabilized approach criteria. Excerpts from Delta’s

FOM, POM/PRM, and airway manual regarding stabilized approaches will be discussed in this

section.

The FOM did address basic aircraft operation parameters in various phases of

flight. In chapter 21, “Training,” under the heading "Pilot Qualification Standards," aircraft

operation parameters during the approach to land are outlined in part as follows:

Note: The tolerances described below, and throughout this document,

represent the performance expected in good flying conditions.

Aircraft Control

Maintains within the following parameters unless otherwise stated:
38

• Airspeed within +/- 10 knots, except for target airspeed

• Heading within +/- 10 [degrees]

• Altitude within +/- 100 feet

Approach

The pilot will maintain aircraft performance within the following tolerances

for the approach being flown.

CAT I Precision Approach Tolerances are listed as follows:

Final approach segment -- Localizer and glide path -- +/- 1 Dot

At DA -- Localizer -- +/- 1⁄2 Dot

 -- Glide path -- +/- 1 Dot

The FOM did not contain specific procedural guidance with regard to pilot actions

if approach tolerances were exceeded. Delta’s MD-88/90 POM guidance concerning flightcrew

procedures in the event of an unstabilized condition is contained in the Supplemental Information

section, under the heading “Wind shear Guidance.” On pages 32-33 of the POM’s

“Supplemental Information” section, it states the following, in part:

The following criteria for indications of an unstabilized flight path are

published only as a guideline.

CRITERIA FOR RECOGNIZING AN UNSTABILIZED FLIGHT

PATH

• +/- 15 KIAS

• +/- 500 fpm vertical speed

• +/- 5o

 pitch attitude

• 1 dot from glide slope

• Unusual throttle position for an extended period of time

• Wind shear system advisory (caution or warning)

When to Initiate a Recovery

Initiate the standard recovery technique when an unstabilized flight path or

marginal aircraft performance is indicated by:

• Wind shear below 1,000 feet [above field elevation] AFE:

♦ Criteria exceeded for an unstabilized flight path or

♦ Wind shear caution or warning annunciated by the wind shear

detection system.

• Severe or extreme turbulence encountered below 1,000 AFE.

• Stall warning encountered:
39

♦ Buffet, stick shaker or stall warning horn.

The Delta airway manual contained similar discussions of stabilized and

unstabilized conditions in chapter 4 (Weather), in the section entitled “Hazardous Weather.” On

page 4-7, under the heading “Wind shear—Decision Tree,” the Delta airway manual outlined the

criteria for unstabilized flightpath, consistent with pages 32-33 of the POM Supplemental

Information listed earlier in this section, and provided an outline for standard recovery technique.

On page 4-11, the Delta airway manual states the following, in part:

Heavy rain may have as significant an effect on airplane performance as wind

shear. Consider using the wind shear adjustment of up to 20 knots when

determining Target Airspeed.

If heavy rain is experienced during approach, initiate prompt attitude

correction to arrest any increase in descent rate, and immediately apply

adequate thrust to maintain Target Airspeed.

1.17.2.1 Previous Safety Board/FAA Actions Regarding Stabilized Approaches

As a result of an accident that occurred on September 8, 1989, involving a Boeing

737 near Kansas City, Missouri, the Safety Board issued Safety Recommendation A-90-131,

which recommended the following to the FAA:

Direct principal operations inspectors [POIs] to verify that the airlines they

surveil have clearly established stabilized approach and missed approach

procedures for nonprecision approaches, such as full-scale deflection of

localizer needle when the airplane is inside the final approach fix.

On May 31, 1991, the FAA revised Air Carrier Operations Bulletin (ACOB) 7-76-

31, directing all POIs to verify that appropriate air carriers have clearly established stabilized

approach and missed approach procedures for nonprecision approaches. The Safety Board

subsequently classified Safety Recommendation A-90-131 “Closed—Acceptable Action.”

As a result of an accident that occurred on June 8, 1992, involving a Beech C99,

near Anniston, Alabama, the Safety Board issued Safety Recommendation A-93-36, which

recommended the following to the FAA:

Require that scheduled air carriers operating under 14 CFR Part 135 develop

and include in their flight operation manuals and training programs stabilized

approach criteria. The criteria should include specific limits of localizer,

glideslope, and VOR needle deflections and rates of descent, etc., near the

airport, beyond which initiation of an immediate missed approach would be

required.
40

On December 29, 1994, the FAA issued Flight Standards Information Bulletin

(FSIB) Air Transportation (FSAT) 94-22, “Stabilized Approaches,” which states the following,

in part:

POLICY. FAA Principal Operations Inspectors (POIs) should strongly

encourage operators to incorporate the stabilized approach concept [contained

in FAA Order 8400.10, paragraph 511] into their approach procedures. POIs

also should ensure that the IFR practices, as discussed in [FAA Order]

8400.10, paragraph 547 [generic CAT I callouts], are incorporated into the

procedures used by all operators who conduct IFR operations.

Based on the FAA’s action, on July 19, 1995, the Safety Board classified Safety

Recommendation A-93-036 “Closed—Acceptable Alternate Action.” The “stabilized approach

concept” guidance referenced in FSAT 94-22, FAA Order 8400.10, paragraph 511, dated

December 20, 1994, states the following, in part:

Maintaining a stable speed, descent rate, vertical flight paths, and

configuration is a procedure commonly referred to as the stabilized approach

concept. Operational experience has shown that the stabilized approach

concept is essential for safe operations with turbojet aircraft, and it is strongly

recommended for all other aircraft.... A stabilized approach for turbojet

aircraft means that the aircraft must be in an approved landing

configuration...must maintain the proper approach speed with the engines

spooled up, and must be established on the proper flightpath before

descending below the minimum “stabilized approach height” specified for the

type of operation being conducted. These conditions must be maintained

throughout the rest of the approach for it to be considered a stabilized

approach. Operators of turbojet aircraft must establish and use procedures

which result in stabilized approaches.... A stabilized approach must be

established before descending below...1,000 feet above the airport or

touchdown zone elevation during any straight-in instrument approach in

instrument flight conditions.

On June 26, 1995, the FAA issued FSAT 95-10A, “Instrument Approach

Procedures and Training,” which contains guidance that “reflects FAA analysis and the latest

information and recommendations [from the NTSB] regarding instrument approach procedures.”

The guidance addresses the “stabilized approach concept,” and states the following, in part:

The “stabilized approach concept” of 8400.10, [paragraph] 511, will be

considered essential for safe operations for “all” (emphasis added) aircraft in

air carrier operations. Moreover, 1,000 feet per minute will normally be

considered the maximum allowable for a stabilized approach inside the final

approach fix. Descent rates in excess of 1,000 feet per minute will be cause

for consideration to abandon the approach.
41

1.17.2.2 Delta’s Actions Regarding Stabilized Approaches

A review of the minutes from Delta’s Joint Standards Meetings and flight

instructor standards meetings that took place between January 1996 and September 1996

indicated that stabilized approach definition, criteria, and guidance had been a topic of

discussion. The minutes from the April 16, 1996, Joint Standards Meeting indicated that an “Old

Business” item was a proposal to further define “stabilized approach” in the FOM. The minutes

indicated that action would be taken on this item before the next FOM revision.

Since the accident, Delta has issued a revision to chapter 7, “Normal Operations,”

of the FOM, which states the following, in part:

Stabilized Approach Requirements

Maintaining a stable speed, descent rate, and vertical/lateral flight path in

landing configuration is a procedure commonly referred to as the stabilized

approach concept. Chapter 21—Training (Pilot Qualification Standards)42

contains the acceptable parameters for a stabilized approach.

Any significant deviation from planned flight path, airspeed, or descent rate

must be verbalized. The decision to execute a go-around is no indication of

poor performance.

WARNING

Do not attempt to land from an unstable approach.

IMC

At 1,000 feet AFE, and on final, the aircraft must be:

• Configured for landing.

• Maintaining stabilized descent rate, if descending.

• On target airspeed within tolerance, or speed being reduced toward target

airspeed if higher was necessary.

At 500 feet AFE, the aircraft must be:

• Maintaining stabilized descent rate not to exceed 1,000 FPM, if

descending.

• On target airspeed within tolerance.

• Established on course.

 42 The guidance and parameters contained in Chapter 21 were previously discussed in

section 1.17.2, “Stabilized Approach Criteria.”
42

CAUTION

These conditions must be maintained throughout the rest of the approach

for it to be considered a stabilized approach. If the above criteria cannot be

established and maintained, at and below 500 feet AFE, initiate a goaround.

VMC....

Crossing the Runway Threshold

As the aircraft crosses the runway threshold it must be:

• Stabilized within tolerance on target airspeed until arresting descent rate at

flare.

• On a stabilized flight path using normal maneuvering.

• Positioned to make a normal landing in the touchdown zone (i.e., first

3,000 feet or first third of the runway, whichever is less).

CAUTION

Initiate a go-around if the above criteria cannot be maintained.

Instrument Approach Procedures

General

Use all suitable electronic and visual systems. If an ILS Glideslope or VASI is

available, do not descend below the ILS Glideslope prior to the Middle

Marker or below the VASI Glideslope until a lower altitude is necessary for a

safe landing.

1.17.3 Crew Resource Management (CRM) Training

Safety Board personnel examined Delta’s Human Factors/CRM training program

and syllabus. According to Delta’s training syllabus, the Human Factors/CRM training includes

an overview of the background of Human Factors/CRM training followed by discussion of CRM

skills and flightcrew roles in areas such as communications, coordination, planning, workload

management, situational awareness management, and decisionmaking. Delta’s CRM training

then focuses on the following seven areas of awareness:

• Crew Specific Behaviors

• Stress

• Fatigue

• Leadership/Followership

• Personality

• Effective Assertion

• Automation Pitfalls
43

Chapter 23 in Delta’s FOM, “Human Factors,” states, “CRM develops the skills,

techniques, attitudes, and behaviors air crews use to direct, control, and coordinate all available

resources towards the safe and effective operation of their aircraft. These skills enhance the

safety and effectiveness of your crew (pilots and flight attendants) as well as the expanded team

(dispatch, line maintenance, ramp service, etc.).” The FOM further states that the captain’s

command authority is not lessened by CRM; however, “inquiry, advocacy, and assertion by

crew/team members allows for better informed decisions.” Delta’s FOM indicates that first and

second officers should “offer or assert [their] perspective when safety and/or efficiency would be

enhanced.”

According to Delta’s training program development program manager, at the time

of the accident, Delta Air Lines provided initial CRM training to newly hired pilots as part of its

initial training program. Additionally, pilots received 3 hours of CRM training during the 2-day

ground school portion of their annual recurrent training, and CRM issues were emphasized

during Delta’s captain and first officer upgrade training.

1.18 Additional Information

1.18.1 FAA Oversight of Airman Medical Certification (Vision)

According to the June 1995 FAA Aeronautical Information Manual (AIM),

chapter 8, “Medical Facts for Pilots”:

All pilots except those flying gliders and free air balloons must possess valid

medical certificates in order to exercise the privileges of their airman

certificates. The periodic medical examinations required for medical

certification are conducted by designated Aviation Medical Examiners

[AMEs], who are physicians with a special interest in aviation safety and

training in aviation medicine.

Pilots who do not meet medical standards may still be qualified under special

issuance provisions or the exemption process. This may require that either

additional medical information be provided or practical flight tests be

conducted.

Title 14 CFR 67.19 discusses the special issue of medical certificates as follows:

At the discretion of the Federal Air Surgeon, a medical certificate may be

issued to an applicant who does not meet the applicable provisions...if the

applicant shows to the satisfaction of the Federal Air Surgeon that the duties

authorized by the class of medical certificate applied for can be performed

without endangering air commerce during the period in which the certificate

would be in force.
44

1.18.1.1 Vision Requirements for Certification

The standards for pilot medical certification are described in 14 CFR Part 67,

which was most recently updated in September 1994. According to Part 67.13, to be eligible for

a first-class medical certificate, an applicant must meet the following vision requirements:

1.) Distant visual acuity of 20/20 or better in each eye separately, without

correction; or of at least 20/100 in each eye separately corrected to 20/20 or

better with corrective lenses (glasses or contact lenses) in which case the

applicant may be qualified only on the condition that he wears those corrective

lenses while exercising the privileges of his airman certificate.

2.) Near vision of at least v=1.00 at 18 inches with each eye separately, with or

without corrective glasses.

3.) Normal color vision.

4.) Normal fields of vision.

5.) No acute or chronic pathological condition of either eye or adenexae that

might interfere with its proper function, might progress to that degree, or

might be aggravated by flying.

6.) Bifocal fixation and vergencephoria relationship sufficient to prevent a break

in fusion under conditions that may reasonably occur in performing airman

duties.

According to current FAA medical certification regulations, the FAA may grant

any class medical certificate to monocular applicants (applicants with only one usable eye), as

long as the applicant demonstrates the required near visual acuity with the usable eye and

demonstrates to the satisfaction of the Federal Air Surgeon that the applicant can perform the

duties authorized by the class of medical certificate applied for without jeopardizing the public’s

safety. In response to the Safety Board’s request for additional information on medical

certification of pilots with one usable eye, the acting manager of the aeromedical certification

division of the FAA’s Civil Aeromedical Institute (CAMI) submitted the following explanation

of FAA policy:

An airman with one eye, or with effective visual acuity equivalent to

monocular (i.e. best corrected distant visual acuity in the poorer eye is no

better than 20/200), may be considered for medical certification, any class,

through the special issuance procedures of Part 67...if:

I) A 6-month period has elapsed to allow for adaptation to monocularity,

II) A complete evaluation by an eye specialist, as reported on FAA Form

8500-7, Report of Eye Evaluation, reveals no pathology of either eye

which could affect the stability of the findings,

III) Uncorrected distant visual acuity in the better eye is 20/200 or better and is

corrected to 20/20 or better by lenses of no greater power than plus or

minus 3.5 diopters spherical equivalent, and

IV) The applicant passes an FAA medical flight test.
45

He further stated, “For a binocular applicant, contact lenses that correct near

visual acuity only or that are bifocal are not considered acceptable for aviation duties; the first for

obvious reasons, the latter because of our concerns for their effectiveness. The use of a contact

lens in one eye for distant visual acuity and a lens in the other eye for near visual acuity is not

acceptable because this procedure makes the pilot an effective ‘alternator,’ i.e. a person who uses

one eye at a time, suppressing the other. Stereopsis43 [binocular vision] is lost. Since this is not

a permanent condition for either eye in such persons, there is no adaptation such as occurs with

permanent monocularity.” A copy of the statement is included in appendix D.

In 1968-1969, a U.S. Air Force (USAF) flight research program44 performed a

series of accuracy landing experiments that documented USAF pilots’ performance with and

without one eye patched, in an attempt to determine the degree of impairment experienced by

pilots as a result of loss of binocular vision. The USAF report stated that in general, the pilots

who participated in the experiments experienced a sense of diminished brightness, a marked lack

of confidence in their ability to accurately judge height, and a significant increase in workload

during monocular landings. The USAF analysis of the data gathered resulted in the following

conclusions:

1. Spot landing performance in jet aircraft is not adversely affected by the

sudden total loss of vision in either eye. This observation has

important implications with regard to aeromedical standards.

2. Significantly steeper approaches are observed during monocular

landings than those observed during approaches made with normal

vision. It is suggested that the pilots’ lack of confidence in their ability

to accurately judge height during monocular approaches was

responsible for the steeper approaches reported.

3. Eye dominance is shown not to affect monocular landing performance

(95% level of confidence).

4. Noticeable increases in pilot workload are subjectively reported during

monocular landings.

5. It is suggested that monocular pilots may not experience significant

losses in their “functional” visual field; a definitive study is indicated.

The USAF report recognized that the experiments did not address the “problem of

restricted peripheral vision” on the blinded side, and indicated that future studies should address

that issue. A copy of the USAF results is included in appendix D.

 43 According to T. J. Tredici, stereopsis “...is the visual appreciation of three dimensions

during binocular vision, occurring during fusional signals from slightly disparate retinal points, which

cause different retinal images in each eye... .” For the remainder of the report, the term “binocular

vision” will be used to indicate stereopsis.

44 Lewis, C.E. Jr., Krier, G.E. Flight Research Program XIV: Landing performance in jet

aircraft after the loss of binocular vision. Aerospace Medicine, September 1969.
46

1.18.1.2 Information/Guidance Available to AMEs and Optometrists

According to the FAA’s September 199645 Guide for Aviation Medical

Examiners, the Federal Air Surgeon has determined that applicants for a first- and/or secondclass medical certificate must demonstrate at least 20/20 distant visual acuity and 20/40 near

visual acuity with each eye separately, with or without correction. Applicants for a third-class

medical certificate must demonstrate a near visual acuity of at least 20/60 in each eye separately,

with or without correction. The Guide contains the following guidance for AMEs with reference

to an applicant’s need for corrective glasses/lenses and the resultant flight limitations:

When correcting glasses are required to meet the near vision standards, an

appropriate limitation will be placed on the medical certificate. Contact lenses

that correct only for near visual acuity are not considered acceptable for

aviation duties.

If the applicant meets the uncorrected near vision standard of 20/40, but

already uses spectacles that correct the vision better than 20/40, it is

recommended that the Examiner enter the limitation for near vision corrective

glasses on the certificate.

The use of a contact lens in one eye for distant visual acuity and another

in the other eye for near visual acuity [monovision contact lenses] is not

acceptable (emphasis added).

For all classes, the appropriate wording for the near vision limitation is

“Holder shall possess corrective glasses for near vision.” Possession only is

required, because it may be hazardous to have distant vision obscured by

the continuous wearing of reading glasses (emphasis added).

For combined defective distant and near visual acuity when unifocal glasses or

contact lenses are used and correct both, the appropriate limitation is: “Holder

shall wear corrective lenses.”

The September 1996 Guide for Aviation Medical Examiners also contained the

following information concerning contact lens use:

Experience has indicated no significant risk to aviation safety in the use of

contact lenses for distant vision correction. As a consequence, no special

evaluation is routinely required before the use of contact lenses is authorized,

and no [Statement of Demonstrated Ability] SODA is required or issued to a

 45 The information contained in the September 1996 Guide for Aviation Medical

Examiners is consistent with the information available to the AME who issued the captain’s most recent

medical certificate.
47

contact lens wearer who meets the standards and has no complications.

Contact lenses that correct near visual acuity only or that are bifocal are

not considered acceptable for aviation duties. Similarly, the use of a

contact lens in one eye for distant visual acuity and a lens in the other eye

for near visual acuity is not acceptable. (Emphasis added.)

The AME who had examined the captain for airman medical certification

indicated that although he was not specifically aware that MV contact lenses were not approved

for use while flying, if the issue had come up with airman medical certificate applicants, he

would have advised them not to use MV correction when flying. He did not recall discussing

MV correction with the captain; further, he indicated that it was unlikely that such a discussion

took place, because he did not know that the captain possessed contact lenses.

Although corrected and uncorrected vision testing is included in the airman

medical certificate examination, AMEs are not required to ask pilots whether they possess/wear

contact lenses; pilots who require vision correction are required to bring contact lenses or glasses

to the examination. Additionally, although the airman medical certificate application, FAA Form

8500-8, contains numerous questions concerning the applicant’s medical history, the application

does not ask whether the applicant uses contact lenses. The AME who examined the captain

reported that if he was aware that a pilot wore contact lenses, he would ask that pilot to bring the

contact lenses to his or her examination; otherwise (as occurred when the captain was examined),

the pilots generally brought their glasses.

According to several optometrists interviewed during this investigation, no

published information tells optometrists that the use of MV contact lenses by pilots while flying

is prohibited. The literature on MV contact lenses provided to optometrists by one manufacturer

(for distribution to patients) indicated, “Monovision is a contact lens fitting technique that lets

you see clearly both near and far...without the bother of bifocals,” and did not refer to any

hazards or contraindications. A copy of the literature on MV contact lenses is included in

appendix D.

1.18.2 Information on Monovision (MV) Contact Lenses

Optometrists indicated that traditionally, bifocal, and even trifocal, spectacles

have been prescribed for individuals who need both distant and near vision correction. However,

they indicated that with increasing frequency, optometrists are prescribing MV contact lenses in

place of bifocal spectacles for these individuals.

According to USAF medical personnel,46 when an individual has symmetrical

binocular vision, the brain fuses the two images presented by the eyes into a single image,

 46 Brooks Air Force Base personnel, including Jose L. Perez-Becerra, Lt. Col., USAF, FS

(Staff Ophthalmologist); Thomas J. Tredici, M.D. (Senior Scientist); and Douglas J. Ivan, Col., USAF,

MC, CFS (Chief, Ophthalmology Branch).
48

resulting in three-dimensional vision, which aids in the determination of distance from objects in

the environment (depth perception). USAF medical personnel also reported that although the

brain is able to fuse the images presented through bifocal spectacles normally, it is unable to fuse

the disparate images presented through MV contact lenses normally, which can result in

monocular vision in individuals wearing MV contact lenses. Additionally, the USAF medical

personnel indicated that the eye wearing MV contact lens correction for near vision will present a

blurred image to the brain when used for distance vision; although the brain will try to

accommodate by “suppressing” the blurred image, that accommodation is rarely complete.

USAF research personnel indicated that stereoscopic vision is normally most

critical in determining the distance from objects close to an individual, although stereoscopic

vision is generally accurate to distances of up to 600 feet. They stated that beyond about 20 to 25

feet, monocular cues,47 such as comparative size, motion parallax, interposition, texture,

convergence, and perspective, usually assume an increasing role in the judgment of distance.

Because the use of MV contact lenses results in degraded depth perception and occasional

blurred images, an individual wearing MV contact lenses will rely more heavily on monocular

cues under all circumstances to judge distance than an individual wearing binocular vision

correction.

1.18.2.1 The Captain’s Use of Monovision Contact Lenses

According to the AME who had routinely examined the captain for airman

medical certification since 1984, the captain had 20/20 vision in both eyes until 1989. Records

indicate that since 1989, the captain’s distance vision remained 20/20 without correction, but his

near vision worsened. The AME stated that before the accident occurred, he believed that the

captain corrected his near vision with glasses.

According to the captain’s optometrist, the captain became a client in February

1990 and first obtained MV contact lenses in 1991. The optometrist indicated that a lot of his

patients were airline pilots, and he knew that the captain was an airline pilot before the accident

occurred. He further stated that he was unaware that the use of MV contact lenses while flying

was not approved. The optometrist told investigators that in general, he felt “someone in a

position of public safety” should use bifocal correction (spectacles) rather than MV contact

lenses. He further stated that binocular vision correction would be preferable for pilots while

performing flying duties, because there is a need for stable near and distant vision in cockpit

situations. He reported that a pilot’s use of MV contact lenses could impair sink rate perception,

depth perception at some distances, and scanning vision, especially on the side with near vision

correction. The captain of Delta flight 554 had near vision correction in the left lens.

The optometrist stated that MV contact lenses can impair depth perception,

especially at distances of less than 20 to 25 feet. He further indicated that the impairment

resulting from using MV contact lenses could make it more difficult to land a small airplane or

 47 Monocular cues are depth cues that do not require binocular vision.
49

parallel park a car; in his opinion, the use of MV contact lenses should not adversely affect depth

perception at distances greater than 25 feet. The optometrist did not perform a depth perception

test on the captain.48 The optometrist did not specifically recall discussing the limitations of MV

contact lenses with the captain when he first prescribed the lenses, and his medical notes did not

indicate that he discussed the issue with the captain.

According to the captain, he began using MV contact lenses several months after

he began using glasses. He indicated that he had been using either bifocal spectacles or MV

contact lenses with distance and near vision correction since 1990. He stated that he became

accustomed to the MV contact lenses easily, and that he had not perceived any deficiency in

vision or depth perception when wearing the MV contact lenses. The captain reported that he

used the MV contact lenses interchangeably with the glasses for general use, and that he used

MV contact lenses for vision correction approximately 75 percent of the time that he flew. The

captain indicated that he had not noted any problems wearing the contact lenses while driving or

flying. He stated that because he had flown with FAA medically certificated pilots who operated

with what he considered to be a worse deficiency (pilots with only one usable eye), he had

believed that MV contact lenses would be acceptable for use by pilots while flying. He stated

that he was unaware that MV contact lenses were not approved for use by pilots while flying.

1.18.2.2 Captain’s Postaccident Vision Test Results

In an attempt to determine whether the captain’s use of MV contact lenses was an

issue in the accident, the Safety Board requested a complete ophthalmological evaluation of the

captain’s vision and depth perception. The captain’s vision, fusion, and binocular vision were

tested and documented under the following conditions: uncorrected, corrected with bifocal

spectacles, and corrected with MV contact lenses.

According to the results of the examination, the captain’s uncorrected distance

vision in both eyes was 20/20 and his uncorrected near vision in both eyes was 20/70. He had

fusion of binocular images at all distances;49 however, his uncorrected near binocular vision (200

seconds/15o of arc) was below the norm,50 and his uncorrected distance binocular (120 seconds)

was only one increment better than the worst measurement unit.51

 48 For details on the captain’s postaccident vision test results, including depth perception,

see section 1.18.2.2.

49 The Worth 4 dot method was used to evaluate fusion.

50 The Titmus method measurements are as follows: best = 40 seconds/15o

 of arc, norm =

40 seconds/15o

 of arc, and worst = 800 seconds/15o of arc.

51 Binocular vision was measured by the Titmus (near) and BVAT (distant) methods.

According to the ophthalmologist who examined the captain, although the Titmus method has a wellestablished and accepted norm, the norm for the BVAT method is not as well standardized. However,

BVAT units of measurement double in incremental increase; the best and worst measurements are 15

seconds and 240 seconds, respectively.
50

Additionally, the examination revealed that the captain’s corrected vision using

bifocal spectacles was 20/20 in both eyes for both near and distant vision; he had fusion of

binocular images at all distances; his near binocular vision (40 seconds/15o of arc) was

documented at the best increment; and his distance binocular vision (120 seconds) was one

increment better than the worst measurement unit.

Finally, the ophthalmologist evaluated the captain’s vision corrected by MV

contact lenses, with the right eye contact lens correcting for distance vision and the left eye

contact lens correcting for near vision. The results indicated that the captain’s distance vision

was 20/20 +2 in the right eye and 20/30 in the left eye, and his near vision was 20/50 in the right

eye and 20/20 in the left. The captain had normal fusion at 3 feet; however, at 20 feet he

exhibited suppression of the left eye. The captain’s near and distant binocular vision using MV

contact lenses was one increment worse than it was using bifocal spectacles.

1.18.2.3 General Aviation Accident Involving Monovision Contact Lenses

During the investigation, the Safety Board became aware of a general aviation

accident previously investigated by the Safety Board that occurred on February 15, 1996. The

general aviation accident involved a private pilot operating a Cessna 210 in degraded day VMC

(low clouds and light snow) near Shelbyville, Illinois.52 The private pilot told the Safety Board

that he “didn’t pull the nose up” during the landing; the airplane bounced, and then touched

down on and blew the nose landing gear tire. The Safety Board determined that the probable

cause of the accident was “the pilot’s misjudged flare and improper recovery from a bounced

landing. Factors relating to the accident were: the pilot’s improper use of procedure by wearing

unapproved correcting lenses, and his resultant decreased depth perception.”

According to a flight instructor who was hired by the private pilot to help him

prepare for a postaccident FAA flight evaluation, the private pilot exhibited a consistent tendency

to begin the landing flare too close to the ground and had difficulty landing with crosswinds. On

July 16, 1996, when the private pilot returned to his AME to renew his medical certificate, the

AME noticed the pilot’s use of MV contact lenses. The AME informed the private pilot that MV

contact lenses were not approved for use by pilots while flying; the pilot returned with his

eyeglasses, and the medical examination was successfully completed. The flight instructor stated

that the pilot’s landings “improved suddenly and dramatically upon switching back to glasses.”

The private pilot indicated that he had been wearing MV contact lenses when the accident

occurred.

Postaccident interviews with the private pilot’s optometrist revealed that he had

prescribed MV contact lenses for the pilot in March 1995. Both the private pilot and the

optometrist indicated that they were unaware of the prohibition against the use of MV contact

lenses by pilots while flying until the pilot visited the AME after the accident.

 52 For more detailed information, see Brief of Accident CHI96LA089.
51

1.18.2.4 Postaccident Delta Air Lines Actions Regarding MV Contact Lenses

Delta records indicate that after this accident occurred, the company issued a

mandatory electronic flight operations bulletin alerting its pilots and medical personnel about the

hazards of MV contact lens use by flightcrew members. The mandatory electronic flight

operations bulletin will show up when a pilot checks in on the computer before the next flight;

the pilot must indicate that he/she has read the bulletin before he/she can continue to check in for

the flight.

1.18.3 Information on Visual Cues/Illusions

According to the FAA AIM, many different visual illusions experienced in flight

can lead to spatial disorientation, landing errors, and even accidents. Section 8-1-5 of the AIM,

dated July 20, 1995, states the following:

Various surface features and atmospheric conditions encountered in landing

can create illusions of incorrect height above and distance from the runway

threshold. Landing errors from these illusions can be prevented by

anticipating them during approaches, aerial visual inspection of unfamiliar

airports before landing, using electronic glide slope or VASI systems when

available, and maintaining optimum proficiency in landing procedures.

Section 8-1-5 describes several specific types of illusions, including featureless

terrain illusion, atmospheric illusions, and ground lighting illusions. These illusions are

described as follows:

(d) Featureless terrain illusion: An absence of ground features, as when

landing over water, darkened areas, and terrain made featureless by snow,

can create the illusion that the aircraft is at a higher altitude than it actually

is. The pilot who does not recognize this illusion will fly a lower

approach.

(e) Atmospheric illusions: Rain on the windscreen can create the illusion of

greater height, and atmospheric haze the illusion of being at a greater

distance from the runway. The pilot who does not recognize these

illusions will fly a lower approach. Penetration of fog can create the

illusion of pitching up. The pilot who does not recognize this illusion will

steepen the approach, often quite abruptly.

(f) Ground lighting illusions: Lights along a straight path, such as a road, and even lights

on moving trains can be mistaken for runway and approach lights. Bright runway and

approach lighting systems, especially where few lights illuminate the surrounding terrain,

may create the illusion of less distance to the runway. The pilot who does not recognize

this illusion will fly a higher approach. Conversely, the pilot overflying terrain
52

which has few lights to provide height cues may make a lower than

normal approach. (Emphasis added.)

As the pilots descended out of the clouds during their approach to land on runway

13, they were in heavy rain conditions, with the windshield wipers operating at the highest

setting. The captain reported that visibility through the windscreen was limited to the arc of the

windshield wipers, with rain obscuring the side windows. The estimated RVR for runway 13

was 3,000 feet, with limited visibility because of fog. According to Fundamentals of Aerospace

Medicine,

53 a perception of a shortened runway, with part of the length obscured by fog and/or

rain, might result in an illusion of “size constancy,” in which a pilot perceives the runway as

more distant than it is.

1.18.4 Information Regarding Special Airports

1.18.4.1 FAA Information Regarding Special Airports

According to 14 CFR 121.445, “Pilot in command [PIC] airport qualification:

Special areas and airports,” the FAA Administrator “may determine that certain airports (due to

items such as surrounding terrain, obstructions, or complex approach or departure procedures)

are special airports requiring special airport [airman] qualifications... .” The regulation further

states,

no certificate holder may use any person, nor may any person serve, as pilot in

command to or from an airport determined to require special airport [airman]

qualifications unless, within the preceding 12 calendar months:

(1) The pilot in command or second in command has made an entry to that

airport (including a takeoff and landing) while serving as a pilot flight

crewmember; or

(2) The pilot in command has qualified by using pictorial means acceptable to

the Administrator for that airport.

...this section does not apply when an entry to that airport (including a takeoff

or a landing) is being made if the ceiling at that airport is at least 1,000 feet

above the lowest MEA [minimum en route altitude] or MOCA [minimum

obstruction clearance altitude], or initial approach altitude prescribed for the

instrument approach procedure for that airport, and the visibility at that airport

is at least 3 miles.

On June 20, 1990, the FAA published AC 121.445-1D, which provides

information concerning the routes and airports where the FAA has determined that pilots require

 53 DeHart, R. L. Fundamentals of Aerospace Medicine. Baltimore: Williams & Wilkins,

1996.
53

special qualifications to operate as pilot in command. Page 2 of AC 121.445-1D, under the

heading “Special Airports,” states the following:

Appendix 1 contains a listing of airports, by regions, where it has been

determined that pilots require special airport qualifications. FAR Section

121.443 [“PIC qualification: Route and airports”] requires, in part, for each

certificate holder to provide a system acceptable to the Administrator for

disseminating the information required therein to ensure that the pilots have

adequate knowledge concerning the areas, and each airport and terminal area

into which the pilot is to serve. Therefore, airports with congested areas and

physical layouts such as John F. Kennedy in New York and O’Hare Field in

Chicago, which do not have terrain problems, are not included.

Page 3 of AC 121.445-1D states the following, in part:

Air carriers are encouraged to recommend additions or deletions to these

listings. Recommendations, along with an explanation of the need for the

addition or deletion, should be submitted to the assigned Principal Operations

Inspector. The Principal Operations Inspector will forward the

recommendation with his/her comments to his/her regional Flight Standards

Division. The regional Flight Standards Division will provide updated

information on these listings, as changes occur, to the Air Transportation

Division, AFS-200, who will make appropriate changes periodically.

During postaccident interviews, the first officer indicated that he believed that

LaGuardia should be classified as a special airport because a pilot landing at the airport for the

first time might have difficulty with the nature of the approaches and the traffic density. He

pointed out, “the visual approach to Runway 31 requires maneuvering the airplane at high bank

angles close to the ground [and] the approach to Runway 13 requires landing over water, a 250

foot DH, and an offset localizer.” LaGuardia was not designated a special airport in appendix 1

of the AC. Airports listed in appendix 1 of the AC were considered to be special airports for a

variety of reasons, including the following:

• Terrain issues—“Mountainous terrain;” “mountainous terrain in immediate

vicinity of airport, all quadrants;” “mountainous terrain on both sides of final

approach;” “airport is surrounded by mountainous terrain. Any go-around

beyond ILS...MAP will not provide obstruction clearance;” “runway located

on mountain slope with high gradient factor;” “special conditions due to

precipitous terrain;” “high terrain;” “high field elevation;” “high altitude

requires special performance;” “lake effect upon thermals on short final

[approach];” “mountainous to 2,300 feet within 3 miles of the localizer.”

• ATC/Approach/Departure issues—“Special arrival/departure procedures;”

“unique arrival/departure procedures;” “unique approach;” “complex ATC

procedures;” “limited approach facilities;” “complex departure procedures;”
54

“all nonprecision approaches;” “no [air traffic control] tower;” “no approach

control;” “traffic complexity;” “traffic density;” “no radar environment.”

• Other issues—“Political sensitivity of corridor adherence;” “limited

information.”

The FAA’s special assistant for air carrier operations indicated that at the time of

the accident, no criteria were published designating special airports, and he did not believe that

such criteria had ever existed. He stated that in October 1996, the FAA met with industry

representatives and developed a list of criteria based on factors such as accident histories, human

performance concerns, and runway anomalies that the FAA could use to develop objective

criteria for designating special airports. He stated that he hoped the FAA would develop a

procedure to add or remove airports from the special airport list and publish criteria for special

airport designation.

1.18.4.2 Delta’s Information Regarding Special Airports

According to Delta’s FOM, the following airport destinations are FAA-designated

Class I special airports:

Asheville, North Carolina; Wilkes Barre/Scranton, Pennsylvania;

Birmingham, Alabama; Burlington, Vermont; Burbank, California;

Washington, D.C. (National Airport); Guadalajara, Mexico; Hilo, Hawaii;

Ketchikan, Alaska; Harrisburg, Pennsylvania; Kahului, Hawaii; Ontario,

California; Palm Springs, California; Reno, Nevada; San Diego, California;

Sondre Stromfjord, Greenland; San Francisco, California; Sitka, Alaska;

Stuttgart, Germany; St. Thomas, Virgin Islands; and airports in the Peoples

Republic of China.

The following Class II special airports (FAA designated, with additional Delta

requirements) are listed in Delta’s FOM:

Eagle, Colorado; Gunnison, Colorado; Jackson Hole, Wyoming; and

Missoula, Montana.

Juneau, Alaska, was listed in the Delta FOM as a Class III special airport (FAA

designated, with lower-than-published minimums authorized), and the Class IV special airports

(Delta designated) were Kalispell, Montana; Helena, Montana; and Mexico City, Mexico.

According to Delta’s FOM, Class II and Class III special airports and Mexico City, Mexico, have

more rigorous flightcrew member initial qualification and currency requirements, which include

a review of pictorial, video, or Qualification Manual information concerning the specific airport

and an initial special airport entry flight under the observation of a company line check airman.

In addition, Class II and Class III special airport qualifications are aircraft specific.
55

2. ANALYSIS

2.1 General

The pilots held appropriate flight and medical certificates; they were trained and

qualified for the flight and were in compliance with the Federal regulations on flight and duty

time. However, the captain was using monovision (MV) contact lenses, which were not approved

by the FAA for use by pilots while flying. The captain indicated in postaccident interviews that

he was not aware that MV contact lenses were not approved for use while flying.

The flight attendants had completed Delta’s FAA-approved flight attendant

training program.

The airplane was properly certificated, and there was no evidence that airplane

maintenance was a factor in the accident.

A review of ATC procedures revealed that the controllers followed proper air

traffic separation rules, and air traffic separation was assured during flight 554’s approach to the

runway. In addition, ATC provided the pilots with timely weather (rain and visibility)

information during their approach to runway 13. No ATC factors contributed to the cause of the

accident.

Although the pilots did not receive several pieces of weather information, Delta

Air Lines provided the pilots with sufficient preflight, en route, and arrival weather information

to allow them to conduct the flight safely; however, because of rapidly changing surface

conditions, the conditions they encountered differed from what was forecast.

Although the pilots encountered a low cloud ceiling and degraded visibility, the

ceiling and visibility were still above the minimums required for the ILS approach. The Safety

Board concludes that although the weather conditions encountered by the pilots during the

approach differed from the forecast conditions, these conditions should not have affected the

pilots’ ability to conduct a safe approach and landing.

The pilots reported that they did not encounter much turbulence after they

descended through 3,000 feet on the approach, and the recorded wind speeds were less than

expected. FDR data from flight 554 and four other airplanes that made the approach to runway

13 between 9 minutes before and 1 minute after the accident disclosed no evidence of significant

windshear. Additionally, no pilot reports of windshear, LLWAS windshear alerts, or wind gusts

were recorded during the 50 minutes preceding the accident. Therefore, the Safety Board

concludes that Delta flight 554 did not encounter windshear during its approach to runway 13 at

LaGuardia.

The pilots performed the instrument approach to runway 13 in low clouds,

moderate-to-heavy rain, fog, and in limited light conditions.
56

Although the pilots did not observe the VASI lights during the approach to

runway 13, postaccident examination revealed that the VASI light system was capable of normal

operation at the time of the accident. Although it is likely that the runway 13 VASI light system

was operating normally when the accident occurred, with the reduced visibility that existed at the

time of the accident, the pilots would not have been able to utilize descent path guidance from

the VASI light system until late in the visual phase of the approach, and then only if they sought

such guidance.

2.2 The Accident Scenario

2.2.1 The Approach and Descent

The pilots reported that the departure, en route, and initial approach portions of

the flight were routine. The CVR transcript indicated that after Delta flight 554 had been cleared

to land on runway 13, the flightcrew of TWA 8630, which was departing from runway 13,

advised ATC that it was aborting its takeoff roll on the runway. ATC asked the TWA pilots to

expedite their turn off the runway, so that Delta flight 554 would not have to execute a missed

approach.

About 20 seconds after their decision to abort the takeoff, the pilots of TWA 8630

reported that they were “turning off,” and LaGuardia ATCT responded, thanking them. About 5

seconds later, TWA 8630 was off of runway 13 and was taxiing southwest on runway 22 towards

taxiway Golf; however, during postaccident interviews, the captain of Delta flight 554 stated that

he was uncertain if the TWA airplane had yet cleared runway 13.

During the seconds after TWA 8630 had aborted its takeoff roll, the CVR

recorded an expletive on the Delta flight 554 captain’s channel. The captain stated that he made

the expletive comment because he believed he might have to perform a missed approach because

of the airplane on the runway; he reported that he was not certain that he would be landing until

he established visual contact with the approach lights.

Based on the FDR data and calculated descent rate information, the airplane was

established in the landing configuration (flaps and landing gear extended), on target airspeed (+/-

4 knots), with an average rate of descent of about 750 feet per minute, and was established on the

localizer and electronic glideslope (+/- 1/10 of a dot) from the time it descended through about

1,000 feet agl (at 1637:05) until it reached an altitude of 431 feet agl (approximately 1638:02).

Between 1638:02 and 1638:08, the airplane’s rate of descent decreased, and the airplane began to

deviate above the glideslope; however, at 1638:09 (just before the airplane exceeded 1 dot

deviation above the electronic glideslope), the captain applied nose-down elevator, and the

airplane began to pitch down. The momentary reduction in descent rate occurred when the

captain later stated that he had been uncertain if TWA 8630 would clear runway 13 in time for

flight 554 to land, and it may have been the result of the captain’s anticipation of (and

preparation for) a missed approach.
57

Regardless of the reason for the reduction in the descent rate, by the time the

airplane began to deviate more than 1 dot above the electronic glideslope (at 1638:10), it appears

that the captain had recognized the deviation and had applied correction in an attempt to

reestablish the airplane on the glideslope. According to the FDR data, about 1638:14, the engine

thrust reduced and the descent rate increased slightly; however, the airplane did not reintercept

the electronic glideslope. FDR data indicated that from 1638:14 until 1638:26, the airplane’s

airspeed and descent were generally steady and on target, and the airplane was in a position from

which a successful landing could be made. At 1638:21, as the airplane descended through 200

feet agl, the pilots were in (degraded) visual conditions; they were aware that guidance from the

electronic glideslope was unusable below 200 feet agl; and they were using other cockpit

instrumentation and outside visual references for glidepath information. The Safety Board

concludes that because the airplane was in stable flight and the captain had taken actions to

correct for a glideslope deviation, the captain’s continuation of the approach after he established

visual contact with the approach lights was not inappropriate.

About 10 seconds before impact, just after the first officer called “sink’s seven

hundred,” the airplane’s rate of descent began to increase. According to FDR data, the airplane’s

calculated sink rate at that time was actually about 1,200 feet per minute. The difference

between the 700 feet per minute rate of descent reported (and presumably observed on the VSI)

by the first officer, and the 1,200 feet per minute rate of descent indicated by the FDR data was

probably the result of the lag time in the non-instantaneous vertical speed information displayed

on the VSI. (This issue is discussed in greater detail in section 2.5.)

FDR data indicated that about 10 seconds before impact, the engine power was

reduced gradually (from 1.2 EPRs at 1638:22, to 1.15 EPRs at 1638:28, to 1.09 EPRs at

1638:31). During this period, the elevator position oscillated, averaging between 2o nose up to

about 8o nose up. The Safety Board concludes that the captain gradually reduced the engine

power because he perceived a need to slightly increase the airplane’s rate of descent; however,

the descent rate increased beyond what the captain likely intended to command. At 1638:30, the

airplane’s descent rate was about 1,500 feet per minute. By 1638:32, the captain had recognized

that corrective action was required and was increasing the nose-up elevator deflection and

increasing the engine power.54 About 2 to 3 seconds before the initial impact, the airplane was

descending about 1,800 feet per minute; however, the trend in vertical velocity started to reverse.

According to the first officer, several seconds before impact he glanced outside

and realized that the airplane was descending short of the runway, and at 1638:33.7, he stated,

“Nose up...nose up.” The first officer stated that the captain had already added power and the

nose of the airplane pitched up; however, it was too late to avoid the accident.

 54 At 1638:32, the EPRs began to increase rapidly (from 1.10 EPRs at 1638:32, to 1.15

EPRs at 1638:33, to 1.25 EPRs at 1638:34, and to 1.55 EPRs at 1638:35).
58

2.2.2 The Landing

The Safety Board sought to determine why the descent rate of flight 554 continued

to increase until a safe landing could no longer be achieved. The Safety Board analyzed the

visual cues in the airport environment, including the airport lighting system and the effect of the

weather at the time of the accident, the effect of the captain’s vision limitations, and the first

officer’s actions and input to the captain during the last 10 seconds of the flight.

The pilots performed the instrument approach and landing in low clouds,

moderate-to-heavy rain and fog (which obscured the VASI lights and the runway environment),

and in limited light conditions. In addition, the pilots indicated that when they descended out of

the clouds, the airplane was positioned over the waters of Flushing Bay (which appeared gray),

with no visible structures to aid in visually judging distance and/or altitude. Although the

weather conditions were sufficient for the approach to be made safely, the low overcast cloud

layer and heavy rain and fog encountered by flight 554 during its approach to runway 13

degraded visual cues that the captain might otherwise have used to gauge the airplane’s rate of

descent/descent path during the visual portion of the approach.

As discussed in section 1.18.3, according to the FAA AIM, visual illusions that

might lead a pilot to perceive that the airplane is higher or more distant from the runway than it is

during an approach can result from the following conditions:

• an absence of ground features [as when landing over water]

• rain on the windscreen

• atmospheric haze/fog

• terrain with few lights to provide height cues

The Safety Board notes that all of these conditions were present when the pilots of

Delta flight 554 descended out of the overcast cloud layer and the captain transitioned to visual

conditions. According to FAA and medical publications55 on the subject of visual illusions,

these conditions could result in improper perception of altitude and descent path; specifically, a

pilot might perceive the altitude to be higher than the airplane’s actual altitude, especially during

periods of reduced visibility, when other visual cues are not available.

Further, the runway 13 edge lights were spaced irregularly—most of the lights

were spaced at intervals less than the maximum interval of 200 feet set forth in AC 150/5340-

24—and the departure end of runway 13 was obscured by rain and fog, so the pilots were visually

presented with a foreshortened runway. Pilots who are accustomed to operating into airports at

which runway lights are spaced at consistent 200-foot intervals might perceive their distance and

angle to the runway differently when presented with runway lights spaced at shorter, irregular

intervals.

 55 FAA AIM and Fundamentals of Aviation Medicine.
59

The Safety Board concludes that the irregular and shortened runway edge light

spacing and degraded weather conditions can result in a pilot making an unnecessarily rapid

descent and possibly descending too soon, especially in the absence of other visual references or

cues. Therefore, the Safety Board believes that the FAA should identify Part 139 airports that

have irregular runway light spacing, evaluate the potential hazards of such irregular spacing, and

determine if standardizing runway light spacing is warranted.

Although the airport and weather conditions that existed at the time of the

accident combined with the irregular (and shortened) spacing of the runway lights presented a

potential challenge for any pilot landing on runway 13, other airplanes used the ILS DME

approach to runway 13 around the time of the accident and landed without incident. In an effort

to understand why the captain of Delta flight 554 was unable to land safely, the Safety Board

analyzed the effect that his use of MV contact lenses had on his vision under those conditions.

Individuals with normal binocular vision use both binocular and monocular cues

for depth perception. Although binocular vision is generally accurate to distances of up to 600

feet, binocular cues are most critical in determining the distance from objects close to an

individual, while monocular cues assume an increased role in the perception of distances from

objects farther away. The Safety Board concludes that the captain’s use of MV contact lenses

resulted in his (unrecognized) degraded depth perception, and thus increased his dependence on

monocular cues (instead of normal three-dimensional vision) to perceive distance. However,

because of the degraded conditions encountered by flight 554, the captain was not presented with

adequate monocular cues to enable him to accurately perceive the airplane’s altitude and distance

from the runway during the visual portion of the approach and landing. This resulted in the

captain’s failure (during the last 10 seconds of the approach) to either properly adjust the

airplane’s glidepath or to determine that the approach was unstable and execute a missed

approach.

The unnecessary increase in descent rate 10 seconds before impact is consistent

with the captain’s degraded binocular vision, because it suggests that he had the impression that

the airplane was slightly higher than it actually was. A flying pilot with normal depth perception

might have perceived the airplane’s increasingly excessive sink rate earlier and either slowed the

rate of descent to make a normal landing possible or performed a missed approach. However,

the captain did not have normal depth perception and did not recognize that anything was wrong

with the approach until about 4 seconds before the accident, when the “aim point shifted down

into the lights.” The captain applied engine power and pitched up and the airplane’s rate of

descent began to decrease; about 2 seconds later, the airplane struck the approach lights and then

the runway deck, where the main landing gear separated from the airplane.

The Safety Board concludes that because of the captain’s use of MV contact

lenses, he was unable to overcome the visual illusions resulting from the approach over water in

limited light conditions (absence of visible ground features), the irregular spacing of the runway

edge lights at shorter-than-usual intervals, the rain, and the fog, and that these illusions led the

captain to perceive that the airplane was higher than it was during the visual portion of the
60

approach, and thus, to his unnecessarily steepening the approach during the final 10 seconds

before impact.

The first officer stated that during the visual portion of the descent and landing he

primarily monitored the cockpit instrumentation, provided the captain with feedback based on

that information, and glanced outside occasionally to monitor the approach visually, while the

captain flew the approach primarily using outside visual references. As stated earlier, at 1638:26,

when the first officer advised the captain “sink’s seven hundred,” the airplane was actually

descending about 1,200 feet per minute. The first officer stated that he never observed a descent

rate indication on the VSI of more than 1,000 feet per minute during the approach descent. Had

the first officer called out information from the airplane’s radar altimeter,56 it would have helped

one or both of the pilots perceive the airplane’s actual descent rate; however, the first officer did

not (and was not required by Delta to) call out radar altimeter information (because he either did

not look at it, or did not perceive the importance of that information) during the approach.

The first officer told Safety Board investigators that he believed that Delta’s

manuals did not contain clearly defined guidance regarding PNF duties during a CAT I ILS

approach once the PF established ground contact. The first officer indicated that during the

approach to runway 13, he followed his own “unofficial” procedures; he primarily monitored the

cockpit instrumentation, provided the captain with feedback based on that information, and

glanced outside occasionally to monitor the approach visually while the captain flew the

approach primarily using outside visual references. The Safety Board notes that after the captain

(PF) reported that he had the approach lights in sight, there were several occasions when the first

officer (PNF) attempted to provide the captain with useful feedback (i.e., speed’s good, sink’s

700, a little slow, nose up), which was not specifically required by Delta’s manuals, before the

airplane struck the runway deck. The Safety Board concludes that during the visual portion of

the approach, when the captain was primarily relying on visual cues, the first officer, who was

primarily monitoring cockpit instrumentation to gauge the airplane’s position with regard to the

runway, provided input to the captain that surpassed what was set forth in the guidance available

to the pilots at that time.

2.3 Delta’s Flightcrew Procedures

When the first officer observed “sink’s seven hundred” in an attempt to provide

the captain with useful vertical speed information during the approach, he unintentionally

provided the captain with misleading vertical speed information because of the 4-second lag time

inherent in the VSI as it was installed in the airplane. Use of radar altitude would have been

more useful, and more correct. If Delta’s manuals had contained either specific PNF callout

instructions using radar altimeter information (i.e., altitudes of 300, 200, 100, 50, 40, 30, 20,

 56 The altitude information displayed on the radar altimeter would represent the

airplane’s radar altitude above the water (not the runway) until the airplane crossed the edge of the

runway deck. However, because the runway 13 touchdown zone elevation is only 13 feet above the

water level, it is likely radar altimeter information would have helped the pilots perceive the airplane’s

actual descent rate.
61

10...), or a specific scan policy to ensure that someone was focused on airspeed, altitude and

approach profile, the first officer probably would have provided the captain with information that

would have been useful in determining the airplane’s position (and rate of change of position)

relative to the runway. Therefore, the Safety Board concludes that the Delta manuals were not

sufficiently specific regarding PNF duties during CAT I ILS approaches after the PF establishes

visual contact with the ground. (The Safety Board recognizes that Delta is revising PF/PNF CAT

I ILS duties listed in its manuals and related pilot training to include specific scan policy

guidance.)

In addition, Delta’s manuals did not specify operational criteria for a stabilized

approach, nor did they contain procedural guidance for pilots to follow if an approach became

unstabilized. The guidance and definitions that did exist regarding stabilized approach criteria

and procedures were either unclear or difficult to locate (the only guidance pertaining to

“unstabilized approaches” was located in the Supplemental Information section, under “Wind

shear Guidance”). Further, the manuals did not contain specific, accessible procedural guidance

about what action a pilot should take if an unstabilized condition developed during an otherwise

stabilized approach. However, as previously noted, the captain flew a stabilized approach until

about 1 second before he reported that he had the approach lights in sight (by which time the

airplane had deviated more than 1 dot above the electronic glideslope), and then he promptly

began to take corrective action. Therefore, the Safety Board concludes that although Delta’s

manuals did not adequately specify operational criteria for a stabilized approach, the lack of

guidance in this area did not contribute to the accident.

The Safety Board notes that Delta personnel had discussed the lack of adequate

information concerning stabilized approaches before the accident, and revisions to the manuals

were being prepared when the accident occurred. Delta’s revised manuals now contain more

thorough information and criteria concerning stabilized approaches. However, the Safety Board

is concerned that if Delta’s manuals contained inadequacies in these “safety of flight” areas other

air carriers’ manuals might also be inadequate. Therefore, the Safety Board believes that the

FAA should require all 14 CFR Part 121 and 135 operators to review and revise their company

operations manuals to more clearly delineate flightcrew member (pilot flying/pilot not flying)

duties and responsibilities for various phases of flight, and to more clearly define terms that are

critical for safety of flight decisionmaking, such as “stabilized approach.”

2.4 Availability of Information About the Hazards of Monovision Contact

Lenses

The AME who examined the captain reported that he was unaware that the

captain used MV contact lenses; he indicated that it would never have occurred to him that the

captain might use MV contact lenses, because the captain’s vision did not indicate the need for

MV contact lens correction. The Safety Board concludes that AMEs need to know if pilot

examinees are using contact lenses, and currently no process is in place to ensure that AMEs are

provided with that information. The Safety Board believes that the FAA should revise FAA

Form 8500-8, “Application for Airman Medical Certificate,” to elicit information regarding

contact lens use by the pilot/applicant.
62

Additionally, the captain and the optometrist who prescribed the MV contact

lenses for the captain were not aware that the use of MV contact lenses by pilots performing

flying duties was not approved by the FAA. This is consistent with the information obtained

during the previously mentioned Safety Board investigation into the general aviation accident

that involved MV contact lens use.57 The Safety Board concludes that information concerning

the possible hazards of MV contact lens use is not well disseminated among optometrists and the

pilot population.

Because the information available to optometrists and pilots is insufficient, the

Safety Board believes that the optometric associations should issue a briefing bulletin to member

optometrists, informing them of the potential hazards of and prohibition against MV contact lens

use by pilots while performing flying duties, and urging them to advise pilot-rated patients of

those potential hazards (MV contact lens’ effect on distance judgments/perceptions). In addition,

the Safety Board believes that the FAA Civil Aeromedical Institute should publish and

disseminate a brochure containing information about vision correction options, to include

information about the potential hazards of MV contact lens use by pilots while performing flying

duties and to emphasize that MV contact lenses are not approved for use while flying.

The Safety Board is aware that since this accident, Delta Air Lines has alerted its

pilots and medical personnel to the hazards of MV contact lens use by flightcrew members. The

Safety Board believes that the FAA should require all 14 CFR Part 121 and 135 operators to

notify their pilots and medical personnel of the circumstances of this accident, and to alert them

to the hazards of MV contact lens use by flightcrew members. Additionally, the Safety Board

believes that the FAA should require all flight standards district office air safety inspectors and

accident prevention specialists to inform general aviation pilots of the circumstances of this

accident and to alert them to the hazards of MV contact lens use by pilots while flying.

2.5 Non-Instantaneous Vertical Speed Indicator (VSI)

As pointed out earlier, during the final 12 seconds before impact, the airplane’s

rate of descent, which had been averaging about 700 feet per minute, began to increase. At

1638:26, as the first officer called out a sink rate of 700 feet per minute (based on VSI

information), the airplane was actually descending about 1,200 feet per minute. Had the first

officer seen a descent rate of 1,200 feet per minute, he would likely have been alarmed and

immediately indicated that to the captain. However, by 1638:33, when the first officer stated,

“nose up,” he had undoubtedly transferred his focus to external cues; thus, the first officer never

saw cockpit instrumentation indicate an excessive rate of descent. (This is consistent with the

first officer’s postaccident statement.) The Safety Board concludes that the lag time in the

display of vertical speed information in the VSI installed in the accident airplane limited the first

 57 For additional information on the general aviation accident, see section 1.18.2.3 or the

Safety Board’s report, CHI96LA089.
63

officer’s ability to provide the captain with precise vertical speed information during the critical

final seconds of the approach, and therefore contributed to the accident.

The Safety Board notes that several Delta check airmen and flight instructors

interviewed during the investigation stated that they believed that most Delta line pilots were

unaware that the vertical speed information presented by the VSIs in the MD-88 was not

instantaneous. If Delta’s MD-88 pilots were unaware that the VSIs in the MD-88 presented them

with non-instantaneous vertical speed information, the Safety Board considers it likely that pilots

with other air carriers/flying other aircraft might also be unaware of the nature of the information

(instantaneous or non-instantaneous) provided by the VSIs in their airplanes. The Safety Board is

concerned that a pilot who is unaware that the VSI in his/her airplane does not provide

instantaneous vertical speed information might be misled into believing that the airplane’s sink

rate is appropriate when it is not (as occurred with the first officer in the accident airplane).

Therefore, the Safety Board concludes that pilots need to be aware of the type of vertical speed

information provided by the VSI installed in their airplane, and to understand the possible

ramifications of that information. Therefore, the Safety Board believes that the FAA should

require all 14 CFR Part 121 and 135 air carriers to make their pilots aware (through specific

training, placards, or other means) of the type of vertical speed information (instantaneous/noninstantaneous) provided by the VSIs installed in their airplanes, and to make them aware of the

ramifications that type of information could have on their perception of their flight situation.

VSIs can be rewired to provide instantaneous vertical speed information in

airplanes that are equipped with an inertial reference unit (IRU). Again, the Safety Board notes

that Delta is replacing the attitude/heading reference system (AHRS) units installed in the MD-88

fleet with IRUs, and will have the capability of upgrading the timeliness of the vertical speed

information displayed on airplanes equipped with IRUs. The Safety Board believes that the FAA

should require all 14 CFR Part 121 and 135 operators to convert, where practical, the noninstantaneous vertical speed instrumentation on airplanes that have IRUs installed to provide

flightcrews with instantaneous vertical speed information.

2.6 Special Airport Designation

The first officer told Safety Board investigators that he believed that LaGuardia

should be designated an FAA special airport; he specifically cited the approaches to runway 31—

which require maneuvering the airplane at high bank angles close to the ground—and runway

13—which require landing over water, a 250-foot DH, and an offset localizer—as being worthy

of special pilot qualification requirements; the Safety Board also received other anecdotal

comments concerning designating LaGuardia a special airport. Because of the northwesterly

prevailing winds and other operational considerations, runway 13 is used less frequently than the

other runways at LaGuardia; the pilots of Delta flight 554 had not performed the approach to

runway 13 in inclement weather conditions, and the first officer indicated that he was not aware

that the runway extended on a pier over the water.

Although 14 CFR 121.445 contains a description of the special pilot qualifications

necessary for special airport operations, and AC 121.445-1D contains a description of the special
64

pilot qualifications required for operating in and out of special airports, a list of designated

special airports, and brief remarks to describe the “special” feature(s) of each designated special

airport, there are no published criteria or procedures for special airport designation. In addition,

the information provided in AC 121.445-1D’s remarks section is general, and does not provide

operators with detailed information as to the justification for special airport designation, nor does

it describe specific approaches, runways, hazards, or obstacles. The Safety Board concludes that

the FAA’s current guidance on special airports contained in AC 121.445-1D is not sufficiently

specific about criteria and procedures for designation of special airports; therefore, the FAA’s

current guidance might not always be useful to air carriers operating in and out of (existing or

potential) special airports.

The Safety Board is aware that the FAA met with industry representatives in

October 1996 to develop a list of factors—based on accident histories, human performance

concerns, runway anomalies, etc.—to use in determining criteria for classification of special

airports. However, the Safety Board is concerned that the FAA has apparently not made any

progress in developing such criteria since that meeting. Therefore, the Safety Board believes that

the FAA should expedite the development and publication of specific criteria and conditions for

the classification of special airports; the resultant publication should include specific remarks

detailing the reason(s) an airport is determined to be a special airport, and procedures for adding

and removing airports from special airport classification.

The Safety Board is also concerned that if an airport is designated “special”

because of a specific approach or runway configuration (i.e., the ILS DME approach to runway

13 at LaGuardia) a pilot who satisfies the special pilot qualification requirements by landing and

departing on a different runway at that airport might not have appropriate familiarization with the

special features of that specific approach or runway configuration and therefore might not

adequately satisfy the intent of the special airport regulation. The Safety Board concludes that

the present requirements for special airport pilot qualifications might not be sufficient to ensure

that pilots who are so qualified have been exposed to the runways and/or approaches at those

airports that make the airport “special.” Thus, the Safety Board believes that the FAA should

develop criteria for special runways and/or special approaches giving consideration to the

circumstances of this accident and any unique characteristics and special conditions at airports

(such as those that exist for the approaches to runways 31 and 13 at LaGuardia) and include

detailed pilot qualification requirements for designated special runways or approaches. Also, the

Safety Board believes that once criteria for designating special airports and special runways

and/or special approaches have been developed, the FAA should evaluate all airports against that

criteria and update its special airport publications accordingly.

2.7 Flight and Cabin Crew Evacuation Actions

The Safety Board considers that in general, the crewmembers’ responses after the

airplane came to a stop were commensurate with the circumstances of this accident. First, the

crewmembers assessed the condition of the airplane and reviewed their options; then, when the

captain was informed that there was a smell of jet fuel fumes in the passenger cabin, he promptly

commanded an emergency evacuation. The Safety Board concludes that the flightcrew
65

coordination appeared adequate, and the decision to evacuate the airplane was appropriate and

timely. Further, the Safety Board concludes that the FAIC, who began shouting evacuation

commands within 2 seconds of the evacuation order, reacted to the evacuation command

promptly and assertively, in accordance with Delta’s flight attendant manuals and training. All

passengers were successfully evacuated through the L-1 door, with minimal evacuation-related

injuries. Although under other circumstances the decision to use only one exit may have critical

consequences, in this case the decision to use only the L-1 door did not have adverse results.

The CVR transcript indicated that while the evacuation was being conducted at

the front of the cabin, the two flight attendants in the aft cabin remained on the interphone trying

to obtain additional evacuation instructions for at least 38 seconds after the captain issued the

evacuation command. About 40 seconds after the evacuation was commanded, the first officer

(who had been assisting with the evacuation at the L-1 door) responded on the interphone to the

aft flight attendants’ inquiry, with instructions to evacuate “forward,” and the aft flight attendants

began to participate in the evacuation. Because the airplane was carrying a light passenger load,

with most of the passengers seated in the front half of the cabin, by the time the aft flight

attendants began evacuation actions, most of the passengers had exited or moved toward the first

class cabin area.

The aft flight attendants stated that they sought further instructions before taking

action because they were concerned that the damage to the airplane and the possibility of spilled

fuel might affect the usability of their exits. According to the guidance contained in Delta’s

flight attendant manual, when an evacuation is commanded, flight attendants should promptly

assess the condition of their assigned exits, activate exits as appropriate, and issue guidance to

passengers. The manual further states that if a flight attendant judges that his or her assigned exit

is not usable, the flight attendant should redirect passengers towards an appropriate exit. The

Safety Board notes that it was appropriate for the aft flight attendants to evaluate and make a

decision regarding the usability of their exits; however, a 38-second delay before beginning

evacuation actions may have been critical if more hazardous conditions (e.g., fire) had

developed.

Delta’s flight attendant manual also indicates that once an evacuation is

commanded, flight attendants should begin the evacuation promptly, and “without further

communication from [the] cockpit.” The Safety Board concludes that the two aft flight

attendants did not react promptly or demonstrate assertive leadership, as specified in Delta’s

flight attendant manuals and training. Therefore, the Safety Board believes that the FAA should

require all 14 CFR Part 121 and 135 operators to review their flight attendant training programs

and emphasize the need for flight attendants to aggressively initiate their evacuation procedures

when an evacuation order has been given.

2.8 CRM Issues

The Safety Board examined the interactions between the pilots, among the cabin

attendants, and between the pilots and the flight attendants, to assess the quality of the CRM

before and after the accident. The evidence suggests that the quality of the interaction between
66

the pilots was good, and that both pilots provided appropriate assistance to each other when

needed, and that individually and together they performed effectively as a crew both before and

after the accident.

As previously discussed, the Safety Board found some deficiencies in the actions

of the aft flight attendants during the evacuation. However, the evidence overall indicates that

the quality of the CRM of the flight and cabin crewmembers of Delta flight 554 was good and in

accordance with Delta’s training and procedures. Therefore, the Safety Board concludes that the

quality of the CRM was not a factor in this accident.

2.9 Other LaGuardia Airport Issues

The Safety Board is aware that because of an anomaly in a data transmission line,

the RVR values from the time of the accident (3,000 feet) might be slightly incorrect. However,

postaccident pilot and air traffic controller statements indicate that the actual visibility at the time

of the accident was at least 3,000 feet. The flight visibility experienced by the pilots was at least

3,000 feet, which is consistent with the estimated (and ATC reported) RVR value, and which is

above the 2,400-foot RVR minimum required for the approach.

In addition, the Safety Board evaluated LaGuardia’s use of an RVR

transmissometer aligned with runway 22 to measure touchdown RVRs for runway 13. Although

the installation is not typical, the FAA has concluded that the transmissometer is situated such

that it can reliably serve both runway 22 and runway 13, and the evidence gathered during this

investigation suggests that the existing installation provided representative data at the time of the

accident. Therefore, the Safety Board concludes that the atypical installation and use of RVR

transmissometer equipment at LaGuardia did not adversely affect the validity of the RVR values

reported at the time of the accident.

According to the FAA, a postaccident evaluation of the LLWAS data revealed

that three of the six LLWAS sensors for LaGuardia might have been producing unreliable data

during the time of the accident. It is not known what effect this might have had on the windshear

detection capabilities of the system. However, surface wind speeds during Delta flight 554’s

approach and landing were relatively low (10 to 15 knots). Also, no wind gusts or LLWAS

windshear alarms were recorded during the 50 minutes before the accident. In addition, there

were no pilot reports of windshear during the 50 minutes before the accident. Therefore, the

Safety Board concludes that the LLWAS equipment anomalies were not a factor in this accident.

However, the Safety Board is concerned with the performance of the LLWAS at

LaGuardia. The Safety Board notes that the FAA is planning to improve and expand the existing

LLWAS at LaGuardia, with commissioning of a new system scheduled for November 1997. The

Safety Board agrees with these efforts by the FAA and urges the FAA to make every effort to

expedite the improvements.
67

3. CONCLUSIONS

3.1 Findings

1. The pilots held appropriate flight and medical certificates; they were trained and qualified for

the flight, and were in compliance with the Federal regulations on flight and duty time.

However, the captain was using monovision contact lenses, which were not approved by the

FAA for use by pilots while flying.

2. The flight attendants had completed Delta’s Federal Aviation Administration-approved flight

attendant training program.

3. The airplane was properly certificated, and there was no evidence that airplane maintenance

was a factor in the accident.

4. No air traffic control factors contributed to the cause of the accident.

5. Although the pilots did not receive several pieces of weather information, Delta Air Lines

provided the pilots with sufficient preflight, en route, and arrival weather information to

allow them to conduct the flight safely; however, because of rapidly changing surface

conditions, the conditions they encountered differed from what was forecast.

6. Although the weather conditions encountered by the pilots during the approach differed from

the forecast conditions, these conditions should not have affected the pilots’ ability to

conduct a safe approach and landing.

7. Delta flight 554 did not encounter windshear during its approach to runway 13 at LaGuardia.

8. Because the airplane was in stable flight and the captain had taken actions to correct for a

glideslope deviation, the captain’s continuation of the approach after he established visual

contact with the approach lights was not inappropriate.

9. The captain gradually reduced the engine power because he perceived a need to slightly

increase the airplane’s rate of descent; however, the descent rate increased beyond what the

captain likely intended to command.

10. Irregular and shortened runway edge light spacing and degraded weather conditions can result

in a pilot making an unnecessarily rapid descent and possibly descending too soon, especially

in the absence of other visual references or cues.

11. The captain’s use of monovision contact lenses resulted in his (unrecognized) degraded depth

perception, and thus increased his dependence on monocular cues (instead of normal threedimensional vision) to perceive distance.
68

12. Because of the captain’s use of monovision contact lenses, he was unable to overcome the

visual illusions resulting from the approach over water in limited light conditions (absence of

visible ground features), the irregular spacing of the runway edge lights at shorter-than-usual

intervals, the rain, and the fog, and that these illusions led the captain to perceive that the

airplane was higher than it was during the visual portion of the approach, and thus, to his

unnecessarily steepening the approach during the final 10 seconds before impact.

13. During the visual portion of the approach, when the captain was primarily relying on visual

cues, the first officer, who was primarily monitoring cockpit instrumentation to gauge the

airplane’s position with regard to the runway, provided input to the captain that surpassed

what was set forth in the guidance available to the pilots at that time.

14. The Delta manuals were not sufficiently specific regarding pilot-not-flying duties during

Category I instrument landing system approaches after the pilot flying establishes ground

contact.

15. Although Delta’s manuals did not adequately specify operational criteria for a stabilized

approach, the lack of guidance in this area did not contribute to the accident.

16. Aviation medical examiners (AMEs) need to know if pilot examinees are using contact

lenses, and currently no process is in place to ensure that AMEs are provided with that

information.

17. Information concerning the possible hazards of monovision contact lens use is not well

disseminated among optometrists and the pilot population.

18. The lag time in the display of vertical speed information in the vertical speed indicator

installed in the accident airplane limited the first officer’s ability to provide the captain with

precise vertical speed information during the critical final seconds of the approach, and

therefore contributed to the accident.

19. Pilots need to be aware of the type of vertical speed information provided by the vertical

speed indicator installed in their airplane, and to understand the possible ramifications of that

information.

20. The Federal Aviation Administration’s (FAA) current guidance on special airports contained

in Advisory Circular 121.445-1D is not sufficiently specific about criteria and procedures for

designation of special airports; therefore, the FAA’s current guidance might not always be

useful to air carriers operating in and out of (existing or potential) special airports.

21. The current requirements for special airport pilot qualifications might not be sufficient to

ensure that pilots who are so qualified have been exposed to the runways and/or approaches

at those airports that make the airport “special.”
69

22. The flightcrew coordination appeared adequate, and the decision to evacuate the airplane was

appropriate and timely.

23. The flight attendant in charge, who began shouting evacuation commands within 2 seconds

of the evacuation order, reacted to the evacuation command promptly and assertively, in

accordance with Delta’s flight attendant manuals and training.

24. The two aft flight attendants did not react promptly or demonstrate assertive leadership, as

specified in Delta’s flight attendant manuals and training.

25. The quality of the crew resource management was not a factor in this accident.

26. The atypical installation and use of runway visual range transmissometer equipment at

LaGuardia did not adversely affect the validity of the runway visual range values reported at

the time of the accident.

27. The low level windshear alert system equipment anomalies were not a factor in this accident.
70

3.2 Probable Cause

The National Transportation Safety Board determines that the probable cause of

this accident was the inability of the captain, because of his use of monovision contact lenses, to

overcome his misperception of the airplane’s position relative to the runway during the visual

portion of the approach. This misperception occurred because of visual illusions produced by the

approach over water in limited light conditions, the absence of visible ground features, the rain

and fog, and the irregular spacing of the runway lights.

Contributing to the accident was the lack of instantaneous vertical speed

information available to the pilot not flying, and the incomplete guidance available to

optometrists, aviation medical examiners, and pilots regarding the prescription of unapproved

monovision contact lenses for use by pilots.
71

4. RECOMMENDATIONS

As a result of the investigation of this accident, the National Transportation Safety

Board makes the following recommendations:

—to the Federal Aviation Administration:

Identify Part 139 airports that have irregular runway light spacing, evaluate the

potential hazards of such irregular spacing, and determine if standardizing

runway light spacing is warranted. (A-97-84)

Require all 14 CFR Part 121 and 135 operators to review and revise their

company operations manuals to more clearly delineate flightcrew member

(pilot flying/pilot not flying) duties and responsibilities for various phases of

flight, and to more clearly define terms that are critical for safety of flight

decisionmaking, such as “stabilized approach.” (A-97-85)

Revise FAA Form 8500-8, “Application for Airman Medical Certificate,” to

elicit information regarding contact lens use by the pilot/applicant. (A-97-86)

Require the Civil Aeromedical Institute to publish and disseminate a brochure

containing information about vision correction options, to include information

about the potential hazards of monovision (MV) contact lens use by pilots

while performing flying duties and to emphasize that MV contact lenses are

not approved for use while flying. (A-97-87)

Require all 14 CFR Part 121 and 135 operators to notify their pilots and

medical personnel of the circumstances of this accident, and to alert them to

the hazards of monovision contact lens use by flightcrew members. (A-97-88)

Require all flight standards district office air safety inspectors and accident

prevention specialists to inform general aviation pilots of the circumstances of

this accident and to alert them to the hazards of monovision contact lens use

by pilots while flying. (A-97-89)

Require all 14 CFR Part 121 and 135 air carriers to make their pilots aware

(through specific training, placards, or other means) of the type of vertical

speed information (instantaneous/non-instantaneous) provided by the vertical

speed indicators installed in their airplanes, and to make them aware of the

ramifications that type of information could have on their perception of their

flight situation. (A-97-90)

Require all 14 CFR Part 121 and 135 operators to convert, where practical, the

non-instantaneous vertical speed instrumentation on airplanes that have
72

inertial reference units installed to provide flightcrews with instantaneous

vertical speed information. (A-97-91)

Expedite the development and publication of specific criteria and conditions

for the classification of special airports; the resultant publication should

include specific remarks detailing the reason(s) an airport is determined to be

a special airport, and procedures for adding and removing airports from

special airport classification. (A-97-92)

Develop criteria for special runways and/or special approaches giving

consideration to the circumstances of this accident and any unique

characteristics and special conditions at airports (such as those that exist for

the approaches to runways 31 and 13 at LaGuardia Airport) and include

detailed pilot qualification requirements for designated special runways or

approaches. (A-97-93)

Once criteria for designating special airports and special runways and/or

special approaches have been developed as recommended in Safety

Recommendations A-97-92 and -93, evaluate all airports against that criteria

and update special airport publications accordingly. (A-97-94)

Require all 14 CFR Part 121 and 135 operators to review their flight attendant

training programs and emphasize the need for flight attendants to aggressively

initiate their evacuation procedures when an evacuation order has been given.

(A-97-95)
73

—to optometric associations:

Issue a briefing bulletin to member optometrists, informing them of the

potential hazards of and prohibition against monovision (MV) contact lens use

by pilots while performing flying duties, and urging them to advise pilot-rated

patients of those potential hazards (MV contact lens’ effect on distance

judgments/perceptions). (A-97-96)

BY THE NATIONAL TRANSPORTATION SAFETY BOARD

JAMES E. HALL

Chairman

ROBERT T. FRANCIS II

Vice Chairman

JOHN A. HAMMERSCHMIDT

Member

JOHN J. GOGLIA

Member

GEORGE W. BLACK, Jr.

Member

August 25, 1997

75

5. APPENDIXES

APPENDIX A—INVESTIGATION AND HEARING

1. Investigation

The National Transportation Safety Board was initially notified of this accident

about 1710 eastern standard time on October 19, 1996, by the FAA’s Eastern Region

Communication Center. One investigator from the Safety Board’s Northeast Regional Office

was immediately dispatched to the scene as investigator-in-charge. In addition, a partial team of

group chairmen/specialists was dispatched from the Safety Board’s headquarters in Washington,

D.C. The partial team comprised the following group specialists: Operations, Air Traffic

Control, and Meteorology. CVR, FDR/Aircraft Performance, Survival Factors, Airports, and

Human Performance specialists also assisted in the investigation.

Parties to the investigation were the FAA, Delta, McDonnell Douglas, and the Air

Line Pilots Association.

2. Public Hearing

No public hearing was held in connection with this accident.
76

APPENDIX B—COCKPIT VOICE RECORDER TRANSCRIPT

NATIONAL TRANSPORTATION SAFETY BOARD

Engineering & Computer Services Division

Washington, D.C. 20594

SPECIALIST’S FACTUAL REPORT OF INVESTIGATION

Cockpit Voice Recorder

NYC97MA005

by

Vincent M. Giuliana

Electronics Engineer/CVR

Warning

The reader of this report is cautioned that the transcription of a CVR tape is not a

precise science but is the best product possible from an NTSB group investigative

effort. The transcript, or parts thereof, if taken out of context, could be misleading. The

attached CVR transcript should be viewed as an accident investigation tool to be used

in conjunction with other evidence gathered during the investigation. Conclusions or

interpretations should not be made using the transcript as the sole source of

information.
77

NATIONAL TRANSPORTATION SAFETY BOARD

Office of Research and Engineering

Washington, D.C. 20594

December 16, 1996

A.

B.

Group Chairman’s Factual Report

by Vincent M. Giuliana

ACCIDENT

Location: LaGuardia Airport

Flushing, NY

Date: October 19, 1996

Time: 0438 eastern daylight time (EDT)

Aircraft: Delta Airlines Flight 554

MD-88, N914DL

NTSB Number: NYC97MA005

GROUP

Chairman:

Member:

Member:

Member:

Member:

Vincent M. Giuliana

Electronics Engineer/CVR

National Transportation Safety Board

Martin H. Potter

Federal Aviation Administration

Greg Saylor

Air Line Pilots Association

Don Alexander

McDonnell Douglas Corporation

Bill Watts

Delta Air Lines

Flight Operations
78

c. SUMMARY

This transcript was derived from a Fairchild Cockpit Voice Recorder (CVR)

(Model A100, S/N 2698) removed from the accident aircraft and delivered to the

audio laboratory of the National Transportation Safety Board.

The playback time of the recording was approximately thirty-one minutes and

forty seconds (31:40). Per approval by the Office of Aviation Safety and the

Office of Research and Engineering directors, and the investigator-in-charge,

the final thirty minutes and nine seconds (30:09) were transcribed. All times

incorporated into the transcript are in eastern daylight times, correlated with a

copy of the LaGuardia Air Traffic Control Tower tape, Local Control position.

D. DETAILS OF INVESTIGATION

Three of the four channels of the CVR contained audio information from the

cockpit area microphone (CAM), the captain’s position and the first officer’s

position. The fourth channel combined audio information from the passenger

cabin public address system and the flight attendant intercom system. The

crewmember channels were of excellent quality, enhanced by the use of the hot

microphone system. There was no structural damage evident on the CVR unit.

Mr. Greg Saylor, representative for the Air Line Pilots Association, believed an

excessive amount of extraneous background (tower) conversation could be

heard during several of the local controller’s transmissions.

On January 7, 1997, both the captain and first officer (accompanied by Mr. Greg

Saylor) reviewed the CVR recording and transcript at the NTSB headquarters in

Washington, DC. Their comments are attached as an appendix to this report.

The transcript begins at 0410:47 as Delta flight five fifty-four is in contact with

the New York Air Route Traffic Control Center. According to a subsequent radio

call at 0412:52, the aircraft is at an altitude of approximately eleven thousand

feet. A

UiM@=p

Electronic Engineer/CVR
79

Transcript of a Fairchild cockpit voice recorder (Model A100, S/N 2698) installed

on a MD-88, N914DL, which was involved in an accident at LaGuardia Airport in

Flushing, NY on October 1 9 1996. 

 LEGEND

CAM

HOT

RDO

-1

-2

-3,-4,-5

-?

NYCNTR

NYAPP

RAMP

COM

NAV

917W

DAL1215

BR960

LGATWR

TWA8630

UAL1 576

INT/PA

Cockpit area microphone

Crewmember hot microphones

Radio transmission from accident aircraft

Voice (or position) identified as Captain

Voice (or position) identified as First Officer

Voice identified as Flight Attendant

Unidentifiable voice

New York Air Route Traffic Control Center

New York TRACON

Delta ramp operations

Unknown radio information

Radio Navigation information

Flight nine seventeen whiskey

Delta flight twelve fifteen

Blue Ridge flight nine sixty

LaGuardia Local Tower Control

TWA flight eighty-six thirty

United Air Lines flight fifteen seventy-six

Flight Attendant intercom and/or passenger public address system
*

#

. . .

()

[]

.

80

Unintelligible word

Expletive deleted

Nonpertinent word (or name)

Pause

Questionable text

Editorial insertion

Break in continuity
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0409:16[Start of Recording]0410:47[Start of Transcript]0410:47HOT-1 lots of fuel.0410:56HOT-2 one to go.0410:59CAM [sound similar to that of altitude alert tone]0411:02HOT-1 did you tell the people to hang onto their hats?0411:04HOT-2 no I didn't .. I probably should have ... I just said cloudy,

windy and rainy.

0411:12HOT-1 that's okay.0411:14HOT-2 [sound of chuckle]0411:20HOT-1 coming up on eleven.0411:31HOT-1 anyway one three at LaGuardia.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0411:33HOT-2 okay.

0411:40NYCNTR delta five fifty-four fly heading of zer

in trail.

0411:44RDO-2 delta five fifty-four heading zero thre0411:46NYCNTR affirmative thanks.

0411:48HOT-2 you're welcome.0411:51HOT-1 she's awfully thankful today for us.0411:57HOT-1 it's ah not straight in by any stretch .. three degree off.0412:07HOT-2 okay .. yeah.0412:11HOT-1 one thirty-two is degrees .. it's ah one oh eight five .. glide

slope at Garde is seventeen forty ... set two-sixty three andtwo fifty.

0412:14NYCNTR delta eleven-sixty affirmative sir .. 

winds at LaGuardia.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0412:24HOT-2 two-fifty two sixty-three alright.0412:29HOT-1 radar's required .. glide slope unusable below two hundred

feet.

0412:31NYCNTR delta five fifty-four turn right fly hea

rejoin the Minks one arrival.

0412:35HOT-1 zero nine zero -

0412:36RDO-2 delta five fifty-four heading zero nine 0412:39NYCNTR delta five fifty-four thanks .. contac

one two five point eight five, bye bye

0412:45RDO-2 delta five fifty-four twenty-five eighty0412:52RDO-2 approach delta five fifty-four eleven 

zero nine zero with delta.

0412:53CAM [sound similar to that of trim alert tone]

0413:00NYAPP delta five seventy-four new york altim
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT

0413:04RDO-2 delta five fifty-four two nine five two.

0413:09HOT-2 two nine five two.0413:11HOT-1 tell 'em that zero nine zero isn't gonna get it with the winds.

0413:15RDO-2 delta five fifty-four was given zero n

arrival .. with the winds like this dfurther right or just go maybe direct 

0413:23NYAPP ah just fly that heading for now is fin0413:27RDO-2 okay zero nine zero thank you delta 

0413:30HOT-1 okay radar's required, glide slope's unusable below two

hundred feet .. final approach course crosses runway centerline and twenty-seven hundred and fifty-four feet fromthreshold .. who cares .. yeah okay so we get .. (slight right

hand) missed approach climb to eight hundred feet then a

left turn to two thousand feet direct to UR which is Orchywhich is three eighty-five which is the outer marker for ...

the other side for two two.

0414:00HOT-2 okay.0414:04HOT-1 and that would be a right-hand teardrop ..... entry.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0414:15HOT-1 forty flaps manual brakes and a short runway seven

thousand feet I believe .... if we turn off at the end it will be ashort taxi in.

0414:26HOT-2 that's right.0414:36HOT-2 let me make one more PA and I'll scare 'em to death.0414:43PA-2 ladies and gentlemen one more update from the flight deck

.. right now we are about fifteen miles from the airport at

LaGuardia and we expect to start our approach prettyshortly here .. right now they have us on an extended vectorjust fitting us into the traffic arriving into the new york area ..

the latest weather reports are it's still raining at the airport

and the winds are out of the southeast .. the velocity'sdecreased somewhat it's now fifteen to twenty miles anhour instead of the thirty to thirty-five they had before .. aswe go through the clouds and the rain we will get a few

bumps as we make our approach and it's probably gonna

be a little bit bumpy all the way until landing .. and as you

get out of the airport and walk to your cars or whatever it willstill be windy and bumpy so it's just one of those days uphere ... we still estimate that we will be to the gate at about

four thirty-five or close to that .. I'd like to thank you again

for flying with us on delta and we hope to see you again

soon .. thank you.

0414:56NYAPP delta five seventy-four turn right he

sequence.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT

0415:01RDO-1 was that for delta five fifty-four?0415:21RDO-1 center did you have a heading for de0415:27NYAPP delta five seventy-four that was for h0415:38NYAPP is that delta five seventy-four or five 0415:43RDO-1 delta five fifty-four is just north of Lu0415:47NYAPP alright, that was for you sir .. a one o0415:51RDO-1 delta five fifty-four heading one one 

0415:54HOT-1 okay you can have it back.0415:55HOT-2 alright.0416:12HOT-2 man it's just sitting over new york .. I mean it's sunny and I

mean it's pretty calm back this way.

0416:15CAM [sound of four chimes similar to that of no smoking chime]
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0416:17HOT-1 let's sit 'em down.0416:18HOT-2 alright.0416:22PA-3 ladies and gentlemen to prepare for landing please bring all

seatbacks and tray tables to their original and locked

position .. all remaining cups and glasses will be picked up

at this time .. we'll be arriving shortly.

0416:32HOT-1 hang on to your hats folks .. ladies and anybody else.0416:34HOT-2 ah still got some spoilers out.0416:35HOT-1 oh shoot.0416:37HOT-2 I didn't even notice it.0416:38HOT-1 I didn't either .... obviously.0416:39HOT-2 let's see airspeed -

0416:39NYAPP delta five fifty-four descend and mai0416:42RDO-2 delta five fifty-four nine thousand fee
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0416:45HOT-2 let's see two eighteen, seventy-three, forty-seven, thirty-five,

and flaps forty one twenty-three plus the additive so -

0416:57HOT-1 there's some rain.0416:59CAM [sound similar to that of trim alert tone]0416:59HOT-1 okay we'll use two eighteen, one seventy-three, one fortyseven and one thirty-five and the additive's going to be quite

stout I gotta feeling .. one twenty-three plus -

0417:11HOT-2 right now it's just sixteen knots so it'd be plus eight but -0417:13HOT-1 I'd say it'd be one thirty-one.0417:15HOT-2 alright.0417:16HOT-1 I don't want to use much more then I have to .. let's see

what it's .. let's play it by ear but I might add a couple to that

if it's gusty.

0417:21HOT-2 okay .. sure .. alright altimeter's two nine five two.0417:26HOT-1 two nine five two set and cross check.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0417:27HOT-2 set and cross checked .. airspeed bugs we just talked about

set cross checked.

0417:32HOT-1 set cross checked ... and approach check too.0417:35HOT-2 alright.

0417:39NYAPP delta five fifty-four turn left heading 

seven thousand.

0417:43RDO-2 delta five fifty-four zero nine zero se

0417:48HOT-1 zero nine zero seven thousand.0417:50HOT-2 seatbelt light is on .. approach briefing complete .. flight and

nav instruments?

0417:55HOT-1 flight and nav instruments are set to one thirty-two and one

oh eight two ah for right now .. I'll get ah let's see eleven

fifteen they got DME on it ..... ah ah eleven ah one oh eight

five excuse me.

0418:08HOT-2 one oh eight five okay .. one thirty-two.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0418:12HOT-1 one oh eight five one thirty-two set on my side, your side on

LaGuardia for now.

0418:15HOT-2 alright.0418:15HOT-1 that's good -0418:16HOT-2 set cross checked -0418:17HOT-1 temperature ten degrees.0418:19HOT-2 okay .. radio baro altimeter bugs?0418:21HOT-1 radio and baro bugs are set at ah let's see we got ah two

sixty-three and two fifty set cross check.

0418:32HOT-2 alright .. two sixty-three baro two fifty radio set cross

checked .. altimeters again two nine five two.

0418:39HOT-1 two nine five two set and cross checked.0418:42HOT-2 no smoking chime switch cycled and on .. nav setup to go.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT

0418:44NYAPP nine seventeen whiskey just v

LaGuardia and you have ATIS delta 

0418:48917W affirmative .. we have delta and we a0418:50NYAPP thank you .. altimeter two nine five z

0419:03HOT-1 * *.0419:13HOT-1 eight for seven.0419:16HOT-2 one to go .... let me give ramp a call ... I'll be off a second.0419:21HOT-1 okay .. I don't see anything on the radar that looks like we

have to go around it yet, do you?

0419:27CAM [sound similar to that of an altitude alert tone]0419:27HOT-2 it looks pretty good .. I'll ask -0419:29HOT-1 just rain.

0419:30RDO-2 ramp five fifty-four we should be the
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT

0419:35RAMP roger five fifty-four you'll be parking 

number six .. electric and air is avacall on the ground.

0419:42RDO-2 alright .. we'll call you on the ground

0419:46HOT-2 gate six .. as published they got power and air at the gate.0419:50HOT-1 super, thank you.0419:51HOT-2 they want us to call them on the ground.0419:53HOT-1 coming up on seven thousand ... I gotta go potty.0419:59HOT-2 boston's got east winds twenty-three gusts thirty ten miles

visibility.

0420:05HOT-1 good the weather, other than that?0420:09HOT-2 still, still let's see.0420:11HOT-1 that's a pretty stout low pressure.0420:12HOT-2 yeah.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0420:13HOT-1 twenty-nine fifty.0420:16HOT-2 zero eight zero at twenty-five gusts thirty ten miles .. twentynine ninety three .. peak winds zero eight zero at thirty-three

.. so it's windy up there so -

0420:24HOT-1 not gonna be a fun day to go out and play.0420:45HOT-1 okay what we got for traffic here .. we got one eight coming

down.

0420:53NYAPP american three seventy new york A

niner five zero.

0421:00HOT-2 they're calling it twenty-nine fifty now.0421:02HOT-1 five zero.

0421:02NYAPP delta five fifty-four turn left heading 

and maintain four thousand.

0421:06RDO-2 delta five fifty-four heading zero 

thousand feet and is it two nine five 

0421:12NYAPP twenty-nine fifty yes.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT

0421:14RDO-2 thank you.

0421:15HOT-1 four thousand feet, fifty degrees.0421:16HOT-2 four thousand .... down to four .. getting ready to fly up the

river, huh.

0421:23CAM [sound similar to that of trim alert tone]0421:25HOT-1 short turn on.0421:31HOT-1 fourteen degrees ... good shape for the shape we're in.0421:36HOT-2 alright.0421:38HOT-1 a little bit of red up there but a short range red .. I don't

know but we probably won't fly through it anyway ... it's

between us and the field ... somebody in it right now at four

thousand feet.

0421:52HOT-2 yup.0421:58HOT-1 okay let's see ... got everything done I think we need for

now .... is this the downwind leg or ah ... crosswind leg for

the turn to the downwind?
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0422:12HOT-2 yeah, crosswind to downwind ... daisy chain.0422:35HOT-1 (is this called) a minimum fuel approach?0422:38HOT-2 yeah.0422:52HOT-1 it's about L over D max isn't it ... clean speed plus ten?0422:55HOT-2 is that right?

0422:55NYAPP usair one eighty-four contact new 

point eight.

0422:57HOT-1 huh?

0422:58RDO-2 delta five fifty-four one twenty point e0423:01NYAPP no delta five fifty-four you stay with 

four contact one two zero point eigh

0423:05HOT-2 alright.0423:07HOT-1 (us) next.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0423:11HOT-2 one twenty point eight I think.0423:16CAM [sound similar to that of altitude alert tone]0423:17HOT-1 five for four.0423:17HOT-2 seven hundred feet to go.0423:28HOT-1 do da do do ... fifteen miles the field the way the crow flies

.... looks like there's some heavy # right over there right

over the airport.

0423:42HOT-2 ah huh.0423:44HOT-1 be long gone by the time we get there as fast as it's moving

though.

0424:03HOT-1 turn final we'll stop.0424:06HOT-2 what's that?0424:07HOT-1 when we turn final we'll 'bout stop.0424:09HOT-2 yeah that's right .. no more ground speed.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0424:24HOT-1 [sound of yawn]

0424:26NYAPP delta five fifty-four reduce speed to o0424:28RDO-2 delta five fifty-four slow to one eighty

0424:30HOT-1 slats please.

0424:30NYAPP delta five fifty-four contact one two z

0424:32CAM [sound similar to that of slat/flap handle actuation]

0424:33RDO-2 delta five fifty-four good day.

0424:37CAM [sound similar to that of trim alert tone]

0424:39RDO-2 approach delta five fifty-four is with 

we're slowing to a hundred eighty kn

0424:43NYAPP delta five fifty-four new york thank yo

0424:44HOT-1 flaps eleven.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0425:00HOT-2 okay you've got flaps eleven.0425:01HOT-1 this thing actually sped up .. did you see that .. we're at two

forty instead of two thirty.

0425:06HOT-2 hum.0425:15HOT-1 a little rain right here.0425:20CAM [sound similar to that of trim alert tone]0425:30HOT-2 want any ignition on?0425:32HOT-1 good idea.0425:33HOT-2 yeah it's heavy rain .. is that one on the list?0425:37HOT-1 that's one of them.0425:38HOT-2 yeah ..... I'll do a clock in case we spend a lot of time -0425:46CAM [sound similar to that of trim alert tone]
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0425:54HOT-1 with the flaps that'll give us a little extra .. cushion.0425:59HOT-2 yeah.0426:17HOT-1 could be fun all the way in man.0426:19HOT-2 [sound of chuckle]0426:21HOT-1 gonna be fun all the way to the ramp.0426:25HOT-2 I laugh now but ... I get to do the walk-around.0426:30HOT-1 you laugh now?0426:32HOT-2 gate two is bad .. it's got a ... it was raining up here last time

.. it doesn't drain well out there.

0426:40HOT-1 what's that?0426:41HOT-2 it doesn't .... the ramp area doesn't drain, it's -

0426:45DAL1215 okay you were blocked but if t

eighteen seven is that correct?
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT

0426:48NYAPP that’s correct delta .. good day.

0426:51HOT-2 eighteen seven.0426:59HOT-1 got us pretty close to this course here ..... maybe they're

gonna take us to the other side.

0427:10HOT-1 I bet he's gonna take us across the top.0427:12HOT-2 and then come back a left turn in.0427:13HOT-1 yup.0427:13HOT-2 yeah.0427:25HOT-1 well if we'd have come straight in like we normally do we'd

have been there by now .. or on time.

0427:29HOT-2 yeah.0427:30HOT-1 just about.0427:44HOT-2 now wouldn't you rather be here doing this than being at

home in sunny georgia?
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0427:47HOT-1 yup .. much rather ... pay's the same ..... I'm making a buck

sixty an hour .. what do you care .. what are you talking

about.

0428:04HOT-2 yeah yeah.0428:06HOT-1 no way I'm gonna (fill) up.0428:10HOT-2 yeah.0428:20HOT-1 bouncing around on a sunday afternoon .. saturday

afternoon.

0428:46HOT-1 I hope that's what he's got in store for us.0429:06HOT-2 huh .. I guess our heading and track are off that much.0429:09HOT-1 yup .. ah probably not ... that's ten thousand foot winds still

computed .. ah it says a hundred and twelve at sixty-one it'sincreased .. it was one forty-five ... or forty-five knots before.

0429:20HOT-2 yeah ... I was just looking at this funny return on the radar ..

on the map page .. the map.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0429:25HOT-1 oh yeah .. that's probably why .. yeah see the sweep only

goes over that far.

0423:26HOT-2 yeah.0429:31HOT-1 the sweep is off the heading not the course, obviously.0429:35HOT-2 yeah.0429:42HOT-1 I never knew that .. you learn something new every day.0429:44HOT-2 I never saw it do that.0429:52HOT-1 you'd think the sweep would be off the course cause that's

pointed off the nose of the airplane.

0429:56NYAPP delta five fifty-four turn left heading 

and maintain three thousand.

0430:01RDO-2 delta five fifty-four heading three six

0430:05HOT-1 three sixty three thousand feet.0430:08HOT-2 this should be a good altitude on this side.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0430:16HOT-1 intercept at twenty-eight hundred at Lymps, so.0430:17HOT-2 yeah.0430:18CAM [sound similar to that of altitude alert tone]

0430:25NYAPP delta five fifty-four turn left heading t0430:28RDO-2 delta five fifty-four heading three thr

0430:30HOT-1 three two .. three two zero.0430:32HOT-2 was it.0430:34HOT-1 well we'll check it .. split the difference.0430:36HOT-2 alright.0430:40CAM [sound similar to that of trim alert tone]

0430:41RDO-2 could you say the heading again 

please.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT

0430:44NYAPP yeah I said three twenty .. you sa

work .. I'll be turning you again in 

five fifty-four ... maintain the headi

thousand.

0430:51RDO-2 delta five fifty-four three twenty than

0430:54HOT-2 three thousand three twenty.0430:59HOT-1 let's go flaps fifteen.0431:00HOT-2 flaps fifteen.0431:02HOT-1 a little more cushion.0431:03HOT-2 alright.0431:06HOT-2 alright you've got flaps fifteen.0431:09HOT-1 that's as good as it gets.0431:13HOT-1 just gained ten knots like a shot.0431:15HOT-2 yeah.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0431:16CAM [sound similar to that of trim alert tone]

0431:19NYAPP delta five fifty-four turn left heading t0431:22RDO-2 delta five fifty-four two three zero.

0431:27HOT-1 two three zero.0431:28HOT-2 I'm gonna come over with you showing the ... (one oh eight

) five.

0431:31HOT-1 how many people are puking in the back?0431:33HOT-2 [sound of chuckle] let's make it good and hot back there.0431:36HOT-1 yeah.0431:42HOT-1 I'm gonna leave it at one eighty for a little bit just unless he

gives us something slower to keep a little cushion.

0431:43CAM [sound similar to that of trim alert tone]

0431:44NAV [sound of morse code ident for IGDI 
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0431:47HOT-1 speed is life .. someone told me that once.0431:50HOT-2 [sound of chuckle] alright ... yeah.0431:51HOT-1 speed is life right.0431:52HOT-2 yeah.

0431:53NYAPP delta five fifty-four turn left heading o

0431:56HOT-1 one eight zero.

0431:56RDO-2 delta five fifty-four heading one eigh0431:59NAV [sound of morse code ident for IGDI 

0432:04HOT-2 you're identified.0432:06HOT-1 one eighty okay ... thank you.0432:10HOT-1 [unknown sound heard only on captain's cvr channel]
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0432:11HOT-1 approach check done?0432:12HOT-2 we're both identified.0432:13HOT-1 [unknown sound heard only on captain's cvr channel]0432:14HOT-2 approach check's complete.0432:14HOT-1 thank you.0432:15HOT-2 I've got a got a palisades park tuned up on ADF too just

something else -

0432:20HOT-1 palisades okay .. and this is the missed approach if we

need it.

0432:23HOT-2 right.0432:32CAM [sound similar to that of alert trim tone]0433:04HOT-1 thought we were going to be inside Lymps .. I guess not ...

this track .... I was looking at the course or looking at the

heading and said oh #.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0433:13HOT-2 yeah .. yeah.

0433:14COM [sound of radio static on captain's an

0433:28HOT-1 still showing sixty-three knots now.

0433:33NYAPP delta five fifty-four turn left heading 

three miles from Lymps .. maintaLymps .. cleared ILS DME runway o

0433:40RDO-2 delta five fifty-four heading one th

three approach.

0433:55HOT-2 yeah I guess the wind's gonna blow us over.0433:58HOT-1 I think you're right.0433:59HOT-2 he's got us a half mile off course ... yeah it's gonna look

funny on this -

0434:01NYAPP blue ridge nine sixty new york altim

ATIS echo is now current advise ec

0434:03HOT-1 it's gonna look real funny plus it's gonna be right behind this

post is where the runway's gonna be.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0434:10HOT-2 yeah.0434:13HOT-1 I might need the windshield wipers on final.0434:15HOT-2 alright.0434:19HOT-2 that's been about ten minutes on the ignition .. you want to

go to -

0434:21HOT-1 let's change it.0434:22HOT-2 alright.0434:22HOT-1 let's (just) put it on one.0434:23HOT-2 alright.0434:26HOT-1 (one of 'em's) gonna get screwed.0434:31HOT-1 we've been cleared for the approach?0434:33HOT-2 we have ... ah it's -
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT

0434:34BR960 and negative echo .. it doesn’t see

blue ridge nine sixty

0434:37HOT-1 how we doing on the -

0434:38NYAPP okay thanks blue ridge nine sixty .. I

0434:39HOT-2 still not getting it .. starting to move now .. course is alive.0434:41HOT-1 okay .. we're good then to go down.

0434:48NYAPP delta five fifty-four contact LaGuard

point seven good day.

0434:52RDO-2 delta five fifty-four one eighteen sev

0434:56HOT-2 "loc" capture.0434:57HOT-1 thank you.0435:00CAM [sound of altitude alert tone and voiced "altitude" repeats

twice]
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0435:15HOT-1 okay the bank angle's fifteen and ah .... gimme flaps ah let's

see -

0435:19LGATWR delta five fifty-four LaGuardia tower.0435:21RDO-2 delta five fifty-four's with you for one 0435:23LGATWR delta five five four you're number tw

(three) seven two mile final the winone two runway one three .. continuyour arrival .. braking action report

seven .. low level wind shear repthree seven also.

0435:24HOT-1 gear down please.0435:26CAM [sound similar to that of landing gear extension]

0435:36RDO-2 delta five fifty-four roger .. and und

land one three.

0435:38HOT-1 twenty -

0435:39LGATWR ah no not cleared to land .. one 

arrival .. accommodate departure pl
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT

0435:43RDO-2 roger.

0435:44HOT-1 twenty-two knots .. flaps twenty-eight and forty ... before

landing checklists .. we're not cleared to land yet.

0435:51HOT-2 okay .. I thought he said twelve knots but he said -0435:52HOT-1 twelve knots?0435:53HOT-2 yeah .. I'll double check that again too .. we're not cleared to

land yet.

0435:57HOT-1 okay .. he'll give it to us again.0435:58HOT-2 ignition "A" .. landing gear?0436:00HOT-1 down and three green.0436:00HOT-2 down and three green ... flaps slats?0436:03HOT-1 we have ah forty forty land.0436:06HOT-2 forty forty land ... autobrakes? ... what would you like?
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0436:09HOT-1 gimme medium.0436:10HOT-2 medium ... spoilers armed.0436:12CAM [sound of click similar to that of spoiler handle arming]0436:13HOT-2 annunciator panel is checked.0436:15CAM [sound similar to that of trim alert tone]

0436:18LGATWR runway one three RVR touchdown 

two thousand two hundred.

0436:22HOT-1 three thousand foot RVR.0436:23CAM [sound similar to that of trim alert tone]0436:23HOT-2 okay.0436:24HOT-1 must be raining hard at the airport.0436:25HOT-2 before landing check is complete ... not cleared to land yet.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0436:37HOT-1 I got one thirty-five on the speed for right now.

0436:41RDO-2 say the winds please.0436:42LGATWR wind now one zero zero one two.

0436:44HOT-1 one two.0436:45HOT-2 okay.0436:45HOT-1 come back a little bit.0436:46HOT-2 alright .. a thousand feet above minimums.0436:54CAM [sound similar to that of trim alert tone]0436:55HOT-1 don't see # yet ... what was the ceiling on the ATIS?0437:00HOT-2 ah .. thirteen ah hundred.0437:03HOT-1 you can forget that.0437:04HOT-2 yeah.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT

0437:08LGATWR twa eighty-six thirty wind one zero 

one three cleared for takeoff traffic one three.

0437:08HOT-1 (try it).0437:10CAM [sound similar to that of windshield wipers start]

0437:13TWA8630 twa eighty-six thirty's cleared for t

thirty's rolling.

0437:16LGATWR thank you.

0437:17CAM [sound similar to that of trim alert tone]

0437:18LGATWR delta five fifty-four the wind now one 

runway one three cleared to land.

0437:22RDO-2 delta five fifty-four cleared to land on

0437:24HOT-2 starting to pick up some ground contact.0437:27HOT-1 one zero at one two .. okay.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT

0437:29TWA8630 twa eighty-six thirty needs to turn off0437:31LGATWR twa eighty-six thirty make the first ri

two .. can you do that for me sir?

0437:31HOT-1 I got the jet.0437:33HOT-2 alright.

0437:37LGATWR [momentary transmission interferen

traffic on a two mile final ah prevent 

0437:41TWA8630 twa eighty-six thirty's turning off.0437:43LGATWR thank you very much .. and ah say 

sir?

0437:48LGATWR twa eighty-six thirty just continue do

the first right turn on taxiway golf r

and ah when you get a chance let 

the abort.

0437:52HOT-1 #.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT

0437:56TWA8630 right turn on golf and we're ah lookin

0437:57HOT-2 two hundred above.

0437:59LGATWR okay no problem .. turn right on gol

bravo bravo and contact ground poi

0438:01HOT-2 speed's good sink's good.

0438:05TWA8630 right on golf .. hold short of bravo b

on point seven.

0438:07HOT-1 no contact yet.

0438:09LGATWR [momentary transmission interferen

exactly what's wrong report the inf

controller.

0438:10HOT-2 one hundred above.0438:11HOT-1 I got the (REIL) .. approach lights in sight.0438:13HOT-2 you're getting a little bit high.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0438:15HOT-2 a little bit above glide slope.0438:17HOT-2 approach lights we're left of course.

0438:18.0LGATWR you are cleared to land delta five fift0438:20.0RDO-2 delta five fifty-four cleared to land.

0438:20.6CAM [sound of GPWS "minimums”]0438:21.8CAM [sound similar to that of windshield wipers increasing to full

speed]

0438:22.4HOT-1 approach lights in sight.

0438:22.9UAL1576 tower united fifteen seventy-six is w

0438:25.6HOT-2 speed's good.0438:26.7HOT-2 sink's seven hundred.

0438:28.2LGATWR united fifteen seventy-six LaGuar

wind one zero zero at one zero ru

action reported good by a seven thre
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0438:30.1HOT-1 I'll get over there.0438:31.1HOT-2 a little bit slow a little slow.0438:33.7HOT-2 nose up.0438:34.2CAM [sound of GPWS "sink rate"]0438:34 .3HOT-2 nose up.0438:35.7CAM [sound of GPWS "sink rate"]0438:36.5CAM [sound of impact]0438:36.9CAM [sound similar to that of power interrupt to CVR]

0438:37LGATWR [continued from previous LGA tran

Bill .. Bill.

0438:38CAM [sound of tone and aural "landing gear" from CAWS starts

and repeats to the end of recording]

0438:43HOT-1 #.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0438:44HOT-2 hundred knots.0438:48HOT-2 sixty knots.0438:49CAM [sound similar to that of windshield wipers speed decreasing]

0438:51HOT-1 #.0438:52HOT-2 hang on hang on.0438:54CAM [sound similar to that of windshield wipers stopping]0438:56HOT-1 # # #.0438:57HOT-2 okay okay settle down Joe .. it's alright it's alright.0438:59HOT-1 okay .. let's see what we got here.0439:04INT/PA-3 stay in your seats.0439:05INT/PA-4 hello.0439:06INT/PA-1 ladies and gentlemen please remain seated at this time.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0439:12INT/PA-1 please remain seated with your seatbelts securely fastened

please.

0439:17CAM-2 we need to get out of the airplane I think.0439:18INT/PA-3 are you alright .. stay in your seats.0439:21CAM-2 get * *.0439:22CAM-1 yeah ... do that.0439:24CAM-3 you alright?0439:26INT/PA-3 I'm just waiting for someone -0439:26INT/PA-1 ladies and gentlemen please abort a -0439:29HOT-1 let's evacuate.0439:32INT/PA-3 @.0439:33HOT-1 well hold hold on a minute.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0439:33INT/PA-4 yeah.0439:34INT/PA-3 stay away from the back.0439:35INT/PA-4 I'm fine I'm fine.

0439:35RDO-2 tower delta five fifty-four.

0439:41INT/PA-3 [unintelligible] stay in your seats .. stay seated.

0439:46RDO-2 tower delta five fifty-four.0439:48LGATWR delta five fifty-four emergency vehic

* can you respond?

0439:52RDO-2 yes we're gonna evacuate the airpl

get everyone off the front of the airp

0439:56CAM-1 (start) the evacuation checklist.

0439:59LGATWR no problem at all evacuate your dis

are responding on *.

0440:01CAM-1 let's evacuate the airplane.
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0440:02CAM-? [male and female voice simultaneously] smelling fuel.0440:03INT/PA [sound of cabin chime]0440:03CAM-1 pardon?0440:04CAM-? [male and female voice simultaneously] smelling fuel.0440:04INT/PA-3 [unintelligible] are you alright?0440:05CAM-2 we need to get out.0440:05CAM-1 evacuate the airplane.0440:06CAM-2 okay.0440:10INT/PA-1 ladies and gentlemen we're going to evacuate the airplane

.. please follow the flight attendants instructions right now.

0440:12CAM-3 release your seatbelts get up get out .. release your

seatbelts get up get out ... release your seatbelts get up get

out.

0440:15INT/PA-4 do you want to go forward or backwards?
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0440:18CAM-1 evacuation checklist.0440:19CAM [sound similar to door opening and slide inflating]0440:20INT/PA [sound of cabin chime]0440:22CAM-? go go.0440:23CAM-3 sit and slide [repeated several times]0440:29CAM-? why don't you go out and meet at the front of the airplane ..

meet at the front of the airplane.

0440:30CAM [sound similar to cockpit call chime]0440:35INT/PA-5 this is @ .. do you want forward?0440:36INT/PA-4 no @ I need the ba - forward.0440:37CAM-1 emergency power switch *.0440:39INT/PA-5 are we going out the back?
INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMUNICA

TIME and TIME andSOURCE CONTENT SOURCE CONTENT0440:40CAM [two sounds similar to cockpit call chimes]0440:43INT/PA-4 I'm wanting to know which way out.0440:45CAM-1 [mostly unintelligible words relating to emergency

evacuation checklist]

0440:46INT/PA-? do not open the window -0440:48INT/PA-2 hello.0440:48INT/PA-4 do you want to go forward?0440:50INT/PA-2 let's come forward yes come forward.0440:56[End of Recording and Transcript]
126

On January 7, 1997, both the captain and first officer reviewed the CVR

recording and transcript at the NTSB headquarters in Washington, DC. Their

comments are as follows:

€ The first officer wants to convey that, “the following two excerpts from the

transcript were made in a joking manner:”

0414:36

HOT-2 let me make one more PA and I’ll scare ‘em to death.

0431:33

HOT-2 [sound of chuckle] let’s make it good and hot back there.

128

APPENDIX D—MEDICAL/VISION INFORMATION

U.S. Department

of Transportation

Federal Aviation

Administration

Mike Monroney

Aeronautical Center

P.O. BOX 25082

Oklahoma City, Oklahoma 73125

April 16, 1997

Mitchell Garber, M.D.

Medical Officer

National Transportation Safety Board

490 L’Enfant Plaza East, S.W.

Washington, D.C. 20594

Dear Dr. Garber

This is in response to our telephone conversation of April 16, 1997

concerning your question: Why does the FAA certify monocular pilots

but does not certify pilots with two eyes who wear a contact lens

in one eye for distant visual acuity and a lens in the other eye

for near visual acuity?

An airman with one eye, or with effective visual acuity equivalent

to monocular (i.e. best corrected distant visual acuity in the

poorer eye is no better than 20/200), may be considered for medical

certification, any class, through the special issuance procedures

of Part 67 (14CFR67.401) if: I) A 6-month period has elapsed to

allow for adaptation to monocularity, II) A complete evaluation by

an eye specialist, as reported on FAA Form 8500-7, Report of Eye

Evaluation, reveals no pathology of either eye which could affect

the stability of the findings, III) Uncorrected distant visual

acuity in the better eye is 20/200 or better and is corrected to

20/20 or better by lenses of no greater power than plus or minus

3.5 diopters spherical equivalent, and, IV) The applicant passes an

FAA medical flight test. If the person is amblyopic rather than

anatomically monocular, the criteria above are slightly different.

For a binocular applicant, contact lenses that correct near visual

acuity only or that are bifocal are not considered acceptable for

aviation duties; the first for obvious reasons, the latter because

of our concerns for their effectiveness. The use of a contact lens

in one eye for distant visual acuity and a lens in the other eye

for near visual acuity is not acceptable because this procedure

makes the pilot an effective “alternator, “ i.e. a person who uses

one eye at a time, suppressing the other. Stereopsis is lost.

Since this is not a permanent condition for either eye in such
129

persons, there is no adaptation such as occurs with permanent

monocularity.

Feel free to contact me if you need any additional information.

Sincerely ,

%!G

0

Melchor Antufiano, J. M.D .

Acting Manager,Aeromedical Certification Division

FAA Civil Aeromedical Institute
130

Flight Research Program: XIV.

Landing Performance in Jet Aircraft

After the Loss of Binocular Vision

CHARLES E. LEWIS, JR., and GARY E. KRIER

NASA Flight Research Center, Edwards, California 93523

LEWIS, C. E., JR., and G. E. KRIER. Flight research program:

XIV. Landing performance in jet aircraft after the /oss of binocular vision. Aerospace Med. 40(9): 957-963. 1969.

Thirteen ( 13) pilots were studied in a T-33A Jet Trainer

during a series of touch-and-go landings. Each flight included

landing approaches with fuIl binocular vision, folIowed by approaches with first the left and then the right eye covered. Both

lateral and Longitudinal miss-distance were photo-optically measured from a specified touchdown point. Performance on final

approach with respect to airspeed control. sink rate, and the

approach angle, was analyzed. Landing errors were clearly

shown not to increase significantly during approaches made with

one (1) eye covered. The pilots were free to select any angle

of descent during approach that they desired. Steeper approaches

were consistently observed when vision was restricted to one eye

than those flown with nomal vision.

One ( 1 ) pilot was studied for three (3) consecutive weeks during which his dominant eye was patched. Landing performance

was analyzed during three (3) flights including thirty-five (35)

landings and compared with control data flown on the day prior

to patching his dominant eye, and six (6) days after removal of

the patch - this delay was necessary to allow resolution of diplopia which had developed during the patched period. Analysis of

there data revealed no significant difference in landing performance with vision restricted to one ( 1 ) eye over the entire period.

These findings have important implications with regard to aeromedical certification standards.

THE SUCCESSFUL COMPLETION of many aerospace operations such as formation flying, landing

maneuvers, and docking of orbital spacecraft often depends on the pilot's ability to precisely position his craft

by means of visual cues alone. This implies the accurate visual estimation of distance in space; visual

depth perception.

The exact mechanism of depth perception in humans

is unclear and has long been a subject of controversy.

It has been well established, however, to be a very

complex function depending on both monocular and

binocular cues. A number of well qualified investigators have discussed, in great detail, the many factors

thought to be important.1-10 This difficult subject will

not be reviewed here; especially since the entire discussion becomes somewhat academic when one must deFrom the NASA Flight Research Center, Ed\vards, Calif.

tide whether or not an airman with impaired binocular

vision is to be certified and potentially entrusted with

several million dollars in flight equipment and the lives

of hundreds of human beings.

In view of the responsibility involved in this decision,

it is tempting to categorically disqualify all but the physically most perfect, but this policy would inevitably

result in the loss of a number of talented and expensively trained aviators. Obviously, it would be desirable to

certify many of these aviators if it could be done so

with safety. Before this can be done, however, some

method of reliably assessing the. risks to be expected, if

any, must be provided.

Relevant information can be found in the analysis of

aircraft accident statistics. Data abstracted for us by

Dr. Stanley from the Federal Aviation Administration files indicates that during the last five years no

one-eyed pilot has been involved in a flight accident

related to vision and more than twenty-six hundred

were flying as of 10 December 196S. These data are

encouraging but are, of course, indirect and inconclusive. Well controlled objective data defining the relationship between pilot performance and binocular vision

would be extremely useful. There is, however, a surprising lack of such data in the literature and the few

studies reported to date are not convincing.

In 1935, Jongbloed11 was unable to demonstrate any

degradation in landing performance following blindfolding of one eye. Conversely, Pfaffmann12 reported

a tendency to flare-out high in pilots whose nasal

visual fields were occluded in such a way that central

binocular cues were eliminated. In his study, though,

landings were made in the center of a large, open field

(one mile square) which deprived the pilots of linear

perspective cues and may have accounted for the differences observed.

In a previous NASA study a total of 155 landings in

a T-33A were successfully performed utilizing an increasingly narrow horizontal field-of-view. The narrowest of these (five degrees horizontal by thirty degrees vertical) produced a vertical slit narrower than

the interpupillary distances of the pilots studied.

“Dr. Stanley Mohler is Chief, Aeromedical Applications Division, AM -100, Office of Aviation Medicine, Federal Aviation

Administration.

Aerospace Medicine . September, 196 9 957
131

FLIGHT RESEARCH PROGRAM XIV LOSS O F BINOCULAR

Roman” observed that stereopsis could not have been

used during these landings since the field-of-view perceived by each eye was entirely different because of the

narrow slit through which the pilot viewed the approach scene. There was, however, no significant decrement in pilot performance as visual toes passed from

binocular to monocular

Guifoyle13, reporting his experiences as a “uniocular

:

[: ___

Fig, 1. The nrc,difiecl eye patch.

Fig 2. A subject pilot w ith the eye patch in place.

.4,.

-..

,,-. , .-. ---- .—w: y ., : , .-” . ,.>, . ,,, ., . J* .,7 . . .-{< .-. . . . . -.

Fig. 3. The T-33.1; all data reported was collected in this

aircra ft.

VISION—LEWIS & KRIER

pilot” in 1938, described a tendency to flare high

initially followed by gradual improvement in his landing

performance during a two-month period after the accidental loss of one eye. A similar but protracted experience was reported to the authors personally by a

NASA pilot who lost vision in his right eye subsequent

to a flight accident in 1967.

Finally, the accomplishments of one-eyed pilots such

as Wylie Post leave little doubt that highly motivated,

well qualified pilots can successfully operate aircraft

after the loss of stereopsis; however, prior to the present

study, the degree of handicap, if any, to be overcome

by such pilots was not known, nor was the length of

time required for return to acceptable performance

levels well understood. Likewise, the extent of immediate impairment of function, if any, following the

sudden loss of stereopsis was unknown. This experiment was undertaken, therefore, to establish, by objective means, both the acute (Phase I) and chronic

(Phase II) effect on pilot landing performance in jet

aircraft associated with the loss of binocular vision.

METHODS

Phase Z—Thirteen pilots qualified to fly the T-33A Jet

Trainer were studied during a series of thirteen touchand-go landings each. Each flight included landings

with full binocular vision, landings with the left eye

covered, and landings with the right eye covered. A

safety pilot was carried in the rear cockpit on all

fights. A standard closed pattern with the landing

gear extended was used. Patching was accomplished

on the downwind leg while the safety pilot flew the

airplane. A standard black clinical eye patch was used,

modified slightly to provide clearance of the eyelashes,

and a tight light seal (Figure 7); this was assured by

entrapping the patch (Figure 2) beneath the oxygen

mask nasally and the crash helmet laterally.

A prominent white line was painted across the North

Edwards Air Force Base Runway eight hundred feet

from the approach end and specified as the touchdown

spot. The pilots were asked to fly power-on approaches

to a fully flared touchdown as near the specified line as

possible. They were not otherwise constrained as to the

type of approach flown except that they were cautioned

in advance against forcing the aircraft onto the runway

without flaring in order to achieve a more precise touchdown.

All pilots studied have normal stereoscopic vision as

measured by the Wertz test. All have normal distant

visual acuity (20/20 or better); two wear corrective

lenses because of minor presbyopic changes. Eye dominance was determined by means of a simple aiming

technique.

The T-33A (Figure 3) was chosen for this experiment

because of its relatively docile handling characteristics,

and because it provided a flat approach profile during

power-on approaches to the flare. This technique assures a sensitive indication of depth perception in that

minor errors in judgment of height at the flare initiation

point creates relatively large errors in longitudinal

95S Aerospace Medicine . September, 1969
132

FLIGHT RESEARCH PROGRAM: XIV. LOSS OF BINOCULAR

touchdown performance.

Prior to flight each pilot was carefully briefed utilizing a standardized protocol. No pilot was aware of the

trend in the data prior to his participation as a subject

in the experiment. In order to obtain the most uniform

landing performance possible, pilots not recently proficient in the T-33A were allowed up to five periods of

practice at a different airfield prior to participation in

this program. After flight each pilot was carefully debriefed and asked to submit his subjective impressions

for inclusion in this report.

Phase II - This phase was designed to explore changes

in pilot performance, if any, over a longer period of

time after the loss of binocular vision, but was discontinued when the trend of the data from Phase I was

established. Consequently, only one pilot, number 12S

from Phase I, was studied; however, the data are of

considerable interest and are included. This pilot was

studied for three consecutive weeks during which his

dominant eye was patched. Landing performance was

analyzed during three flights including thirty-five landings and compared with control data flown on the day

prior to patching and six days after removal of the

patch. This delay was necessary to allow resolution of

diplopia which had developed during the experimental

period.

INSTRUMENTATION

Longitudinal and lateral misses about the specified

touchdown spot were photo-optically measured by

means of simultaneous motion pictures taken from a

point fifteen hundred feet abeam the touchdown spot

and on the centerline two hundred feet beyond the

departure end of the runway. Arriflex Model 16S 16mm

motion picture cameras were used in both positions. The

side camera was equipped with a 150-mm lens and fitted

with a panning head so that the aircraft could be

smoothly tracked throughout approach and touchdown.

The centerline camera was equipped with a 100-mm

lens, mounted on a three-foot tripod, aIigned with the

centerline of the runway and fixed in position. Both

cameras were operated at 24-frames/sec which produced

at the landing speeds observed a longitudinal resolution

of ten feet and a vertical resolution of .25 feet. Longitudinal resolution was improved to less than three feet

through interpolation behveen frames by careful examination of the smoke generated as the tire contacted the

runway at touchdown. Linear scale factors were calibrated on each film by comparison of known dimensions

on the aircraft. Suitable brightly colored targets were

placed alongside the runway and positioned such that

their image on the side camera film appeared at one

hundred foot intervals relative to the runway centerline

including eight stations on either side of the selected

touchdown spot. The zero touchdown line was identified with a larger square target painted alternately

black and white. (Figure 4).

All pilots were instrumented for electrocardiogram,

respiratory rate, respiratory volume, normal acceleration

and voice comments from both the subject pilot and

VISION—LEWIS & KRIER

the safety pilot. These measurements were made to

estimate the cardiorespiratory stresses associated with

this experiment and will be the subject of a subsequent

report.

RESULTS

Data reduction of the landing films was accomplished

on the Telereadex Evaluator Model 29A. Landing data

thus obtained was punched on cards using the Telecordex Encoder Type 2S2E and the IBM Type 523

Summary Card Punch. Subsequently the data cards generated were processed on the Flight Research Center’s

——. . . . -.- —. —.. . —, . . --

/“.;. ,

,..1

/’ ~~

,, . . . . .:

-w:,’ : F:~:+”,’ ‘ ~ ‘.” : f’ -

~,:;i: .—. ..— . ‘“ --l ;_k ‘~.:: :5

Fig. 4. The North Edwards Air Force Base Runway showing

arrangement of targets and the side camera in position.

o,s “.

r!, ”

1

a0.,.

Fig. 5. Data reduction schema
133

FLIGHT RESEARCH PROGRAM: XIV. LOSS OF BINOCULAR

IBM 36040 Computer using a program especially written for this project that provided automatically: (Figure

5)

1. Longitudinal and lateral miss analysis.

2. Analysis of performance on final approach with

respect to airspeed control, sink rate, and the approach

angle.

3. Plotting of fitted curves for the three treatments

studied.

4. The necessary statistical analyses; Two-way analysis of variance, (ANOVA), “F-Tests, and regression

analysis.

Phase I—Longitudinal miss-data along with the standard errors observed are presented in Table I. Surprisingly, overall monocular performance was better

than the corresponding overall binocular performance;

however, the difference observed was not statistically

TABLE I. AVERAGE LONGITUDINAL MISS DISTANCES AND

STANDARD ERRORS IN FEET

Landing Vision

pilot — timbind

m. Le[t Eye Right Eye hfonocufar Binmurar

1+3 103.3 = 92.0 71.3 = 61.5 88.3 = 78.2 151.1 * 145.4

141 139.9 = M.1 105.2 = 72.4 122.5 t 63.9 53.3 * ,47.5

14’2 112.8 = 126.0 73.0 z 59.9 92.9 * 93.7 260.2 = 97.5

149 66.8 2 50.7 68.4 = 73.9 66.6 2 63.3 60.4 = 41.6

120 73.8 = 20.0 97.4 t 143.7 83.6 = 102.6 248.6 = 90.3

150 374.5 * 231.2 155.7 t 71.7 265.1 * 184.7 226.8 = 152.6

146 127.4 2 129.7 273.3 * 24?.5 200.4 * 194.4 146.4 % 65.4

140 79.6 2 41.2 136.4 * 143.0 118.0 = 103.3 122.2 z 107.9

128 =.3 * 140.9 94.0 2 73.6 181.2 t 112.4 203.1 = 203.6

lsa 6S.4 = 83.6 72.4 * 91.0 77.s z 68.4 63.5 = 91.3

201 66.1 = 54.0 . *.8 = 81.1 76.4 = 68.9 iM.5 : 36. 4

215 160.8 = 142.9 12s.2 = 133.5 143.0 = 138.3 238.4 = 227.8

214 915.3 = 256.9 103.6 = 76.0 209.4 * 189.4 157.6 = 182.5

Av,rarc 152.0 & 17.4 114.0 = 17. 4 133.0 * 8.7 158.1 * 17.4

TABLE II. TWO-WAY ANALYSIS OF VARIANCE

(DATA, LONGITUDINAL MISS DISTANCE 1X FEET)

F

Source of Sum of h[e>n &er- F@ .05 F@ .01 Variation d.f. Squares huarc -lion Table Table

Pdou 12 433347.93 36128.99 2.29 2.05 2.34 Trcacmcnu 2 59341.46 2%70.74 1.B8 3.80 4.98

tatemction (P XT 1 2 4 463W.65 19293.52

Error 117 1842~.23 *573L9 ‘“22 ‘“76 “95

Toul 155 2798917.W

S.E. = 125.51

.Stgnihcant at 5 perctnv 1,,.1

TABLE III. EFFECT OF PILOT Difference AND LOSS OF

BINOCULAR VISION ON LANDING PERFORMANCE

Landing a = 8.05 a = 0.01

Performance Variable 1 Vari*Ie 2 , Varhble 1 vial. 2

Variable Simif. Si~i[. Signif. .Signil.

VISION-LEWIS & KRIER

significant. The ANOVA summary on which this conclusion was based is presented in Table II. Data

relevant to lateral misses, sink rate on final approach,

indicated airspeed on final approach and the approach

angle flown were analyzed in exactly the same manner.

The combined results from these analyses are presented

in Table III at confidence levels of both 95 percent

and 99 percent. Note that the pilot effects (variable 1),

as expected, are significantly different; also that the

effect on landing performance of restricted vision

(variable 2) was not significantly different for either

lateral and longitudinal misses.

Analysis of the approaches flown reveal highly significant differences in the technique chosen by the pilots

during monocular approaches. Interestingly, except for

one pilot whose approach performance plots almost

exactly overlay, steeper approaches (Figure 6) were observed during monocular landings than those observed

during corresponding binocular controls although none

of the pilots was aware of this difference at the time.

These steeper approaches are reflected in the differences

in airspeed, sink rate, and the approach angle shown in

Table III.

Data that describe the pilot population studied with

TABLE IV. PILOT AGE, EXPERIENCE, AND EYE DOMINANCE

PilOt ASC Experience Dominant

Gde [Y”) (H,, ) Eye

143 34 2,650 Left

141 43 Io,m Right 14~ 3a 5,103 Right

149 33 3,103 Right

lm 37 2,303 Right

150 36 3,2cO R,ght

146 33 2,m R\ght

140 40 5,0m Nghc

128 39 2,1C0 Right

m7 43 4,2M Right

215 36 3,637 Right

214 30 2,22? Left

138 47. 5.291 Altcmator

Avera$e 37.6 3,975.7

TABLE V. LONGITUDINAL MISS DISTANCES AND STANDARD

ERRORS 1X FEET VERSUS EYE DOMINANCE

(Rearranged from Table 1)

Landing Vision

Pilot Non. Dominant Dominant Binocular

Codes Patched Patched Vision

143 105.3 * 9?.0 71.3 = 61.5 151.1 * 145.4

141 105.2 * Y2.4 139.9 * 54.1 533 t 47.5

142 73.0 = 59.9 112.8 = 126.0 260.2: 97.5

149 66.4 * 73.9 6S.8 2 50.7 60.4 = 41.6

120 97.4 * 143.7 73.8 = 20.0 248.6 = w.3

150 155.Y * 71.7 37+.5 2 251.2 226.8 * 152.6

146 273.3 2 242.5 127.4 ? 129.7 146.4 * a3.4

140 156.4 * 143.0 79,6 2 41.? 122.2 * 107.9

128 94.0 z 73.6 2M.3 = 140.9 203.1 t 205.6

m7 W.ff = 81.1 66.1 * 5+.0 103,5 = 36.4

215 125.2 * 133.5 160.8 * 1+2.9 2S8.4 % 227.8

214 315.3 + 256.9 103.6 = 76.0 157.6 = 138.5

137.9 * 39.7 137.2 = 31.6 163.8 = 2S7
134

FLIGHT RESEARCH PROGRAM: XIV. LOSS OF BINOCULAR

respect to age, experience, and eye dominance are pre.

sented in Table IV, Longitudinal miss distances from

Table I rearranged with respect to dominance are presented in Table V. The average performance with the

dominant eye patched is seen to be almost identical to

the average performance with the non-dominant eye

patched. Again, the monocular performance appears

slightly superior to the corresponding binocular control

data but the difference was not statistically significant.

Phase II-Data obtained from the pilot studied in

Phase II are presented in Table VI along with the

standard errors observed. The average binocular performance observed is slightly better than the average

monocular performance observed, however, flights

number 3 and 4 were flown in the presence of a significant quartering tailwind which materially degrades

pilot landing performance in the T-33A. In spite of

this, statistical examination of the data ( ANOVA ) has

shown these treatments not to be significantly different.

Performance on final approach for all five flights

studied is presented in Figure 7. The striking similarity to the data presented in Phase I is observed.

This becomes even more impressive when it is realized

that the flights were flown in markedly different wind

conditions and flight number 5 was flown four weeks

later than flight number L Finally, the data from both

phases were tested for learning effect by analysis of

variance and rank correlation but none could be demonstrated.

VISION--LEWIS & KRIER

DISCUSSION

In this study, pilots’ spot landing performance was

measured during landings with vision restricted to

monocular cues only. These data are compared with

suitable controls flown during the same flight with full

binocular vision. Landing performance judged on the

sole criteria of misses about a predetermined spot on

the runway was not significantly affected by the loss

of stereopsis. Significant differences in the techniques

chosen to accomplish these approaches have been

observed.

With the exception of the senior author, the pilot

population studied is a highly experienced group of

test pilots. The results expressed herein, therefore, are

not considered representative of even the jet pilot popuTABLE VI. AVERAGE LONGITUDINAL MISS DISTANCES IN FEET

Landing Vision (

Monocular

Flight No. (Dominant Eye Patched ) Binocular

1 1!6.3 = 1M,7

2 126.4 s 71.2

s 169.1 = 149.6

4 166.6 = 150.1

5 132.6 = !31.7

A\,crase 152.4 = 20.8 1i9.6 = 25.2

.

1400-

.

Is.oof

:

12.cQ- 0

11 .w- 0

❑

.

10.OO- 0

Fig. 6. Typical final approach performance, Phase I.

Aerospac e Medicine . September, 1969 961
135

FLIGHT RESEARCH PROGRAM : XIV. LOSS OF BINOCULAR VISION-LEWIS & KRIER

l,ca.

COMPOSITE PILOTIZa

.----RIGHT EYE PATCH

,0,00.

e-m *Arch

*W

am

?mG

: Cno .

:

. <

: se

s

lation and certainly not representative of general aviation pilots. Caution must be exercised therefore in the

widespread application of these data.

In the group studied, the results obtained have conclusively shown that the one-eyed pilot can precisely

perform the spot landing task; indeed, it would appear

that he suffers no impairment of function whatever

even immediately following the sudden loss of stereopsis. This argues strongly in favor of granting aviators,

in this experience category, full Class I flying status.

It is recognized in this regard that the experiment

reported does not treat the problem of restricted peripheral vision on the blind side. The authors have observed, however, while watching the subjects in this

experiment, that a different pattern of head motions

was used with one eye covered than those observed

while flying with normal vision. Consider also that the

peripheral visual field of a single eye is very little

different than that of two eyes except for the presence

of the nose, the cheekbones, and the supra-orbital structures. By cocking his head slightly to favor the blind

side and changing his mode of head motion, it may be

that the one-eyed pilot suffers very little loss of what

we have come to call the “functional” peripheral fieldof-view. A formal experiment designed to explore this

point will be conducted at the Flight Research Center

during 1969 and reported later.

Subjective comments were solicited from each pilot

following his flight and analyzed as part of this study.

All pilots studied were impresssd, with the difference

in perception after patching either eye. M any reported

a sensation of diminished brightness generally; most

reported” a “marked lack of confidence in their ability to

accurately judge height. Some felt their ability to

judge height was not significantly altered, but were

quite reluctant to depend on this information which

may have been responsible for the tendency to fly the

higher final approaches observed. Most pilots reported

a significant increase in workload during monocular

landings.

962 Aerospace Medicine September, 1969

Fig. 7. Combined final approach

performance, Phase II.

CONCLUSIONS

In the pilot population studied:

1. Spot landing performance in jet aircraft is not

adversely affected by the sudden total loss of vision in

either eye. This observation has important implications

with regard to aeromedical standards.

2. Significantly steeper approaches are observed during monocular landings than those observed during approaches made with normal vision. It is suggested that

the pilots' lack of confidence in their ability to accurately judge height during monocular approaches was

responsible for the steeper approaches reported.

3. Eye dominance is shown not to affect monocular

landing performance (95% level of confidence).

4. Noticeable increases in pilot workload are subjectively reported during monocular landings.

5. It is suggested that monocular pilots may not

experience significant losses in their "functional" visual

field; a definitive study is indicated.

REFERENCES

1. OCLE, K. N.: On stereoscopic depth perception. Jwrn. <o]

Exper. Pwch., 48:360, 19%.

2. O G L E, K. N.: Som’~ ~~:~s-of,:stereos~pic depth perception. ]oum. Optic.. SOc. Am.t 57.:~’8.’:l967. ~ * fi ..,,,. .,?,.,, ------- y,.:,.\\ 3. HA-, C. ‘S,: ,Interre.~tlOn” gf:. rnOqONl?r and bfi~k.r

acuities irijj~ti~~_rna~ ~~l~Of,+riJ;~guidistance judsrnent.

., iiy$~~~

: ~1958? >’w.+~ spth ‘perception In monocular

~:n,dg,b;;$-~~”g~

“5. CmIs, -P.A.

. . .2— : ;.:-:,, ,-. ~j.,~

‘,72 LrvurGs~x, ‘P’:._,. ----------

‘““”’ ‘.srnoriocrslar~ apd ~uniocular I SOC. u. ;Kingd&. 37:434447, 1937 .

=3+. ,,..: ‘

~:, >V.: Depth perception in a>.iation Jour .

#g:; 2: 1945.

C.: ‘~eha’tnhle ground in the matter of the

pilot of’ iircraft. Tr. Ophth.
136

COCKPIT NOISE INTENSITY: 15 LIGHT AIRCRAFT-TOBIAS

8. DIAJIOXD, S: Time, space and stereoscopic vision; visual tli ght safety consider~tions zt supersonic speeds. Aero.

sprrcc Jfed. 30: 1959.

9. ROSE, H. \V.: \lonocular depth perception in flying. J. Au.

Afcd., s, x952.

10. BELOSTOTSNY, Y. J{.: Clubinnoye zreniye pri dvizherrii golovoy ( Depth Perception and Head \Iovements ). Problemy

fiziologicheskoy optiki, Volume 8, 1953 ( NAS.\ n F .

11360, Xovember 1967).

11, JOXCBLOED, J.: Landing carried out by experienced avi~tors

\vith the use of one eye only. Ada Brecia iVeerfund 5:

123-125, 1935.

12. PFA~tANN, C.; Aircraft landings without binocular CUES:

A study based upon observations made irI flight h.

Jour. of PWC?I. 81: 1948.

13. PERRY, J. J., \V. H. DANA and D. C. BACON, Jn.: Flight investigation of the landing task in a jet trainer with r~

stricted fields of vie\v. NASA TN D-4018, Jwe 1967.

14. RO>IAN, J., J. J. P ERR Y, L. R. CARPEXnR, and S. .iw>z:

Flight research program: VI. Heart rate and landing

error in restricted field of view landings. Aero.rpae Jfed.

38: 1967.

15. CUSFOYLE, \v. J. Y.: Experiences of a uniocrdar pilot of

aircraft. Tr. Oplttlz. Sot. U. Kingdom 57: 1937.
137

Summary of the results of Dr. Arlene Drack's Ophthalmology Evaluation

on Captain Joseph Broker

Uncorrected Vision:

Distant vision Near vision

Right eye 20/20 20/70

Left eye 20/20 20/70

Vision wearing bifocal glasses:

Distant vision Near vision

Right eye 20/20 20/20

Left eye 20/20 20/20

Vision wearing monovision contact lenses:

Distant vision Near vision

Right eye 20/20+2 20/70

Left eye 20/30 20/20

Both 20/15-2 20/20

Worth 4 dot test

Uncorrected vision: fusion at all distances

Vision wearing bifocal glasses: fusion at all distances

Vision wearing monovision contact lenses: fusion at 3 feet, suppression of the left eye at distance

Titmus (near) stereopsis test

Uncorrected vision: 200 seconds/15 minutes of arc

Vision wearing bifocal glasses: 40 seconds/15 minutes of arc

Vision wearing monovision contact lenses: 80 seconds/15 minutes of arc

BVAT (distance) stereopsis test

Uncorrected vision: 120 degrees

Vision wearing bifocal glasses: 120 degrees

Vision wearing monovision contact lenses: 240 degrees
138

7 Mar 97

MEMORANDUM FOR THE NATIONAL TRANSPORTATION SAFETY BOARD

ATTENTION: DR. MITCH GARBER

FROM AL/AOCO

2507 Kennedy Circle

Brooks AFB TX 78235-5117

SUBJECT: Consultation Response Case # NTSB ID: NYC97MA005

1. Thank you for the opportunity to review Ibis case. This package is in response to your

inquiry in reference to case # NTSB lD: NYC97MA005; where a 48 year-old male pilot

wearing “monovision” contact lenses as his current optical correction was involved in a

landing mishap, under IMC conditions.

2. We would like to begin with a brief background on “monovision”, " Monovision" is an

optical technique of fitting presbyopic patients (who need reading glasses) with one contact

lens for distance correction, and the other lens for near correction . It is well documented in
139

the literature that on average “monovision” (MV) lenses produce a minor reduction in high

contrast visual acuity when compared with the use of full binocular distance and near

correction (BV)(l ). Clinically measured near stereoacuity (fine depth perception) can be

expected to diminish from 40 arc sec to 50 arc sec ( BV) to 80 to 100 arc sec (MV) using a

+2.00 add. Stereopsis is more sensitive to monocular blur than to simiIar amounts of

binocular blur. Sensory functions, such as contrast sensitivity and stereoacuity, are affected

most. In 1982, Larson WL, and Lachance A., published a study in reference to stereoscopic

acuity with induced refractive errors. Their findings confirm and amplify those of previous

reports because they demonstrated that stereopsis is scarcely affected when lenses are added

symmetrically. On the other hand, lens asymmetry caused a systematic reduction in

stereoacuity which was related to the amount of the imbalance(2). Clinically significant

anisometropia (the difference in correction between the eyes) is known to cause amblyopia

and decreased stereopsis, but the amount of anisometropia required to do this is usually on

the order of 1.00 D or more. Other study result indicate that considerably smaller amounts

of anisometropia may induce visual performance penalties. So, we can conclude that a

relative visual blur in one eye induced by correction imbalances leads to a decrement greater

than if both eyes are equally blurred together (4), and could be regarded as a potential

problem it’ the anisometropia is greater than 1.00 diopter or more.

3. Answering your specific questions:
140

A. How would the degradation of stereopsis associate with monovision contact lenses likely

affect the ability of this pilot to correctly assess his altitude, glide path, and descent rate,

given the prevailing conditions ?

Given the poor weather conditions, and after reviewing the submitted package, we can

summarize that all the visual cues for this landing were minimal putting them in a

visually deprived environment. Stereopsis would be decreased somewhat by monovision

and other gross depth perception cues would also be minimal such as perspective straight

ahead (couldn’t see the end of the runway). More gross peripheral or side cues such as

motion paraIIax were also compromised being obscured by rain. Thus, they were in an

extremely visually deprived environment where the loss of any critical visual

performance ability, such as stereopsis (binocularity) would be more critical to bolster the

sparse monocular cues. This assumes that the mishap pilot had normal stereopsis to

begin with, which is an important issue in this case. In MV, there may be some residual

fine stereopsis, but for the reasons stated above it will be somewhat decreased. Thus, his

overall ability to judge depth based cues would be decreased over normal binocular

function. Other situational factors contributed to the overall degradation of the visual

scene: poor visibility. recentered approach to the runway, so that if the instrument

approach was not within parameters, then the 10SS of stereopsis might contribute to 10SS of

visual performance and increased reaction times at a time when it least could be afforded.

In other words, others will need to judge the approach mechanics to determine if it was

salvageable even with perfect capabilities. and if it was, then monovision effects certainly
141

degraded his visual performance over a normal pilot in this case and in our opinion,

further degraded the situation. Stereopsis would have been helpful under such conditions.

We consulted an active duty USAF senior pilot to help us in the interpretation of the

printout from the Flight Data Recorder. In his opinion, this was a classic example of

“duck under" on instrument approach. He was unable to determine the technical impact

of the optical correction related to this case, but he agreed a pilot would have needed all

of his normal depth perception and vision skills during this potentially unsalvageable

landing scenario, regardless of vision status. He agreed that other possible contributing

factors incIuded: the weather, diminished visual cues, flying over water, sparse

peripheral visual cues, visibility, etc. He also added that the approach itself would need

to be questioned by competent authorities as to whether it was recoverable or not, even

before the visual cues would enter into the picture, meaning that once a decision to land

was made, compromised vision and stereopsis didn’t help.

B. How long might it take for this pilot, wearing his contact lenses, to clearly change his

focus from the instrument panel to the runway. considering visual blur and any potential

deformation of the lens of the dominant eye due to prolonged accommodation while in

instrument flight?

Presbyopes (1) with remaining accommodative function might be expected to experience

some confusion between the accommodation system and MV conditions, particularly in

the intermediate viewing range. In theory, MV patients with reading add powers less than

2 D, should be able to control accommodation to maintain clear vision in the distant eye
142

from the nearpoint to optical infinity. In 1988 (5) Schor C. and Erickson P., studied the

patterns of binocular suppression and accommodation in monovision. They found that

some subjects wearing MV lenses were able to retain a clearly perceived binocular image

continuously throughout both monocular ranges of clear vision. Others achieved this

only when the initial object position was in the range of clear vision of the nondominant

eye. These results suggest that most presbyopes are well equipped to coordinate

accommodation with target distance changes under less critical but typical real viewing

conditions.

As we all know, accommodation time increases with age. If he was in monovision mode

(if properly fit) his accommodation / disaccommodation times would be shorter, since

one eye is instantly available for near (w/o accomodating and one is instantly available

for distance.

C. Would the use of MV lenses render this pilot particularly susceptible to any common

visual illusions, such as aerial perspective or size constancy?

We believe, based on AOCO experience, that monovision does not cause true visual

illusions. However, it does compromise the quality of the overall visual scene and

binocular function. We know that the blurred view for distance in the CL wearing “near”

eye interfere with the overall perception of the distant scene in the uncorrected other eye,

such that the scene becomes clearer by “shutting” the MV eye. This occurs across the

entire contrast spectrum. The potential effects of MV correction during driving or flying
143

activities are of concern. Deficits of visual acuity and contrast sensitivity during MV

(especially when the conditions are near threshold) may reduce targte identification,

“Ghosting”, which can be present in MV is attributed to incomplete suppression of the

interocular blur. If this should be present, these secondary images can be distracting. The

ability to suppress the blur may improve with adaptation, but performance levels

equivalent to those with normal binocular vision may never be achieved. This in

combination with acute disturbances in steropsis, is why the USAF does not recommend

this approach to correct presbyopic aircrew.

D. How would the use of MV Ienses affect the ability of this pilot to accurately see and

interpret cockpit instruments?

For the same reasons expressed above, it is our believe that MV would probably not

interfere with the perception and interpretation of the near scene (the cockpit).

E. How do you feel that the issue of differing near and distant visual acuity can be most

safely handled in the pilot population?

Throughout aviation history, the near and distance visual acuity issue is not a new one

and has become even more of a problem, especially in the military, as older aircrew

continue to want to fly high performance aircraft. It is less of a problem in commercial

aircraft. It is the position of the USAF that bifocals cheaply, safely, and easily correct the

most of the functional problems associated with presbyopia Up to the age of 50 years, and

trifocals possibly are more helpful above that age. In some cases. an additional add on
144

the top of the lens the so-called “double D“ add, maybe useful in the commercial cockpit

Furthermore, although progressives adds are not authorized in military aircraft because of

blurred images inferotemporally, and nasally, coordination of eye/head movements,

adaptability issues, and cost, the commercial or equivalent military cockpit is a much

more friendlier environment for their use. Bifocal contacts and particularly monovision

scenarios are not allowed. Obviously, all corrective lenses should be fitted to both eyes in

such a way that they are not interfering with normal binocularity.

F. What is the Air Force policy on MV lenses in pilots and what is the basis for that policy?

Because of the above already expressed and other reasons. the current Air Force policy in

reference to MV lenses for aircrew, mitigates strongIy against monovision and bifocal

contact lenses.

REFERENCES:

1. Erickson P., Schor. C. Visual Function With Presbyopic Contact Lens Correction.

Optometry andVision Science. Vol. 67, No. 1, pp. 22-28, Sept 1989.

2. Larson, WL., Lachance. A. Stereoscopic Acuity with Induced Refractive Errors. American

Journal of Optometry& Physiological Optics, Vol. 60, No. 6, pp. 509-513. Nov 1982.

3. Peters, HB. The Influence of Anisometropia on StereoSensitivity. Special American

Academy of Optometry Report. American Journal of Optometry, pp. 120-123, Feb 1969.
145

4. Wetheimer, G., Mckee, SP. Stereoscopic Acuity With Defocused and Spatially Filtered

Retinal Images, J.Opt. Sot. Am.,Vol.70. No.7, July 1980.

5. Schor, C., Erickson, P. Patterns Of Binocular Suppression and Accommodation In

Monovision. Am. J. Optom Physiol Opt., 1988:65:853-861.

Staff Ophthalmologist

THOMAS J. TREDICI, M.D.

Senior Scientist

DOUGLAS J. IVAN, Col, USAF. MC, CFS

Chief, Ophthalmology Branch
146

Nature has her way of reminding us that time is

passing. One of the most common signs of growing

older is when it becomes difficult to focus clearly

on objects close to you. This usually means it’s time

to wear bifocals or reading glasses.

When you reach the age for bifocals, you can reach

for Acuvuc for Monovision. Monovision is a contact

lens fitting technique that lets you see clearly both

near and far. Acuvuc gives you the added convenience

of disposable contact lenses.

Whether you've already joined the millions of adults

who have trouble seeing near, or you’re headed in

that direction, you can look forward to the freedom

of reading and other close-up activities without the

bother of bifocals.

The easier way to see near and far.

Monovision is a different vision correction system

than bifocal contact lenscs and doctors have used

it for years. With Monovision, your contact lenses

let you see clearly from near and far effortlessly

If you currently wear bifocals or reading glasses,

Acuvue for Monoviaion frees you from the nuisances

associated with them. Your field of vision is greater,

because there are no eyeglass frames interrupting

your peripheral vision. Acuvue also means no more

glasses to put on and take off, misplace or lose.

And you won’t have glasses sliding down your nose.

Or fogging up.

Disposable ContactsThat F,., ~oN:;;;g; Can I)isp(
147

The better way to wear contact lenses.

If you’ve beenwearingordinary contact lenses, Acuvue

Disposable Contact Lenses give you extra convenience. Just wear a pair of Acuvue for up to a week and

throw them away.Then replace them with a fresh;

new pair. There’s no cleaning. No messy solutions. And

no lost or damaged lens emergencies.

Monovision can also be used with Acuvue contact

lenses fit for daily wear use. With a daily wear schedule, it is recommended that you replace the lenses

every two weeks, and your eye doctor may simplify

your cleaning and disinfecting regimen by deciding

that enzymatic cleaning can be eliminated altogether.

What’smore, by replacing your lenses frequently

there’s no discomfort from long-term deposit buildup.

No wonder Acuvue is the contain lens doctors

prescribe-and wear-the most.

Ask your eyecare professional if Acuvue for Monovision

is right for you. If it is, you can start with a Free Trial

pair* Then you can finally say bye-bye to bifocals and

the hassles that go with them !

*Professional exam fees not included

~se Of Bifocals.
148

APPENDIX E—WEATHER INFORMATION

NATIONAL TRANSPORTATION SAFETY BOARD

Office of Aviation Safety

Washington D.C. 2059 4

Meteorological Factual Report

NYC97MAO05

February 13, 1997

A. ACCIDENT

Location: La Guardia Airport, Flushing, New York [KLGA]

Date: October 19, 1996

Time: 2038 UTC

Aircraft: McDonnell Douglas MD-88, N914DL, Delta Air Lines

Flight 554 [DAL 554].

B. WEATHER GROUP

Chairman: Gregory D. Salottolo, National Transportation

Safety Board, Washington D.C.

Member: Arlan D. Ellmaker, Manager Meteorology, Delta

Air Lines, Inc., Atlanta, Georgia.

Member: James P. Johnson, Air Line Pilots Association,

Glenview, Illinois.

c. DETAILS OF INVESTIGATIO N

Note in the report all times Coordinated Universal Time

(UTC) based on the 24 hour clock unless noted. All heights above

mean sea level (MSL) unless noted. Heights in surface weather observations and terminal forecast above ground level (AGL) . All

directions with reference to true north unless noted. Z = Coordinated Universal Time. All distances in statute miles unless

noted. Eastern Daylight Time (EDT) = Z - 4 hours. McIDAS - Man

computer Interactive Data AccessSystem.McIDAS is an interactive

meteorological analysis and data management computer system. McIDAS

is administered by personnel at the Space Science and Engineering

Center at the University of Wisconsin at Madison. Data are accessed

and analyzed on an IBM Ps/2 Model 77 Computer.

*t&f~’ At I I’&[-L.i’(’: til(;<Li @.i”lc4LtlkTu i@> al~e GV[:LICL2(C: L:C’+14.

~L~k>[.[ ~LCf~~S~$p~=~~ft~~$i~nlL’~ C\L~(~~~\ ‘~~?’i-tL’5 4~~’i”i(t’x
149

The 21OOZ National Weather service (NWS) Surface Analysis showed

a low pressure center in central New Jersey with a weak occluded

front extending to the east and southeast. Strong easterly winds

and rain were noted to the north and northeast of the low

pressure center (See Attachment 1) .

Surface Weather Observation s

An Automated Surface Observing System(ASOS) was installed at

KLGA. The ASOS data is edited and augmented by a certified

weather observer from Weather Experts Inc. The weather office 1S

located on the third floor of the Marine Air Terminal which is

located about 3,700 feet southwest of the approach end of runway

13. The following observations are for KLGA (See Attachments 2,

3,4):

2027Z . . Special . . Winds 080 degrees at 14 knots; visibility 3/4

mile; heavy rain; mist; ceiling 800 feet broken, 1,300 feet

overcast; temperature 14 degrees C; dew point 14 degrees C;

altimeter setting 29.49 inches of Hg.; tower visibility 2 1/2

miles; pressure falling rapidly; runway 04 visual range 4,000

variable 4,500 feet; cumulative precipitation sensor inoperative.

2034Z . . Special . . Winds 090 degrees at 12 knots; visibility 1/2

mile; heavy rain; fog; ceiling 800 feet broken, 1,100 feet

broken, 1,900 feet overcast; temperature 14 degrees C; dew point

14 degrees C; altimeter setting 29.50 inches of Hg.; tower visibility 2 1/2 miles;pressure falling rapidly; runway 04

runway visual range 4,000 to 4,500 feet;cumulative precipitation

sensor inoperative.

2051Z . . Winds 070 degrees at 13 knots; visibility 1 mile; heavy

rain; mist; ceiling 800 feet broken, 1,100 feet broken, 1,900

feet overcast; temperature 14 degrees C; dew point 14 degrees C;

altimeter setting 29.50 inches of Hg.; tower visibility 2 1/2

miles; pressure falling rapidly; runway 04 runway visual range

4,000 to 5,OOO feet; cumulative precipitation sensor inoperative.

According to the Weather Observer on duty at the time of the

accident all equipment with the exception of the cumulative

precipitation sensor was operating. All observations were

transmitted to the tower within 30 seconds of the observation

time. The Weather Observer also indicated that he called the

tower to notify tower personnel of these observations.

The following wind, present weather, and visibility information is from the 5 minute ASOS data:
150

2025Z . . 080 degrees at 17 knots . . Heavy rain . . 1 1/4 miles

2030Z . . 090 degrees at 14 knots . . Heavy rain . . 3/4 mile

2035Z . . 090 degrees at 11 knots . . Heavy rain . . 1/2 mile

2040Z . . 060 degrees at 16 knots . . Heavy rain . . 1/2 mile

2045Z . . 060 degrees at 16 knots . . Heavy rain . . 3/4 mile

The following is from the 1 minute ASOS enqineerinq data (See

Attachments 5 and 6) :

Time . . UTC.

VIS1 . . 1 minute average

VIS2 . . 1 minute average

VIS3 . . 1 minute average

WDIR . . 2 minute average

WSP . . 2 minute average

GDIR . . Maximum 5 second

GSP . . Maximum 5 second

visibility statute miles sensor 1.

visibility statute miles sensor 2.

visibility statute miles sensor 3.

wind direction degrees.

wind speed knots.

average wind direction degrees.

average wind speed knots.

Visibility (VIS) in statute miles is calculated using the

following formula: (3 / Extinction Coefficient [kilometers]) X

0.621371 statute mile per kilometer [National Weather Service,

September 1995] .

Time VIS1 VIS2 VIS3 WDIR WSP GDIR GS P

2030 .55 .79 .87 087 14 093 16

2031 .59 83 .78 090 14 092 17

2032 .58 .88 .77 092 14 100 14

2033 . 5 2 . 8 5 . 8 0 093 13 089 13

2034 . 4 1 . 8 5 . 6 3 091 12 089 13

203 5 . 4 4 . 7 9 . 5 7 090 11 097 12

203 6 . 4 0 . 7 7 . 6 0 084 11 077 12

203 7 . 4 7 . 7 7 . 5 8 077 12 064 15

2038 . 4 9 . 7 3 62 071 14 054 15

203 9 . 5 7 . 6 9 : 5 2 0 6 5 1 5 063 18

204 0 . 8 2 . 9 3 062 16 066 18

Wx . . Present weather.

PRESS1 . . Pressure inches of Hg. from pressure sensor 1. PRESS2 . . Pressure inches of Hg. from pressure sensor 2. PRESS3 . . Pressure inches of Hg. from pressure sensor 3. Pressure sensors are located in the weather office.

T . . Temperature degrees F.

TD . . Dew point temperature degrees F.
151

2038 R+ 29.44 7 29.44 1 29.44 8 58 58

203 9 R+ 29.445 29.439 29.446 58 58

2040 R+ 29.445 29.438 29.446 58 58

* From data printout.

ASOS Sensor Locations

Two visibility sensors (VIS1 and VIS3) are located about

1,480 feet southwest of the approach end of runway 13.

The third visibility sensor (VIS2) is located about 1,850

feet east of the approach end of runway 13.

The wind, temperature, and dew point sensors are located

about 1,480 feet southwest of the approach end of runway 13.

TWO ceilometers are located about 1,480 feet southwest of

the approach end of runway 13. A third ceilometer is located

about 1,850 feet east of the approach end of runway 13.

A review of the METAR (Aviation Routine Weather Report)/ SPECI

(Special Weather Report) reports, 5-minute ASOS observations,

l-minute archive ASOS engineering data, and the ASOS maintenance

log was made at the request of the NTSB by the National Weather

Service. The following are summarized excerpts from the National

Weather Service report dated December 27, 1996.

During the time period 1949Z to 2059Z all of the sensors were

operational and the following sensors were in automatic mode of

operation: ambient/dew point temperature; precipitation

identification; wind speed and direction; and precipitation

accumulation gauge. Heavy rain was reported during this time

period but the precipitation gauge did not provide any’

accumulations . Therefore, ASOS placed a Maintenance Indicator

sign ($) and a PNO (precipitation amount not available) at the

end of the reports and observations. There were edit actions

taken by the observer during this period where the sky condition,

visibility, and precipitation accumulations were backed–up for

unrepresentativeness. The observer also provided augmentation for

Runway Visual Range (RVR) information. With the exception of the rain gauge, ASOS appears to be operating normally.

Rain Gauge Recor d

The amount of rain estimated from the rain gauge record for the

time period 2030Z to 2045Z was 0.09 inch ( rainfall rate 0.36

inch per hour) . The rain gauge is located on the roof of the

Marine Terminal Building (See Attachments 7 and 8).
152

National Weather Service Observing Handbook No. 7 Part 1 defines

heavy rain as rain occurring at a rate of more than 0.30 inch per

hour; more than 0.03 inch in 6 minutes.

Runway Visual Range (RVR)

RVR for the Runway 13 Touchdown was estimated from a plot of

transmittance for the Runway 13 transmissometer obtained from the

Federal Aviation Administration (FAA) . According to the FAA

[memo from the Manager of the Airways Facilities Division to the

Manager of the Recommendations and Quality Assurance Division,

dated November 22, 1996] one transmissometer serves as both the

runway 13 and runway 22 touchdown RVR. When it became desirable

to have RVR for runway 13 touchdown, it was determined that the

transmissometer, as sited, could also serve runway 13. Readings

would be valid if the runway 13 edge lights were set equal to, or

higher than runway 22. To accomplish this a comparator circuit

was devised. Since this transmissometer is correctly sited for

both touchdowns, the one recording is acceptable for both

runways. The following values were obtained from the plot of

transmittance:

Runway 13 Touchdown

Chart Time Transmittance % RVR Feet

2030Z 78 3,500

2035Z 75 3,000

2040Z 80 3,500

The minimum value of transmittance for the chart time period

2030Z to 2040Z inclusive was 72%. This results in a RVR of 2,800

feet. The minimum value occurred at a chart time of about 2037Z.

Runway 04 Touchdown

Chart Time Transmittance % RVR Feet

2030 85 4,500

2035 85 4,500

2040 84 4,500

The minimum value of transmittance for the chart time period

2030Z to 2040Z inclusive was 79%. This results in a RVR of 3,500

feet. The minimum value occurred at a chart time of about 2039Z.

Note: Light Setting 5, Day Conditions, Tasker 500, Baseline 250

feet.

Runway 13 Touchdown

LS3 . . Light Setting 3 . . Day Conditions

LS4 . . Light Setting 4 . . Day Conditions
153

Chart Time Transmittance % RVR LS3

2030

RVR LS4

78

2035

3,000 3,000

75

2037

2,600 2,600

72 2,200

2040

2,200

80 3,500 3,500

Attachment 9 . . Plot of Transmittance Runway 13 Touchdown.

Attachment 10 . . Plot of Transmittance Runway 04 Touchdown.

Attachment 11 . . Conversion Table Transmittance to RVR LS5.

Attachment 12 . . Conversion Table Transmittance to RVR LS3 and

LS4 .

According to the FAA [reference above 11/22/96 memo] the

transmissorneter at the approach end of runway 31 was installed to

provide departure minimums for that runway. The equipment was

designated as runway 13 rollout to simplify paperwork since there

was no runway 31 identifier when the RVR was installed. Runway 13

is a Category I and has no “rollout” RVR.

According to the FAA there is no plot of transmittance for the

runway 31 transmissometer ( Telephone conversation FAA Eastern

Region 12/16/96).

14 CFR 91.175(h) . . .

Comparable values of ground visibility and RVR . .

RVR Visibility (statute miles)

1,600 1/4

2,400 1/2

3,200 5/8

4,000 3/4

4,500 7/8

5,000 1

6,000 1 1/4

Low Level Wind Shear Alert System (LLWAS)

A Phase I I LLWAS was installed and operational at KLGA at the

time of the accident. The KLGA LLWAS consists of 6 wind sensors.

One wind sensor is located near the center of the airport and 5

wind sensors are placed in locations surrounding the airport (See

Attachment 13) . Alerts are generated for the following sectors:

centerfield, northeast, southeast, southwest, and northwest.

According to an individual at MIT Lincoln Laboratories, in the

Phase II LLWAS there are station, triangle, and edge alerts. The

Phase II LLWAS is designed to issue a station alert if there is

an indication of an anomalous wind at any sensor. In the Phase II

LLWAS the test for an anomalous wind is that the sensor wind

differ from the network mean by a statistically and operationally

significant amount. This test requires at least a 15 knot vector

difference, and may require a larger difference if the winds on
154

the network have a recent history of severe gustiness. For the

Phase II LLWAS four consecutive station alerts are required

before a wind shear alert is issued (there are ten seconds

between polls for the Phase 11 LLWAS). The Phase II LLWAS also

estimates wind field divergence on all triangles and edges of

reasonable size that can be formed by locations of the sensors.

If excessive divergence is detected for four consecutive polls a

wind shear alert is issued. Because of the small number of

sensors most Phase II LLWAS alerts are based on station alerts.

When an alert status is detected at a station, edge, or triangle,

a sector alert is issued. The Phase II LLWAS has a 7 percent

chance that an issued alert is false (93 percent chance that an

alert is valid) . According to an individual who was associated

with the LLWAS program “ This system, if it does issue an alert,

it should be taken seriously.” The precise location of a wind

shear event at an airport can not be accurately determined by a

Phase II LLWAS. Therefore, a Phase 11 LLWAS sector alert should

be interpreted as indicating a possible hazardous wind shear not

necessarily confined to a particular location (sector) but

possible at any location on the airport.

The following information was obtained from LLWAS data provided

by the FAA on October 22, 1996.

Northwest (NW) wind sensor data and Center Field Average (CFA)

wind data. . Wind = Wind Direction Degrees Magnetic / Wind Speed

knots.

The Northwest Wind Sensor is located about 5,468 feet northwest

of the approach end of runway 13.

Time

20:36:56

20:37:06

20:37:16

20:37:26

20:37:36

20:37:46

20:37:56

20:38:06

20:38:16

20:38:26

20:38:36

20:38:46

20:38:56

20:39:06

Wind (NW)

070/09

080/08

080/08

080/08

080/12

080/13

080/12

090/14

080/16

080/14

080/13

080/14

080/14

080/15

CFA Wind

100/11

100/11

100/11

090/12

090/12

090/12

090/12

090/13

090/13

090/13

090/14

090/14

090/14

090/14

No gusts were reported from 20:OO:06Z to 20:49:56Z inclusive.

No system alarms were noted from 20:00:06Z to 20:49:56Z

inclusive .
155

LLWAS data are contained in Attachments 14,15,16.

WSR-88D data from Upton, New York (KOKX)

The following estimated winds for 20402 are from the KOKX WSR-88D

Velocity Azimuth Display Vertical Wind Profile ( Product time

21342) (See Attachment 17):

Height Wind [Direction degrees / Speed Knots]

1,000 083/60

2,000 090/65

3,000 105/70

4,000 108/70

5,000 109/65

A meteorologist at the NWS Forecast Office at Upton, New York was

interviewed by phone on October 22, 1996. The following is a

summary of the interview:

A WSR-88D image for 20402 at the .5 degree elevation scan was

reviewed. At KLGA the beam height is at about 4,500 feet. The

reflectivity image indicated heavy showers a few miles south of

KLGA. Radial Velocities were 26 knots northeast of KLGA and 45

knots southwest of airport. A WSR-88D horizontal shear

calculation indicated 10 knots per 2 nautical miles in the area

of KLGA. A mesocyclone signature or significant shear was not

seen. For a beam height near 9,000 feet velocities of 22 to 30

knots south of KLGA and 40 to 50 knots north of KLGA were noted.

A WSR-88D horizontal shear calculation showed 10 knots per 2.5

nautical miles. The meteorologist commented that he saw nothing

real significant in these data. He saw no signatures of rotation

and the data indicated all targets moving away from radar. He

also commented that the WSR-88D did not identify anything in the

area that met “storm” criteria. Spectrum Width values in the area were 8 to 12 knots. The meteorologist stated that the 10/20/0000Z

upper air observation was not available because of equipment

failure and the strong winds.

Review of KOKX WSR-88D Data

An Archive Level II doppler weather radar tape from the Upton,

New York (KOKX) WSR-88D doppler weather radar was obtained from

the National Climatic Data Center in Asheville, North Carolina.

The data on the tape were reviewed on a Hewlett Packard X-Station

using Motif Interactive Radar Analysis Software (Motif-IRAS) .

Reference : Priegnitz, D.L., 1995 : IRAS: Software to

display and analyze WSR-88D radar data, Eleventh
156

International Conference on Interactive Information and

Processing for Meteorology, oceanography, and Hydrology,

Boston, American Meteorological Society, 197-199.

The approach end of runway 13 at KLGA is located about 265

degrees at 46 nautical miles from KOKX. At a radar elevation

angle of .48 degrees the center of the beam at the approach end

of runway 13 is at a height of about 3,943 feet. The beam width

is about 4,635 feet.

Attachments 18 and 19 are Plan Position Indicator (PPI)

Motif–IRAS KOKX WSR–88D Radar Reflectivity Images for the times

of 2034:16Z and 2040:08Z. The images are color enhanced. The

color bar at the bottom corresponds to radar reflectivities in

dBZ. Range rings are every 10 kilometers and the azimuth interval

is 5 degrees. True north is to the top. The overlay is centered

at the approximate location of the approach end of runway 13 at

KLGA. The elevation angle is .48 degrees.

Attachments 20 and 21 are Constant Altitude PPI (CAPPI)

Motif–IRAS KOKX WSR-88D Radar Reflectivity Images for the times

of 2034:162 and 2040:08Z. The images are color enhanced. The

color bar at the bottom corresponds to radar reflectivities in

dBZ. Range rings are every 10 kilometers and the azimuth interval

is 5 degrees. True north is to the top. The overlay is centered

at the approximate location of the approach end of runway 13 at

KLGA. Altitudes are in kilometers (km) . The elevation angle IS

.48 degrees.

Values of radar reflectivity in dBZ, radial velocity [VR] in

meters per second, and spectrum width [SW] in meters per secon d

were generated using Motif-lRAS. Values are noted in the

following Table :

DIST . . Distance in kilometers from approach end of runway 13 at

KLGA (along 310 degrees true radial).

dBZl . . Radar reflectivity in dBZ for 2034:16Z.

dBz2 . . Radar reflectivity in dBZ for 2040:08Z.

VR1 . . Radial velocity (easterly component) in meters per second

for 2034:16Z.

VR2 . . Radial velocity (easterly component) in meters per second

for 2040:08Z.

SW1 . . Spectrum width in meters per second for 2034:16Z.

SW2 . . Spectrum width in meters per second for 2040:08Z
157

dBZl maximum and minimum values = 48.0 dBZ and 37.5 dBZ. Rainfall

rates corresponding to the above dBZ values are 1.79 and 0.29

inches per hour respectively. Liquid water contents corresponding

to the above dBZ values are 1.90 and .48 grams per cubic meter.

dBZ2 maximum and minimum values = 44.5 dBZ and 34.5 dBZ, Rainfall

rates corresponding to the above dBz values are 0.93 and 0.18

inches per hour respectively. Liquid water contents corresponding to the above dBZ values are 1.20 and 0.32 grams per cubic meter.

dBZ1 at approach end of runway 13 = 47.5 dBZ. This corresponds to

a rainfall rate of 1.52 inches per hour and a liquid water

content of 1.78 grams per cubic meter.

dBZ2 at approach end of runway 13 = 44.0 dBZ. This corresponds to

a rainfall rate of 0.93 inches per hour and a liquid water

content of 1.12 grams per cubic meter.

Liquid water content calculated using M = 3.44X10-3Z”5714

( Greene

and Clark; Monthly Weather Review; July 1972) .

M = Liquid Water Content grams per cubic meter.

Z = Weather radar reflectivity millimeters to the sixth power

divided by meters cubed (Z = 10dBz’lO).

Rainfall rate calculated using R = (2/300)-714 ( Federal

Meteorological Handbook Number 11; June 1990; Chapter 5) .

R = Rainfall Rate in millimeters per hour.

Z = Weather radar reflectivity millimeters to the sixth power

divided by meters cubed (Z = 10dgz’lO).

VIP/DBZ Conversion Table

NWS VIP . . . National Weather Service Video Integrator and Processor

Level. .

WSR-88D LVL . . . WSR-88D Doppler Weather Radar Level.

PREC MODE dBZ . . . Precipitation Mode dBZ.

RAINFALL . . Rainfall in inches per hour.

WSR-88D LVL PREC MODE DBZ RAINFALL

o <5

1 5t0 9

2 10 to 14

3 15 to 19 .01 in/hr

20 to 24 .02 in/hr

5 25 to 29 .04 in/hr

6 30 to 34 .09 in/hr
158

Strong

4 9 45 to 49 1.10 in/hr

Very Strong

5 10 50 to 54 2.49 in/hr

Intense

6 11 55 to 59 >5.67 in/hr

Extreme 12 60 to 64

13 65 to 69

14 70 to 7 4

15 GTE 75

Satellite Data

Geostationary Operational Environmental Satellite (GOES) 8 Data

were reviewed on the Safety Board's McIDAS Workstation. Images

for Bands 1,2,3,4 were generated.

Attachments 22 and 23 . . GOES visible images (Band = 1) for 20322

and 20452; 1 kilometer resolution; cross box = location of KLGA;

images are contrast stretched. The 20452 image shows convection

in the area of KLGA.

Attachments 24 and 25 . . GOES infrared images (Band = 2) for

20322 and 2045Z; 4 kilometer resolution; cross box = location of

KLGA; images are color enhanced using the Color Enhancement Table

ICE4 .

Attachments 26 and 27 . . GOES infrared images (Band = 3) for 20322 and 2045Z; 8 kilometer resolution; cross box = location of

KLGA; images are contrast stretched.

Attachment 28 and 28A . . GOES infrared images (Band = 4) for

2032Z and 20452; 4 kilometer resolution; cross box = location of

KLGA; images are color enhanced using Color Enhancement Table

ICE4. Displaying these images in succession on a video monitor

(looping) shows cloud movement to the northwest. Radiative

temperatures (cloud top temperatures) at KLGA for 2032Z and 20452

are about -34.2 and -36.2 degrees C respectively. Using upper air

data from Albany, New York for October 20 at 0000Z, radiative

temperatures of -34.2 and -36.2 degrees C result in cloud tops

near 29,000 feet. See Attachment 28B.

Color Enhancement Table ICE4
159

Segment

1

2

3

4

5

6

7

8

9

# Temperature (degrees C)

-.7 to -2.7

-3.2 to -15.2

-15.7 to -31.2

-32.2 to -41.2

-42.2 to -52.2

-53.2 to -58.2

-59.2 to -62.2

-63.2 to -80.2

-81.2 to -109.2

(degrees K)

272.5 to 270.5

270.0 to 258.0

257.5 to 242.0

241.0 to 232.0

231.0 to 221.0

220.0 to 215.0

214.0 to 211.0

210.0 to 193.0

192.0 to 164.0

Upper Air Data

Upper air data from Albany, New York for October 20, 1996 at

0000Z is as follows:

LEVEL. . .Height Millibars

TEMP . . .Temperature Degrees C

DEW PT.. .Dew Point Temperature Degrees C

DIR. . .Wind Direction Degrees True

SPEED. . .Wind Speed Meters per Second

HEIGHT . ..Height Meters Above Mean Sea Level

Albany is located about 119 nautical miles north of KLGA.

STATION:72518 DAY/TIME:96294 000000 LAT/LoNG:427500 737999

LEVEL

1000.0

984.0

974.5

939.2

925.0

905.0

871.7

850.0

840.0

837.0

833.0

825.0

821.0

808.9

779.3

769.0

760.0

750.7

746.0

723.1

720.0

700.0

690.0

TEMP

11.6

10.6

9.9

7.1

6.0

5.1

3.5

2.4

3.0

3.0

3.6

5.8

6.8

6.5

5.8

5.6

4.8

4.1

3.8

1.5

1.2

0.4

0.0

DEW PT

6.6

3.6

3.7

3.9

4.0

3.4

2.3

$::

-5.0

-6.4

-19.2

-18.2

-17.3

-15.2

-14.4

-14.2

-8.3

-5.2

-5.7

-5.8

-9.6

-9.0

DIR

70.0

66.9

65.0

75.0

75.0

85.0

100.0

105.0

108.6

109.6

111.1

114.0

115.5

120.0

120.0

120.0

120.0

120.0

120.0

120.0

120.0

120.0

120.0

SPEED

8.2

12.7

15.4

16.4

16.9

18.5

22.1

24.6

25.6

25.9

26.3

27.1

27.5

28.8

29.8

29.6

29.5

29.3

29.0

27.7

27.9

29.3

31.2

HEIGHT

89.0

223.8

304.0

609.0

735.4

914.0

1219.0

1424.7

1520.7

1549.7

1588.6

1667.2

1707.1

1829.0

2134.0

2243.1

2339.2

2439.0

2490. 6

2743.0

2777.7

3004.3

3119.7
160

688.0

675.0

670.2

662.0

644.8

596.4

551.7

500.0

471.0

417.0

400.0

383.6

309.4

300.0

250.0

246.7

235.3

233.0

220.0

200.0

194.1

167.7

155.0

151.0

150.0

144.7

128.0

119.0

114.0

113.3

100.0

93.8

86.2

66.5

44.6

14.3

0.2

-0.9

-1.0

-1.3

-2.3

-5.2

-8.1

-11.7

-14.7

-20.8

-22.9

-25.3

-37.5

-39.3

-50.3

-51,0

-53.7

-54.3

-57.5

-57.7

-58.3

-61.0

-62.5

-62.7

-62.1

-61.5

–59.3

-60.6

-61.3

-61.2

-59.3

-61.3

-62.7

-58.5

-62.3

-56.7

-4.7

-1.9

-1.9

-1.9

-3.1

-6.5

-10.0

-14.4

-17.4

-23.6

-25,7

-28.6

–43.2

-45.3

-56.3

-57.0

-59.7

-60.3

-63.5

-65.7

-66.3

-69.0

-70.5

-70.7

-70.1

-69.9

–69.3

-70.6

-71.3

-71.3

-70.3

-72.3

–73.7

-70.5

-74.3

-70.7

120.0

120.0

120.0

120.0

120.0

125.0

125.0

130.0

130.0

130.0

130.0

125.0

125.0

130.0

130.0

130.0

135.0

135.0

144.5

160.0

165.0

170.0

165.0

165.0

165.0

165.0

168.1

170.0

174.4

175.0

31.5 3143.0

34.0 3295.9

34.9 3353.0

34.6 3451.4

33.9 3658.0

28.8 4268.0

24.6 4878.0

23.1 5649.3

21.6 6097.0

20.0 7012.0

21.0 7324.0

21.6 7621.0

31.3 9146.0

32.4 9365.2

36.5 10585.2

37.0 10670.0

40.6 10975.0

40.6 11037.6

35.7 11406.5

27.7 12008.4

28.2 12195.0

36.0 13109.0

24.1 13599.6

19.6 13760.9

18.5 13802.0

14.9 14024.0

11.6 14789.3

9.7 15243.0

9.3 15511.7

9.2 15548.0

16328.9

16728.1

17250.9

18866.9

21357.1

28477.9

PARCEL: DEW PT.= 277.1 POT. TEMP= 285.4 EQUIV.POT.TEMP= 300.3 MIX= 5.7

PRECIP.WATER= 19.2 CONV.TEMP= 29.6 FCST M A X= 0.0 LIFTED INDEX= 17.0

TOTALS= 27.4 EQUIL.PRES.= 771.1 K-INDEX= 5.7 SWEAT INDEX=159.8

Astronomical Data

At KLGA for a date / time of October 19, 1996 / 2038Z:

Altitude of Sun . . 15.2 degrees. Bearing to Sun . . 241.3 degrees. Altitude of Moon . . 24.5 degrees. Bearing to Moon . . 143.8 degrees. Percent Illumination of Moon . . 51 %
161

Area Forecast (FA)

Information pertinent to the investigation contained in the

National Weather Service FA (BOSC FA 191745) issued October 19 at

1745Z and valid until October 20 at 0600Z is as follows:

Southeast New York..

Clouds broken to overcast at 1,500 feet layered through Flight

Level 20,000 feet. Visibility 3 to 5 miles in light rain, mist.

Wind 070 degrees at 15 knots gusts 30 to 35 knots.

The FA was issued by the Aviation Weather Center in Kansas City,

Missouri.

An Area Forecast (FA) is a forecast of Visual Flight Rules

(VFR) clouds and weather conditions over an area as large as

the size of several states. It must be used in conjunction

with the AIRMET Sierra bulletin for the same area in order

to get a complete picture of the weather. The Area Forecast

together with the AIRMET Sierra bulletin are used to

determine forecast enroute weather and to interpolate

conditions at airports that do not have terminal forecasts.

The Area Forecast consists of a:

a) Synopsis section which is a brief summary of the location

and movement of fronts, pressure systems, and circulation

patterns for an 18 hour period.

b) VFR clouds and weather section which is a 12 hour

forecast, in broad terms, of clouds and weather significant

to flight operations plus a 6 hour categorical outlook.

Reference: Aviation Weather Center, Kansas City, Missouri.

In-Flight Weather Advisories

The following in-flight weather advisories were issued by the

Aviation Weather Center in Kansas City, Missouri:

AIRMET Tango Update 3 for Turbulence . . and Low Level Wind

Shear. .

Issued October 19 at 1345Z and valid until October 19 at 2000Z.

..See SIGMET Uniform series for severe turbulence,

Occasional moderate turbulence below Flight Level 18,000 feet [FL

180] in area of moderate to strong winds associated with surface
162

low off the New Jersey coast and strong upper trough. The area

encompassed by this AIRMET included KLGA. See Attachment 29.

Occasional moderate turbulence between FL 180 and FL 400

..associated with strong upper trough and jetstream. The area

encompassed by this AIRMET included KLGA. See Attachment 29A.

The AIRMET also noted . . Low Level Wind Shear potential over

large portion of the mid Atlantic / Southern New England States.

AIRMET Zulu Update 2 for Ice and Freezing Level..

Issued October 19 at 1345Z and valid until October 19 at 2000Z.

Occasional moderate rime or mixed icing in cloud and in

precipitation between 11,000 feet and FL 240.

Freezing level 4,000 to 6,oOO feet. The area encompassed by this

AIRMET included KLGA. See Attachment 30.

AIRMET Sierra Update 2 Correction [COR] for IFR..

Issued October 19 at 1415Z and valid until October 19 at 2000Z.

Occasional ceiling below 1,000 feet and visibility below 3 miles

in precipitation, mist, and fog. The area encompassed by this

AIRMET included KLGA. See Attachment 31.

AIRMET Tango Update 4 for Turbulence. .and LOW Level Wind Shear. .

Issued October 19 at 1945Z and valid until October 20 at 0200Z.

..See SIGMET Uniform and Whiskey Series for Severe Turbulence

Conditions. .

Occasional moderate turbulence below 15,000 feet in areas of

strong winds associated with surface low and general rough

terrain. The area encompassed by this AIRMET included KLGA. See

Attachment 32.

Occasional moderate turbulence between FL 180 and FL 380

associated with strong upper trough and shear zones aloft. The

area encompassed by this AIRMET included KLGA. See Attachment 33.

The AIRMET also noted LOW Level Wind shear potential over a

number of states including Southeastern New York.

AIRMET Zulu Update 3 for Ice and Freezing Level..

Issued October 19 at 1945Z and valid until October 20 at 0200Z.

Occasional moderate rime or mixed icing in cloud and in

precipitation between 11,000 feet and FL 220. Freezing level

sloping upward 8,000 to 10,000 feet northeast of an Atlantic

City, New Jersey [ACY] to Syracuse, New york [SYR] line. The area

encompassed by this AIRMET included KLGA. See Attachment 34.
163

AIRMET Sierra Update 3 for IFR. .

Issued October 19 at 1945Z and valid until October 20 at 0200Z.

Ceiling below 1,000 feet and visibility below 3 miles in moderate

rain, mist, and fog. The area encompassed by this AIRMET included

KLGA. See Attachment 35.

SIGMET Uniform 2 issued October 19 at 1645Z and valid until

October 19 at 2045Z..

Moderate occasional severe turbulence below 16,000 feet in area

of strong winds and generally rough terrain.

KLGA was included in the area encompassed by this SIGMET. See

Attachment 36.

SIGMET Uniform 3 issued October 19 at 2000Z and valid until

October 20 at 0000Z..

Moderate occasional severe turbulence below 14,000 feet in the

area of strong winds and general rough terrain.

KLGA was included in the area encompassed by this advisory. See

Attachment 37.

SIGMET Uniform 4 issued October 19 at 2030z and valid until

October 20 at 0030Z..

Moderate occasional severe turbulence below 14,000 feet in the

area of strong winds. Low level wind shear also expected.

KLGA was included in the area encompassed by this advisory. See

Attachment 38.

AIRMETs and SIGMETS are issued by the Aviation Weather Center in

Kansas City, Missouri.

An AIRMET (AIRman’s Meteorological Information) advises of

weather that maybe hazardous other than convective activity,

to single engine, other light aircraft, and Visual Flight

Rule (VFR) pilots. However, operators of large aircraft may

also be concerned with these phenomena. The items covered

are:

In the AIRMET Sierra bulletin:

a) Ceilings less than 1,000 feet and/or visibility less than

3 miles affecting over 50% of the area at one time.

b) Extensive mountain obscuration.

In the AIRMET Tango bulletin:

a) Moderate turbulence.

b) Sustained surface winds of 30 knots or more at the

surface.
164

In the AIRMET Zulu bulletin:

a) Moderate icing.

b) Freezing levels.

AIRMETs are routinely issued for 6 hour periods beginning at

0145Z during Central Daylight Time and at 0245Z during

Central Standard Time.

References: Weather Service operations Manual Chapter D–22;

Aviation Weather Center, Kansas City, Missouri.

A SIGMET (Significant Meteorological Information) advises of

weather potentially hazardous to all aircraft other than

convective activity. In the conterminous U.S., items covered

are:

a) Severe Icing.

b) Severe or extreme turbulence or clear air turbulence not

associated with thunderstorms.

c) Widespread dust storms, sandstorms, or volcanic ash

lowering surface and/or in-flight visibility to less than 3

miles.

d) Volcanic eruption.

References: Weather Service operations Manual Chapter D–22;

Aviation Weather Center, Kansas City, Missouri.

The following Urgent Center Weather Advisory (UCWA) was issued by

the meteorologist at the New York Center Weather Service Unit:

UCWA issued October 19 at 2000Z and valid until October 19 at

2100Z. .[ZNY] UCWA 01 192000 - 192100].

Strong low level wind shear. Gain/loss up to 30 knots reported within 200 feet of the surface New York Metro area. Severe

turbulence also reported.

The area encompassed by this advisory included KLGA. See

Attachment 39.

A Center Weather Advisory (CWA) is an aviation weather

warning for conditions meeting or approaching national

In-Flight Advisory (AIRMET, SIGMET, or Convective SIGMET)

criteria. The CWA is primarily for use by air crews to

anticipate and avoid adverse weather conditions in the en

route and terminal environments. The CWA should reflect

conditions at the time of issuance and/or be a short range

forecast. CWA’s are issued by Center Weather Service Unit

Meteorologists at the Air Route Traffic Control Centers.
165

Reference: Weather Service Operations Manual Chapter D-25,

10/25/96.

Meteorological Impact Statement (MIS)

The following MIS (ZNY MIS 01 Valid 191435 to 200200) was issued

by a meteorologist at the New York Center (ZNY) Center Weather

Service Unit. The MIS was issued October 19 at 1435Z and was

valid until October 20 at 0200Z.

. . For ATC Planning Purposes Only . .

Moderate occasional severe turbulence below Flight Level 20,000

feet mainly west through southwest portions of ZNY in area of

strong winds and general rough terrain. See SIGMET Uniform 1 

valid until 1745Z. Occasional moderate turbulence remaining ZNY

including New York Metro with Low Level Wind Shear.

Frequent moderate icing in cloud and in precipitation throughout

ZNY from 9,000 to 20,000 feet.

IFR/Low IFR ceilings / visibility throughout in moderate rain

showers / heavy rain. Winds east to east-northeast 20 knots

frequent gusts to 35 to 40 knots. Winds aloft from Flight Level

2,000 to 5,OOO feet east to southeast near 50 knots with Wind

Shear potential.

A Meteorological Impact Statement (MIS) is an unscheduled

flow control and flight-operations-planning forecast. It

details weather conditions that are expected to adversely

impact the flow of air traffic in the Center Weather Service

Unit (CWSU) area of responsibility. The MIS is a forecast

and briefing product intended for those personnel at Air

Route Traffic Control Centers, the Air Traffic Control

System Command Center, and large terminal air traffic

control facilities responsible for making flow control and

flow control-related decisions. MISS are issued by National

Weather Service Meteorologists at CWSUS in the Air Route

Traffic Control Centers.

Reference: National Weather Service Operations Manual,

Chapter D-25.

Terminal Aerodrome Forecast (TAF)

The TAF for KLGA issued by he National Weather Service Forecast

Office in Upton, New York is as follows:

October 19 at 1800Z . . Winds 080 degrees at 30 knots with gusts

to 42 knots; visibility 3 miles; light rain; mist; ceiling 800

feet overcast; wind shear at 2,000 feet/wind 100 degrees at 50
166

knots.

Tempo October 19 at 1800Z to October 20 at 1200Z . . Visibility 1

mile; moderate rain; mist; ceiling 400 feet overcast.

Becoming October 20 at 1100Z to October 20 at 1200Z . . winds 060

degrees at 26 knots gusts to 36 knots; visibility 5 miles; light

rain; mist; ceiling 1,000 feet overcast.

Local Airport Advisory

A Local Airport Advisory for high winds for KLGA issued by the

National Weather Service Forecast Office in Upton, New York is as

follows:

October 19 at 1200z to October 20 at 1200Z. . . Winds from the east-northeast 20 to 30 knots with gusts to 35 to

50 knots possible/forecast during the period.

The advisory was disseminated to the weather office at KLGA at

0952z on October 19.

Flight Release Weather

The following weather information was included in the Flight

Release of DAL 554:

KLGA observation for 1651Z . . Winds 080 degrees at 23 knots gusts

to 38 knots; visibility 2 miles; moderate rain; mist; ceiling

1,200 feet broken, 1,800 feet broken, 2,200 feet overcast;

temperature 16 degrees C; dew point 14 degrees C; altimeter

setting 29.54 inches of Hg.; peak wind 070 degrees at 38 knots at

1647Z; tower visibility 2 1/2 miles; pressure falling rapidly.

Destination forecast for KLGA generated by Delta Air Lines

Meteorological Staff:

LGA Amendment 1 (AMD 01) . . 1720Z to 2200Z . .

Ceiling 600 feet broken, 1,200 feet overcast; visibility 2 miles;

light rain; fog; winds 090 degrees at 24 knots gusts to 42 knots;

occasional ceiling 400 feet overcast; visibility 1 mile; moderate

rain: fog; isolated thunderstorm.

Enroute surface weather.

Government Weather Alerts ..SIGMET Uniform 2 [see In Flight

Weather Advisory Section].

Delta Meteorological Staff Airport Alerts. .

LGA.. October 19 at 1711Z to October 20 at 0000Z . . Moderate to
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strong turbulence climb / descent below Flight Level 7,000 feet

with low level wind shear likely due easterly surface winds gusts

to 35 knots becoming westerly surface winds accompanying 2000Z to

2200Z surface frontal passage. According to a Delta Air Lines’

meteorologist strong turbulence = severe turbulence.

Delta Air Lines has a staff of 18 meteorologists and one manager.

The office is located in Atlanta, Georgia. They provide upper air

forecasts for turbulence and expected areas of thunderstorms.

Surface meteorologists provide forecasts for 14 Delta terminals.

Other terminal forecasts are provided as necessary.
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Questions to Delta Airlines and Responses

The following are answers to written questions submitted to Delta Air Lines by the NTSB

Meteorological Group Chairman:

1) QUESTION: Which National Weather Service in flight weather

advisories, AIRMETs, SIGMETs, Convective SIGMETs, and Center Weather

Advisories, are included in the Flight Release? For those advisories

not included why are they not included? What Delta Air Lines’ weather

products are included in the Flight Release?

ANSWER: All Delta flight releases include SIGMETs and Convective

SIGMETs, issued by the National Weather Service, that are pertinent to

the route of flight.

AIRMETs are not included since they are advisories issued only to

amend the area forecasts concerning weather phenomena which are

potentially hazardous to aircraft having limited capability. Center

Weather Advisories are not included since they are issued for ATC use

to alert pilots of existing or anticipated adverse weather conditions

within the next 2 hours. The information from both AIRMETs and CWAS

is reviewed by Delta’s meteorologists for possible dissemination in

the form of a DELTA AIRPORT ALERT.

Delta’s meteorologists provide terminal forecasts to selected cities.

They also provide Turbulence Alerts and Thunderstorm Alerts. Airport

Alerts for icing and low level wind shear not associated with

thunderstorms are also issued for departure, destination and alternate

airports.

2) QUESTION: Which National Weather Service in flight weather

advisories, AIRMETs, SIGMETs, Convective SIGMETs, and Center Weather

Advisories, are disseminated to Flight Crews while enroute? How are

they disseminated? For those advisories not disseminated why are they

not disseminated? What Delta Air Lines’ weather products are

disseminated to enroute flight crews? How are they disseminated?

ANSWER: All new SIGMETs or Convective SIGMETs are reviewed by the

dispatcher and if contents have changed from previous SIGMETs the

advisory will be disseminated to the flight via Radio or ACARS. The

same is true for Delta Alerts issued by the Delta Meteorologists.

3) QUESTION: Which advisories, AIRMETs, SIGMETs, Convective SIGMETs,

and Center Weather Advisories, does 14 CFR 12 1.601 require to be

provided to Flight Crews? For those advisories not requiredto be

provided to flight crews why are they not required?

ANSWER: 14 CFR 121.601 only states that prior to and during a flight

the dispatcher shall provide all available weather information that

may affect the safety of the flight.
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4) QUESTION: How does Delta Air Lines satisfy the weather

dissemination requirements of 14 CFR 121.601?

5) ANSWER: Delta Air Lines satisfies the weather dissemination

requirements of 14CFR 121.601 via the Metrology briefing message

attached to each flight release, and through the dispatcher’s use of

Radio or ACARS.

6) QUESTION: How is weather information accessed by Delta Air Lines’

meteorologists and dispatchers? How are Center Weather Advisories

accessed?

ANSWER: Weather information is accessed from the NWS via FAA

teletype circuits; DIFAX charts and via an outside vendor. The

information in turn is provided to the dispatcher thru Delta’s

computer system. Center Weather Advisories are accessed on one of the

weather circuits, located in the Metrology section.

7) QUESTION: Were the contents of the National Weather Service SIGMET

Uniform 3 (BOSU WS 192000Z) provided to the flight crew of DAL 554?

When and how was the information contained in this SIGMET provided?

If the information contained in this SIGMET was not provided to the

flight crew why was it not provided?

ANSWER: The contents of NWS SIGMET Uniform 3 were not provided to

the flight crew of DAL 554. SIGMET Uniform 3 was not provided to the

flight crew of DAL 554 since only the flight level top of possible

turbulence was changed and the valid time of SIGMET Uniform 2 included

the arrival period of DAL 554.

8) QUESTION: Were the contents of New York Center Weather Advisory 01

(ZNY1 UCWA 01 192000Z-192100Z) provided to the flight crew of DAL 554?

When and how was the information contained in the Center Weather

Advisory provided? If the Center Weather Advisory was not provided to

the flight crew why was it not provided?

ANSWER: The contents of New York Center Weather Advisory 01 were not

provided to the flight crew of DAL 554 nor to the dispatcher. Center

Weather Advisories, by definition, are issued for ATC use. The Delta

Metrologists had already issued an AIRPORT ALERT for LGA at 19/1711Z

for moderate to strong turbulence below flight level 7,000 feet with

low level wind shear likely.
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