AIRCRAFT ACCIDENT BRIEF 

NTSB/AAB-02/01 (PB2002-910401) 

EgyptAir Flight 990, Boeing 767-366ER, SU-GAP 

60 Miles South of Nantucket, Massachusetts 

October 31, 1999 

 

• Page 39 has been updated to correct a reference to left and right outboard ailerons. (27 Mar 02) 

The original statement referred to both ailerons as ìleftî. 

 

THESE CORRECTIONS ARE INCLUDED

IN THIS VERSION OF THE PUBLISHED REPORT:
Aircraft Accident Brief

EgyptAir Flight 990

Boeing 767-366ER, SU-GAP

60 Miles South of Nantucket, Massachusetts

October 31, 1999

NTSB/AAB-02/01

PB2002-910401

National Transportation Safety Board

Adopted March 13, 2002

490 L’Enfant Plaza, S.W.

Washington, D.C. 20594
National Transportation Safety Board. 2002. EgyptAir Flight 990, Boeing 767-366ER, SU-GAP, 

60 Miles South of Nantucket, Massachusetts, October 31, 1999. Aircraft Accident Brief 

NTSB/AAB-02/01. Washington, DC.

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

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

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Contents

Factual ...................................................................................................................................1

Analysis ................................................................................................................................52

Attachments

A: EgyptAir Flight 990 Cockpit Voice Recorder Transcript 

B: Response of the Egyptian Civil Aviation Authority to the Draft Report of the 

National Transportation Safety Board

NTSB/AAB-02/01

Accident Number: DCA00MA006

Operator/Flight Number: EgyptAir flight 990

Aircraft and Registration: Boeing 767-366ER, SU-GAP

Location: 60 miles south of Nantucket, Massachusetts

Date: October 31, 1999

Adopted On: March 13, 2002

FACTUAL 

On October 31, 1999, about 0152 eastern standard time (EST), EgyptAir

flight 990, a Boeing 767-366ER (767), SU-GAP, crashed into the Atlantic Ocean about

60 miles south of Nantucket, Massachusetts. EgyptAir flight 990 was being operated

under the provisions of Egyptian Civil Aviation Regulations (ECAR) Part 121 and

U.S. 14 Code of Federal Regulations Part 129 as a scheduled, international flight from

John F. Kennedy International Airport (JFK), New York, New York, to Cairo International

Airport, Cairo, Egypt.1

 The flight departed JFK about 0120, with 4 flight crewmembers,

10 flight attendants, and 203 passengers on board. All 217 people on board were killed,

and the airplane was destroyed. Visual meteorological conditions prevailed for the flight,

which operated on an instrument flight rules (IFR) flight plan.

National Transportation Safety Board

Washington, D.C. 20594

Aircraft Accident Brief

1 Under the provisions of Annex 13 to the Convention on International Civil Aviation, the investigation

of an airplane crash occurring in international waters falls under the jurisdiction of the airplaneís country of

registry (in this case, Egypt). At the request of the Egyptian Government, the National Transportation Safety

Board assumed full responsibility for the investigation. Parties to the investigation included the Federal

Aviation Administration (FAA), Boeing Aircraft Company, and Pratt & Whitney (P&W) Aircraft Engines.

The Egyptian Civil Aviation Authority (ECAA) designated an accredited representative to the investigation

on behalf of the Egyptian Government. EgyptAir provided a technical advisor to the ECAA and the

investigation. The Federal Bureau of Investigation (FBI) also assisted in the investigation. The National

Oceanic and Atmospheric Administration, U.S. Navy, and U.S. Coast Guard assisted in the search and

recovery operations.

E PLURIBUS UNUM

NATIONAL TRA S PORTATION

B OAR D

SAFE T Y

N
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NTSB/AAB-02/01

HISTORY OF FLIGHT

On October 30, 1999, the accident airplane departed Los Angeles International

Airport (LAX), Los Angeles, California, as EgyptAir flight 990, destined for Cairo, with a

scheduled intermediate stop at JFK. EgyptAir flight 990 landed at JFK about 2348 eastern

daylight time (EDT)2 and arrived at the gate about 0010 EDT on October 31, 1999.

Because of the 10-hour scheduled en route flight time from JFK to Cairo, ECAR

Part 121, Subpart Q, required that the accident flight have two designated flight crews

(each crew consisting of a captain and first officer). According to the EgyptAir flight

dispatcher who accompanied the two accident flight crews from their hotel in New York

City to the airport, they departed the hotel about 2330 EDT on October 30 and arrived at

JFK about 40 minutes later, about the same time as the airplane, inbound from LAX,

arrived at the terminal gate.

According to air traffic control (ATC) records, by 0101, the pilots of EgyptAir

flight 990 had requested, received, and correctly read back an IFR clearance from ATC.

ATC transcripts further indicated that between about 0112 and 0116, air traffic controllers

issued a series of taxi instructions to EgyptAir flight 990. At 0117:56, the pilots advised

the local controller that they were holding short of the departure runway (runway 22 right

[22R]) and that they were ready for takeoff. The local controller instructed EgyptAir

flight 990 to taxi into position and hold on runway 22R and, at 0119:22, cleared the

accident flight for takeoff. The first officer acknowledged the takeoff clearance, and, about

0120, the airplane lifted off runway 22R.

Shortly after liftoff, the pilots of EgyptAir flight 990 contacted New York Terminal

Radar Approach (and departure) Control (TRACON). New York TRACON issued a series

of climb instructions and, at 0126:04, instructed the flight to climb to flight level

(FL) 2303

 and contact New York Air Route Traffic Control Center (ARTCC). According

to ATC and cockpit voice recorder (CVR) records, at 0135:52, New York ARTCC

instructed EgyptAir flight 990 to climb to FL 330 and proceed directly to DOVEY

intersection.4

According to the CVR transcript,5 about 0140 (20 minutes after takeoff), as the

airplane was climbing to its assigned altitude, the relief first officer suggested that he

relieve the command first officer at the controls,6

 stating, ìIím not going to sleep at all. I

might come and sit for two hours, and thenÖ,î indicating that he wanted to fly his portion

of the trip at that time. The command first officer stated, ìBut IÖI slept. I slept,î and the

2 At 0200 EDT on October 31, 1999, local time in the eastern United States changed from 0200 EDT

to 0100 EST. Unless otherwise indicated, all times in this document are EST, based on a 24-hour clock. 

3 FL 230 is 23,000 feet mean sea level (msl), based on an altimeter setting of 29.92 inches of mercury.

4 This clearance resulted in EgyptAir flight 990 passing through a type of special-use airspace referred

to as a ìwarning area.î New York ARTCC and U.S. Navy records indicated that the warning area was not in

use by the U.S. Navy at the time of the accident. For additional information, see the Air Traffic Control

Group Chairmanís Factual Report and its attachments.

5 A complete, English-language transcript of the CVR is attached to this report. 
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NTSB/AAB-02/01

relief first officer stated, ìYou mean youíre not going to get up? You will get up, go and

get some rest and come back.î The command first officer then stated, ìYou should have

told me, you should have told me this, Captain [relief first officerís surname].7 You should

have said, ë[command first officerís first name]ÖI will work first.í Just leave me a

message. Now I am going to sit beside you. I mean, now, Iíll sit by you on the seat. I am

not sleepy. Take your time sleeping and when you wake up, whenever you wake up, come

back, Captain.î

The relief first officer then stated, ìIíll come either wayÖcome work the last few

hours, and thatís all.î The command first officer responded, ìNoÖthatís not the point, itís

not like that, if you want to sit here, thereís no problem.î The relief first officer stated, ìIíll

come back to you, I mean, I will eat and come back, all right?î The command first officer

responded, ìFine, look here, sir. Why donít you come so thatÖyou want them to bring

your dinner here, and Iíll go to sleep [in the cabin]?î The relief first officer stated, ìThatís

good.î The command first officer then stated to the command captain, ìWith your

permission, Captain?î

At 0140:56, the CVR recorded the sound of the cockpit door operating. About

1 second later, the command first officer stated in a soft voice, ìDo you see how he does

whatever he pleases?î At 0141:09, the command first officer stated, ìNo, he does

whatever he pleases. Some days he doesnít work at all.î At 0141:51, the CVR again

recorded the sound of the cockpit door operating. Sounds recorded during the next minute

by the CVR (including a whirring sound similar to an electric seat motor operating, a

clicking sound similar to a seat belt operating, and some conversation) indicated that the

command first officer vacated and the relief first officer moved into the first officerís seat.

Flight data recorder (FDR) and radar data indicated that the airplane leveled at its

assigned altitude of FL 330 at 0144:27. At 0147:19, New York ARTCC instructed

EgyptAir flight 990 to change radio frequencies for better communication coverage. The

command captain of EgyptAir flight 990 acknowledged and reported on the new

frequency at 0147:39.8

At 0147:55, the relief first officer stated, ìLook, hereís the new first officerís pen.

Give it to him please. God spare you,î9

 and, at 0147:58, someone responded, ìyeah.î

6 When two flight crews are used, EgyptAir designates one crew as the command flight crew and the

other as the relief flight crew. Although EgyptAir has no written or formal procedures for command/relief

flight crew transitions, postaccident interviews with EgyptAir flight crewmembers indicated that the

command and relief flight crews typically agreed upon transfer-of-control procedures for a flight before

departure. The interviews indicated that the most common procedure involved the command flight crew

flying the airplane for the first 3 or 4 hours of the flight, then the relief flight crew assuming control until

about 1 to 2 hours before landing. The command flight crew would then resume control of the airplane and

complete the flight. 

7 Postaccident interviews with several EgyptAir pilots indicated that the relief first officer was often

addressed as ìcaptainî as a title of respect because he had instructed many of the EgyptAir pilots at the

Egyptian flight training institute before he was hired by EgyptAir. 

8 This was the last transmission to ATC from the accident airplane. Although some irregularities in

ATC handling were noted during the investigation, they were not relevant to the accident. For additional

information, see the Air Traffic Control Group Chairmanís Factual Report and its attachments and addenda. 
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NTSB/AAB-02/01

At 0148:03, the command captain stated, ìExcuse me, [nickname for relief first officer],

while I take a quick trip to the toiletÖbefore it gets crowded. While they are eating, and

Iíll be back to you.î While the command captain was speaking, the relief first officer

responded, ìGo ahead please,î and the CVR recorded the sound of an electric seat motor

as the captain maneuvered to leave his seat and the cockpit. At 0148:18.55, the CVR

recorded a sound similar to the cockpit door operating.

At 0148:30, about 11 seconds after the captain left the cockpit, the CVR recorded

an unintelligible comment.10 Ten seconds later (about 0148:40), the relief first officer

stated quietly, ìI rely on God.î11 There were no sounds or events recorded by the flight

recorders that would indicate that an airplane anomaly or other unusual circumstance

preceded the relief first officerís statement, ìI rely on God.î

At 0149:18, the CVR recorded the sound of an electric seat motor. FDR data

indicated that, at 0149:45 (27 seconds later), the autopilot was disconnected.12 Aside from

the very slight movement of both elevators (the left elevator moved from about a 0.7° to

about a 0.5° nose-up deflection, and the right elevator moved from about a 0.35° nose-up

to about a 0.3° nose-down deflection)13 and the airplaneís corresponding slight nose-down

pitch change, which were recorded within the first second after autopilot disconnect, and a

very slow (0.5° per second) left roll rate, the airplane remained essentially in level flight

about FL 330 for about 8 seconds after the autopilot was disconnected. At 0149:48, the

relief first officer again stated quietly, ìI rely on God.î At 0149:53, the throttle levers were

moved from their cruise power setting to idle, and, at 0149:54, the FDR recorded an

abrupt nose-down elevator movement and a very slight movement of the inboard ailerons.

Subsequently, the airplane began to rapidly pitch nose down and descend.

9 The context of this statement indicates that the relief first officer was talking to the command first

officer and that the ìnew first officerî to whom the relief first officer was referring was a pilot who had been

in the cockpit earlier in the flight and who was seated in the cabin at the time of this statement. (According to

the Cockpit Voice Recorder Group Chairmanís Factual Report, an Arabic-speaking member of the Cockpit

Voice Recorder Group identified the voices of six flight crewmembers and one flight attendant recorded in

the cockpit at various times during the accident flight.)

10 According to the CVR transcript, ìthe five Arabic speaking members of the [CVR] group concur that

they do not recognize this as an Arabic word, words, or phrase. The entire group agrees that three syllables

are heard and the accent is on the second syllable. Four Arabic speaking group members believe that they

heard words similar to ëcontrol it.í One English speaking member believes that he heard a word similar to

ëhydraulic.í The five other members believe that the word(s) were unintelligible.î For additional

information regarding the computer analysis of this comment, see the section titled, ìCockpit Voice

Recorder.î 

11 This phrase (recorded on the CVR in Arabic as ìTawakkalt Ala Allahî) was originally interpreted to

mean ìI place my fate in the hands of God.î The interpretation of this Arabic statement was later amended to

ìI rely on God.î According to an EgyptAir and ECAA presentation to Safety Board staff on April 28, 2000,

this phrase ìis very often used by the Egyptian layman in day to day activities to ask Godís assistance for the

task at hand.î 

12 No autopilot disconnect warning tone was heard on the CVR recording. According to the system

design, an autopilot disconnect warning is generated unless the autopilot is disconnected manually, either by

clicking the control yoke-mounted autopilot disconnect switch twice within 0.5 second or by moving the

autopilot switch on the instrument panel. 
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NTSB/AAB-02/01

Between 0149:57 and 0150:05, the relief first officer quietly repeated, ìI rely on

God,î seven additional times.14 During this time, as a result of the nose-down elevator

movement, the airplaneís load factor15 decreased from about 1 to about 0.2 G.16 Between

0150:04 and 0150:05 (about 10 to 11 seconds after the initial nose-down movement of the

elevators), the FDR recorded additional, slightly larger inboard aileron movements, and

the elevators started moving further in the nose-down direction. Immediately after the

FDR recorded the increased nose-down elevator movement, the CVR recorded the sounds

of the captain asking loudly (beginning at 0150:06), ìWhatís happening? Whatís

happening?,î as he returned to the cockpit.

The airplaneís load factor decreased further as a result of the increased nose-down

elevator deflection, reaching negative G loads (about -0.2 G) between 0150:06

and 0150:07. During this time (and while the captain was still speaking [at 0150:07]), the

relief first officer stated for the tenth time, ìI rely on God.î Additionally, the CVR

transcript indicated that beginning at 0150:07, the CVR recorded the ìsound of numerous

thumps and clinks,î which continued for about 15 seconds.

According to the CVR and FDR data, at 0150:08, as the airplane exceeded its

maximum operating airspeed (0.86 Mach), a master warning alarm began to sound. (The

warning continued until the FDR and CVR stopped recording at 0150:36.64

and 0150:38.47, respectively.)17 Also at 0150:08, the relief first officer stated quietly for

the eleventh and final time, ìI rely on God,î and the captain repeated his question,

ìWhatís happening?î At 0150:15, the captain again asked, ìWhatís happening, [relief first

officerís first name]? Whatís happening?î At this time, as the airplane was descending

through about 27,300 feet msl, the FDR recorded both elevator surfaces beginning to

move in the nose-up direction. Shortly thereafter, the airplaneís rate of descent began to

decrease.18 At 0150:21, about 6 seconds after the airplaneís rate of descent began to

decrease, the left and right elevator surfaces began to move in opposite directions; the left

13 Throughout the FDR data for the accident airplane (including data recorded during uneventful

portions of the accident flight and during previous flights and ground operations), small (less than 1° )

differences between the left and right elevator surface positions were observed. The left and right elevator

surface movements were consistent (that is, moved in the same direction about the same time) where these

offsets were observed. According to Boeing, there are several factors that could result in differences between

the left and right elevator surfaces, including rigging of the elevator control system, tolerances within the

systemís temperature compensation rods, routing differences between the left and right elevator control

cables, friction distribution within the system, the accuracy of the sensors used to measure elevator position,

and differences in FDR sampling times for the left and right elevator parameters. 

14 Although earlier statements made by the relief first officer were recorded by the hot microphone at the

first officerís position, the ìI rely on Godî statements were not, which was consistent with these statements

being spoken relatively quietly. For additional information, see the section titled, ìAudio Information

Recorded by First Officerís Hot Microphone.î 

15 An airplaneís normal load factor is approximately perpendicular to the airplaneís wings. Although

the terms ìvertical load factor,î ìvertical acceleration,î and ìnormal load factorî are often used

interchangeably, for the purposes of this document, the term ìload factorî is used. 

16 A G is a unit of measurement of force on a body undergoing acceleration as a multiple of its weight.

The normal load factor for an airplane in straight and level flight is about 1 G. As the load factor decreases

from 1 G, objects would become increasingly weightless, and at 0 G, those objects would float. At load

factors less than 0 G (negative G), loose objects would float toward the ceiling, and, at -1 G, those objects

would accelerate toward the ceiling. 
6

NTSB/AAB-02/01

surface continued to move in the nose-up direction, and the right surface reversed its

motion and moved in the nose-down direction.

The FDR data indicated that the engine start lever switches for both engines

moved from the run to the cutoff position between 0150:21 and 0150:23.19

Between 0150:24 and 0150:27, the throttle levers moved from their idle position to full

throttle, the speedbrake handle moved to its fully deployed position, and the left elevator

surface moved from a 3o nose-up to a 1o nose-up position, then back to a 3o nose-up

position.20 During this time, the CVR recorded the captain asking, ìWhat is this? What is

this? Did you shut the engine(s)?î Also, at 0150:26.55, the captain stated, ìGet away in

the engines,î21 and, at 0150:28.85, the captain stated, ìshut the engines.î At 0150:29.66,

the relief first officer stated, ìItís shut.î 

Between 0150:31 and 0150:37, the captain repeatedly stated, ìPull with me.î

However, the FDR data indicated that the elevator surfaces remained in a split condition

(with the left surface commanding nose up and the right surface commanding nose down)

until the FDR and CVR stopped recording at 0150:36.64 and 0150:38.47, respectively.

(The last transponder [secondary radar] return from the accident airplane was received at

the radar site at Nantucket, Massachusetts, at 0150:34.)22

Information about the remainder of the flight came from the airplaneís two debris

fields and recorded primary radar data from long-range radar sites at Riverhead, New

York, and North Truro, Massachusetts, and the short-range radar site at Nantucket. The

height estimates based on primary radar data from the joint use FAA/U.S. Air Force

(USAF) radar sites indicated that the airplaneís descent stopped about 0150:38 and that

the airplane subsequently climbed to about 25,000 feet msl and changed heading from 80o

to 140o before it started a second descent, which continued until the airplane impacted the

ocean.

17 The cessation of the FDR and CVR recordings was consistent with the loss of electrical power to the

recorders that resulted from the engines being shut off. Although the FDR recorded different parameters at

different sampling rates and at slightly different times, the last subframe of recorded data was recorded

at 0150:36.64. 

18 According to calculations based on FDR data, the airplaneís maximum rate of descent was

about 39,000 feet per minute (fpm); this rate was recorded at 0150:19. 

19 The engine start lever switches control the flow of fuel to the engines and are located on the center

console between the pilot positions. When these levers are moved to the cutoff position, fuel flow to the

engines is stopped, and the engines stop operating within about 5 or 6 seconds. They are spring-loaded,

lever-lock design switches that must be pulled up to release from one detent before they can be moved to the

other position, where they will engage in another detent. 

20 The Safety Boardís simulator tests demonstrated that an EgyptAir pilot similar in size to the

command captain was able to occupy the captainís seat without physical interference; brace himself against

the center console or floor structure; readily apply back pressure on the control column; and reach the

throttles, speedbrakes, and other controls on the central console with the seat in its aft position. (The Board

recognizes that the simulations could not duplicate the near 0 G loads recorded by the FDR during the

accident sequence; however, such near 0 G loads were present only momentarily after the recovery started

and should not have substantially affected the fore-and-aft forces either pilot could generate once normally

seated and effectively braced.)
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NTSB/AAB-02/01

Airplane wreckage was located in two debris fields, about 1,200 feet apart,

centered at 40° 21' north latitude and 69° 46' west longitude. The accident occurred at

night in dark lighting conditions.

PERSONNEL INFORMATION

The Safety Board reviewed the command and relief flight crewís flight and duty

times and found no evidence that they were outside the limits established by applicable

regulations. Because the command captain and the relief first officer were identified as

being the only two crewmembers in the cockpit during the accident sequence, information

on only these two crewmembers is included in this section.23 The cabin crew comprised

10 flight attendants. In addition, several nonduty EgyptAir flight crewmembers were on

board the accident airplane.

Command Captain Information

The command captain, age 57, was hired by United Arab Airlines24 on July 13,

1963. He held an Egyptian airline transport pilot certificate with Boeing 707, 737-200, and

767-200 and -300 type ratings. The command captainís most recent medical certificate

was issued on October 21, 1999, and he was found to be medically fit to fly with glasses in

accordance with the standards specified in ECAR Part 67, ìMedical Standards and

Certification.î According to his family, the command captain had suffered from chronic

back problems but was addressing them and had no recent changes in his health.25

The command captainís most recent proficiency check was satisfactorily

completed on March 9, 1999, and his most recent recurrent training was satisfactorily

completed on August 14, 1999. According to EgyptAir records, at the time of the accident,

the command captain had flown approximately 14,384 total flight hours, including

6,356 hours in the 767. The Safety Boardís review of EgyptAir training records for the

21 According to participants in the Cockpit Voice Recorder Group (which included several

Arabic/English speakers), occasionally the direct translation of Arabic words into English resulted in

awkward or seemingly inappropriate phrases. Throughout the CVR transcript, the Cockpit Voice Recorder

Group provided as direct a translation as possible; however, it did not attempt to interpret or analyze the

words or the intent of the speaker.

22 Surveillance radars fall into two categories: primary (also known as ìsearchî) and secondary (also

known as ìbeaconî). Secondary radar broadcasts an interrogation signal to which equipment on board an

airplane automatically responds by transmitting information to the ground-based site for processing and

display. Secondary radar returns contain an identification code and altitude data. Primary radar broadcasts

radio waves and detects the reflections of the waves off objects (including airplanes). Primary radar

reflections do not contain any unique identification information. (For additional information, see the Aircraft

Performance Group Chairmanís Aircraft Performance Study.)

23 For more detailed information regarding the background and recent activities of all EgyptAir

flight 990 crewmembers, see the Operational Factors Group Chairmanís Factual Report and its addendum

and the Human Performance Group Chairmanís Factual Report and its addendum.

24 In 1971, United Arab Airlines was renamed EgyptAir.

25 There was no mention of treatment for chronic back problems in the captainís records at EgyptAir.
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NTSB/AAB-02/01

command captain indicated that he had accomplished all required checkrides and

satisfactorily performed all required maneuvers.

The command captain arrived in New York the afternoon of October 28, 1999,

after serving as a captain on EgyptAir flight 989 from Cairo to JFK. (Additional

information about the command captain is contained in the public docket on this accident.) 

Relief First Officer Information 

The relief first officer, age 59, was hired by EgyptAir on September 8, 1987. He

held an Egyptian commercial pilot certificate with 737-200 and 767-200 and -300 type

ratings.26 The relief first officerís most recent medical certificate was issued on July 28,

1999, and he was found to be medically fit to fly with glasses in accordance with the

standards specified in ECAR Part 67. According to a close friend, the relief first officer

had no family history of major medical difficulties and did not complain of headaches,

indigestion, or other medical problems before the accident.

The relief first officerís most recent proficiency check was satisfactorily

completed on June 19, 1999, and his most recent recurrent training was satisfactorily

completed on December 19, 1998. According to EgyptAir records, at the time of the

accident, the relief first officer had flown approximately 12,538 total flight hours,

including 5,191 hours in the 767. The Safety Boardís review of EgyptAir training records

for the relief first officer indicated that he had accomplished all required checkrides and

performed all required maneuvers.

Before EgyptAir hired him, the relief first officer was a flight instructor, first for

the Egyptian Air Force and later for a Government-operated civilian flight training

institute in Egypt. The relief first officer became a Major in the Air Force before he

transitioned to the flight training institute, where he eventually became the chief flight

instructor.

The relief first officer arrived in New York City the afternoon of October 28, 1999,

after serving as a first officer on EgyptAir flight 990 from LAX to JFK. (Additional

information about the relief first officer is contained in the public docket on this accident.)

AIRPLANE INFORMATION

The accident airplane, SU-GAP, a 767-300 series airplane27 (model 767-366ER

[extended range]), serial number (S/N) 24542, was manufactured by Boeing and delivered

new to EgyptAir on September 26, 1989. According to EgyptAir records, it had

33,354 total hours of operation (7,594 flight cycles)28 at the time of the accident. It was

26 The relief first officer did not upgrade to captain even though he was eligible to do so in the

early 1990s. Colleagues stated that he did not upgrade because he preferred the benefits of seniority in the

first officer position. According to EgyptAir, the relief first officer became ineligible to upgrade after his

55th birthday in February 1995.

27 The 767-300 is a low-wing, twin-engine, transport-category airplane.
9

NTSB/AAB-02/01

configured to seat a maximum of 10 first-class, 22 business-class, and 185 economy-class

passengers and to carry cargo.

The accident airplane was equipped with two P&W 4060 turbofan engines.

Company maintenance records indicated that the No. 1 (left) engine, S/N 724126, was

installed on the accident airplane on April 19, 1998, and had operated about 25,708 hours

since new and that the No. 2 (right) engine, S/N 724127, was installed on the accident

airplane on June 3, 1998, and had operated about 19,316 hours since new.

767 Longitudinal Control System Information

Because the accident sequence involved a sustained unusual motion about the

airplaneís pitch axis, the Safety Board examined the 767ís longitudinal flight control

system. According to the Boeing 767 Maintenance Manual, the 767ís longitudinal flight

control system includes two (left and right) sets of linked elevator surfaces (inboard and

outboard), which are attached to the rear spar of the movable horizontal stabilizer by

hinges. Each outboard elevator surface is driven by three power control actuators (PCA).

Because the outboard and inboard surfaces are linked, the inboard elevator surfaces move

when the outboard elevator surfaces are driven. Hydraulic power for elevator PCA

movement is provided by the 767ís three independent hydraulic systemsóeach hydraulic

system powers one of each elevator surfaceís PCAs, which provides redundancy within

the elevator control system. (Components in the elevator control system are shown in

figures 1a and 1b.)

Two parallel sets (one operated from the captainís side, the other from the first

officerís side) of flight control components move the elevator surfaces. Control column

inputs made at the captainís position are linked directly to the actuators for the left

elevator surface, whereas control column inputs made at the first officerís position are

linked directly to the actuators for the right elevator surfaces. The two parallel sets of

flight control components are linked together at the forward and aft override

mechanisms/linkages and slave cable interconnects. Flight control commands from the

captainís and first officerís control columns are transmitted through linkages and cables29

from the front of the airplane to the left and right aft quadrant assemblies, respectively.

The aft quadrant assemblies then translate the inputs to the respective bellcrank

assemblies and the input control rods for each of the three elevator PCAs for each

outboard elevator surface.

28 A flight cycle is one complete takeoff and landing sequence.

29 The cables for the captainís (left-side) system are routed below the floor boards, and the cables for the

first officerís (right-side) system are routed above the cabin ceiling.
NTSB/AAB02/01

POWER CONTROL ACTUATORS (PCAíS)

(3 LOCATIONS ON EACH OUTBOARD ELEVATOR)

LEFT INBOARD ELEVATOR

(RIGHT SIDE EQUIVALENT)

LEFT AFT QUADRANT

RIGHT AFT QUADRANT

FWD

OUTBD

SIN

AFT QUADRANTINTERCONNECTROD

AFT QUADRANTSOVERRIDEMECHANISM

LEFT OUTBOARD ELEVATOR

(RIGHT SIDE EQUIVALENT)

FEEL COMPUTER

HORIZONTAL STABILIZER

FEEL ANDCENTERING UNIT

AUTOPILOTCONTROL SERVO(3 LOCATIONS)

OVERRIDE MECHANISM

LOST MOTION

DEVICE

(2 LOCATIONS)

SLAVE CABLE QUADRANT

(2 LOCATIONS)

CAPTAINíS CONTROL COLUMN

FIRST OFFICERíS CONTROL COLUMN

CONTROLCOLUMNSOVERRIDEMECHANISM

TENSIONREGULATORQUADRANT(2 LOCATIONS)

STICK SHAKER

(2 LOCATIONS)

NOT 

FIRST OFFICERíS

ELEVATOR CONTROL

CABLES

LEFT AFT QUADRANT

OUTPUT ARM

CONTROL ROD

RIGHT AFT 

OUTPUT ARM 

CAPTAINíS

ELEVATOR CONTROL

CABLES

Figure 1a. Diagram of the components in the entire 767 elevator control system.
NTSB/AAB-02/01

RIGHT OUTBOARD ELEVATOR LEFT OUTBOARD ELEVATOR

PCA INPUT ARM (6 LOCATIONS)

L L

L

C C

R R

R

SLAVE INTERCONNECT CAB

RIGHTINBOARD ELEVATOR

POSITIONTRANSMITTER(2 LOCATIONS)

STABILIZER

STICK NUDGER

FEEL AND CENTERING UNIT

AUTOPILOT CONTROL SERVOS

AFT QUADRANTS

SLAVE CABLEQUADRANT(2 LOCATIONS)

BELLCRANKASSEMBLY(6 LOCATIONS)

POWER CONTROLACTUATOR (PCA)(6 LOCATIONS)

LEFTINBOARD ELEVATOR

C

FWD

Figure 1b. Diagram of the aft 767 elevator control system components.
12

NTSB/AAB-02/01

After control cable movement is translated to input control rod movement, the

control rods move control valves inside the PCAs, allowing high-pressure hydraulic fluid

to flow to one side or the other of the actuatorsí pistons (depending on the direction of the

input), resulting in elevator movements that correspond to the direction of the input. When

the elevators reach the commanded position, feedback linkages move the control valves to

a position in which the hydraulic fluid is blocked off, resulting in no further movement of

the actuator piston or elevator.

Testing, evaluation, and analysis of the 767 elevator system showed that any

movement of the control columns (whether pilot-induced or not) would have resulted in

concurrent, identifiable movements of the elevators, which would have been recorded on

the FDR.

An elevator feel-and-centering unit transmits hydraulic and mechanical feel forces

to hold the elevator at the neutral (trimmed) position when no control column force is

applied. It also provides feedback (or feel) force to the control column that increases as the

control column is moved forward or aft. The feel forces provided are essentially equal at

both pilot positions because of the connections between the left and right elevator systems.

The captainís and first officerís control columns have authority to command full

travel of the elevators under most flight conditions and normally work together as one

system. However, the two sides of the system can be commanded independently because

of override mechanisms at the control columns and aft quadrant. Therefore, if one side of

the system becomes immobilized, control column inputs on the operational side can cause

full travel of the nonfailed elevator. In addition, in many cases, control column inputs on

the operational side can also result in nearly full travel of the elevator on the failed side

through the override mechanisms. The elevator PCAs are installed with compressible

links located between each bellcrank assembly and PCA input control rod to provide a

means of isolating a jammed PCA, thus allowing the pilots to retain control of that

elevator surface through its two remaining (unjammed) PCAs. 

767 Elevator Blowdown Information 

During ground operations, the 767 elevator PCAs can drive the elevators through a

range of motion from 28.5° in the nose-up direction to 20.5° in the nose-down direction.

However, in-flight elevator deflections can be limited by the aerodynamic forces acting on

the elevator. The maximum position to which the elevator can move is that which balances

the aerodynamic forces that are acting on the elevator surfaces against the force produced

by the elevator PCAs and is referred to as its ìblowdownî position. Thus, as the airplaneís

airspeed increases (increasing the aerodynamic forces acting against the elevator PCAs),

the elevatorsí range of motion is increasingly limited.

The maximum output force produced by the elevator PCAs is generated by the

hydraulic system pressure acting on the PCAsí piston area; if all three elevator PCAs are

working properly, the total output force for each elevator surface is the sum of the forces

produced by all three of that elevatorís PCAs. When a dual elevator PCA failure occurs,30
13

NTSB/AAB-02/01

the forces produced by the two failed PCAs would overpower the opposing force

produced by the one nonfailed PCA. The resultant initial force on the elevator surface in

the failed direction would be equivalent to a single functioning PCA operating at

100 percent of its maximum force. The failed PCAs would resist the backdriving force31

with a force equivalent to about 130 percent of a single functioning PCA. The high

internal pressures required for activation of the PCAsí pressure relief valves allow the

PCAsí pistons to resist the aerodynamic backdriving movement with more force than

normal operating pressures would allow. Therefore, if a dual PCA failure occurred in

flight, the elevator would initially move to a position consistent with a single functioning

PCA operating at 100 percent of its maximum force, balanced against the aerodynamic

forces affecting the elevator surface. As the airspeed increases, the failed elevator surface

would remain at this initial position until the backdriving forces exceeded those of a single

PCA operating at 130 percent of its normal capability, at which point the deflection of the

failed elevator surface would decrease.32 (Figure 2 is a comparison of the elevator

positions recorded by the accident airplaneís FDR with failed and nonfailed elevator

positions following a dual PCA failure.)

767 Autoflight Systems Information 

The 767 autoflight systems include the autopilot/flight director, yaw damper,

automatic stabilizer trim, Mach trim, maintenance monitoring, instrument landing system

deviation monitor, and thrust management systems. The thrust management system

includes autothrottle control.

767 Autopilot Information

The 767 autopilot/flight director system consists (in part) of three separate

autopilot systems that can be used singly or in combination to provide automatic control

of the ailerons, elevator, stabilizer, and rudder control systems when operating in selected

flight modes. Any one of the three autopilot systems can control the airplane in the normal

climb, cruise, descent, and approach modes.

30 The Safety Board thoroughly examined the dual elevator PCA failure scenarios during its

investigation of this accident. For more information, see the section titled, ìPotential Causes for Elevator

Movements During the Accident Sequence.î

31 The term ìbackdrivingî refers to the effect of aerodynamic forces that act on the elevator surface and

move the surface in the direction opposite to that being commanded (by the two failed PCAs, in the case of

a dual elevator PCA failure). This backdriving force increases as an airplaneís airspeed increases.

32 For additional information, see the section of this report titled, ìPotential Causes for Elevator

Movements During the Accident Sequence.î
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NTSB/AAB-02/01

The 767 autopilot system controls the airplaneís movement about the pitch axis by

using the elevators for dynamic control of the airplaneís pitch and the horizontal stabilizer

to trim out steady-state elevator deflections. When the autopilot is engaged and the

airplane is in a steady-state flight condition, the autopilot is designed to keep the elevators

near their neutral (or faired) position, using the elevators primarily for short-term dynamic

adjustments (such as those necessitated by atmospheric disturbances). The elevators are

also used for small trim adjustments, such as those necessitated by fuel consumption

during flight. As these small elevator adjustments accumulate over time, the elevator

deflections move further from their neutral (or faired) position. When the elevatorsí

deflections reach a threshold value, the autopilot ìretrimsî the horizontal stabilizer and the

elevator returns to a neutral (or faired) position. According to Boeing, when the autopilot

system is disconnected, the force applied by the autopilot actuator to the elevator control

system is removed, and, if the horizontal stabilizer has not been adjusted recently, small

Figure 2. Comparison of the elevator positions recorded by the accident airplaneís 

FDR with failed and nonfailed elevator positions following a dual PCA failure. 

.
15

NTSB/AAB-02/01

elevator movements result. Boeing representatives indicated that the following

circumstances could result in elevator movements at the time of autopilot disconnect:

ï Differences between the neutral position recognized by the autopilot and the

actual neutral position of the elevator feel-and-centering unit would result in

the autopilot actuator holding a force that would be released when the system

is disconnected. 

ï The autopilot may have moved the elevators since it last trimmed the stabilizer,

placing the elevators at a position other than their neutral position at the time of

disconnect. When the autopilot is disconnected, the elevators would return to

the neutral position commanded by the feel-and-centering unit. (During

steady-state flight conditions, this situation occurs because of the effect of fuel

consumption on the airplaneís center of gravity.) According to Boeing, ìthis

type of elevator motion upon autopilot disconnect is inherent in the operation

of the autopilot system.î

ï Pilot forces on the control column at the time of manual autopilot disconnect

can affect the movement of the elevator. (The autopilot can be disconnected

manually by double-clicking the control yoke-mounted autopilot disconnect

switch.) 

ï Mechanical aspects of the elevator control system (including friction, the

effects of compliance in the system,33 variations among individual autopilot

actuator units, and variations in the centering detent force) can cause elevator

movement at the time of autopilot disconnect.

Boeingís 767 Maintenance Manual indicates that if the autopilot disconnects

because of a system failure, the following cockpit warnings and annunciations would

occur: 

ï the red autopilot disconnect warning light illuminates, 

ï the red master warning light illuminates, 

ï the engine indication and crew alerting system computer displays an autopilot

disconnect message, and 

ï a siren alert sounds. 

Although these autopilot disconnect warnings and annunciations are also

generated when the autopilot is disconnected by pressing the autopilot manual disconnect

switch on the control wheel, pressing the manual disconnect switch a second time within

0.5 second resets, and thus cancels, the systemís disconnect warnings and annunciations

before they are displayed to the flight crew. The 767 autopilot warnings and annunciations

system contains multiple redundancies. For example, two warning signals are generated

33 Compliance in the elevator system can occur as a result of cable stretch; yield, give, or elastic

deformation in linkages (that does not damage the linkages but allows additional motion); and variations in

tolerance buildups throughout the system.
16

NTSB/AAB-02/01

for each of the warning functions listed above: one warning signal uses software logic that

is powered by normal power (which would be inhibited by a loss of normal power or a

computer failure), and the other uses hardware logic that is powered by 28-volt alternating

current standby power.

767 Autothrottle Information

The 767ís thrust management system provides autothrottle control based on

selected modes, existing conditions, and engine limitations. The autothrottle can be

operated independently of or with the autopilot system. The autothrottle servomotor

generator is connected to the throttle levers through a clutch pack assembly, which, when

overridden,34 allows the pilots to make manual thrust inputs when the autothrottle is

engaged. Movement of the throttle levers aft of the autothrottle commanded position for a

given flight condition would require a manual force of about 9 lbs at the throttle levers to

override the autothrottle servomotor clutch.

When the autothrottle function is engaged, it controls throttle lever movement. The

maximum autothrottle commanded throttle lever movement rate for a normally

functioning autothrottle system is 10.5° per second. Manual throttle lever inputs can

exceed this rate; for example, the accident airplaneís FDR recorded throttle lever

movement at a rate of 25° per second at the beginning of the accident sequence. The

minimum throttle lever position that the autothrottle can command varies as a function of

the airplaneís speed and the autothrottle mode selected. For the accident airplaneís flight

conditions and the selected autothrottle mode at the beginning of the accident sequence,

this position would have been 40° to 50° . The FDR recorded a throttle lever position of

about 33° at the beginning of the accident sequence.

Reported Autopilot Anomalies in the Accident Airplane

During interviews conducted at the request of the Egyptian Government on

February 21, 2001, an EgyptAir captain who had flown the accident airplane from Newark

International Airport (EWR), Newark, New Jersey,35 to LAX on October 30, 1999,

reported that he had experienced difficulties with the autopilot during a portion of that

flight.36 The captain told investigators that the autopilot was ìhuntingî for the glideslope

at 8,000 to 10,000 feet msl during the approach to LAX and that, because he was

uncomfortable with the autopilotís performance, he disconnected it. The captain reported

that his three subsequent attempts to reengage the autopilot to intercept the glideslope in

34 A manual force of about 9 pounds (lbs) is required to override the clutch.

35 The October 30, 1999, EgyptAir flight from Cairo was scheduled to land at JFK but diverted to EWR

because of weather.

36 During interviews conducted 3 days after the accident, the captain that had flown the airplane from

EWR to LAX on October 30, 1999, described several noncritical anomalies (a deactivated thrust reverser, an

intermittent air conditioning pack ìinoperativeî light, a full aft lavatory holding tank, and the autopilot

anomaly previously mentioned) but stated that the airplane was ìalmost perfect.î The first officer of the

flight to LAX did not describe the autopilot anomaly.
17

NTSB/AAB-02/01

flight were unsuccessful; therefore, he continued the approach and landed the airplane

manually. This captain told investigators that the autopilot operated normally when he

engaged it on the ground after landing at LAX. Examination of the accident airplaneís

maintenance logbooks revealed no autopilot-related maintenance writeups, and no

subsequent autopilot anomalies were verbally reported.

Examination of the FDR data for the October 30th flight to LAX revealed that at

the time the captain reported he disconnected the autopilot because it was ìhuntingî for

the glideslope during the approach to LAX, the autopilot was operating in its LOC

(localizer approach) mode, which does not have glideslope intercept capability. The FDR

data indicated that, later in the approach to LAX, when the captain tried to reengage the

autopilot using the APP (approach) mode, which has both localizer and glideslope

intercept capability, the airplane had descended far enough below the glideslope that the

autopilot system could not capture the glideslope signal.37

The Safety Boardís review of the FDR data revealed that nine autopilot

disconnects were recorded on the accident airplaneís 25-hour-long FDR tape: one just

before landing at Cairo the day before the accident; one just before its next landing at

EWR; four during the approach to LAX (during which the reported autopilot difficulties

occurred); one on the ground at LAX; one just before landing at JFK the night of the

accident flight; and one immediately preceding the accident sequence. No elevator

movement was recorded after the autopilot disconnect that occurred on the ground at

LAX. The elevator movements recorded following the other eight autopilot disconnects

were primarily in the trailing-edge-down (TED) direction and were less than 0.88° in

magnitude. According to Boeing, the elevator movements recorded by the accident

airplaneís FDR were consistent with the movements that would be expected as a result of

the normal operation of the autopilot on a properly rigged 767.

Accident Airplane Maintenance Information

During its investigation of the EgyptAir flight 990 accident, the Safety Board

reviewed EgyptAirís maintenance program and maintenance recordkeeping procedures

and conducted a detailed examination of the accident airplaneís maintenance records. The

Boardís review revealed that the accident airplane had been maintained in accordance

with EgyptAirís continuous airworthiness maintenance inspection program for its

767 fleet. Additionally, the accident airplaneís maintenance records indicated that all

applicable airworthiness directives (AD) had been complied with; no related discrepancies

were noted. Further, the Boardís review of the accident airplaneís technical log sheets

from July 29 to October 30, 1999, revealed no pertinent unresolved discrepancies.

37 According to Boeing, the autopilot is designed to capture the glideslope signal when the proper

autopilot mode is selected if the airplane is within 80 feet of the glideslope.
18

NTSB/AAB-02/01

FAA Service Difficulty Reports (SDR)38 and accident and incident data from all

operators flying 767s between 1990 and 2000 were also reviewed by investigators.

Although some elevator-related SDRs were noted,39 there were no documented

maintenance trends or anomalies that were relevant to the circumstances of this accident.

767 Bellcrank Anomalies

On March 8, 2000, Boeing personnel reported to the Safety Board that Boeing had

been informed of an air carrier incident involving a 767 in which failed bellcrank shear

rivets were found in the left inboard and left center elevator PCA bellcrank assemblies.40

The bellcrank shear rivets are designed to shear if an elevator PCA jam occurs, the

compressible links between the bellcrank assemblies and the PCA input arms are

bottomed out,41 and a force of about 50 lbs is applied to the control column. Research and

testing indicated that sheared rivets in a bellcrank assembly could result in an elevator

PCA disconnect. Such a failure is discussed briefly later in this section and in detail in the

section titled, ìPotential Causes for Elevator Movements During the Accident Sequence.î

Boeing and the FAA conducted additional tests and research to further investigate

why the rivets failed and what the possible repercussions of such a failure would be,

including metallurgical examination of high-time bellcranks, material properties testing

on old and new bellcranks, review of bellcrank failure rate data obtained from

767 operators, and examination of maintenance procedures to determine whether changes

in procedures and/or intervals were warranted. The Safety Board monitored the FAAís and

Boeingís tests and research into the bellcrank shear rivet failures.

The research conducted by Boeing and the FAA revealed that single bellcrank

shear rivet failures had occurred on other 767s, some of which might not have been

detected during the single hydraulic system maintenance check that is to be conducted by

767 operators every 400 flight hours.42 On August 17, 2000, Boeing issued Service

Bulletin 767-27A0166, which described methods by which failed bellcrank shear rivets

that might not be detected during the single hydraulic system maintenance check could be

identified. Subsequently, the FAA issued AD 00-17-05, effective September 11, 2000,

which required all 767 operators to perform a one-time functional check of one shear rivet

in all six elevator PCA bellcrank assemblies within 30 days, reworking or replacing the

bellcrank assembly if needed. AD 00-17-05 indicates the following:

[F]ailure of two [of the three] bellcrank assemblies on one side can result in that

single elevator surface [but not both surfaces] moving to a hardover position

independent of pilot command resulting in a significant pitch upset recoverable by

the crew. Failure of [all] three bellcrank assemblies on one side can cause an

elevator hardover that may result in loss of controllability of the airplaneÖthe

FAA has received no factual information that indicates that this incident is related

to [the EgyptAir flight 990] accidentÖ.The cause of that accident is still under

investigation.

38 Through its SDR program, the FAA collects information about mechanical failures from reports

submitted by aircraft operators or maintenance facilities, as required by regulations.
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NTSB/AAB-02/01

Because the FAA received reports that the one-time functional check required by

AD 00-17-05 revealed failed shear rivets on several 767-300 airplanes, on March 5, 2001,

the FAA issued AD 01-04-09, effective March 20, 2001, which required all 767 operators

to perform repetitive functional testing of the elevator control system to determine

whether the elevator PCAs are properly rigged and accomplish followup actions

(including depth penetration inspection of the shear rivets),43 as necessary. AD 01-04-09

required operators to perform the repetitive testing of the elevator control system at least

every 400 flight hours, beginning within 90 days of the ADís effective date. Although the

cause of the bellcrank shear rivet failures has not yet been determined, Boeing and the

FAA are continuing to study the issue.

One of the mechanical failure conditions evaluated by the Safety Board during the

EgyptAir flight 990 investigation involved disconnection of the input linkages to two of

the three PCAs on one elevator surface. This failure condition could be caused by the

failure of any of the components that comprise the elevator PCAsí input linkage systems,

including the bellcranks. As further discussed in the section titled, ìPotential Causes for

Elevator Movements During the Accident Sequence,î the Boardís tests and simulations

indicated that the nonfailed elevator and the airplane are controllable from either control

column with a dual PCA disconnect on one elevator surface. Those tests showed that

neither a dual disconnection nor a triple disconnection (such as would result from a triple

bellcrank failure) on one elevator surface would produce elevator deflections that matched

the FDR data from the accident sequence.

39 The SDRs included two reports of anomalous elevator behavior on the same United Airlines 767, the

first incident occurred on September 12, 1994, and the second on June 20, 1996. Both incidents involved

ìstiffî or ìfrozenî elevator flight controls, and, in both cases, the pilots regained control of the elevator by

applying higher-than-normal pressure on the control column. Postincident examination of the elevator

system components revealed no discrepancies. 

The Safety Board is also aware of the following two similar, more recent incidents: 

1) On March 27, 2001, an American Airlines 767 experienced elevator control difficulties during

an approach to land. The pilots landed safely using horizontal stabilizer trim for pitch control

and reported that as they taxied to the gate, they ìbroke [the elevator] freeî by applying a

higher-than-normal force on the control column. Postincident examination revealed no

discrepancies in the elevatorís mechanical flight control rigging, PCAs, pushrods, bellcranks,

or shear rivets; however, during postincident examination, investigators observed water

dripping directly on elevator system components in the empennage.

2) On April 23, 2001, the pilots of another 767 experienced elevator control binding during the

approach to land. The pilots applied additional force to the control column, and the elevator

binding released. Postincident examination revealed no evidence of mechanical anomalies;

however, investigators observed an accumulation of water and ice in the empennage around

the elevator system components.

Additional tests indicated that water could freeze on the elevator components and create the effects

described by these flight crews and observed in the FDR data of the two recent incidents. (FDR data were

not available for the two earlier incidents.) The Safety Board compared the FDR data from the two recent

incidents with that from EgyptAir flight 990 and found no similarities. Boeing and the FAA are evaluating

possible corrective actions related to preventing or limiting water from entering the 767 empennage,

freezing at altitude, and impinging on elevator system components.
20

NTSB/AAB-02/01

METEOROLOGICAL INFORMATION

The Safety Boardís review of data from the National Climatic Data Center

National Radar Mosaic (from about 0100 through 0230 on October 31, 1999) and other

meteorological data revealed no record of significant meteorological conditions in the area

at the time of the accident. No pilot reports indicating any significant meteorological event

were transmitted in the accident area between about 2300 EDT on October 30 and 0700 on

October 31, 1999.

FLIGHT RECORDERS

The FDR and CVR were recovered from the Atlantic Ocean by U.S. Navy

remote-operated vehicles on November 9 and November 14, 1999, respectively. Upon

recovery, they were immediately packed in water to prevent/delay the onset of corrosion

and shipped to the Safety Boardís laboratory in Washington, D.C., for readout.

Cockpit Voice Recorder

The CVR installed on the accident airplane was a Fairchild model A-100,

S/N 3193. Although the CVR unit exhibited external and internal structural damage and

the recording medium (magnetic tape) was wet, the tape was otherwise in good condition.

The CVR recording consisted of four channels of audio information, the following three

of which recorded usable audio information: the cockpit area microphone (CAM) and the

hot microphones at the captainís and first officerís positions.44 The quality of the audio

information recorded by the CAM was good, whereas the quality of the audio information

recorded by the hot microphone at the first officerís position was excellent until 0141:11,

after which time it was poor.45 The audio information recorded by the hot microphone at

the captainís position was difficult or impossible to decipher throughout most of the

recording.46

40 This anomalous condition was discovered when a drooping elevator surface was observed during a

preflight inspection; there were no reports of in-flight anomalies before this discovery. The air carrierís

maintenance personnel found sheared rivets in the bellcranks, which they repaired. The system was

functionally checked after the repair, and the airplane was returned to service. The air carrier reported the

anomalous condition and repair to Boeing and has reported no further anomalies. FDR data were not

available.

41 For the purposes of this report, the compressible links are described as ìbottomed outî when they

have been deflected to the full extent of their travel in either direction.

42 The single hydraulic system maintenance check tests the operation of each PCA individually by

powering each of the airplaneís three hydraulic systems, one at a time. An inoperative elevator PCA will not

operate the elevator when powered by its hydraulic system. A PCA with a failed bellcrank shear rivet will

not operate the elevator properly.

43 Indications of an improperly rigged PCA can occur as a result of yielded or failed shear rivets in a

bellcrank assembly.

44 The fourth channel of audio information recorded by the CVR is usually recorded through audio

equipment at a cockpit jumpseat position. The FAA does not require a fourth channel to be installed/used on

airplanes equipped with CVRs.
21

NTSB/AAB-02/01

The CVR recording started at 0119:13, as the flight was cleared for takeoff from

runway 22R at JFK. As previously discussed, the cessation of the CVR recording at

0150:38.47 (shortly after the FDR recorded the airplaneís loss of engine power) was

consistent with the loss of electrical power to the recorder that occurred after the engines

were shut off.

Two transcripts were prepared of the entire 31-minute 30-second recording, one in

Arabic/English words and phrases exactly as spoken on the accident flight and the other

with Arabic words translated to English. As stated previously, throughout the CVR

transcript, the Cockpit Voice Recorder Group provided as direct a translation as possible,

without attempting to interpret the words or the intent of the speaker. According to

participants in the Cockpit Voice Recorder Group (which included several Arabic/English

speakers), occasionally the direct translation of Arabic words into English resulted in

awkward or seemingly inappropriate phrases.

Cockpit Voice Recorder Sound Spectrum and Speech Studies

The Safety Board conducted CVR speech and sound spectrum studies to document

any unknown sounds and to verify and expand on the information contained in the CVR

transcript.47 The results of these studies are discussed in the following sections.

Audio Information Recorded by First Officerís Hot Microphone 

The Safety Boardís study of the CVR information recorded by the hot microphone

at the first officerís position during the accident flight revealed that, at 0141:03, the CVR

recorded a decrease in the audio level of the first officerís hot microphone system, and, at

0141:11, the CVR recorded a rustling sound through the first officerís hot microphone

system. According to a member of the Speech Examination Study Group, this rustling

sound resembled the sound of the headset being stowed as the command first officer

45 The Safety Board uses the following categories to classify the levels of CVR recording quality:

excellent, good, fair, poor, and unusable.

ï An excellent recording is one that is very clear and easily transcribed.

ï A good recording is one in which most of the crew conversations can be accurately and easily

understood. The transcript that is developed may indicate unintelligible several words or

phrases. Any loss in the transcript can be attributed to minor technical deficiencies or

momentary dropouts in the recording system or to a large number of simultaneous

cockpit/radio transmissions that obscure each other.

ï A poor recording is one in which a transcription is nearly impossible because a large portion of

the recording is unintelligible.

The quality of audio information recorded by the hot microphone at the first officerís position is

discussed further later in this report.

46 The captain apparently did not use the hot microphone system; however, depending on the nature and

volume of the captainís communications, the sounds were recorded by the CAM.

47 For additional sound spectrum and speech study information, see the Cockpit Voice Recorder Group

Chairmanís Factual Report/Sound Spectrum Study and the Speech Examination Study Factual Report.
22

NTSB/AAB-02/01

prepared to leave the first officerís position. Until this time, the hot microphone at the first

officerís position had recorded the first officerís utterances clearly, as well as some

additional cockpit noises and conversations; however, subsequently, this microphone

(which is a part of the first officerís headset assembly) provided muffled recordings of

some, but not all, of the cockpit conversations. Command and relief first officer

statements after 0141:11 were recorded more clearly by the CAM.

The study concluded that the recording quality of the first officerís hot microphone

was excellent while the command first officer wore the headset/microphone and poor

when the headset/microphone was believed to be stowed.48 After 0150:24, the first

officerís hot microphone stopped recording cockpit conversation and started recording a

sudden increase in background noise. The speech evaluation study indicated that this most

likely occurred because a pilot inadvertently activated the air-to-ground/interphone button

on the back of the control wheel and thereby altered the amplitude of the recording to the

amplitude level set at the individual pilot position.

Speech Sample Information

All speech samples analyzed in the speech study were captured through the CAM

located in the overhead panel. Investigators identified recorded speech samples for six

EgyptAir crewmembers that were in the cockpit at various times during the accident

flight, including the command captain, the relief first officer, the command first officer,

the EgyptAir 767 chief pilot, and two nonduty first officers on board the airplane.

All utterances made after the captain departed the cockpit (at 0148:18) were

analyzed to the extent possible; however, in part because of occasional loud background

noise in the cockpit after that time, only 15 of the 23 utterances recorded by the CAM after

such time were strong enough (relative to background noise) to be analyzed by computer

for fundamental frequency (pitch) and formant dispersion49 information.

Fundamental Frequency and Speech Duration Information 

Research50 has shown that fundamental frequency and speech duration vary

characteristically among speakers and often convey information about the speakerís

psychological stress. The Safety Board has used the following guidelines51 with regard to

fundamental frequency for evaluating the degree of psychological stress experienced by a

speaker:

48 The study stated that the exact stowage location of the headset was unknown; however, according to

an EgyptAir representative, it would normally be stowed in the storage console, which located at the first

officerís right side, or in his flight bag, which is located just aft of the storage console.

49 Formants, which determine many aspects of perceived speech, are frequencies at which the vocal

tract above the larynx (acting as a filter because of its normal modes of vibration) will allow maximum

energy to pass from the sound produced by the vocal cords. Formant dispersion refers to the relative spacing

between successive formants. 
23

NTSB/AAB-02/01

ï An increase in fundamental frequency of about 30 percent (compared with that

individualís speech in a relaxed condition) would be characteristic of a stage 1

level of stress, which could result in the speakerís focused attention and

improved performance.

ï An increase in fundamental frequency of between 50 to 150 percent would be

characteristic of a stage 2 level of stress, which could result in the speakerís

performance becoming hasty and abbreviated; however, the speakerís

performance would not display gross mistakes.

ï An increase in fundamental frequency of between 100 to 200 percent would be

characteristic of a stage 3 level of stress, or panic, which could result in the

speakerís inability to think or function logically or productively.

On the basis of these guidelines, the CVR speech study concluded that the relief

first officer exhibited no more than a 25 percent increase in fundamental frequency,

compared to what he exhibited during routine flight, when he made any of his ìI rely on

Godî statements and when he stated, ìitís shut,î during the emergency sequence.

However, the speech study concluded that the command captain exhibited an increase in

fundamental frequency of 29 percent when he stated, ìwhatís happening?,î shortly after

he returned to the cockpit and of between 47 and 65 percent when he stated, ìget away in

the engines,î ìshut the engines,î ìpull,î and ìpull with me,î during the emergency

sequence, compared to what he exhibited during routine flight.

Previous research has also shown that speech duration often becomes shorter (that

is, speaking rate becomes faster) when psychological stress increases. Speech duration

measurements were performed on the phrase ìI rely on Godî (repeated by the relief first

officer 11 times between 0148:39 and 0150:08). The CVR transcript indicated that the first

utterance of the phrase ìI rely on Godî was spoken faintly, about 1 minute 6 seconds

before the autopilot was disconnected, and had a duration of 1.02 seconds. The second

utterance of this phrase, which occurred about 5 seconds before the throttle levers were

moved to idle and while the airplane was still in level flight, had a duration of 0.81 second.

The remaining nine utterances of this phrase, which began about 8 seconds later (as the

airplane began its abrupt nose-down pitch and steep descent), varied in duration from 0.73

to 0.87 seconds, with pauses of 0.51 and 0.70 seconds between successive utterances.

50 For additional information, see Williams, C. E. and Stevens, K. N. 1981. ìVocal Correlates of

Emotional States.î Speech Evaluation in Psychiatry. Grune & Stratton. New York, New York; Ruiz, R.;

Legros, C.; and Guell, A. 1990. ìVoice Analysis to Predict the Psychological or Physical State of a Speaker.î

Aviation, Space, and Environmental Medicine. Vol. 61. p. 266-71; Johannes, B.; Salnitski, V. P.; Gunga, H.;

and Kirsch, K. 2000. ìVoice Stress Monitoring in SpaceóPossibilities and Limits.î Aviation, Space, and

Environmental Medicine. Vol. 71. p. A58-65; Brenner, M.; Doherty, E. T.; and Shipp, T. 1994. ìSpeech

Measures Indicating Workload Demand.î Aviation, Space, and Environmental Medicine. Vol. 65. p. 21-6;

Brenner, M.; Mayer, D.; and Cash, J. 1996. ìSpeech Analysis in Russia.î Methods and Metrics of Voice

Communications. Ed. B. G. Kanki and O. V. Prinzo. Department of Transportation, Federal Aviation

Administration, and Office of Aviation Medicine. DOT/FAA/AM-96/10. Washington, DC; and National

Transportation Safety Board. 1999. Uncontrolled Descent and Collision with Terrain, USAir Flight 427,

Boeing 737-300, N513AU, near Aliquippa, Pennsylvania, September 8, 1994. Aircraft Accident Report.

NTSB/AAR-99/01. Washington, DC. 

51 For additional information, see NTSB/AAR-99/01. 
24

NTSB/AAB-02/01

According to the speech study, the relief first officerís rate of speech did not increase

significantly when saying, ìI rely on God,î during the pitchdown and descent.

The Safety Board also examined the length of time between the relief first officerís

ìI rely on Godî statements for evidence of psychological stress. About 67 seconds passed

between the first and second utterances of the phrase, 8.1 seconds passed between the

second and third, and 0.51 to 0.70 seconds passed between subsequent utterances of the

phrase. According to the speech study, after the second utterance, the data suggested a

ìrhythmic repetition of the phrase rather than an accelerating trend, as might be expected

with increased psychological stress.î

The speech study concluded that, although the relief first officerís speech

displayed some evidence of increased psychological stress between the first and second

utterance of ìI rely on Godî (when the airplane was still in level flight at cruise altitude),

there was no evidence of increased psychological stress in the relief first officerís speech

after he uttered the phrase the second time. As previously discussed, after the second

utterance of the phrase, the airplane departed level flight to a steep nose-down pitch

attitude and experienced an increased nose-down pitch attitude and rate of descent and a

decrease in its load factor (to negative Gs) while the relief first officer repeated, ìI rely on

God,î the last nine times.

Unintelligible Comment

The Safety Boardís audio examination and sound spectrum analysis of the

unintelligible comment that was recorded by the CAM at 0148:30 showed that it appeared

to have characteristics consistent with human speech. It consisted of three syllables, with

the accent on the second syllable, and was probably spoken very softly (as shown by very

poor speech signal definition). The speech examination study indicated that the comment

was preceded by 19.2 seconds without speech and followed by 9.2 seconds without

speech, suggesting that it was an isolated statement rather than part of a conversation.

Unfortunately, the speech segment was not long or clear enough to determine what was

said and who said it. However, two speech characteristics of the unintelligible commentó

fundamental frequency and formant dispersionódisplayed values that, of the six pilotsí

speech that had been recorded earlier on the CVR tape, most closely resembled the speech

values displayed by the relief first officer.

As previously discussed, and as noted as follows in the CVR transcript:

The five Arabic speaking members of the [CVR] group concur that they do not

recognize this as an Arabic word, words, or phrase. The entire group agrees that

three syllables are heard and the accent is on the second syllable. Four Arabic

speaking group members believe that they heard words similar to ëcontrol it.í One

English speaking member believes that he heard a word similar to ëhydraulic.í

The five other members believe that the word(s) were unintelligible.
25

NTSB/AAB-02/01

Because the content of the comment (the word[s] and the language in which it was

spoken) could not be positively identified, the members of the Cockpit Voice Recorder

Group agreed to characterize the comment as ìunintelligible.î

Flight Data Recorder

The FDR installed on the accident airplane was a Sundstrand Data Corporation

(now named Honeywell Aerospace Electronic Systems) Universal Flight Data Recorder,

S/N unknown. Although the FDR unit exhibited external and internal structural damage

and the recording medium (magnetic tape) was wet, the tape was otherwise in good

condition. After waveform recovery techniques were used to correct areas of weak FDR

signals, a complete set of accident flight data, from takeoff through the last recorded FDR

parameter (which was recorded at 0150:36.64),52 was prepared.

Flight performance parameters recorded by the FDR included the following:

pressure altitude; airspeed (computed); engine rpm; pitch; roll; heading; angle of attack;

normal (vertical), longitudinal, and lateral acceleration (load factors); left and right

elevator positions; left and right inboard and outboard aileron positions; left and right

trailing edge flap positions; rudder position; and horizontal stabilizer position. In addition,

the FDR recorded speedbrake handle position, throttle resolver angle, autopilot

engagement/disengagement, engine low oil pressure, and engine fuel cut signals. The

FDR was not required to and did not record control wheel, control column, or spoiler

positions nor did it record control wheel and column forces.53 Excerpts from the FDR data

plots and CVR transcript are shown in figures 3a through 3h.

52 As previously discussed, the last FDR parameter was recorded at 0150:36.64, and the cessation of the

FDR data was consistent with the loss of electrical power that resulted from the engines being shut off.

53 Although control column position was not recorded by the FDR, the Safety Boardís testing and

evaluation of the 767 elevator system showed that any movement occurring at the control columns would

have resulted in concurrent, identifiable movements of the elevators, which would have been recorded on

the FDR. For additional information, see Flight Data Recorder Group Chairmanís Factual Report and its

attachments. Also, see the section of this report titled, ìTests and Research,î for a discussion of the

airplaneís performance during the emergency/accident sequence, as determined by the Safety Boardís

evaluation of the available FDR, radar, weather, and airplane performance data.
NTSB/AAB02/01

Figure 3a. A graph depicting selected FDR data from 1:47.40 to 1:48.40.
NTSB/AAB-02/01

Figure 3b. A graph depicting selected FDR data from 1:48.40 to 1:49.40.
NTSB/AAB02/01

Figure 3c. A graph depicting selected FDR data from 1:49.40 to 1:50.40.
NTSB/AAB-02/01

Figure 3d. A graph depicting selected FDR data from 1:49.40 to 1:50.40.
NTSB/AAB02/01

Figure 3e. A graph depicting selected FDR data from 1:49.40 to 1:50.40.
NTSB/AAB-02/01

Figure 3f. A graph depicting selected FDR data from 1:49.40 to 1:50.40.
NTSB/AAB02/01

Figure 3g. A graph depicting selected FDR data from 1:49.40 to 1:50.40.
NTSB/AAB-02/01

Figure 3h. A graph depicting selected FDR data from 1:49.40 to 1:50.40.
34

NTSB/AAB-02/01

WRECKAGE INFORMATION

About 70 percent of the airplane was recovered during the initial recovery

operations, which began on the morning of October 31 and ended on December 22, 1999.

Subsequent recovery efforts conducted between March 29 and April 3, 2000, resulted in

the recovery of the left engine and additional pieces of airplane wreckage.

Sonar mapping of the wreckage site depicted two distinct underwater debris fields,

which were identified by recovery personnel and investigators as the western and eastern

debris fields. These debris fields were about 366 meters (1,200 feet) apart from center

point to center point. The western debris field, which was estimated to be 62 meters by

66 meters and was centered about 40° 20' 57" north latitude, 69° 45' 40" west longitude,

contained mainly parts associated with the left engine and various other small pieces of

wreckage (including portions of two wing panels, fuselage skin, horizontal stabilizer skin,

and the majority of the nose landing gear assembly). The eastern debris field, which was

estimated to be 83 meters by 73 meters and was centered about 40° 20' 51" north latitude,

69° 45' 24" west longitude, contained the bulk of the airplaneís fuselage, wings,

empennage (including the outboard tips of the right and left elevators and all recovered

elevator PCAs), right engine, main landing gear, and flight recorders. Many pieces of

floating wreckage (including pieces of the right and left elevator surfaces)54 were

recovered from the waterís surface in or near the eastern debris field shortly after the

accident; specific recovery locations for some of these pieces were not noted. The small

size of most of the recovered pieces of wreckage was consistent with the airplane

impacting the water at a high speed. The locations of the two main wreckage debris fields

were consistent with the accident airplaneís flightpath, as indicated by the primary radar

data.55

The Safety Board leased a commercial vessel to recover the wreckage that had

settled on the ocean floor. Pieces of wreckage were recovered from a depth of about

230 feet using a clamshell scoop and a crane, loaded (using a front loader) into containers

on the recovery vessel, and moved to shore. Upon reaching shore, the containers of

wreckage were lifted off the recovery vessel and rinsed thoroughly twice. The containers

were then moved into the hangar at Quonset Point, Rhode Island, where they were tipped

onto their sides. The wreckage was then moved out of the containers onto the floor using

rakes and shovels. Once on the hangar floor, the wreckage was spread evenly by a front

loader to assist the drying process. During this process, FBI and Safety Board

investigators examined the recovered wreckage for evidence of fire or explosion damage.

The FBI placed identification tags on some of the debris; accident investigators then

documented all of the debris.

Four of the elevatorsí six PCAs (the center and outboard right elevator PCAs and

two elevator PCAs whose positions could not be determined)56 were recovered.

Postaccident examination revealed that all four of the recovered PCAs exhibited

54 In total, about 37 percent of the total elevator surface area was recovered.

55 For additional information, see the section titled, ìReview of Radar Data.î
35

NTSB/AAB-02/01

impact-related damage. One of the four also exhibited the following two unusual

characteristics on its internal mechanisms: (1) the pin that attaches the spring guide to the

valve slide was sheared, and (2) a portion of the bias spring (about one full coil) was

improperly positioned over the head portion of the spring guide. It could not be

determined whether these conditions existed before impact or whether they were impact

related. The Safety Boardís measurements of these components indicated that the inside

diameter of the servo valve cap into which the bias spring and spring guide fit was

0.872 inch and that the outside diameter of the spring guide at its widest point was

0.749 inch, leaving a clearance of 0.123 inch between the spring guide and the servo valve

cap. Measurements indicated that the bias spring wire had a diameter of 0.031 inch.

Impact marks and damage were observed on other components in this PCA; however,

there was no evidence of scraping, abrasion, or other marks on the improperly positioned

bias spring or adjacent surfaces that would indicate that these metal parts had jammed in

the PCA.57

Five of the elevatorsí six bellcranks (all three right elevator and two of the left

elevator bellcrank assemblies) were recovered. Postaccident examination of the recovered

bellcrank assemblies revealed that all of the shear rivets in the recovered bellcrank

assemblies were sheared,58 with the sheared surfaces appearing consistent with shear

overstress. However, the rivets in some of the bellcrank assemblies sheared in a direction

opposite to others; shear rivets in the two recovered bellcrank assemblies from the left

elevator surface and in the inboard bellcrank assembly from the right elevator surface

were sheared as if the bellcrank arms were moving to a higher relative angle, whereas the

shear rivets in the middle and outboard bellcrank assemblies from the right elevator

surface were sheared as if the bellcrank arms were moving to a lower relative angle. Most

of the recovered elevator control linkages were found broken or otherwise damaged.

Examination of the fracture surfaces on the recovered pieces of wreckage revealed

that the fractures were consistent with failures generated by a high-speed impact. None of

the fracture surfaces examined exhibited any sign of preexisting fatigue or corrosion. No

evidence of foreign object impact damage or pre- or postimpact explosion or fire damage

was observed.59

56 The right elevator center PCA was identified as such because of its location in recovered horizontal

stabilizer wreckage. The right elevator outboard PCA was identified as such by EgyptAir personnel, who

matched the PCAís S/N to their maintenance documents for the accident airplane. The condition of the other

two recovered PCAs precluded identification of their location on the airplane.

57 The Safety Board recognizes that a jam between two surfaces can occur without leaving any physical

evidence. However, as discussed in the Boardís report on the September 8, 1994, accident involving USAir

flight 427, tests conducted in connection with that accident investigation showed that physical evidence of a

jam was always observed after tests involving hardened steel chips jammed and/or sheared in a PCA.

58 As previously discussed, the shear rivets are designed to fail when they are subjected to about 50 lbs

of force or more at the control column, the PCA is jammed, and the compressible links are bottomed out. In

addition, shear rivets may fail as a result of impact or recovery-related forces.

59 For additional information, see Systems Group Chairmanís Factual Report and its appendixes and

addendum, Materials Laboratory Factual Report, and Structures Group Chairmanís Factual Report and its

appendixes and addendum.
36

NTSB/AAB-02/01

Examination of the left engine (which was recovered relatively intact) revealed

evidence of little, if any, rotation at the time of impact. The right engine was severely

broken up, and only about 80 percent of it was recovered. Examination of the recovered

portions of the right engine showed evidence of little, if any, rotation at the time of impact.

The observed deformations on the right engine were consistent with a steep impact angle,

whereas observed deformations on the left engine were consistent with an inverted,

slightly aft-end-down impact angle. Although the recovery location of and damage to the

left engine were consistent with it separating from the airplane before impact, no evidence

of any preimpact catastrophic damage or fire was observed on either engine.60

TESTS AND RESEARCH

Review of Radar Data 

Five radar sites detected primary and/or secondary returns from EgyptAir

flight 990. These sites are located at North Truro, Massachusetts; Riverhead, New York;

Gibbsboro, New Jersey; Oceana, Virginia; and Nantucket, Massachusetts. The Safety

Boardís examination of the available radar data revealed that four of the five radar sites

recorded no sequence of primary or secondary radar returns that intersected EgyptAir

flight 990ís position at any time nor did they reveal any radar returns consistent with a

projectile or other object traveling toward the accident airplane. Although the Riverhead

radar site recorded numerous radar returns near the flightpath of EgyptAir flight 990

within 5 minutes of the accident, none of the radar sites with areas of coverage that

overlapped this area of Riverheadís coverage recorded similar radar returns. Consultation

with the USAF Radar Evaluation Squadron revealed that the primary returns in question

from the Riverhead radar site were caused by radio frequency interference from the Bucks

Harbor, Maine, long-range radar site.

No secondary radar returns were received from EgyptAir flight 990 after 0150:36

(about the time the CVR and FDR stopped recording); however, after this time, several

radar sites recorded primary radar returns that continued along the accident airplaneís

extended flightpath from its last recorded radar position. As previously discussed, these

primary radar data (with extrapolated FDR data and simulation results) indicated that after

the airplaneís FDR and CVR stopped recording, the airplane descended to an altitude of

about 16,000 feet msl, then climbed to about 25,000 feet msl and changed heading from

80o to 140o before it began its second descent, which continued until it impacted the

ocean.61

60 For additional information, see Powerplants Group Chairmanís Factual Report.

61 For additional information, see the Aircraft Performance Group Chairmanís Aircraft Performance

Study.
37

NTSB/AAB-02/01

Accident Sequence Study 

The Safety Board used the FDR, radar, winds aloft, and 767 performance data to

determine the accident airplaneís motions and performance during the accident sequence.

These data (and associated calculations) indicated the following:

ï Aside from the very slight movement of both elevators (the left elevator moved

from a 0.7° to about a 0.5° nose-up deflection, and the right elevator moved

from a 0.35° nose-up deflection to about a 0.3° nose-down deflection)62 and

the airplaneís corresponding slight nose-down pitch change, which were

recorded within the first second after autopilot disconnect at 0149:45, and a

very slow (0.5o per second) left roll rate, the airplane remained essentially in

level flight about FL 330 for about 8 seconds after the autopilot was

disconnected.

ï At 0149:53, the left and right throttles were retarded to the aft idle stop

(equivalent to a throttle lever angle of about 33o) at a rate of about 25o per

second.63 About 1 second after the start of the throttle movement, the FDR

recorded slight motion in the inboard ailerons, the left elevator surface moved

to about a 3.4o TED position, and the right elevator surface moved to about a

3.8o TED position.64

ï At 0149:54, the airplane began to pitch nose down, reaching a pitch attitude of

about 40o nose down at 0150:15. During the dive, the wings remained within

about 10o of level and the heading remained about 80o, increasing to about 85o

between 0150:20 and 0150:33.

ï Between 0150:05 and 0150:06, the FDR recorded additional movements in the

inboard ailerons, and the left and right elevators moved an additional 1.5o TED

to about 5.5o TED. Before this time, the load factor had been about 0.2 G; after

this time, the load factor decreased to about -0.1 G. Between 0150:06 and

0150:10, the FDR began to record ìLow Engine Oil Pressureî signals for both

engines; the FDR recorded these signals until after the load factor increased to

above 0 G between 0150:17 and 0150:21.65

62 Throughout the FDR data for the accident airplane (including data recorded during uneventful

portions of the accident flight and during previous flights and ground operations), small (generally less

than 1° ) differences between the left and right elevator surface positions were observed. The elevator

surface movements were consistent (that is, moved in the same direction about the same time) where these

offsets were observed.

63 As previously mentioned, at the accident airplaneís flight conditions at the beginning of the accident

sequence, the minimum autothrottle commanded throttle lever position would have been between 40o and

50o; this value would have decreased as the airplaneís airspeed increased. The maximum autothrottle

commanded throttle lever movement rate for a normally functioning autothrottle system is 10.5o per second. 

64 Elevator movement in the TED direction would result in a decrease in the airplaneís lift and load

factor and an increase in the airplaneís nose-down attitude.
38

NTSB/AAB-02/01

ï At 0150:08, as the airplane passed through about 30,800 feet msl, the airplane

exceeded its maximum operating airspeed (0.86 Mach), and the Master

Warning alarm sounded. The maximum rate of descent recorded during the

dive was about 39,000 fpm at 0150:19, as the airplane descended through

about 24,600 feet msl. At 0150:23, the airspeed reached its peak calculated

value of 0.99 Mach, as the airplane descended through about 22,200 feet msl.

ï At 0150:15 and about 27,300 feet msl, the left and right elevator surfaces

started to move slowly (about 0.6o per second) in the trailing-edge-up (TEU)

direction, back toward their neutral position. The pitch angle, angle of attack,

and load factor also started to increase at this point, so that when the FDR

recorded the last data for the accident flight at 0150:36.64, the pitch angle had

increased to about 8o nose down, and the airplane was experiencing about

2.4 Gs.

ï Between 0150:18 and 0150:27, the FDR recorded TEU movements of the left

and right outboard ailerons and the left inboard aileron.66

ï At 0150:21, the left and right elevator surfaces started to split (that is, to move

asymmetrically). The right elevator surface started to move TED, whereas the

left elevator surface moved TEU. This split between the left and right elevator

surface positions continued to the end of the FDR data, varying in magnitude

but averaging about 4o difference between the surfaces (see figure 2).

ï Between 0150:21 and 0150:23, the engine start lever switches for both engines

moved from the run to the cutoff position.

ï Between 0150:24 and 0150:25, both throttle handles moved full forward.

ï Between 0150:25 and 0150:26, the speedbrake handle moved to its fully

deployed position. Coincident with this activity, between 0150:24 and

0150:27, the left elevator surface moved briefly in the TED direction (from

3o TEU to 1o TEU) before it returned to 3o TEU.

ï Almost immediately after the speedbrakes were deployed at 0150:26, the left

elevator surface deflection increased further, reaching its maximum deflection

of more than 3.8o nose up about 0150:30.67 After 0150:30, the left elevatorís

nose-up deflection gradually reduced, until the data for that parameter ended at

0150:36 with a left elevator deflection of about 2.3o nose up.

65 The Safety Boardís examination of Boeingís 767 certification flight test data revealed that the low oil

pressure warnings for P&W 4060 engines would occur when the engineís oil pressure drops below 70 lbs

per square inch, as occurred when the accident airplane was operating at low (near 0) load factors. (For

additional information, see Powerplants Group Chairmanís Factual Report and appendixes 1 through 8.)

66 According to Boeing, these movements were consistent with the effects of blowdown on those

surfaces as documented during flight tests. However, the outboard aileron split recorded by the FDR after

about 0150:27, which is discussed later in this section, was not consistent with the flight test data.

67 As previously discussed, Safety Board simulations demonstrated that a pilot in the left seat could have

moved his right hand from the control wheel to the throttle, advanced the throttles, moved his hand a little to

the left, and deployed the speedbrakes in the 3 to 4 seconds it took for these events to occur.
39

NTSB/AAB-02/01

ï Between 0150:21 and 0150:24, the right elevator surfaceís nose-down

deflection increased gradually, then increased rapidly until just after 0150:25,

when the nose-down deflection briefly reduced from about 2.35o to about 1.9o

nose down. Between 0150:21 and 0150:23, the engine start levers moved to the

cutoff position. At 0150:26, the right elevatorís nose-down deflection began to

increase again, reaching its maximum nose-down deflection of about 3.2o at

0150:29. Subsequently, the right elevatorís deflection moved generally toward

a nose-up position, with occasional movements in a nose-down direction;

when the FDR data ended, the right elevator deflection was 0.2o nose down.

ï Between 0150:27 and 0150:32, the FDR recorded a split condition in the

outboard ailerons (the left outboard aileron maintained its approximate presplit

deflection, while the right outboard aileron began to move in a TED direction).

68

The outboard ailerons had been moving in a TEU direction since 0150:18.

ï During the elevator split, the larger movements of the left and right elevators

individually corresponded with changes in the load factor (see figure 4). For

example, between 0150:30 and 0150:36, the recorded movements of the right

elevator (lower graph) are reflected in the load factor profile (upper graph).

ï No secondary radar returns were received from the accident airplane after the

last data were recorded by the FDR at 0150:36.64.

ï Performance calculations based on primary radar returns indicated that the

airplaneís rapid descent stopped at an altitude of about 16,000 feet msl. The

primary radar returns indicated that the airplane then began to climb, reaching

about 25,000 feet msl about 0151:15. During this climb, the airplaneís heading

changed from about 80o to about 140o.

ï After 0151:15, the data indicated that the airplane began a second rapid descent

that continued until it impacted the ocean.

Seven primary radar returns from the airplane were recorded during the second

dive; the altitude estimates from these returns are subject to potentially large errors, which

introduces significant uncertainty into the performance calculations during the second

dive. However, the data indicate that the airplane impacted the ocean about 0152:30, with

an average descent rate during the second dive of about 20,000 fpm.

68 Wind tunnel tests and computational fluid dynamics analyses show that a small sideslip angle and/or

roll rate could produce large changes in the aerodynamic forces acting on the outboard ailerons at speeds

approaching Mach 1.0, but these forces would not likely be strong enough to cause the split elevator

condition recorded by the accident airplaneís FDR. For additional information, see Aircraft Performance ñ

Addendum #1.1, Addendum to Group Chairmanís Aircraft Performance Study, including appendixes B and

C (correspondence from Boeing, dated April 12 and 16, 2001).
40

NTSB/AAB-02/01

Potential Causes for Elevator Movements During the Accident Sequence

Investigators used Boeingís six-degree-of-freedom, full-flight engineering

simulator (which incorporated, to the maximum extent possible, the flight characteristics

of the 767) to evaluate whether the accident airplaneís recorded pitch motions were

consistent with the elevator position movements recorded on the FDR.69 The results

showed that the elevator movements required to make the simulator duplicate the pitch

motions and flightpath recorded on the FDR were consistent with the elevator movements

recorded by the FDR throughout the recorded data, even during the time that the data

69 The simulator data are based on wind tunnel tests and updated with available flight test data. The

maximum Mach number for which the simulator is programmed (Mach 0.91) corresponds to the airplaneís

never-exceed airspeed. The maximum speed calculated for the accident airplane during the accident

sequence was Mach 0.99 at 0150:23. To evaluate the performance of the airplane at Mach numbers greater

than 0.91, the simulatorís database was adjusted to reflect extrapolations, based on 777 wind tunnel tests.

(The 767 and 777 have aerodynamically similar horizontal stabilizers and elevators.)

01:49:40 01:49:45 01:49:50 01:49:55 01:50:00 01:50:05 01:50:10 01:50:15 01:50:20 01:50:25 01:50:30 01:50:35 01:50:40

-6

-4

-2

0

2

4

6

8

ELEVATOR & STAB TRAILING EDGE DOWN

ELEVATOR & STAB TRAILING EDGE UP

Surface Position, deg.

 Left Elevator

 Right Elevator

 Stabilizer (Units)

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

ACK ASR-9 Time, HH:MM:SS EST

Normal Load Factor, g's

Figure 4. Graphs depicting the accident airplaneís normal load factor response to

elevator and stabilizer movement.
41

NTSB/AAB-02/01

indicated a split between the left and right elevator surfaces.

70 The investigation attempted

to determine if any mechanical failures could have caused these elevator movements.

The Systems Group reviewed numerous potential failure scenarios to evaluate

whether any of them might have been capable of causing the elevator surface movements

recorded on the FDR during the accident sequence, including failures associated with the

elevator systemís flight control cables,71 failures associated with elevator surface PCAs,72

and other system-related failures.73 On the basis of the results of failure modes and effects

analyses, the Safety Board ruled out all but four of these potential failure scenarios

because they failed to reflect the accident flightís elevator movements in obvious and

significant ways.74 For example, it was determined that neither an autopilot malfunction

nor EMI75 would have caused any elevator movements during the accident sequence.76

Although some of the other scenarios could have caused some elevator movements, the

nature and degree of those movements differed so greatly from the elevator movements

recorded during the accident flight that they did not warrant further consideration.

However, the failure modes and effects analyses showed that the following four

elevator failure scenarios (each of which involves two failures) warranted further study

because they could potentially cause nose-down elevator movements or a split elevator

condition that might resemble some portions of the data recorded on the accident flightís

FDR:

1. Disconnection of the input linkages to two of the three PCAs on the right

elevator surface. This failure scenario could be caused by the failure of any of

the components that comprise the actuator input linkage system, including the

bellcranks.

70 For additional information, see Systems Group Chairmanís Factual Report and its appendixes and

addendums, Flight Data Recorder Group Chairmanís Factual Report and its attachments, Cockpit Voice

Recorder Group Chairmanís Factual Report and Sound Spectrum Study, and the Aircraft Performance

Group Chairmanís Aircraft Performance Study and its attachments and addendum.

71 The cable-related failures considered included a single failed elevator body cable; a failed slave cable;

a failed component or other object falling on elevator cables; a cable tension regulator failure; an aft pressure

bulkhead failure, resulting in cable displacement; and a cable break combined with a jam in the same cable.

72 The elevator PCA-related failure scenarios considered included an input rod/cable jammed at an

offset position (position jam), an input arm for a single PCA jammed at an offset position to command a

specific control surface rate of movement (rate jam), failure of the bellcrank assemblies on all three of the

PCAs on a single elevator surface, jam of the input linkage or servo valve of one PCA with a high breakout

force compressible link (a high breakout force compressible link would allow more force to be transmitted

to the input linkages of the nonfailed side before compressing and negating the jammed PCA),

disconnection of the input linkages to two of the three PCAs on a single elevator surface, a jam of the input

linkage or servo valve on one PCA and the disconnection of the input linkage to another PCA on a single

elevator surface, and a jam of the input linkages or servo valves in two of the three PCAs on a single elevator

surface.

73 The other system-related failures considered included erroneous stick nudger activation; air in the

hydraulic system and elevated return pressure; hydraulic system failure to one surface; elevator position

transducer disconnect, resulting in erroneous indications on the FDR of an elevator surface offset or split; a

single linkage disconnect downstream of feel unit; a failure of the elevator feel unitís attachment to aircraft

structure; electromagnetic interference (EMI); and an autopilot malfunction such as a servo jam, resulting in

a hardover autopilot output. 
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2. A jam of the input linkages or servo valves in two of the three PCAs on the

right elevator surface. In order for this failure scenario to occur, the internal

slides of the affected servo valve would first have to be moved (by manual or

autopilot input) to an offset position and then jam. Although such jams could

theoretically occur in either direction, all tests and simulations involving

jammed elevator PCAs were intentionally configured to produce nose-down

(rather than nose-up) elevator input.

3. A jam of the input linkage or servo valve in one PCA and the disconnection of

the input linkage to another PCA on the right elevator surface.

4. A jam in the elevator flight control cable connecting the right-side control

column to the right aft quadrant assembly combined with a break in the same

cable. (Four variants of this scenario were studied. For additional information,

see the Systems Group Chairmanís Factual Report and its addendum regarding

the cable break/jam and PCA jam with high breakout force [compressible link]

ground testing.) 

For further evaluation, the Systems Group conducted ground tests on an

instrumented 767 to record the elevator systemís response to each of these failure

scenarios. During the ground tests, the test airplaneís systems were configured to simulate

the accident airplaneís altitude and airspeed. The Systems Group also studied the effect

that each failure scenario would have on the elevator control system and calculated the

effect on the elevators that each scenario would have had at the specific conditions of the

accident flight at the time of the initial pitchdown. The results of the tests, studies, and

calculations were as follows:

1. Disconnection of the input linkages to two of the three PCAs on the right

elevator surface.

ï During the ground tests, the failed elevator surface was driven to its full

nose-down position and would not respond to nose-up flight control inputs

from either control column. A study of the elevator control system indicated

that if this scenario occurred in flight, it would result in an initial deflection of

the failed surface to a position consistent with a single functioning elevator

PCA operating at 100 percent of its maximum force (as limited by

aerodynamic blowdown forces); the failed elevator surface would resist being

74 For additional information, see Systems Group Chairmanís Factual Report and its appendixes.

75 EMI is electromagnetic radiation that is emitted and/or received by an electronic device and adversely

affects the performance of that device or other devices. 

76 An autopilot malfunction was ruled out as a potential cause of the elevator movements because the

autopilot was disconnected before the beginning of the nose-down elevator movements. Even assuming that

the autopilot was engaged during the accident sequence, the elevator movements recorded by the FDR

exceeded the maximum inputs that could be commanded by the autopilot. EMI was ruled out because

elevator surface movements are not electrically actuated (and, therefore, are not susceptible to the effects of

EMI) except through the autopilot. (When the autopilot is not engaged, elevator surface movements on the

767 are mechanically signaled and hydraulically actuated.) 
43

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backdriven with a force equivalent to about 130 percent of a single functioning

PCA.77 Calculations showed that at 280 knots (the accident airplaneís airspeed

when the initial descent began), this position would initially have been about

6o nose-down elevator deflection, and the degree of deflection would be

reduced as the airplaneís speed increased above 290 knots. See figure 2 for

additional elevator blowdown position information.78

ï During the ground tests, the nonfailed elevator surface remained in its

prefailure position unless it received inputs from either control column. A

study of the elevator control systemís force balance and calculations of the

effect of this failure under the conditions of the accident flight indicated that

the nonfailed surface would remain in its prefailure position.

ï During the ground tests, either control column could be used to control the

nonfailed elevator surface and to command the full travel of that surface

available at the existing flight condition. The Safety Boardís study of the

elevator control system indicated that under the accident flight conditions,

inputs from either control column would have resulted in corresponding

movement of the nonfailed elevator surface.

2. A jam of the input linkages or servo valves in two of the three PCAs on the

right elevator surface.

ï During the ground tests, the failed elevator surface was driven to its full

nose-down position and would not respond to nose-up flight control inputs

from either control column. A study of the elevator control system indicated

that if this scenario occurred in flight, it would result in an initial deflection of

the failed surface to a position consistent with a single functioning elevator

operating at 100 percent of its maximum force (as limited by aerodynamic

blowdown forces); the failed elevator surface would resist being backdriven

with a force equivalent to about 130 percent of a single functioning PCA. As

discussed in connection with the previous failure scenario, calculations showed

that, under the conditions of the accident flight, this position would initially

have been about 6o nose-down elevator deflection, and the degree of deflection

would be reduced as the airplaneís speed increased above 290 knots.

ï During the ground tests, the nonfailed elevator surface moved to about

4o nose-down deflection in the same direction as the failed surface. A study of

the elevator control systemís force balance and calculations of the effect of this

failure under the conditions of the accident flight indicated that the nonfailed

surface would move to a position corresponding to 30 lbs of feel force.79

77 For a detailed explanation of why a failed surface would deflect to this position, see the Aircraft

Performance Group Chairmanís Factual Report and its addendum 1.1.

78 Elevator hinge moment data provided by Boeing were used to estimate the 767 elevator blowdown

positions during the first three failure scenarios. Boeing extrapolated available elevator data based on

Boeing 777 wind tunnel data, which were available for Mach numbers 0.91, 0.94, and 0.96. (As previously

stated, the 767 and 777 have aerodynamically similar horizontal stabilizers and elevators.)
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Calculations showed that under the conditions of the accident flight when the

initial descent began, the degree of deflection for the nonfailed surface would

be the same as during the ground tests (about 4o).

ï During the ground tests, either control column could be used to control the

nonfailed elevator surface and to command that surface in either the nose-up or

the nose-down direction.80 The Safety Boardís study of the elevator control

system indicated that under the accident flight conditions, inputs from either

control column would have resulted in corresponding movement of the

nonfailed elevator surface.

3. A jam of the input linkage or servo valve in one PCA and the disconnection of

the input linkage to another PCA on the right elevator surface.

ï During the ground tests, the failed elevator surface was driven to its full

nose-down position and would not respond to nose-up flight control inputs

from either control column. A study of the elevator control system indicated

that if this scenario occurred in flight, it would result in an initial deflection of

the failed surface to a position consistent with a single functioning elevator

operating at 100 percent of its maximum force (as limited by aerodynamic

blowdown forces); the failed elevator surface would resist being backdriven

with a force equivalent to about 130 percent of a single functioning PCA. As

discussed in connection with the previous failure scenarios, calculations

showed that, under the conditions of the accident flight, this position would

initially have been about 6o nose-down elevator deflection, and the degree of

deflection would be reduced as the airplaneís speed increased above 290 knots.

ï During the ground tests, the nonfailed elevator surface moved to about

2.1o nose-down deflection in the same direction as the failed surface. A study

of the elevator control systemís force balance and calculations of the effect of

this failure under the conditions of the accident flight indicated that the

nonfailed surface would move to a position corresponding to 15 lbs of feel

force. Calculations showed that under the conditions of the accident flight

when the initial descent began, the degree of deflection for the nonfailed

surface would be the same as during the ground tests (about 2.1o).

79 Feel force is the amount of force generated by the aircraftís feel-and-centering unit. In normal

operation, the feel force is a function of control column deflection and aircraft flight condition. If a jam of

the input linkages or servo valves in two of the three PCAs on a single elevator surface occurred, the

airplaneís feel-and-centering unit would provide a force to oppose the forces needed to deflect the

compressible links on the input side of the failed elevator PCAs.

80 To avoid shearing the test airplaneís bellcrank rivets during the ground tests evaluating the two failure

scenarios that involved jammed PCA linkages and/or servo valves, full travel of the elevator surface was not

commanded. However, a study of the elevator control system indicated that full travel of the nonfailed

surface could have been achieved under these two failure scenarios, if commanded.
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NTSB/AAB-02/01

ï During the ground tests, either control column could be used to control the

nonfailed elevator surface and to command that surface in either the nose-up or

the nose-down direction. The Safety Boardís study of the elevator control

system indicated that under the accident flight conditions, inputs from either

control column would have resulted in corresponding movement of the

nonfailed elevator surface.

4. A jam in the elevator control cable connecting the right-side control column to

the right aft quadrant assembly combined with a break in the same cable.

ï During the ground tests, the left elevator surface moved to nose-down

deflections of 1.2o to 3.9o and the right elevator surface moved to nose-down

deflections of 1.4o to 5.0o, depending on the scenario tested. Analysis of the

elevator system indicated that if such failures occurred in flight, the resultant

elevator surface positions would not have varied as a result of changes in the

aerodynamic forces acting on the elevator in the same manner as the previous

three failures because all three PCAs would still be functioning properly.

ï During the ground tests for all break/jam combinations, either control column

could be used to control both elevator surfaces. Testing showed that a pull from

either control column of 25 lbs would result in sufficient movement of both

elevators in a nose-up direction to be evident on the FDR. A pull from either

control column of 50 to 100 lbs would result in sufficient movement of both

elevators in a nose-up direction to either reverse or significantly slow the

airplaneís nose-down dive.

Pilots from Boeing, EgyptAir, the FAA, and the Safety Board evaluated the

controllability of the airplane following the first three of these failure scenarios in

Boeingís fixed-base engineering simulator. The simulations assumed that the right

elevator was affected by the failure scenario being evaluated and duplicated the airplaneís

response to the occurrence of that scenario. As previously mentioned, the simulator

reflected the flight characteristics of the 767 to the maximum extent possible. Although all

flight conditions (for example, airspeed, altitude, roll attitude, load factor, and pitch

attitude) were calculated correctly in the simulator, the fixed-base simulator could not

duplicate the physical sensations that would have resulted from these flight conditions.

For example, the load factors that would be produced under actual flight conditions were

not produced in Boeingís fixed-base simulator nor were the actual attitude changes that

would have occurred in flight.81 In addition, the simulator did not model the override

mechanisms between the two control columns.

Simulations of the three failure scenarios showed that it was possible to regain

control of the airplane using either control column and return it to straight and level flight

using normal piloting techniques and that the airplane could be trimmed to hands-off level

flight after each of the three failure scenarios occurred.82 Further, for all three failure

81 The simulatorís cockpit displays did replicate the visual cues (cockpit instrument displays and

out-the-window presentation) that would have been present during actual flight.
46

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scenarios, full recovery was possible even when no efforts were made to recover the

airplane until 20 seconds after the failure occurred. Although additional force beyond that

required for recovery from a dive of this magnitude without a failure was necessary in all

tested scenarios, the nonfailed surface responded immediately to nose-up inputs and

recovery could be accomplished by a single pilot using either the left or right control

column. Although the recovery was easier and the required control column force was

reduced when stabilizer trim was used, it was not necessary to use stabilizer trim to

recover from any of the three failure scenarios. Further, the simulations also demonstrated

that the engines could have been restarted throughout most (if not all) of the recovery from

the dive and/or the subsequent climb and that the airplane could have been returned to

straight and level flight after the recorders stopped recording. The elevator deflections

resulting from the fourth scenario were less extreme, and would therefore be easier to

recover from, than those resulting from the first three failure scenarios.

Additional Information

Submissions

The Safety Board received submissions from EgyptAir,83 Boeing, and P&W.84

(Note: The fourth failure scenario [a cable jam with a break of the same cable] was studied

after these submissions were received; therefore, these submissions do not reference this

scenario.)

EgyptAirís April 28, 2000, Presentation

During EgyptAirís April 28, 2000, presentation to the Safety Board, its

representatives stated, in part, the following:

ï The suicide scenario is not consistent with data and facts of [the EgyptAir

flight 990] accident.

82 For additional information, see Systems Group Chairmanís Factual Report and its addendum

regarding the ground and simulation testing.

83 EgyptAir provided the Safety Board with a presentation and several documents and letters that

documented its position, including the following: a presentation, dated April 28, 2000; a formal submission,

dated August 11, 2000; and a document, dated January 12, 2001, titled, ìResponse of EgyptAir to

October 31, 2000, Submission of The Boeing Company Regarding the EgyptAir Flight 990 Investigation.î

These documents and letters are available in the public docket for this accident.

84 The Egyptian Government also provided the Safety Board with additional documents, including the

following: (1) the Egyptian Governmentís comments regarding the Boardís draft report of this accident,

(2) the Egyptian Governmentís own report regarding this accident, and (3) the Egyptian Governmentís

addendum to its report regarding this accident. Although these documents are not submissions, and therefore

are not discussed in this section, they are available for review. The Egyptian Governmentís comments

regarding the Boardís draft report are attached to this report, and the Egyptian Governmentís accident report

and its addendum are available in the public docket for this accident.
47

NTSB/AAB-02/01

ï [Left and right] elevator deflection as a result of right elevator dual PCA jam is

consistent with the FDR data where Boeing data is valid.

ï In the area beyond the airplane normal design envelope where the data is not

valid, all the flight control behavior is uncertain, control surfaces are subject to

flutter.

ï The right elevator middle and outboard bellcrank rivets shear direction is

consistent with a jammed PCA reacting against pilot input to move the elevator

up.

ï Analysis revealed that there are a lot of [radar] returns forming continuous

paths crossing the flightpath of [EgyptAir flight 990], which may reflect

deliberate [evasive] action by one of the pilots.

EgyptAirís August 11, 2000, Submission

In its August 11, 2000, submission, EgyptAir asserted that ground tests and

simulations conducted during the investigation were flawed because simulations were

conducted using Boeingís published 767 data and ìdid not reflect the actual operation of

the airplaneî; steady-state values were used to calculate the control column forces in

various dynamic flight conditions, thus invalidating conclusions; and extrapolation of data

for calculated airplane speeds in excess of those for which test data existed (Mach 0.91)

ìcannot produce accurate results.î

EgyptAir also argued in its submission that the relief first officer did not

deliberately cause the accident. According to the submission, ìthe deliberate act theory

was based, in large part, on the initial inaccurate translation of an expression repeated

several times by the [relief] first officerÖ[which] has been eliminated not only by credible

evidence and analysis but also by accurate translation of the CVR.î EgyptAir further

stated that (1) the relief first officer had no motive to kill himself or others aboard

EgyptAir flight 990; (2) the relief first officer did not use his seniority to insist that he be

allowed to fly the airplane; (3) the relief first officer may not have been alone in the

cockpit at the onset of the dive; and (4) the captain returned to the cockpit almost

immediately after the dive started, and there was no indication of a struggle or

disagreement between the two flight crewmembers. EgyptAir further stated that ìthe

cockpit conversations showed an effort at teamwork rather than a crew working at cross

purposes.î Further, EgyptAir indicated that several of the relief first officerís actions were

not consistent with a deliberate attempt to crash the airplane. For example, it stated that

the cockpit door was not closed and locked; the throttle levers were moved to idle,

whereas engine power would have accelerated the descent; and more radical flight control

inputs were available (more nose-down elevator deflection or aileron and rudder with

elevator deflections) but not used.

EgyptAir also contended in its submission that at least three flight crewmembers

were in the cockpit during the descent, as evidenced ìby the fact that if either the captain

or [relief] first officer had let go of their control columns to shut the engines or to deploy
48

NTSB/AAB-02/01

the speedbrakeÖthe aircraft would have pitched down at the same time.î The EgyptAir

submission further stated that the split elevators ìdo not support the conclusion that there

was a struggle in the cockpitî because (1) the CVR provides no indication of a struggle,

argument, or refusal to follow a command; (2) the FDR recorded control surface positions

but did not record the control column position or forcesóìaccordingly, one cannot

conclude from examining only the FDR data that pilot input to his control column caused

the elevators to be in a given positionî; and (3) ìat the same moment the elevators split,

both outboard ailerons moved upwardÖwhen this unusual aileron movement occurred

during the dive, the aircraftís speed was approaching Mach 1.0, and no published

performance data is available to predict what will occur to ailerons at these high speeds. It

is likely, however, that aerodynamic shocks or flutter were occurring at the control

surfaces.î

In its submission, EgyptAir summarized its position as follows:

ï Accordingly, from an impartial review of the factual evidence gathered during

the investigation, it is clear that the [relief] first officer did not intentionally

dive the aircraft into the ocean.

ï At this point in the investigation considering the factual evidence gathered, it is

clear that the first officer did not commit suicide. Further investigation of the

elevator control systemís design in conjunction with the other factual

information available is necessary before a conclusion can be reached

regarding the true cause of this accident. Specifically, further engineering

analysis, including wind tunnel tests, is necessary to examine the dual actuator

malfunction in the speed ranges for which current data is not available. In

addition, further investigation of radar data is also necessary to completely rule

out the possibility of conflicting traffic. Until this work is accomplished, the

cause of this accident cannot be truly established.

ï An analysis of the facts and of the elevator control systemís design indicates

that malfunctions in two PCAs on the right elevator may have precipitated the

airplaneís dive. This dual PCA malfunction may have consisted of a latent or

nearly latent failure in one PCA that may have existed for a period of time

followed by a jam of a second PCA shortly before the dive.

ï The facts do not support the initial, and widely reported, theory that the [relief]

first officer deliberately dove the plane toward the ocean.

ï Without further information concerning the data from military and FAA radar,

one cannot rule out the possibility that the [relief] first officer may have been

attempting to avoid or maneuver the aircraft out of a perceived dangerous

situation at the time the dive occurred.

Boeingís Submission

Boeingís October 31, 2000, submission indicated that none of the mechanical

failure modes examined during the investigation were consistent with the FDR data
49

NTSB/AAB-02/01

because (1) ìthe FDR elevator positions did not displace to the positions [predicted by the

failure mode and effects analysis] during the initial pitchoverî and (2) ìthe elevator

motions after the initial pitchover indicate that both surfaces were functioning normally.î

Boeing also considered several operational scenarios, including collision

avoidance, rapid descents, response to engine oil pressure lights, and loss of thrust on both

engines. Boeingís submission stated that, ìEgyptAir 990 crew actions were determined to

be inconsistent with the performance of standard Boeing recommended operating

procedures and training for the 767 airplane.î

In its submission, Boeing summarized its position as follows:

ï Flight control surface movements recorded on the [FDR] are capable of

generating the airplane flight path recorded by the [FDR] and radar.

ï Based on the examination of the recovered wreckage, Boeing did not find any

evidence of a failure condition within the airplane flight control system that

could have caused or contributed to the initial pitchover, or prevented recovery

from the dive.

ï Boeing participated in examining all potential failure conditions developed

during the investigation and could not find a failure condition that: (1) matched

the data recorded by the [FDR] or (2) resulted in a condition that was not

recoverable by the pilot.

ï Therefore, Boeing does not believe that the loss of EgyptAir 990 was the result

of a mechanical failure of the aircraft or aircraft systems.

EgyptAirís January 12, 2001, Response to Boeingís Submission

In its January 12, 2001, response to Boeingís submission, EgyptAir stated that

Boeing did not ìaccount for orÖcomment onî the FAAís ADs regarding bellcrank shear

rivet failures in its submission. However, EgyptAirís response to Boeingís submission

indicated that it could not determine whether the bellcrank shear rivet failures were

involved in the accident, ì[the FDR data were] remarkably consistent with test data of a

jam of two right elevator servos in the trailing edge down position.î EgyptAir further

stated that ìthe differences between the test data and the FDR can be adequately explained

as either performance variances within normal limit or limitations of the test facilities and

protocols.î

Additionally, EgyptAirís response to Boeingís submission indicated that there was

evidence of a mechanical malfunction of the elevator system; specifically, EgyptAir cited

the reported autopilot difficulties during an approach to LAX the day before the accident

and the downward elevator deflections recorded by the FDR at autopilot disconnect.

EgyptAir stated the following:

[This evidence] shows that an anomaly existed in the flight 990 elevator system

even before the aircraft left New York for Cairo on October 31, 1999óa latent
50

NTSB/AAB-02/01

defect that could not be detected by the crew. In light of these facts, it is plausible

to believe thatójust as [the captain of the flight into LAX] had done a day

earlieróthe [relief] first officer on flight 990 disconnected the autopilot after

observing some unusual movement of the column.

The EgyptAir response to Boeingís submission also stated that examination of the

recovered wreckage ìindicated damage to the elevator system prior to impact.î

Specifically, EgyptAir asserted that the damage to the right outboard PCA (sheared pin

and improperly positioned bias spring) and right elevator bellcrank shear rivets (failed in

opposite directions) likely occurred before the airplane impacted the ocean.

Further, in its response to Boeingís submission, EgyptAir reiterated its position

that its analysis of the elevatorís motions85 indicated that the elevator split observed in the

FDR data was not the result of a struggle between the captain and the relief first officer.

The response stated that the split ìmay [have been] the result of the loss of the right

elevator.î To support this statement, EgyptAir asserted that (1) there was no indication on

the CVR transcript that a struggle occurred in the cockpit; (2) the uncommanded elevator

positions might have resulted from unique aerodynamic phenomena as the airplaneís

speed increased; (3) when an FDR records elevator position, it is actually recording the

sensor position, which does not, by itself, indicate the position of the elevator or the

control column; and (4) the pitch and roll motions recorded during the last 15 seconds of

FDR operation were ìmuch closer to the expected aircraft performance if the right

elevator is missing.î

EgyptAirís response to Boeingís submission also stated the following:

EgyptAir has determined that the FDR flight profile after the split is consistent

with the expected aircraft performance only if the right elevator has departed the

airplaneÖ.this conclusion is based upon the absence of expected rolling moment

that would have been induced by a differential deflection of the elevatorsÖshown

on the FDR.

In addition, EgyptAirís response stated the following:

ï Boeingís engineering simulator did not provide an accurate model of real

aircraft performance.

ï Boeing often ignored the more reliable ground test results.

ï Boeingís selective use of test data resulted in inconsistent conclusions.

ï Boeingís conclusions regarding crew actions are erroneous.

85 For its analysis of the elevator motions, EgyptAir used the methods of Roskam (Airplane Design,

Part VI, Roskam Aviation and Engineering Corporation).
51

NTSB/AAB-02/01

In its response to Boeingís submission, EgyptAir summarized its position as

follows:

ï Boeingís submission to the NTSB [National Transportation Safety Board]

dated October 31, 2000, contains many inaccuracies, omissions, and the

selective use of evidence.

ï Boeingís own ground test and simulator data does not support its conclusion

that FDR data is inconsistent with a dual jam scenario.

ï A dual PCA control valve failure on the right elevator is consistent with the

EgyptAir flight 990 FDR data.

ï There is physical evidence consistent with a malfunction in the elevator control

system which might be a plausible cause for the accident.

P&Wís Submission

In an October 6, 2000, letter, P&W stated that it believed that ìthe facts, as

gathered to date, sufficiently represent Pratt & Whitneyís perspective on this crash.

Therefore, Pratt & Whitney will not be providing a further submission to be considered

during the development of the final report.î
52

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ANALYSIS

General 

The command captain and relief first officer were properly certificated and

qualified and had received the training and off-duty time prescribed by applicable

regulations and company requirements. (For more detailed information regarding the

background and recent activities of all EgyptAir flight 990 crewmembers, see the

Operational Factors Group Chairmanís Factual Report and the Human Performance

Group Chairmanís Factual Report and their addendums.)

The accident airplane was properly certificated and was equipped, maintained, and

dispatched in accordance with applicable regulations and industry practices.

The Safety Boardís review of air traffic control (ATC) information revealed no

evidence of any ATC problems or issues related to the accident. Further, examination of

the recovered airplane wreckage and cockpit voice recorder (CVR), flight data recorder

(FDR), ATC, weather, and radar data revealed no evidence that an encounter with other air

traffic or any other airborne object was involved in the accident or that weather was a

factor in the accident.

Examination of the wreckage revealed no evidence of preexisting fatigue,

corrosion, or mechanical damage that could have contributed to the airplaneís initial

pitchover.86 (The condition of the recovered elevator power control actuators (PCA) and

bellcrank shear rivets is discussed in the next section titled, ìMechanical Failure/Anomaly

Scenarios.î) No evidence of explosion or fire damage or foreign object impact damage

was found.

Additionally, the Safety Boardís examination of the accident airplaneís

maintenance records revealed no evidence of any mechanical problems that could have

played a role in the accident sequence. Although during interviews conducted at the

request of the Egyptian Government more than 1 year after the accident an EgyptAir 767

captain reported that he had experienced autopilot difficulties in the accident airplane

during the approach to Los Angeles International Airport (LAX), Los Angeles, California,

the day before the accident, these difficulties were likely the result of improper autopilot

approach mode selection. Additionally, as previously noted, neither the captain nor the

first officer of the flight to LAX reported any autopilot anomalies in the airplaneís

maintenance logbooks, and the first officer of that flight did not mention any autopilot

difficulties during interviews conducted 3 days after the accident. Although the captain

reported several minor anomalies during these interviews (including an autopilot

86 For additional information, see the Systems Group Chairmanís Factual Report and its addendum and

the Materials Laboratory Factual Report.
53

NTSB/AAB-02/01

anomaly), he told investigators that the airplane was ìalmost perfect.î No autopilot

difficulties were reported by the flight crew that flew the airplane from LAX to John F.

Kennedy International Airport (JFK), New York, New York, immediately before the

accident flight nor did they report any autopilot anomalies in the airplaneís maintenance

logbooks. Further, the Boardís examination of the FDR data before and after all recorded

autopilot disconnects in the 25 hours of data recorded by the FDR (including the accident

flight) revealed no evidence of abnormal autopilot or elevator surface behavior.

The Safety Boardís review of ATC, FDR, CVR, and radar information indicated

that the airplaneís movements during the accident flight were routine until about 0149:54

(9 seconds after the autopilot disconnect occurred), when an abrupt sustained nose-down

elevator motion occurred. A review of the FDR data indicated that the accident airplaneís

pitch motion before and during the accident sequence was consistent with the elevatorsí

recorded movements. Boeingís full-flight engineering simulator was used to evaluate the

consistency of the elevator positions with the pitch motions recorded on the FDR. During

these evaluations, the elevator movements required to make the simulator duplicate the

pitch motions recorded by the accident airplaneís FDR and the flightpath developed from

the available data closely matched the elevator movements recorded by the FDR. Further,

the recorded load factors were consistent with the recorded movements of both elevator

surfaces throughout the recorded data, even during the time that the data indicated a split

between the left and right elevator surfaces (see figure 4).87

The results of the Safety Boardís examination of CVR, FDR, radar, airplane

maintenance history, wreckage, trajectory study, and debris field information were not

consistent with any portion of the airplane (including any part of the longitudinal flight

controls) separating throughout the initial dive and subsequent climb to about 25,000 feet

mean sea level (msl). It is apparent that the left engine and some small pieces of wreckage

separated from the airplane at some point before water impact because they were located

in the western debris field about 1,200 feet from the eastern debris field. Although no

radar or FDR data indicated exactly when (at what altitude) the separation occurred, on the

basis of aerodynamic evidence and the proximity of the two debris fields, it is apparent

that the airplane remained intact until sometime during its final descent. Further, it is

apparent that while the recorders were operating, both elevator surfaces were intact,

attached to the airplane, and placed in the positions recorded by the FDR data and that the

elevator movements were driving the airplane pitch motion, and all associated recorded

parameters changed accordingly.

Mechanical Failure/Anomaly Scenarios 

The Safety Board evaluated possible mechanical failure and pilot action scenarios

in an attempt to determine whether they were consistent with the elevator movements

made during the accident sequence. As previously discussed in the section titled,

87 The engineering simulator was modified to model the left and right elevator surfaces independently,

and, using split elevator movements similar to those recorded on the FDR, the simulator was able to

duplicate the FDR-recorded pitch history.
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ìPotential Causes for Elevator Movements During the Accident Sequence,î the

investigation ruled out all but four possible anomalies and failure scenarios as potential

factors in the accident because they diverged too far from what was reflected on the

accident flightís FDR to warrant further consideration.88 Analysis showed that the effects

of four failure scenarios (each of which involves dual failures) bore some resemblance to

some portions of the accident flightís FDR data. Specifically, initially it appeared that each

of these failure scenarios could potentially cause nose-down elevator movements or a split

elevator condition that might resemble those recorded on the accident flightís FDR. Those

four failure scenarios were (1) disconnection of the input linkages to two of the three

PCAs on the right elevator surface,89 (2) a jam of the input linkages or servo valves in two

of the three PCAs on the right elevator surface,90 (3) a jam of the input linkage or servo

valve in one PCA and the disconnection of the input linkage to another PCA on the right

elevator surface,91 and (4) a jam in the elevator flight control cable connecting the

right-side control column to the right aft quadrant assembly combined with a break in the

same cable.92 Therefore, the wreckage from the accident airplane was examined for

possible evidence of PCA anomalies, and the predicted elevator movements resulting

from these failure scenarios were evaluated and compared with the data from the accident

flight.

As previously mentioned, one of the recovered PCAs was found with a pin (that

attached the spring guide to the servo valve slide) sheared and one coil of the bias spring

improperly positioned over the head portion of the spring guide. However, there were no

marks on any of the surfaces or any deformation of the spring coil to suggest that the

spring coil had become jammed between the servo cap and the spring guide, as would be

expected if such a jam had occurred.93 Moreover, investigators measured the clearances

between these components and determined that those clearances were large enough that

even if a coil of the bias spring had become misplaced between the spring guide and the

servo valve cap, no jam would have resulted.94 Further, the FDR data preceding the

accident sequence do not show any evidence of a single jammed PCA.95

88 For additional information, see Systems Group Chairmanís Factual Report and its appendixes.

89 This would result in the failed surface moving to a nose-down deflection of about 6o and the nonfailed

surface remaining at its prefailure position.

90 This would result in the failed surface moving to a nose-down deflection of about 6o and the nonfailed

surface moving to a nose-down deflection of about 4o.

91 This would result in the failed surface moving to a nose-down deflection of about 6o and the nonfailed

surface moving to a nose-down deflection of about 2.1o.

92 This would result in the left elevator moving to a nose-down deflection of between 1.2o and 3.9o and

the right elevator moving to a nose-down deflection of between 1.4o and 5.0o (depending on which variation

of this scenario is being tested). 

93 As previously mentioned, the Safety Board recognizes that a jam between two surfaces can occur

without leaving any physical evidence. However, as discussed in the Boardís report on the accident

involving USAir flight 427, physical evidence of a jam would be expected if a hardened steel component

(such as the bias spring in this case) were to become jammed between two surfaces because such evidence

was always observed after tests involving hardened steel chips jammed/sheared in a PCA. 94 Even if two coils of the spring had somehow become displaced into the space between the spring

guide and servo valve cap wall, there would still have been sufficient clearance to avoid a jam. 
55

NTSB/AAB-02/01

Most of the recovered elevator control linkages were broken; however, this type of

damage is typical following a high-speed water impact and underwater wreckage recovery

operations. The shear rivets in the recovered elevator bellcrank assemblies were sheared in

different directions; however, the Safety Board considers it likely that the rivets sheared as

a result of impact or recovery-related forces. Nonetheless, on the basis of the examination

of the structure alone, the absence or presence of a jammed or disconnected input linkage

or a jam in the servo valve in one of the accident airplaneís elevator PCAs could not be

established.

However, ground tests, studies, and calculations showed that each of the first three

failure scenarios would have resulted in airplane and flight control movements that were

inconsistent with the accident airplaneís elevator movements. Specifically, each of those

three failure scenarios would have caused the failed elevator surface to move to, and

remain at, a position consistent with a single functioning PCA operating at 100 percent of

its maximum force. The failed elevator surface would resist being backdriven with a force

equivalent to about 130 percent of a single functioning PCA and would not have

responded to nose-up flight control inputs. If one of these scenarios occurred at the

accident airplaneís indicated airspeed at the time of the initial dive (280 knots), the failed

elevator surface would have initially moved from its prefailure position (close to neutral)

to about a 6o nose-down position.96 However, the initial elevator movement (for both

elevator surfaces) on the accident airplane recorded during the accident sequence was to a

nose-down position of only about 3.6° .

97

The Safety Board also compared the recorded elevator movements following the

initial upset to elevator movements resulting from the first three failure scenarios. As the

airplaneís speed increased after the initial upset, the maximum deflection value associated

with the three failure scenarios would have decreased in response to the increased

aerodynamic forces on that surface. However, subsequent movements of both elevator

surfaces on the accident airplane deviated repeatedly, for sustained periods of time in both

the nose-up and nose-down directions,98 from the maximum deflection values that the

failure scenarios would have produced, at times exceeding the maximum deflection values

by several degrees. As shown in figure 2, the elevator movement profile from the accident

95 FDR and ground test data indicated that a single PCA failure would have resulted in much higher

offsets between the two elevator surfaces than were recorded during the accident flight and on the ground

before takeoff. During the accident flight, the slight offset that was recorded by the FDR was only 47 percent

of the offset that would be expected if a latent single PCA failure had occurred. On the ground before

takeoff, the recorded offset was only 27 percent of what would be expected if a latent single PCA failure had

occurred.

96 As previously discussed, failure scenarios resulting in nose-up motions of the elevators were also

possible but were not considered relevant to this accident investigation.

97 As discussed in the section titled, ìAccident Sequence Study,î the initial deflection for the left

elevator surface was about 3.4o, and the initial deflection for the right elevator surface was about 3.8o. As

shown in the graphical representations of the recorded elevator positions, a position of about 6o can be easily

distinguished in the data from a position of either 3.4o or 3.8o. 

98 The failure scenarios would not preclude additional commanded nose-down movement of the failed

elevator surface. However, commanding additional nose-down movements would be inconsistent with an

attempt to recover the airplane.
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NTSB/AAB-02/01

flight differs significantly throughout the accident sequence from the elevator movement

profile that would have resulted from any of these three failure scenarios,99 indicating that

neither elevator surface on the accident airplane was limited by a mechanical failure but,

rather, that both surfaces were responding normally to flight control inputs. Therefore, the

first three failure scenarios are inconsistent with the elevator movements recorded after

the initial upset.

Similarly, the elevator movements that would have followed any variant of the

fourth failure scenario are also inconsistent with the accident airplaneís recorded elevator

movements after the initial upset. The Safety Board notes that, in one of the four

variations of this scenario (a jam in the aft portion of the elevator control cable combined

with a cable break forward of the jam), the initial elevator positions match those on the

accident airplane. However, this similarity between the failure scenario and the accident

airplaneís elevator movements lasts only a few seconds. For the remainder of that

variation of the scenario (and for the entire duration of the other three variations of this

failure scenario), the elevator positions are inconsistent with those of the accident

airplane.

In addition, if one of the first three failure scenarios had occurred, the nonfailed

surface would have responded immediately to any nose-up flight control inputs from

either control column and would have resulted in an increase in the magnitude of the

difference between the two elevator surface positions (because the failed surface would

remain at its failure-induced position). If the fourth failure scenario had occurred, both

elevator surfaces would have responded immediately to nose-up inputs from either control

column. However, the FDR data from the accident flight showed that there was no

significant nose-up elevator movement or difference between the two elevator surface

positions for the first 28 seconds of the accident sequenceóuntil the captain returned to

the cockpit.100 If a failure had actually occurred, this would indicate that no attempts were

made to recover the airplane for the first 28 seconds after the initial pitchdown. Further,

after the captain returned to the cockpit, both elevator surfaces began moving together in

the nose-up direction, indicating that neither surface was limited by a mechanical failure

but, rather, that both surfaces were responding normally to flight control inputs. Similarly,

later in the accident sequence, when the elevator split occurred, the right elevator

deflected well beyond the maximum position possible for a failed elevator surface in any

99 The Safety Board recognizes that there was some uncertainty in the aerodynamic hinge moment data

used to calculate the elevator movement profiles for the failure scenarios depicted in figure 2, especially at

Mach speeds greater than 0.91. However, for the initial elevator movement on the accident flight to match

the elevator deflections in response to the failure scenarios, the aerodynamic hinge moment data used to

calculate the failure scenario profiles would have to have been about 79 percent greater than assumed. The

Board considers this amount of error to be extremely unlikely, particularly because the initial elevator

movement occurred below Mach 0.91, where hinge moment data were validated by certification flight tests.

100 As previously mentioned, throughout the FDR data for the accident airplane (including data recorded

during uneventful portions of the accident flight and during previous flights and ground operations), small

(less than 1° ) differences between the left and right elevator surface positions were observed. Even where

these offsets were observed, the elevator surfaces always moved in the same direction about the same time.

However, beginning at 0150:21, the elevator surfaces moved in opposite directions and remained there until

the FDR ceased recording.
57

NTSB/AAB-02/01

of the first three failure scenarios. However, the elevator movements during the split are

well within the limits of a pilot-commanded movement.

After reviewing all of the inconsistencies between the effects of the four potential

failure scenarios evaluated in depth, the actual behavior of the airplane, and the

controllability of the airplane in the event of such failures, the Safety Board determined

that none of these failure scenarios occurred during the accident sequence.101 Therefore,

these four failure scenarios can be ruled out along with all of the other potential failure

scenarios considered during this investigation.

The Safety Board also conducted simulations in which pilots from Boeing,

EgyptAir, the Federal Aviation Administration (FAA), and the Board evaluated the

controllability of the airplane following an initial upset that might have been caused by

any of these failure scenarios. During these simulations, the pilots were consistently able

to regain control of the airplane and return it to straight and level flight using normal

piloting techniques, and the airplane could be trimmed to hands-off level flight. In fact, the

767ís redundant actuation system is designed to allow pilots to overcome dual failures

such as these.

Even though increased control forces were necessary, recovery could be

accomplished by a single pilot using either the left or right control column.102 Further, the

simulations also demonstrated that the airplane could climb to about 25,000 feet msl with

the engines shut down, even with the speedbrakes extended. The simulation also

documented that the engines could have been promptly restarted and (assuming there were

no opposing pilot inputs) that the airplane could have been recovered during the climb

after the recorders stopped recording. Although the Safety Board recognizes that the

simulator did not duplicate the accident airplaneís actual flight conditions in every way,103

such limitations are not uncommon in simulations, and the Board takes those limitations

into account when evaluating simulator results. In this case, the Board determined that the

differences were not significant and did not affect the validity of the results of the

simulations.

Immediately after the airplaneís initial nose-down dive, the relief first officer

would have felt an immediate uncomfortable sensation as the airplaneís load factor

decreased to near 0 Gs. He should also have noted sudden changes in the airplaneís pitch

attitude, pitch rate, airspeed, and altitude. In response to these obvious cues, the relief first

officer did not attempt to counter the dive by commanding nose-up elevator, a largely

intuitive pilot response to initiate a recovery.

101 Further, although the first three failure scenarios evaluated in depth involved simultaneous dual PCA

failures at the start of the accident sequence, as previously discussed, it is also clear from the FDR data that

no latent jam of a single PCA occurred before the accident sequence.

102 As a former chief flight instructor with 5,191 hours in the 767, the relief first officer should have been

readily able to regain control of the airplane.

103 For more information about the limitations of Boeingís simulator, see the section titled, ìPotential

Causes for Elevator Movements During the Accident Sequence.î
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NTSB/AAB-02/01

Nor did the relief first officer exhibit any audible expression of anxiety or surprise

or call for help during the airplaneís initial dive or at any time during the remainder of the

recorded portions of the accident sequence. Further, the relief first officer did not respond

to the captainís repeated question, ìWhatís happening?î after the captain returned to the

cockpit. Rather, he continued his calm repetitions of the phrase ìI rely on Godî (which

began about 74 seconds before the airplaneís dive began) for 2 to 3 seconds, and then

became silent, despite the captainís repeated requests for information. The absence of any

reaction from the relief first officer (such as anxiety or surprise, a nose-up elevator input to

regain control of the airplane, or a request for assistance) to the airplaneís sudden

departure from cruise flight to a steep descent is not consistent with his encountering an

unexpected mechanical problem. Whereas the captainís audible alarm and the content of

his statements in reaction to the situation upon returning to the cockpit were consistent

with the reaction of a pilot who has encountered an unexpected flight condition, the

passive behavior of the relief first officer was not.

The primary radar data indicated that the airplane climbed for about 40 seconds

after the FDR stopped recording before it rapidly descended again and impacted the

ocean. Therefore, the relief first officer and captain had about 83 and 69 seconds,

respectively, from the time the airplane began its initial nose-down pitch until it began its

second (final) descent, in which to regain control of the airplane; return it to level flight

and restart the engines; or at least establish the airplane in a gradual, controlled glide while

attempting an engine restart. (If control of the airplane had been regained during this time,

the flight crew would have had several minutes in which to restart the engines.) However,

a successful recoveryóalthough possibleówas not accomplished.

In summary, the investigation did not reveal any evidence of a failure condition

within the airplaneís elevator system that would have caused or contributed to the

airplaneís initial pitchover or prevented the flight crewís successful recovery from the

airplaneís rapid descent. Further, the relief first officerís reaction was inconsistent with his

having encountered an unexpected airplane anomaly. Therefore, the investigation

determined that neither the nose-down elevator movements nor the failure to recover from

those movements could be explained by a mechanical failure.

Pilot Action Scenario

Simulations showed that certain combinations of pilot inputs could result in

elevator motions consistent with those recorded by the accident airplaneís FDR and a

flightpath consistent with the FDR and radar data for the accident airplane.104 Therefore,

the Safety Board evaluated the actions of the pilots as recorded on the CVR, in the context

of all of the evidence gathered in this investigation, to determine whether pilot action

provided a possible explanation for the accident scenario.

104 For additional information, see Systems Group Chairmanís Factual Report and its appendixes and

addendums, Flight Data Recorder Group Chairmanís Factual Report and its attachments, Cockpit Voice

Recorder Group Chairmanís Factual Report and Sound Spectrum Study, and Aircraft Performance Group

Chairmanís Aircraft Performance Study and its attachments and addendum.
59

NTSB/AAB-02/01

Events Before and During the Initial Descent, While the Relief 

First Officer Was Alone in the Cockpit 

About 20 minutes after takeoff (about 0140), the relief first officer suggested that

he relieve the command first officer. A transfer of control this early in the flight was

contrary to the EgyptAir practice typically agreed-upon by flight crews of waiting until

3 or 4 hours into the flight before relieving the command crewmembers. The command

first officer initially reacted with surprise and resistance to the relief first officerís

suggestion that he assume first officer duties at that time, indicating that the relief first

officerís suggestion was unexpected. However, after some discussion, the command first

officer agreed to the change, and sounds recorded by the CVR indicated that, about 0142,

the command first officer vacated and the relief first officer moved into the first officerís

seat.

About 0147, the relief first officer asked an unidentified crewmember to return a

pen to another first officer, who was in the cabin. The unidentified crewmember agreed

and left the cockpit. At 0148:03, the command captain excused himself from the cockpit,

saying that he wanted to ìtake a quick trip to the toiletÖbefore it gets crowded.î While

the command captain was excusing himself, the CVR recorded the sound of an electric

seat motor, presumably the captainís, as he maneuvered to leave his seat and the

cockpit.105 At 0148:18.55, the CVR recorded a sound similar to the cockpit door

operating.

The Safety Board considered whether another flight crewmember might have been

in the cockpit with the relief first officer during this time period. However, careful

laboratory examination of the CVR recording indicated that the CVR did not record any

speech or human sounds other than those attributed to the captain and relief first officer

from 0148:30 until the end of the recording at 0150:38.47.106 The Board determined that

the possibility that another person, especially a pilot, was present during the airplaneís

sudden transition from cruise flight to steep descent and did not audibly express surprise at

the abrupt change in the flight situation (as the captain did when he returned to the

cockpit) or offer help/suggestions on how to deal with the emergency situation was

extremely unlikely. Therefore, the evidence indicates that the relief first officer was alone

in the cockpit from about 0148:19, when the command captain left the cockpit, to

0150:06, when he returned to the cockpit.

Ten seconds after the unintelligible comment was made (at 0148:40), the relief

first officer stated quietly, ìI rely on God.î At 0149:18, the CVR recorded a ìwhirring

105 This electric seat motor was recorded by the cockpit area microphone (CAM) but not by the hot

microphone at the first officerís position, which (as previously discussed) was likely stowed at the first

officerís side of the airplane. Because of its position on the right side of the airplane and its directionally

sensitive nature, it is likely that all seat motions recorded by the hot microphone at the first officerís position

after 0141 represented motions of the right seat.

106 As previously discussed, about 0148:30, the CVR recorded an unintelligible comment that could not

positively be attributed to any previously identified crewmember. Two speech characteristics of the

unintelligible comment (fundamental frequency and formant dispersion) more closely resembled values

displayed by the relief first officer than by the other voices evaluated.
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NTSB/AAB-02/01

sound similar to [the] electric seat motor operating.î Because the relief first officerís seat

was likely moved into an aft position because the command first officer had vacated the

seat, and in light of the autopilot disconnect and subsequent flight control movements, the

whirring sound is consistent with the relief first officer moving his seat forward into a

position from which he could manually fly the airplane.107 Thus, all manual flight control

inputs made after 0148:19, until the command captainís return to the cockpit at 0150:06,

must have been made by the relief first officer.

The absence of an autopilot disconnect warning tone on the CVR recording when

the autopilot disconnected at 0149:45 is consistent with the autopilot being manually

disconnected by rapidly double-clicking on the control yoke-mounted autopilot

disconnect switch. Because the relief first officer was alone in the cockpit, the evidence

indicates that he manually disconnected the autopilot. The Safety Boardís examination

revealed no evidence in the CVR, FDR, ATC, or radar data of any system malfunction,

conflicting air traffic, or other event that might have prompted the relief first officer to

disconnect the autopilot; therefore, there was no logical operational reason for the relief

first officer to disconnect the autopilot while in cruise flight over the ocean. Further, as

previously stated, the Boardís testing and evaluation of the 767 elevator system showed

that none of the failure modes examined during this investigation would have resulted in

control column movements without concurrent identifiable movements of the elevators,

which would have been observed in the FDR data. The FDR did not record any unusual or

alarming elevator movements before the autopilot was disconnected; therefore, it is

unlikely that the relief first officer was prompted to disconnect the autopilot because he

sensed unusual control column movements.

Aside from some very slight elevator movements and a very gradual left roll, the

airplane remained in level flight at flight level 330 for about 8 seconds after the autopilot

was disconnected. As previously discussed in the section titled, ì767 Autopilot

Information,î such slight movements are normal and expected when the autopilot is

disengaged and the pilot takes manual control of the airplane. There was no indication of

an upset or loss of control at this time.

At 0149:48, the relief first officer again quietly stated, ìI rely on God.î

At 0149:53, the throttle levers were retarded (moved from their cruise power setting to

idle). This throttle lever movement occurred at a rate that was more than twice that which

the autothrottle can command. Further, the throttle levers moved 10o to 15o beyond the

minimum position that the autothrottle would have been able to command at the existing

flight conditions to the throttle leversí full aft idle stop, about 33o.108 Movement of the

throttles aft of the autothrottle commanded position requires a manually applied force of

about 9 pounds on the throttle levers to override the autothrottle servomotor clutch. Thus,

it is apparent that the throttle lever movements at 0149:53 were caused by the relief first

officerís manual inputs and were not the result of autothrottle commands.109

107 This electric seat motor sound was recorded by both the CAM and the hot microphone at the first

officerís position, further confirming that this sound represented a motion of the relief first officerís seat.

108 This throttle lever position was consistent with manually input throttle lever positions recorded by the

FDR earlier in the accident flight.
61

NTSB/AAB-02/01

At 0149:54, the FDR recorded a very slight movement of the inboard ailerons and

both elevator surfaces beginning to rapidly pitch nose down (to about 3.6° nose-down

deflection). The nose-down elevator movement began after the throttle levers started to

move to idle; therefore, the relief first officer did not move the throttle levers to idle in

response to the nose-down elevator movement. As previously noted, the relief first officer

did not audibly express surprise or seem anxious or disturbed by the airplaneís sudden and

extreme nose-down movement or the reduction in load factor to near 0 G, nor did he call

for help during the accident sequence. Again, there was no evidence in the CVR, FDR,

ATC, or radar data of any system malfunction, conflicting air traffic, or other event that

would have prompted the relief first officer to adjust the throttle levers at all, let alone take

an action as drastic as moving the throttle levers to the idle position while in cruise flight

at night over the ocean or to then command a sustained nose-down elevator movement.

About 11 seconds after the initial nose-down movement of the elevators, the FDR

recorded additional (larger) movements of the inboard ailerons and the elevators started to

move further in the nose-down direction, decreasing the airplaneís load factor to negative

G loads. The relief first officer would have been gripping the control wheel with his

hand(s) when he applied these significant nose-down elevator control column inputs. It is

unlikely that he could make such significant control column inputs without (intentionally

or unintentionally) also affecting the control wheelís lateral position and thus providing

some input to the ailerons. Therefore, these inboard aileron movements, and those that

occurred at 0149:54 (both of which were coincident with changes in the relief first

officerís inputs to the control column), are consistent with evidence indicating that the

relief first officer was providing manual inputs to the flight controls during the accident

sequence.

Events After the Command Captain Returned to the Cockpit

Immediately after this increase in nose-down elevator movement, at 0150:06, the

CVR recorded the command captain exclaiming, ìWhatís happening? Whatís

happening?,î as he returned to the cockpit.110 At 0150:08, the captain repeated his

question. While the captain was still speaking and moving toward his seat in the forward

portion of the cockpit (at 0150:07 and again at 0150:08), the relief first officer quietly

repeated, ìI rely on God.î111 However, the relief first officer did not answer the captainís

question. The Safety Board considers it unlikely that the captainówho was likely

109 The Safety Board notes that several of its incident and accident investigations (including EgyptAir

flight 990) might have benefited from a visual record of cockpit images/events. On April 11, 2000, the

Board issued Safety Recommendations A-00-30 and -31. Safety Recommendation A-00-30 asked the FAA

to require that all aircraft operated under 14 Code of Federal Regulations (CFR) Part 121, 125, or 135 and

currently required to be equipped with a CVR and FDR be retrofitted with a crash-protected cockpit image

recording system by January 1, 2005. Safety Recommendation A-0-31 asked the FAA to require that all

aircraft manufactured after January 1, 2003; operated under 14 CFR Part 121, 125, or 135; and required to

be equipped with a CVR and FDR be equipped with two crash-protected cockpit image recording systems.

The Board specified that the cockpit image recording system should have a 2-hour recording duration and be

ìcapable of recording, in color, a view of the entire cockpit including each control position and each

actionÖtaken by people in the cockpit.î Safety Recommendations A-00-30 and -31 are currently classified

ìOpenóUnacceptable Response.î 
62

NTSB/AAB-02/01

focusing on getting into his seat, troubleshooting the upset, and attempting to regain

control of the airplaneówould have suspected at this point that the relief first officerís

actions were directly contributing to the airplaneís dive.112 Rather, the captain likely would

have assumed that the relief first officer was also attempting to regain control of the

airplane and would work cooperatively with him.

As previously discussed, the relief first officerís passive behavior in response to

the airplaneís nose-down movements and the captainís questions is not consistent with

what would be expected from a pilot who was dealing with an unexpected or undesired

airplane problem. To the contrary, the timing of the increased nose-down elevator

movement and the corresponding decrease in load factor was consistent with the relief

first officer having increased the forward control column pressure when the captain

returned to the cockpit.

At 0150:15, as the airplane continued to descend rapidly in a 40° nose-down

attitude, the captain again asked, ìWhatís happening, [relief first officerís first name]?

Whatís happening?î Again, the relief first officer did not respond to the captainís question.

Although the relief first officer remained unresponsive to the captainís queries, there is no

specific evidence to indicate that the captain suspected at this point that the relief first

officerís actions were causing the airplaneís dive.

At the same time, as the airplane was descending through about 27,300 feet msl,

both elevator surfaces began moving to reduced nose-down deflections. Shortly thereafter,

the airplaneís rate of descent began to decrease. Because there was no evidence that the

relief first officer had attempted to regain control of the airplane before this, the Safety

Board considers it likely that these movements were the result of nose-up flight control

inputs made by the captain after he returned to the cockpit.113 Six seconds later

110 Although the CAM recorded all of the captainís remarks, the ìWhatís happening? Whatís

happening?î comments at 0150:06 were of a poorer recording quality and less audible than similar remarks

made at 0150:08 and 0150:15. The evidence from both microphones was consistent with the captain

speaking from outside the cockpit or the rear portion of the cockpit when he made the earlier statement and

from the forward portion of the cockpit when he made the later statements, suggesting that the captain was

moving forward as he made these statements. Further, the content and tone of the captainís statements were

consistent with his trying to understand an unexpected situation upon his return to the cockpit.

When the captain asked, ìWhatís happening? Whatís happening?î at 0150:06, his words were not

recorded by the hot microphone at the first officerís position; however, the hot microphone recorded the

captainís subsequent remarks until it stopped recording cockpit conversation at 0150:25. (None of the relief

first officerís comments during the accident sequence were recorded by the hot microphone. For additional

information, see the section titled, ìAudio Information Recorded by First Officerís Hot Microphone.î)

111 The Safety Board considers it likely that the captain never heard any of the relief first officerís ìI rely

on Godî statements. None of these statements were recorded by the hot microphone at the first officerís

position, suggesting that they were spoken very quietly. (By contrast, the hot microphone at the first officerís

position did record the captainís statements of ìWhatís happening?î as he moved to his seat at the forward

portion of the cockpit [at 0150:08] and again after he was seated in his seat [at 0150:15], despite the fact that

the captain was farther from that hot microphone.)

112 The visual difference between pushing forward on the control column and pulling aft on the control

column to create elevator movements of the magnitude recorded on the FDR would not have been readily

apparent to the captain in the darkened cockpit during the unexplained crisis, especially when he was trying

to understand the many abnormal events and sensations that were occurring during the dive.
63

NTSB/AAB-02/01

(at 0150:21), both elevator surfaces passed through their neutral positions into nose-up

deflections. However, less than 1 second later, the right surface reversed its motion and

moved back in the nose-down direction, and the left surface continued to move in the

nose-up direction.

According to Boeingís tests and research, with the elevator PCAs operating

normally, the accident airplaneís elevators would have only been minimally affected by

the aerodynamic forces that would have resulted from the small sideslip angle, roll rates,

and the Mach numbers that existed during the accident sequence. Therefore, it follows that

the elevator split recorded by the FDR was the result of flight control inputs to each

elevator surface and not the result of aerodynamic forces on those surfaces.114 (In contrast,

Boeing indicated that an outboard aileron split recorded between 0150:27 and 0150:32

could be explained by the aerodynamic effects of the small sideslip angles and roll rates

calculated to have been present at that time.)115

Testing confirmed that the left and right elevator surfaces could be moved in

different directions by differential column movements from the relief first officer and

captain in the cockpit. As intended by the elevator control system design, the elevators

would split, each surface following the movements of the control column on its side (the

left elevator moving in response to the left column movement, and the right elevator

moving in response to the right column movement). The opposing control column inputs

likely existed during the 7 to 8 seconds before the elevator split (when both elevators were

moving in a trailing-edge-up direction); however, the elevator split would not occur until

the difference between the two control column forces was great enough to engage the

override mechanism. Tests conducted in a 767 simulator and airplane (on the ground)

demonstrated that pilots with heights and weights similar to those of the command captain

and relief first officer could apply enough force on the control column to produce and

maintain the split elevator condition recorded by the FDR.

The captainís actions just after the elevator split began were consistent with an

attempt to recover the airplane and the relief first officerís were not. In rapid sequence,

113 During the Safety Boardís tests and simulations, a pilot similar in height and weight to the EgyptAir

flight 990 command captain was physically able to move from the aft cockpit into the captainís seat, to brace

himself against the control console or floor structure, and to apply enough back pressure on the control

column to match the physical pulling forces computed to have been required to generate the split elevator

condition recorded by the FDR. However, the pilot stated that it was physically difficult or uncomfortable

for him to manipulate the control column while kneeling on the floor or standing behind the captainís seat

and suggested that, given his build and his need to manipulate the controls, the captain of EgyptAir

flight 990 would almost certainly have attempted to enter his seat immediately upon his return to the

cockpit.

As previously discussed, the simulator did not duplicate the accident airplaneís actual flight

conditions in every way; for example, the simulator did not duplicate the negative G loads recorded by the

FDR. However, once the captain was normally seated and effectively braced, these forces should not have

substantially affected the maximum fore-and-aft forces he could generate. Further, the G loads on the

accident airplane did not remain negative for long; FDR data show that the G loads increased to greater than

1/2 G within 2 to 3 seconds of the start of the recovery.

114 For additional information, see Boeingís April 16, 2001, letter in the public docket for this accident.

115 For additional information, see Boeingís April 12, 2001, letter in the public docket for this accident.
64

NTSB/AAB-02/01

just after the elevator split began, the engine start lever switches were moved to the cutoff

position, the throttle levers were advanced to full throttle, and the speedbrakes were

deployed.116 After the throttle levers were advanced (but the engines did not respond), the

captain reacted with surprise, asking the relief first officer, ìWhat is this? What is this?

Did you shut the engine(s)?î117 The timing and direction of the left elevator motions

during this time suggest that the captain, who had likely been using both hands to pull aft

on the left control column, released his right hand to advance the throttles and deploy the

speedbrakes, resulting in a decrease in his total aft pressure on the control column, which

was reflected in the decrease in the left elevatorís nose-up deflection that was recorded by

the FDR at this time. Subsequently, when the captain likely had returned his right hand to

the control column, the FDR recorded a corresponding increase in the left elevatorís

nose-up deflection. As previously stated, tests and simulations demonstrated that a pilot

seated in the captainís position could easily have advanced the throttles, moved his hand a

little to the left, and deployed the speedbrakes in the 3 to 4 seconds it took for these events

to occur.

Concurrent with the brief downward motion of the left elevator that was recorded

when the throttles were advanced and the speedbrakes deployed, a brief downward motion

of the right elevator was recorded. This movement of the right elevator suggests that when

the captainís aft pressure on the left control column decreased, the relief first officerís

sustained forward pressure on the right control column caused that column to move

forward briefly. Although it would have been physically possible for the relief first officer

to have advanced the throttles and deployed the speedbrakes, the evidence does not

support the notion that the relief first officer performed these actions. Rather, the evidence

indicates that the relief first officer moved the engine start lever switches to the cutoff

position (a counterproductive action, in terms of recovery), whereas the captain deployed

the speedbrakes in an attempt to arrest the airplaneís descent.

Additionally, the surprised reaction from the captain when the engines did not

respond to the throttle movement (ìWhat is this? What is this? Did you shut the

engine(s)?î) suggested that it was he (not the relief first officer) who advanced the throttle

levers. This response clearly indicated that the captain was unaware that the engine start

lever switches had been moved to the cutoff position, that such an action was at odds with

his intentions, and that it was, therefore, not part of a mutual, cooperative troubleshooting

exercise between the captain and relief first officer.

At 0150:26.55, the captain stated, ìGet away in the engines,î and at 0150:28.85,

he stated, ìshut the engines.î118 At 0150:29.66, the relief first officer responded for the

first (and only) time after the captain returned to the cockpit, stating, ìItís shut.î

116 Tests and simulations demonstrated that the magnitude of the elevator split would vary, but a split

could be maintained even when the pilot in the left seat temporarily removed his right hand from the control

yoke to advance the throttles and deploy the speedbrakes and the pilot in the right seat temporarily removed

his left hand from the control yoke to move the engine start lever switches to the cutoff position.

117 The Safety Board notes that the captainís statement ìWhat is this? What is this? Did you shut the

engine(s)?î might reflect the beginning of a suspicion that the relief first officerís actions were not

appropriate for recovery.
65

NTSB/AAB-02/01

Between 0150:31 and 0150:37, the captain repeatedly asked the relief first officer to ìpull

with meî on the control column. However, the FDR data indicated that the elevator

surfaces remained in a split condition (with the left surface commanding nose up and the

right surface commanding nose down) until the last data were recorded by the FDR at

0150:36.64.

As with the earlier portion of the accident sequence (before the captainís return to

the cockpit), the relief first officerís responses during this portion of the accident sequence

did not indicate that he was surprised or disturbed by the events. Similarly, his rate of

speech and fundamental frequency when he repeated, ìI rely on God,î and stated, ìItís

shut,î did not indicate any significant increase in his level of psychological stress. In

contrast, the captainís fundamental frequency was about 65 percent higher when he

repeatedly asked the relief first officer to ìpull with meî during the elevator split period

than it was during routine flight, reflecting an increased level of psychological stress.

As previously discussed, simulations showed that even if a failure condition had

affected the elevator system, it would have been possible to regain control of the airplane

at any time during the recorded portion of the accident sequence and to have restarted the

engines and recovered the airplane during the climb after the recorders stopped. However,

those simulations assumed that there were no opposing pilot inputs. The captainís failure

to recover the airplane can be explained, in part, by the relief first officerís opposing flight

control inputs. It is possible that efforts to recover the airplane after the airplane lost

electrical power were also complicated by the loss of electronic cockpit displays.

In summary, the evidence establishes that the nose-down elevator movements were

not the result of a failure in the elevator control system or any other airplane system but

were the result of the relief first officerís manipulation of the airplane controls. The

evidence further indicates that the subsequent climb and elevator split were not the result

of a mechanical failure but were the result of pilot inputs, including opposing pilot inputs

where the relief first officer was commanding nose-down and the captain was

commanding nose-up movement. The Safety Board considered possible reasons for the

relief first officerís actions; however, the Board did not reach a conclusion regarding the

intent of or motivation for his actions.

118 This sentence, ìGet away in the engines,î is an example of a phrase where direct translation of the

Arabic words into English with no attempt to interpret or analyze the words resulted in an awkward or

seemingly inappropriate phrase. In this case, it is possible that the captain, surprised to realize that the

engines had been shut off, was trying to tell the relief first officer to leave the engines alone. However,

research indicates that poor word choice, improper grammar, and the use of incomplete phrases can be

symptomatic of high levels of psychological stress in a speaker.
66

NTSB/AAB-02/01

Summary

1. The accident airplaneís nose-down movements did not result from a failure in

the elevator control system or any other airplane failure.

There was no evidence of any failure condition within the elevator system of

the accident airplane that would have caused or contributed to the initial

pitchover or prevented a successful recovery.

No mechanical failure scenario resulted in airplane movements that matched

the flight data recorder data from the accident airplane.

Even assuming that one of the four examined failure scenarios that the

investigation evaluated in depth had occurred, the accident airplane would

still have been recoverable because of the capabilities of the Boeing 767ís

redundant elevator system.

2. The accident airplaneís movements during the initial part of the accident

sequence were the result of the relief first officerís manipulation of the

controls.

At the relief first officerís suggestion, a transfer of control at the first officerís

position occurred earlier than normal during the accident flight.

The relief first officer was alone in the cockpit when he manually

disconnected the autopilot and moved the throttle levers from cruise to idle;

there was no evidence of any airplane system malfunction, conflicting air

traffic, or other event that would have prompted these actions.

The nature and degree of the subsequent nose-down elevator movements were

not consistent with those that might have resulted from a mechanical failure

but could be explained by pilot input.

There was no apparent reason for the relief first officerís nose-down elevator

inputs.

The relief first officerís calm repetition of the phrase ìI rely on God,î

beginning about 74 seconds before the airplaneís dive began and continuing

until just after the captain returned to the cockpit (about 14 seconds into the

dive), without any call for help or other audible reaction of surprise or alarm

from the relief first officer after the sudden dive is not consistent with the

reaction that would be expected from a pilot who is encountering an

unexpected or uncommanded flight condition.

The absence of any attempt by the relief first officer to recover from the

accident airplaneís sudden dive is also inconsistent with his having

encountered an unexpected or uncommanded flight condition.

The relief first officerís failure to respond to the command captainís questions

(ìWhatís happening? Whatís happening?î) upon the captainís return to the

cockpit is also inconsistent with the reaction that would be expected from a

pilot who is encountering an uncommanded or undesired flight condition.
67

NTSB/AAB-02/01

3. The accident airplaneís movements after the command captain returned to the

cockpit were the result of both pilotsí inputs, including opposing elevator

inputs where the relief first officer continued to command nose-down and the

captain commanded nose-up elevator movements.

Nose-up elevator movements began only after the captain returned to the

cockpit.

Testing showed that recovery of the airplane was possible but not

accomplished.

Seconds after the nose-up elevator movements began, the elevator surfaces

began moving in different directions, with the captainís control column

commanding nose-up movement and the relief first officerís control column

commanding nose-down movement.

After the elevator split began, the relief first officer shut down the engines.

The captain repeatedly asked the relief first officer to ìpull with me,î but the

relief first officer continued to command nose-down elevator movement.

The captainís actions were consistent with an attempt to recover the accident

airplane and the relief first officerís were not.

Probable Cause

The National Transportation Safety Board determines that the probable cause of

the EgyptAir flight 990 accident is the airplaneís departure from normal cruise flight and

subsequent impact with the Atlantic Ocean as a result of the relief first officerís flight

control inputs. The reason for the relief first officerís actions was not determined.

Attachment A

EgyptAir Flight 990 Cockpit Voice Recorder Transcript

 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0119:13 START OF RECORDING START OF TRANSCRIPT

0119:20 TWR ...nine ninety heavy, the wind is two 

runway two two right, RVR is more runway two two right, cleared for ta

0119:32 RDO-2a cleared for takeoff. confirm climbin0119:36 TWR negative sir. the runway two two rig

thousand. you fly the Gateway Climthousand. 

0119:43 RDO-2a following Gateway, clear for takeoff 

EgyptAir nine nine zero heavy. 

0119:45 CAM-? okay. 0119:52 CAM-? ***. 0119:54 CAM-1a cabin crew advised? 0119:54 HOT-2a in the name of God, the Merciful, the Compassionate. cabin 

crew takeoff position. 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0119:58 CAM [sounds similar to increase in engine RPM] 0120:07 CAM [sounds similar to nose wheel traveling over bumps on 

runway] 

0120:19 HOT-2a eighty knots, throttle hold. 0120:22 CAM-1a cross check. 0120:40 HOT-2a V one. 0120:41 HOT-2a rotate. 0120:42 HOT-2a positive rate of climb both side. 0120:46 CAM-1a gear. 0121:06 HOT-2a one thousand. 

0121:07 TWR EgyptAir nine ninety heavy contact 

point seven. 

0121:11 RDO-2a one two five seven, bye. 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT

0121:14 RDO-2a departure, EgyptAir nine eight nine 

0121:18 DEP EgyptAir nine ninety heavy New Yo

climb and maintain uh, one three th

0121:25 RDO-2a climbing one three thousand, nine n

0121:40 CAM-? ***. 0121:41 CAM-1a flaps *. 0121:45 CAM [sound similar to flap handle movement] 0121:52 CAM-? ** two sixty. 

0121:57 DEP EgyptAir nine ninety heavy turn left 

SHIPP. 

0122:00 RDO-2a direct SHIPP, nine nine zero heavy

0122:05 HOT-2a turn right direct SHIPP, execute sir? 0122:08 CAM-1a did he tell you turn left? 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0122:08 HOT-2a yes, establish. 0122:11 CAM-1a flaps up. 0122:15 CAM [sound similar to flap handle movement] 0122:16 CAM-1a did you enter it or not yet? 0122:17 HOT-2a I entered it. 0122:19 CAM-? ***. 0122:28 HOT-2a execute, execute? 0122:31 HOT-2a *. 0123:32 CAM-1a please reset the... okay. 0123:35 HOT-2a after take off. 0123:39 CAM-1a (after take off) 0123:41 HOT-2a landing gear lever off, flaps up, after takeoff checks 

complete. 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0125:11 CAM [brief interruption in audio similar to CVR tape splice] 0125:20 HOT-2a at your service, sir. 0125:24 CAM-? ***. 0125:26 HOT-2a no, I didn't enter two nine zero. I entered three one zero. 0125:32 CAM-3 that's why it gave you maximum altitude. 0125:35 HOT-2a I swear I entered three one zero. 0125:40 HOT-2a ten thousand climbing. 0125:42 CAM-1a thirty three. 0125:48 HOT-2a I had even entered two nine zero. 0126:02 HOT-2a we're already in the middle of the Atlantic... 

0126:03 DEP EgyptAir nine ninety heavy climb an

three zero and contact New York cefive five. 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT

0126:10 RDO-2a one three four five five, two three ze

0126:14 CAM-1a how much, two three zero? 

0126:35 RDO-2a New York, EgyptAir nine nine zero 

0126:39 CTR1 EgyptAir nine nine zero, go. 

0126:42 RDO-2a your frequency. 

0126:46 CTR1 EgyptAir nine nine zero, go ahead. 

0126:47 RDO-2a ah, approaching three thousand, up 

zero. 

0126:54 CTR1 roger. 

0127:13 CAM-3 [unintelligible conversation in background] 0127:51 HOT-2a aaahhh. 0127:52 HOT-2 [tone similar to cabin crew call chime] 0127:54 CAM-? [sounds similar to coughing] 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0127:58 CAM-3 [unintelligible conversation in background] 0129:14 HOT-2a one zero one three. 0129:20 HOT-2a after takeoff (checks) complete. 0129:28 CAM-3 the chart, Adel... 0129:29 HOT-2a what, sir? 0129:31 HOT-2a the chart, sir? 0129:33 CAM [unintelligible conversation in background] 0129:33 CAM-3 the chart of the Atlantic. 0129:39 HOT-2a aye aye... would you like, sir, the atlas or the one... both 

available. 

0129:42 CAM-? ***. 0129:48 CAM [sound similar to rustling papers] 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT

0129:54 CTR1 EgyptAir nine ninety, say the altitud

0129:57 RDO-2a uh, leaving, approaching one niner 

0130:04 CTR1 EgyptAir nine ninety, roger. 

0130:07 HOT-2a Mademoiselle, Madame, if you please, I want a bottle of 

water and a cup of coffee, two creams, yes, two creams, and one sugar. Captain Habashi, would you like to drink something? Captain Hatem, would you like to drink something? 

0130:23 CAM-? [sounds similar to coughing] 0130:45 CAM-? [unintelligible conversation in background] 0130:55 CAM-? where is our chart? 0130:57 CAM-? [sounds similar to coughing] 0131:05 CAM-? [sounds similar to coughing] 0131:19 HOT-2a it seems that Samir left it, sir. 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT

0131:24 CTR1 EgyptAir nine ninety, New York one 0131:29 RDO-2a one three two one five, bye. 

0131:33 HOT-2a don't bother yourself, sir. 

0131:39 RDO-2a New York center EgyptAir niner nin

evening, approaching two two zero 

0131:47 CTR2 EgyptAir niner niner zero, New Yor

0131:54 CAM-? [sounds similar to coughing] 0132:03 HOT-2a [sound similar to yawn] 0132:06 HOT-2a one thousand to level. 0132:06 CAM-3 didn't he bring you the chart? 0132:07 HOT-2a what? 0132:09 CAM-3 didn't he give you the chart? 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0132:10 HOT-2a no, I asked him,"where is our chart," and I think he put it on 

the drawer or... 

0132:17 CAM-3 he should have plotted for you ***. 0132:18 HOT-2a that guy was busy, the one who plots, he told me that I had 

come late. 

0132:25 CAM [sound of click] 0132:33 CAM-3 [unintelligible conversation] 0132:51 CAM [two high-low tones similar to cabin crew call chime] 0132:58 HOT-2a merci, sir. 0133:00 HOT-2a just a bottle of water. 0133:01 CAM-? [sounds similar to coughing] 0133:05 CAM [sound similar to cockpit door operating] 0133:35 CAM [sound of click] 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0133:50 CAM-3 * Adel. 0133:52 HOT-2a merci, sir, excuse me. 0133:55 CAM-? *. 0134:01 HOT-2a thank you, sir. thanks. 0134:04 CAM [sound similar to cockpit door operating] 0134:10 CAM-? thank you, Commandant. may your blessings be multiplied. 0134:11  [brief interruption in audio on all CVR channels] 0134:13 CAM-? [sound similar to clearing of throat] 0134:15 CAM [sound similar to cockpit door operating] 0134:25 HOT-2a Ayyad, if you want to take these things now, take them. 0134:28 CAM-4 what? 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0134:29 HOT-2a If you want to take these things, take them. 0134:31 CAM-4 (sure) 0134:33 CAM [sound similar to cockpit door operating] 0134:44 CAM-? *** . 0134:53 CAM [sound similar to cockpit door operating] 0135:08 HOT-2a what's new? what's wrong with you? 0135:13 CAM-1a that's nonsense. 0135:14 HOT-2a yeah, of course. 0135:14 CAM-1a quite frankly, that's nonsense. I don't accept it. 0135:17  [brief interruption in audio on all CVR channels] 0135:17 HOT-2a a market, it's a market in the cockpit. 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0135:20 CAM-1a I don't accept this situation. never... you can't call that flying. 

by Great God, call it anything else. that has nothing to do with flying, this business... I didn't want to cause trouble for one reason only: just because Hatem is here and he will see before him how the situation is. 

0135:44 HOT-2a Captain, you... 0135:44 HOT-2a all of this because of this good-for-nothing guy named 

Ayyad... 

0135:46 CAM-1a what? 0135:47 HOT-2a this Ayyad who keeps saying Zulu Alpha... Zulu Alpha. 0135:49 CAM-1a I am aware of it. 0135:50 HOT-2a he sat here and entered three nine. 

0135:52 CTR2 EgyptAir nine ninety climb and main

zero, cleared direct DOVEY. 

0135:57 RDO-2a three three zero, direct DOVEY, Eg

0136:02 CAM-1a between me and you this is not work, by God seriously. 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0136:05 HOT-2a no, not at all. 0136:08 CAM-1a Hisham is telling me that -- I don't know -- he has simulator 

tomorrow. 

0136:11 HOT-2a execute... VNAV? 0136:18 CAM-1a you see, he is telling me he has simulator tomorrow... is that 

any good? he is coming straight from Los Angeles, you know, and he is going to have simulator. 

0136:26 CAM [sound similar to cockpit door operating] 0136:38  [brief interruptions in audio on all CVR channels] 0136:42 CAM-1a what's your opinion about the crowding on this plane? 0136:44 CAM-3 what crowding? 0136:47 CAM-1a the crew that is aboard this plane. 0136:50 CAM-3 there is one going back that has simulator and another 

whom I have told in Egypt to come back on the same airplane from Los Angeles direct to Egypt for training... what difference does it make? 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0136:59 CAM-1a what? 0137:00 CAM-3 what difference does it make? 0137:00 CAM [sound of squeak] 0137:01 CAM-1a no, it doesn't make any difference to me. I, I am saying that 

for their sake. 

0137:07 CAM-3 because those, you see, are not active. 0137:08 CAM-1a I know that. I didn't say anything. but I mean when you are 

surprised to see people about whom you don't know anything. It's good that you are here, you know. I don't know, I mean, anybody could... 

0137:24 CAM-3 isn't the extra crew written in the general dec? 0137:28 CAM-1a I mean, as long as you are here, there is no problem, you 

are here. if you were not here, anyone could tell me, "Captain Hatem," should I say okay? 

0137:38 CAM-3 no, I sent a telex concerning this operation. 0137:40 CAM-1a bravo for you. 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0137:41 CAM-3 ***. 0137:41 CAM-1a bravo for you, bravo for you, and what about the one that 

doesn't have? 

0137:45 CAM-3 what do you mean by the one that doesn't have? 0137:46 CAM-1a the one that comes aboard and doesn't have any document 

that says that he should board. 

0137:49 CAM-3 they're all reported to the station from Egypt, each with his 

own schedule. anyone who will come back should inform the station in Egypt. 

0137:55 CAM-? [sound similar to clearing of throat] 0137:57 CAM-1a good, what about the one who comes back and nobody 

knows anything about him? 

0138:01 CAM-3 I gave my instructions in the station... 0138:05 CAM-1a fine. that's what I told them, I, I, I'm not a trouble maker. I 

mean you know me. I don't need any headache. I'm telling them I am looking after all your interests. when you all are covered, neither the station nor any pilot can argue with you all, and should anything happen to you, you see, nobody could say I know nothing about you. 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0138:12 CAM [sound similar to cockpit door operating] 0138:28 CAM-3 why, why would I put anybody, Habashi? 0138:28 CAM-? yes. 0138:31 CAM-1a no, that's what I'm saying. 0138:32 CAM-3 even if somebody makes a mistake, we'll cover him too. 0138:35 CAM-1a I'm not saying anything. I'm not saying anything but I get 

surprised by three, four people going back and I know nothing. everyone is telling me that he has work in Egypt *. 

0138:50 HOT-2a may God make the seven six prosperous, Captain Habashi. 

tomorrow, we'll have a hard time up there. let us be, "Uncle Haj". 

0138:56 CAM-1a why, "Uncle", by God? 0138:58 HOT-2a very sweet, may our Lord make it prosperous. sweet, sweet. 0139:00 CAM-1a have we ever shorted you? [sound of laughter] 0139:01 HOT-2a that's why I'm saying to you, sir, may our Lord make it 

prosperous, but we'll have a hard time... 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0139:04 CAM-1a this man is saying, he's saying to you, "even the one that 

makes a mistake, I will cover him." I mean, where can you see someone who says that? 

0139:11 HOT-2a so, why are you upset, Captain? 0139:12 CAM-1a I'm not upset, I'm only speaking because I'm actually finding 

people about whom I know nothing, that's why they got upset with me. 

0139:21 HOT-2a the man didn't get upset or anything. 0139:22 CAM-1a no, I'm not talking about those. when I say, "people, please, 

anyone not scheduled on the plane should have something saying that he should board the plane," am I wrong in saying that? but I didn't tell anybody to board or not to board or, "you have it" or "you don't have it." 

0139:40 CAM-3 nobody can go back without receiving instructions. 0139:43 CAM-1a that's what I'm telling you... 0139:45 CAM-3 nobody can go back like this on his own. nobody can go 

back without receiving instructions. 

0139:51 CAM [sound similar to cockpit door operating] 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0139:56 CAM-1a how are you, Jimmy? 0139:58 CAM-2b how are you, sir? 0139:58 CAM-? *. 0139:59 CAM-1a what's new? 0139:59 HOT-2a I slept, I swear. 0140:00 CAM-2b just wait, let me tell you something. I'm not going to sleep at 

all. I might come and sit for two hours, and then... 

0140:07 HOT-2a but I, I, I slept. I slept. 0140:09 CAM-2b you mean you're not going to get up? you will get up, go and 

get some rest and come back. 

0140:14 HOT-2a you should have told me, you should have told me this, 

Captain Gamil. you should have said, "Adel... 

0140:16 CAM-2b did I even see you? 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0140:16 HOT-2a ... I will work first." just leave me a message. now I am 

going to sit beside you. I mean, now, I'll sit by you on the seat. I am not sleepy. take your time sleeping and when you wake up, whenever you wake up, come back, Captain. 

0140:28 CAM-2b I'll come either way... 0140:28 HOT-2a Captain... 0140:31 CAM-2b come work the last few hours, and that's all. 0140:35 HOT-2a no... that's not the point, it's not like that, if you want to sit 

here, there's no problem. 

0140:37 CAM-2b I'll come back to you, I mean, I will eat and come back, all 

right? 

0140:42 CAM [sound similar to cockpit door operating] 0140:43 HOT-2a fine, look here, sir. why don't you come so that... you want 

them to bring your dinner here, and I'll go sleep. 

0140:49 CAM-2b that's good. 0140:52 HOT-2a with your permission, Captain. 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0140:56 CAM [sound similar to cockpit door operating] 0140:57 HOT-2a [spoken in a soft voice] do you see how he does whatever 

he pleases? 

0140:59 CAM-1a do you know why that is? that's because you all get upset 

with me. 

0141:03 HOT-2a I'm not upset with you, what is it to me? [audio level from 

first officer's hot microphone system diminishes] 

0141:03 CAM-1a I don't mean you specifically, Adel. son, you are... 0141:07 CAM-2a I mean I like you. 0141:07 CAM-1a look, are you a youngster? 0141:09 CAM-2a no, he does whatever he pleases. some days he doesn't 

work at all. 

0141:11 HOT-2 [rustling sound heard through first officer's hot microphone 

system] 

0141:12 CAM-1a that's why I'm saying. you see, it's just like you heard. when 

I told him about those who want to go back, what did he say? he said, "never mind, I have them covered." 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0141:20 CAM [sound similar to cockpit door operating] 0141:20 CAM [whirring sound similar to electric seat motor operating] 0141:24 CAM-1a the conversation just happened in front of you. 0141:26 CAM [sound of click] 0141:28 CAM-2a doesn't he want to work with Raouf, or what? 0141:30 CAM-1a it's possible, it's possible, God knows. look, you don't have a 

male or female camel tied up in this situation [figuratively meaning: you have no personal interest at stake], as they say. right? by the Prophet, he's just talking nonsense. 

0141:44 CAM [sound similar to cockpit door operating] 0141:45 CAM-1a that's it. 0141:46 CAM-? enter, Monsieur. 0141:47 CAM-2a please, sir, do you need these, sir? 0141:51 CAM [sound similar to cockpit door operating] 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT

0141:52 CTR2 EgyptAir nine ninety, I have your oc

0141:55 CAM-1a oceanic is ready? go ahead. 

0141:57 RDO-2a go ahead nine nine zero. 

0142:00 CTR2 EgyptAir nine ninety, you're cleared 

Alpha, via after DOVEY, NAT TRACmaintain flight level three three zeroeight zero. 

0142:13 RDO-2a EgyptAir nine nine zero, cleared to 

SANTIAGO three three zero, eight (message) identification, three zero 

0142:24 CTR2 EgyptAir nine ninety, readback corr

0142:26 RDO-? [sound similar to brief unmodulated 

0142:31 CAM-2a everything's under control. 0142:32 CAM-2b what? 0142:33 CAM-2a everything's under control, Haj. 0142:34 CAM-2b okay, chief. 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0142:35 CAM [whirring sound similar to electric seat motor operating] 0142:35 CAM-1a thanks, Addul. [nickname for Adel] 0142:39 HOT-2 [sound of clicks similar to seat belt buckle operating] 0142:41 CAM-2a ** these things. 0142:42 CAM-2b all right, all right, go rest. 0142:43 CAM [sound of click] 0142:43 CAM-1a ***. 0142:44 CAM-? [sounds similar to clearing of throat] 0142:46 CAM [sound of clunk] 0142:47 CAM-2a how many do you want ** ? 0142:56 CAM [sound of thump] 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0142:59 CAM-1a how are you, Jimmy? 0143:00 CAM-2b why did you bring up this subject again? 0143:04 CAM-1a look, it's the same story with these number threes... 

[reference to additional repositioning crewmembers] 

0143:07 CAM [sound of click] 0143:08 CAM-1a ... so when they fly as active crew... what are they going to 

do? 

0143:09 CAM [whirring sound similar to electric seat motor operating] 0143:11 CAM-1a you tell me. 0143:12 CAM-2b it's disorganized. 0143:13 CAM-1a no, that's why I mentioned it to him. 0143:14 CAM-2b and you... 0143:15 CAM-1a weren't you sitting there listening to me? 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0143:16 CAM-2b I mean, you don't... don't... 0143:18 CAM-1a no. 0143:19 CAM-2b he's trying to please them. just so you know. 0143:22 CAM-1a oh yes, didn't he say if somebody made a mistake... 0143:24 CAM-2b yeah. 0143:25 CAM-1a you know, I don't harm anyone, I will cover for him. 0143:28 CAM-2b like I'm telling you. 0143:29 CAM-1a I told him it's all right. 0143:30 CAM-2b he's trying to please them. 0143:31 CAM-1a did you give the instructions that they should come aboard? 

he said to me, "I always send telex messages." that's it. 

0143:37 CAM [sound of click] 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0143:38 CAM-2b he's trying to please them. as long as he pleases them, 

don't worry your head. 

0143:47 CAM [sound of two thumps] 0143:50 CAM [sound of two clicks] 0143:52 CAM-1a since when do I worry my head... 0143:53 CAM [two consecutive whirring sounds similar to electric seat 

motor operating] 

0143:54 CAM-1a I mean, you know. 0143:56 CAM-2b they, they... the word is that @ @ @ is making trouble. you 

are making trouble, that's what's being said by everyone. just so you know. 

0144:06 CAM-1a I don't care. 0144:09 CAM-2b these guys are a bunch of #. and what's more, they are 

being controlled by the guy named, under the leadership of, of the guy named, the # named @, you know? 

0144:22 CAM-1a ***. 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0144:24 CAM-2b don't worry your head. you're good hearted. 0144:26 CAM-1a I mean... you know me, it doesn't make any difference to 

me. but when kids start that way... 

0144:35 CAM [sound of two clicks] 0144:37 CAM-1a I told him, I told him later that if I saw anyone aboard that 

didn't get permission from anybody and who also keeps going back and forth, even with permission, he won't fly with me. I won't fly with him, I'm not willing. I don't want to fly with anyone, even if it comes to me not flying, and if they can prevent me from flying, that's fine, what can I say to them? 

0145:04 CAM-2b these kids are forming a clique with each other, just so you 

know, under the leadership of @ @. @ @ controls that group. he has @ ear, as well as... this kid is clever and cunning. 

0145:10 CAM [brief interruptions in audio on all CVR channels] 0145:25 CAM-1a who? 0145:27 CAM-2b that's him. 0145:29 CAM [sound of click] 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0145:30 CAM-1a which one? 0145:35 CAM-2b that's enough. 0145:35 CAM-2b don't you have the flight report with you, Adel? 0145:37 CAM-2a I've got it, sir, I've got it. 0145:41 CAM-1a what's with you, why did you get all dressed in red like that? 0145:47 CAM [sound similar to cockpit door operating] 0145:48 CAM-1a when do you have simulator? 0145:49 CAM-5 Wednesday. 0145:50 CAM-1a what's today? 0145:51 CAM-5 Sunday... Saturday. 0145:56 CAM [sound of two clicks] 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0145:59 CAM-1a hey guy, why didn't you take tomorrow's plane? 0146:00 CAM-5 I tried (because the plane is the plane named thousand). 0146:03 CAM-1a why burn yourself out? 0146:05 CAM-5 because I'm a pilot (thousand). I made three (trips). I'm sick 

and taking medication. 

0146:10 CAM-? maybe tomorrow? 0146:11 CAM-6 * do you all want something else? 0146:12 CAM-2b no, no, no. 0146:13 CAM-6 ***. 0146:15 CAM-2b that's really, really fantastic. 0146:17 CAM-6 ***. 0146:18 CAM-2b thanks a lot. 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0146:18 CAM [sound similar to cockpit door operating] 0146:20 CAM-2b not at all, sir. 0146:23 CAM [several clicks] 0146:30 CAM [unintelligible background conversation] 0146:37 CAM-? (I know @ @) 0146:40 CAM-1a where is @ @? 0146:42 CAM-? (he's in a hotel in Dubai) 0146:44 CAM-1a what? 0146:45 CAM-? (he's in a hotel in Dubai) [sound of chuckle] 0146:46 CAM-1a why, where did he go? 0146:48 CAM [sound similar to two hand claps] 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0146:49 CAM-1a eh? 0146:49 CAM-? *. 0146:51 CAM-1a did he leave like @ @, or what? [sound of chuckle] 0146:52 CAM [sound similar to three hand claps] 0146:53 CAM-? no, no, no. 0146:54 CAM-? that @. 0146:55 CAM-2b @ left for good? 0146:56 CAM-1a they say @ came back again. 0146:56 HOT-2 [whirring sound similar to electric seat motor operating] 0146:58 CAM-? he came back? I wish. 0147:00 CAM-1a Adel, weren't you the one who told me that he came back? 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0147:03 CAM-2a yes, yes, I heard. 0147:08 CAM [sound similar to cockpit door operating] 

0147:19 CTR2 EgyptAir nine ninety change to my f

point niner two. 

0147:25 RDO-1a one two five nine two, good day. 

0147:31 CAM-? ***. 0147:34 CAM [sound similar to cockpit door operating] 

0147:40 RDO-1a New York, EgyptAir ah, nine nine z

0147:45 CTR2 EgyptAir nine ninety, roger. 

0147:51 CAM-1a is that the route? even if it/she didn't want * ... 0147:55 CAM-2b * look, here's the new first officer's pen. give it to him 

please. God spare you. 

0147:58 CAM-? yeah. 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0148:01 CAM-2b to make sure it doesn't get lost. 0148:03 CAM-1a excuse me, Jimmy, while I take a quick trip to the toilet... 0148:04 CAM [whirring sound similar to electric seat motor operating, 

heard only using digital filter] 

0148:04 CAM [sound of click] 0148:05 CAM [sound similar to cockpit door operating] 0148:08 CAM-2b go ahead please (go ahead please). 0148:09 CAM [sound of several clicks] 0148:10 CAM-1a ...before it gets crowded. while they are eating, and I'll be 

back to you. 

0148:18.55 CAM [sound similar to cockpit door operating] 0148:22.70 CAM [sound of thunk] 0148:23.30 CAM [sound of clink] 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0148:30.69 CAM-? *** [The five Arabic speaking members of the group concur 

that they do not recognize this as an Arabic word, words, or phrase. The entire group agrees that three syllables are heard and the accent is on the second syllable. Four Arabic speaking group members believe that they heard words similar to "control it". One English speaking member believes that he heard a word similar to "hydraulic". The five other members believe that the word(s) were unintelligible.] 

0148:34.80 CAM [sound of click and thump] 0148:39.92 CAM-2b I rely on God. [heard faintly] 0148:49.30 CAM [sound of thump] 0148:53.10 CAM [sound of faint, muffled thump] 0148:56.31 CAM [sound of thump] 0148:57.93 CAM [series of thumps and clicks starts and continues for 

approximately seventeen seconds] 

0149:18.30 CAM [sound of light thump] 0149:18.37 CAM [whirring sound similar to electric seat motor operating, also 

heard through first officer's hot microphone system] 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0149:30.16 CAM [sound of two faint thumps and one louder thump] 0149:47.54 CAM [sound of two clicks and two thumps] 0149:48.42 CAM-2b I rely on God. 0149:53.32 CAM [one loud thump and three faint thumps] 0149:57.33 CAM-2b I rely on God. 0149:58.75 CAM-2b I rely on God. 0149:58.78 CAM [four tones similar to Master Caution aural beeper] 0150:00.15 CAM-2b I rely on God. 0150:01.60 CAM-2b I rely on God. 0150:02.93 CAM-2b I rely on God. 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0150:04.42 CAM-2b I rely on God. 0150:04.72 CAM [sound of loud thump] 0150:05.89 CAM-2b I rely on God. 0150:06.37 CAM-1a what's happening? what's happening? 0150:07.07 CAM-2b I rely on God. 0150:07.11 CAM [sound of numerous thumps and clinks continue for 

approximately fifteen seconds] 

0150:08.20 CAM [repeating hi-low tone similar to Master Warning aural starts 

and continues to the end of recording] 

0150:08.48 CAM-2b I rely on God. 0150:08.53 CAM-1a what's happening? 0150:11.50 CAM-? *. 0150:15.15 CAM-1a what's happening, Gamil? what's happening? 
 INTRA-COCKPIT COMMUNICATION AIR-GROUND COMMU

TIME & TIME & SOURCE CONTENT SOURCE CONTENT0150:19.51 CAM [four tones similar to Master Caution aural beeper] 0150:24.92 CAM-1a what is this? what is this? did you shut the engine(s)? 0150:25.00 HOT2 [change and increase in sound, heard only through first 

officer's hot microphone system] 

0150:26.55 CAM-1a get away in the engines. [translated as said] 0150:28.85 CAM-1a shut the engines. 0150:29.66 CAM-2b it's shut. 0150:31.25 CAM-1a pull. 0150:32.75 CAM-1a pull with me. 0150:34.78 CAM-1a pull with me. 0150:36.84 CAM-1a pull with me. 0150:38.47 END OF RECORDING END OF TRANSCRIPT
Attachment B

Response of the Egyptian Civil Aviation Authority to the

Draft Report of the National Transportation Safety Board 

EGYPTIAN CIVIL AVIATION AUTHORITY

RESPONSE TO DRAFT REPORT OF THE NATIONAL

TRANSPORTATION SAFETY BOARD CONCERNING

THE INVESTIGATION OF THE ACCIDENT INVOLVING

EGYPTAIR FLIGHT 990, A BOEING 767-300ER

SU-GAP, OCTOBER 31, 1999

Prepared pursuant to Annex 13

to the Convention on International

Civil Aviation
RESPONSE TO DRAFT REPORT OF THE NATIONAL

TRANSPORTATION SAFETY BOARD CONCERNING

THE INVESTIGATION OF THE ACCIDENT INVOLVING

EGYPTAIR FLIGHT 990, A BOEING 767-300ER

SU-GAP, OCTOBER 31, 1999

On April 19, 2001, the United States National Transportation Safety Board (NTSB) 

delivered a draft report regarding the investigation of the accident involving EgyptAir Flight 990, 

a Boeing 767ER, on October 31, 1999. Flight 990 was on a scheduled passenger flight from 

John F. Kennedy International Airport in New York to Cairo, Egypt when it crashed into the 

Atlantic Ocean approximately 60 miles southwest of Nantucket Island, Massachusetts.

The NTSB’s draft report, prepared under a delegation from the Government of Egypt to 

the Government of the United States pursuant to the provisions of Annex 13 of the Convention 

on International Civil Aviation, reflects a limited and incomplete investigation and a 

corresponding inadequate analysis. More importantly, an objective consideration of the evidence 

accumulated during the investigation shows that the NTSB, in its draft report, used selected facts 

and speculative conclusions to support a predetermined theory, instead of determining what 

probable cause, if any, an unbiased evaluation of all of the evidence would support.

In particular, the NTSB’s conclusion that the probable cause of the accident is the 

deliberate action of the relief First Officer is not supported by any evidence of intent or motive 

that would explain the First Officer’s alleged conduct. Indeed, the NTSB omits any discussion 

of motive and intent and of the facts in the record that squarely contradict a theory of deliberate 

pilot action. Equally, if not more disturbing, is the NTSB’s total disregard of the relevance of the 

unequivocal evidence of either sheared or deformed bellcrank rivets, not only on EgyptAir 990, 

but also on other Boeing 767 aircraft. Notably, neither the NTSB nor Boeing is able to explain 

the cause of these documented abnormalities. These sheared and deformed rivets are direct 

evidence of a potential defect in the airplane’s elevator system and may well indicate either a full 

or partial jam of one or more elevator PCA’s. Indeed, the NTSB acknowledges in its draft report

that the internal damage to one of the right elevator PCA’s of Flight 990 exhibited “unusual 
2

characteristics” that “might or might not have been impact-related” (emphasis added). It is 

inconceivable that the NTSB can credibly proffer a probable cause based on pilot action when it 

admits the existence of unexplained damage to a critical elevator component.

These shortcomings in both investigation and analysis compelled the Egyptian Civil 

Aviation Authority (ECAA) to prepare its own report and analysis, attached hereto as Appendix 

A, which is incorporated in the ECAA’s response to the NTSB draft report. The ECAA’s 

response, which includes the ECAA’s comments, is submitted to the NTSB pursuant to the 

provisions of Annex 13.

In addition to setting forth the ECAA’s own accident report, this response addresses three 

areas: (A) NTSB Procedural Irregularities and Adherence to Accident Investigation Standards; 

(B) Incomplete Investigation Actions/Missing Data; and (C) Discussion of Specific Issues in the 

NTSB Draft Report.

BACKGROUND

Immediately following the accident involving EgyptAir Flight 990, a Boeing 767-300ER, 

SU-GAP, in the Atlantic Ocean on October 31, 1999, the Government of Egypt sent an accident 

investigation team to participate with the NTSB. The Egyptian Investigative Team (the Egyptian 

Team or EIT) was led by the Egyptian Accredited Representative from the ECAA with 

experienced technical support from EgyptAir. The Egyptian Team participated in every phase of 

the investigation and on every NTSB working group for the entire 18-month period between the 

date of the accident and the delivery of the draft NTSB accident report.

The Egyptian Team made a formal presentation and submission on the accident issues to 

the NTSB on April 28, 2000. The Director General of the ECAA presented a detailed safety 

recommendation letter to the Administrator of the Federal Aviation Administration (FAA) on 

June 4, 2000. The letter contained three safety recommendations, addressing Boeing 767 

bellcrank/elevator flight control, pilot training, and maintenance issues. The ECAA’s safety 

recommendations resulted in two Airworthiness Directives by the FAA and a decision by the 
3

Boeing Commercial Aircraft Company (Boeing) to evaluate design changes as the terminating 

action for the repetitive inspection of the bellcrank assembly on the Boeing 767. In January 

2001, the Egyptian Team submitted a detailed report to the NTSB docket which outlined several 

technical inaccuracies in the accident submission that was made by Boeing. Finally, the 

Egyptian Team submitted numerous comments, reports and letters to the NTSB accident docket 

related to various aspects of the accident investigation and its factual record. The full record of 

Egyptian participation in the investigation serves as the foundation for the following comments.

I. The NTSB’s Investigation Was Marked By Procedural 

Irregularities and the Failure to Follow Accepted Accident 

Investigation Standards

The investigation of the EgyptAir 990 accident was marked by early and ongoing “leaks” 

of information from the NTSB, and by public statements of the NTSB Chairman and “other 

sources close to the investigation.” The early release of information, especially relating to the 

cockpit voice recorder (CVR) and the flight data recorder (FDR) and the statements by the 

NTSB Chairman and other NTSB officials, established in the minds of the media, the public, and 

the aviation industry that the accident was caused by a deliberate act of the First Officer. This 

became the so-called “suicide theory.”

The release of selected CVR and FDR data, and the NTSB’s public discussion of it as 

purportedly reflecting a deliberate act, occurred in November 1999, less than two days after the 

recorders had been recovered. Furthermore, the announcement by the NTSB that it was 

considering turning the investigation over to the FBI came after an incorrect translation of the 

conversations on the CVR which were in Arabic. CVR information was also released before 

there was any investigation by a CVR working group. Standard NTSB procedure is to convene a 

CVR working group, made up of representatives of the various parties, which then develops a 

transcript of the cockpit conversation, based on the technical and cultural knowledge of the 

group members. This did not occur. Instead, the NTSB staff listened to the Arabic 

conversations, accepted the incorrect translation of a non-Egyptian American translator, 
4

interpreted that translation without any cultural information, and then, less than 48 hours after the 

recorders were recovered, leaked information and made public statements concerning the CVR. 

The NTSB’s actions, unfortunately, resulted in an extraordinary waste of time, effort, and 

resources by the Egyptian Team, Boeing, and the NTSB. Instead of participating in an ongoing, 

objective investigation, focused on safety issues, the Egyptian Team was constantly forced to 

address the false issue of suicide. Despite the accumulation of substantial evidence showing that 

the suicide theory was incorrect and that there were serious airworthiness issues related to the 

Boeing 767 elevator bellcrank control system, the NTSB continued to make public statements 

which denied the existence of any mechanical issues and fueled speculation regarding the socalled suicide theory. In particular, the NTSB repeatedly asserted that it had found no 

mechanical cause for the accident. These statements -- not balanced by any corresponding 

comment that no non-mechanical cause had been found -- created a virtually unassailable public 

perception that the accident was attributable to the actions of the First Officer. The NTSB’s 

actions were consistently contrary to their own procedures and to those contained in Annex 13.

The NTSB’s persistent focus on the deliberate act scenario resulted in less than adequate 

investigation plans for other standard parts of the investigation. This was especially evident in 

the areas of the Systems Group, Aircraft Performance Group, and the Metallurgical Group. The 

Egyptian Team was forced to push for broader investigation plans and expanded tasks and 

schedules just to assure that basic aircraft accident issues were addressed. One example of the 

NTSB’s failure to pursue basic investigative steps was its refusal to conduct any metallurgical 

examination of any elevator bellcrank rivets or power control actuators (PCA) until an Egyptian 

Team member, in January 2000, insisted that this be done. The result was a full-scale 

metallurgical analysis. The focus on the bellcrank issues and the Boeing inspection procedure, 

which the ECAA brought to the FAA’s attention, led to a special investigation by the FAA in 

July 2000 and two Airworthiness Directives related to sheared bellcrank rivets and the 

inadequate Boeing inspection procedure.
5

A second example of the NTSB’s limited investigation was its reluctance to conduct 

comprehensive aircraft performance testing in the flight simulators at Boeing. The superficial 

level of the first simulator tests led to further testing, but only at the insistence of the Egyptian 

Team. As late as March 2001, a new series of simulator tests was scheduled by the NTSB to 

resolve selected technical questions. Even after these latest tests, many issues remain concerning 

the validity of the simulator tests.

Another example was the NTSB’s continuous refusal to conduct any analysis or tests 

concerning the recorded behavior of the ailerons of the accident aircraft. This was despite the 

FDR data which showed that Flight 990, while seemingly under control and in the process of 

recovery from the initial steep dive, suddenly experienced “split” elevators and abnormal aileron 

movements. The NTSB theorized that the abnormal aileron movement was caused by shock 

waves or other extraordinary aerodynamic phenomena as the airplane approached the speed of 

sound. However, the NTSB refused to consider these same shock waves as the possible 

explanation for the FDR data showing a “split” in the elevators. Instead, with no proof 

whatsoever, the NTSB concluded that the split of the elevator surfaces was due to opposite 

control forces in the cockpit – in other words, a fight between the Captain and the relief First 

Officer for control of the airplane. Although there was no evidence of a struggle, the NTSB used 

the elevator data to support its deliberate act scenario -- while, at the same time, it ignored any 

serious investigation of the unexplained behavior of the ailerons.

Along these same lines, the Egyptian Team continually requested that the NTSB and 

Boeing perform wind tunnel tests on the Boeing 767 flight control systems at the same speeds 

experienced by Flight 990 -- up to .99 Mach. There is no validated Boeing data on the 767 

airplane above .91 Mach; consequently, any conclusions about the performance of the airplane at 

higher speeds are necessarily based upon the extrapolation of .91 Mach data -- an extremely 

speculative technique when dealing with transonic speeds. The requests for wind tunnel testing 

to obtain accurate performance data were denied. Consequently, a thorough aircraft performance 

analysis to explain the meaning of the FDR data and the forces working on the airplane has not 
6

been accomplished. Curiously, at the same time that Boeing refused to conduct any wind tunnel 

tests1 for this accident, it announced on March 15, 2001, that it had just completed wind tunnel 

tests on the new Boeing 767-400ER at speeds up to .97 Mach. The tests were completed in 

February 2001 at the U.S. Air Force Arnold Engineering Development Center at the Arnold Air 

Force Base in Tennessee.

The Egyptian Team repeatedly requested a more detailed spectrum analysis of certain 

sounds recorded on the CVR in the period just before the accident event started. This included 

the unexplained phrase “Control it.” Chairman Hall, early in the investigation, suggested 

bringing in a Russian spectrum analysis expert to assist in this area. Although the NTSB had 

used this expert previously, it never sought his services and never explained its decision to the 

Egyptian Team. Nevertheless, the Egyptian Team continued to make requests for other spectrum 

analysis of CVR voices and sounds that the NTSB refused to undertake. This is contrary to what 

is required in a thorough accident investigation -- and is inconsistent with the NTSB’s 

procedures in accident investigations where U.S. carriers have been involved.

Other areas where the investigation was incomplete and/or where requests from the 

Egyptian Team were not addressed include:

• There was a perfunctory treatment of the recorded radar data of Flight 990. Only 

after the Egyptian Team insisted was there any effort to analyze the radar data. In 

addition, the investigation of radar issues was hampered by the absence of certain 

critical data. For example, 18 requests were made by the Egyptian Team for 

specific radar data and information. To date, eight of the requests have been 

refused with the explanation that the data is classified and is not available to the 

FAA or to the NTSB investigation. The Egyptian Team complained to U.S. 

Government officials that this is contrary to ICAO standards which require that 

 

1 Through Boeing meeting with Egyptian Investigation Teem on late May 2001, Boeing presented some limited 

wind tunnel test data regarding aileron and elevator.
7

such information be made available to accident investigation authorities. The 

Egyptian Team also volunteered to take whatever steps might be necessary to 

protect any sensitive information. The Egyptian requests for further radar 

analysis were based on the appearance of high-speed radar returns on tracks 

converging with Flight 990. The official response from the NTSB and the FAA 

was that the returns in question were “clutter or strobing,” although no work was 

done to verify this speculative conclusion.

• There were constant inaccuracies in the FDR data. On five occasions, the NTSB 

presented the “final” FDR data to the Egyptian Team and each time sufficient 

errors were identified to require the “final” report to be withdrawn and 

recomputed.

• Key aircraft components were not recovered even though a second effort was 

conducted to recover more wreckage. The second effort, scheduled for 10 days, 

lasted only 2 days and was initiated and undertaken without any consultation with 

the Egyptian Team. Critical components that were not recovered include two 

elevator PCA’s, one bellcrank assembly, the RAT, the QAR and portions of the 

elevators.

• The Egyptian Team was hampered by the inability to communicate and 

coordinate directly with Boeing, Honeywell and other component manufacturers. 

All communications were required to go through the NTSB which, often at the 

group chairman level, filtered, modified, or in some cases, denied the Egyptian 

request.

The most serious shortcoming of the NTSB investigation was the failure to seek out and 

address all the related safety issues. Once fixated on the deliberate act theory, the NTSB 

virtually ignored the airworthiness issues that subsequently emerged relative to the Boeing 767 

elevator bellcrank assemblies. These matters were brought to the attention of the FAA only after 

the ECAA took the initiative.
8

The Egyptian Team attempted to have the bellcrank issue thoroughly investigated by the 

NTSB Systems Group. Failing in this effort, the Egyptian Team took the unusual step of 

preparing a safety recommendation letter from the Director General of the ECAA directly to the 

FAA Administrator. The letter described the factual findings and the safety problems that had 

been identified in the EgyptAir 990 accident investigation. The three recommendations, sent to 

the FAA on June 4, 2000, stated:

1. Require a cockpit indication in the Boeing 767 that would alert the flight crew to 

abnormal PCA operation wherein a single fault in the elevator could result in 

uncommanded elevator movement. Until such a cockpit indicator is installed, 

require operators of Boeing 767 airplanes to perform daily -- rather than 400-hour 

-- checks of the elevator system to identify faults in the elevator system;

2. Review the Boeing 767 elevator control system design and conduct further 

examination of the causes of the reported discrepancies found in the elevator 

actuator bellcrank, and;

3. In conjunction with Boeing, develop cockpit crew procedures to aid the flight 

crew in identifying, isolating, and negating an uncommanded elevator hard-over 

condition.

These safety issue recommendations prompted action by the FAA which requested that 

Boeing undertake specific tests on the Boeing 767 elevator control system. The NTSB did not 

participate in this testing even though the issues arose from the Flight 990 accident investigation 

and appeared to be relevant to the accident. In any event, the identification and resolution of 

these safety issues should have come through the NTSB to the FAA.

The tests initiated by the FAA resulted in dramatic safety findings. In a July 20, 2000, 

Boeing message to all operators, Boeing stated that the test “ . . . results revealed that the 

Elevator Power Control Actuator, Maintenance Planning Document Item Number 27-31-00-5B 

test, which is required at a 400-hour interval, may not detect a failed hydraulic.” As a result, “. . 

. the single system hydraulic test passed even though there was a sheared bellcrank in one 
9

system.” The Boeing document further advised that “a representative of the FAA witnessed the 

sheared bellcrank test and advised that an Immediate (emergency) Adopt Airworthiness 

Directive will be released concerning this issue. . . .” The Emergency Airworthiness Directive 

was issued in August 2000. 

As a result of the findings of this Emergency Airworthiness Directive which required the 

prompt inspection of elevator bellcrank rivets, a second Airworthiness Directive was issued on 

March 20, 2001 which imposed a more comprehensive and frequent inspection of elevator 

components. This AD called for “. . . repetitive testing of the elevator control system to 

determine if an elevator power control actuator (PCA) is rigged incorrectly due to yielded or 

failed shear rivets in a bellcrank assembly for the elevator PCA, and follow-on actions, if 

necessary. This action is necessary to prevent continued operation with yielded or failed shear 

rivets in a bellcrank assembly for the elevator PCA, which could result in reduced controllability 

of the airplane. This action is intended to address the identified unsafe condition.”

Finally, Boeing has announced that it is in the process of evaluating design changes to the 

Boeing 767 elevator control system related to the bellcrank.

Clearly, a thorough and objective investigation by the NTSB would have identified this 

safety issue. Instead, the issue was addressed only after the NTSB refused to do the requisite 

analysis and after the Director General of the ECAA went directly to the FAA. Of primary 

significance to the accident investigation is that the dual elevator PCA failure identified by the 

Egyptian Team in January 2000 produces a flight profile very similar to that of the EgyptAir 

Flight 990 accident.

Finally, the NTSB’s decision to include raw, unverified U.S. Federal Bureau of 

Investigation (FBI) reports in the EgyptAir accident docket illustrated the NTSB’s preoccupation 

with a deliberate act theory to the exclusion of a thorough consideration of the potential 

mechanical deficiencies acknowledged by Boeing. The FBI had conducted an investigation of 

the First Officer’s background and had concluded that there was no evidence of a criminal act –

no evidence of a deliberate act or a suicide – by the First Officer. The anonymous FBI reports 
10

had no place in an NTSB aircraft accident safety investigation; yet, the NTSB decided to include 

them in the public docket just days before the docket was opened. The result was the publication 

of unsubstantiated reports which slandered the First Officer and his family, had no bearing on the 

First Officer’s ability to fly and provided no evidence that the First Officer intended to crash the 

airplane. At the same time, the NTSB deliberately ignored evidence provided by the Captain of 

an earlier flight on the accident airplane where he had experienced autopilot problems that had 

caused him to disconnect the autopilot. The NTSB not only failed to conduct any investigation 

of autopilot anomalies, it also excluded the evidence of these problems from the public docket.

From the beginning of this investigation, the Egyptian Team has insisted on only two 

things: First, that the investigation be complete and thorough; and second, that the evidence 

receive objective and unbiased evaluation. Unfortunately, the NTSB’s draft report shows that 

neither of these objectives has been achieved.

II. Status Of Investigations Actions

As described above, during the course of the investigation, there were numerous 

instances where the NTSB was reluctant to pursue standard accident investigation issues except 

at the insistence of the Egyptian Team. In other instances, either the NTSB or Boeing failed to 

provide satisfactory information relevant to the accident investigation.

From November 1999 through August 2000, the NTSB directed the Egyptian Team to 

make its investigative requests directly to the NTSB. After the Technical Review meeting in 

October 2000, the parties agreed that any additional technical requests would be submitted 

directly to Boeing. A summary of the current status submitted by the Egyptian Team is 

presented below. This information is divided into two parts. Part1 lists requests submitted 

directly to the NTSB, and part 2 reflects requests made to Boeing.
11

1. Requests submitted directly to NTSB

Reference Egyptian Investigation Team Requests Reason of request and current status

Exhibit 9- Systems

Elevator Hardware 

examination and analysis. 

EIT asked for more studies and data to explain the 

abnormalities that were found in one of the right 

elevator power control actuators. EIT showed its 

disagreement with delivered Boeing study. (EIT 

comments has been officially submitted to NTSB 

on June 29, 2000)

To support the analysis of the anomalies observed 

with one of the recovered PCA’s.

Status: Boeing provided two letters:

- Dynamic Analysis right PCA B-200-17066-

ASI, 29-Sep-00

- Dynamic Analysis right PCA B-200-17066-

ASI, 20-Oct-00

These studies are still considered to be 

incomplete.

EIT requested recovery of the following 

components: 

• RAT (Ram Air Turbine).

• QAR (Quick Access Recorder).

• The elevator remaining surfaces.

• One elevator input bellcrank.

• The following flight control actuators: 

ß Two elevator power control actuators 

(PCA).

ß One elevator autopilot servo actuator.

ß Two outboard aileron actuators.

ß Two outboard spoiler actuators.

ß One inboard aileron actuator.

Only the inboard aileron actuator was recovered 

during the second wreckage recovery effort, March 

2000.

To acquire more data to support the investigation 

analysis 

Non of the requested component has been 

recovered yet. 

Boeing letter, “Split 

Elevator Failure Scenario” 

dated July 21, 2000.

EIT requested an answer from Boeing regarding the 

discrepancies between the Ground Test results and 

Boeing analysis for the elevator PCA’s failure. 

(EIT request has been officially submitted to NTSB 

on June15, 2000)

To validate Boeing analysis of the “Split Elevator 

Failure Scenario”.

Boeing presented the following letters:

767 elevator control System Operation with 

Regard to Column Splits, Aft quadrant splits, and 

column jam B-H200-17026-ASI, B-H200-17026-

ASI-R1, B-H200-17083-ASI-R1, dated 2-Aug00, 14-Sep-00 and 20-Oct-00 respectively

- Explanation of two 767 elevator system 

Characteristics observed during dual PCA 

Fault ground testing, B-H200-17027-ASI, 

dated 4 Aug-00.

- 767 Elevator control friction and hysteresis, 

B-H200-17028-ASI dated 7-Aug-00

EIT commented about these letters during the 

Boeing Meeting, Nov 2000.

EIT requested:

• Additional information regarding ADC/ IRS 

To visualize the cockpit indication during the dive, 

and to support investigating pressurization system
12

Reference Egyptian Investigation Team Requests Reason of request and current status

• additional information regarding the effect of 

aircraft high rate of descent on the operation of 

the pressure controllers. 

(EIT request has been submitted to Boeing through 

an E-mail on July 14, 2000 with a copy to the 

NTSB, on July 21, 2000)

EIT did not receive Boeing response. Items are 

still opened.

Exhibit 13 Aircraft 

Performance

Group Chairman’s 

Performance Study.

The EIT asked for some more studies relevant to 

accident and not included in the performance study 

(when, where and why engine separation occurred, 

radar interference study, ...)

 To support the performance analysis and the 

study of possible aircraft disintegration.

The NTSB presented Aircraft Performance 

Addendum #4, “Engine separation study”, dated 

03 April 01, and revised version on April 

09,2001. 

EIT disagrees with the study conclusion

Group Chairman’s 

Performance Study. 

Addendum # 1

EIT asked the NTSB to apply the same 

methodology used for the elevator split study on the 

Aileron split (Study has been made by the EIT)

EIT did not receive NTSB answer

To support the analysis for the split elevator 

movement at the end of the dive.

Boeing presented the letters:

- Aileron Behavior, B-H200-17216-ASI, dated 

12 April 2001.

- Elevator Behavior, B-H200-17219-ASI,

dated 16 April 2001.

 These letters contain descriptive information 

without any analysis.

EIT requested to conduct wind tunnel tests to 

examine the ailerons and elevators behavior at 

speeds near the sonic speed

(EIT request has been officially submitted to NTSB 

on June 22, 2000)

To investigate the abnormal behavior of the 

ailerons and elevators during the dive

EIT received some incomplete data during 

Boeing presentation in Cairo, May 2001. 

Exhibit # 12 Cockpit Voice 

Recorder

Sound Spectrum study EIT asked the NTSB to:

Record the cockpit door operation and the cooling 

pack switches sounds during a flight test at an 

altitude of 33000 ft 

(EIT request has been officially submitted to NTSB 

on May 2000 and August 11, 2000)

To support the analysis for identifying the 

unknown sounds in the cockpit before and during 

the dive.

EIT did not receive NTSB answer yet

Do proper spectrum study for the word 

“Control It” and the following sounds. (Egyptian 

Civil Aviation submission August, 2000)

To identify the persons occupying the cockpit 

before and during the dive.

EIT did not receive NTSB answer yet

Exhibit # 3 ATC The following requests have been made to the 

FAA and assistant secretary of state for answers to 

questions that continue to be critical to the 

To support identifying the radar returns that were 

observed in the vicinity of EgyptAir 990 before 

beginning of the dive.
13

Reference Egyptian Investigation Team Requests Reason of request and current status

investigation of EgyptAir Flight 990:

1. Letter of agreement between FAA and the US 

armed forces concerning special use of warning 

area W506

2. The list of the activated warning areas during 

October 1999 (conditions period of releasing 

back to FAA)

3. Multiple radar coverage charts for New York 

and Boston Centers at FL 50, 100, 200 and 300.

4. Multi radar tracking mosaic clutter and 

interference study for radar sites. 

5. The configuration of the ZNY ATC system 

including radar and flight data processors, radar 

and voice data recorders, voice communication 

switching systems and the relevant radar sites.

6. The radar coverage charts, the last flight check 

reports, the interference and clutter charts and 

the antenna radiation patterns (PSR & NSSR) 

for GIBBSBORO (GIB), Riverhead NY, 

{RIV), North Truro, MA (NOR), Bucks 

Harbor, ME (BUC) and Nantucket radar sites 

(ARSR-4 & ASR-9).

7. The explanation of why the targets of Squawk 

5606, 1216, 3835 & 6757 are existing in the 

navy file and do not exist in the Airforce file 

while the source of both files is the Riverhead 

NY radar site. 

8. The radar data of the following targets:

- The target of squawk 2655 which was 

detected by five radars up to 06:18:25 UTC 

in the same area and date of the accident 

and no data shows after that time, albeit it 

was still at flight level 330 and within the 

radar coverage of the five radars (more 

information was received later but only up 

to 06:22:15 UTC}.

- The military aircraft ARISE 57, squawk 

1625 which was in the radar contact with 

the same controller (R86) of MSR990.

- The Royal Jordanian aircraft RG262 

NYC/AMC 

9. The clutter and interference studies for the 

radar sites, RIV, ZNY, and NOR.

10. Available technical data to analyze any 

This request was submitted to the NTSB, the 

FAA and the State Department, no response is 

provided to the EIT on the basis of “Classified 

Information”. 
14

Reference Egyptian Investigation Team Requests Reason of request and current status

interference affecting RIV.

11.Complete file of Riverhead Radar from Airforce

from 06:30 to 07:05 UTC including: 

Mode C validity

Mode 3 validity

Radar measured altitude

Decimal Latitude/longitude

Range and Azimuth angles from Radar site 

Exhibit # 10 Flight Data 

Recorder

EIT requested an explanation for inner marker 

signal which was recorded at the final phase of 

dive.

To find the explanation for the inner marker 

signal recorded at the end of the dive. 

Boeing comment on Action items received on 

October 20, 2000, contained description for the 

event. 

Item is still opened

EIT requested a complete analysis for the elevator 

behavior after autopilot disconnect events through 

the last 25 hours recorded data.

To support the study regarding the causes for 

autopilot disconnect.

Boeing presented the letters:

- Autopilot disconnects on DFDR B-H200-

17114-ASI, dated 22 Nov, 2000

- Autopilot disconnects evaluation B-H200-

17201-ASI, dated 22 March, 2001

EIT does not agree with the conclusions

2- Requests submitted directly to Boeing

Reference Egyptian Investigation Team Requests Reason of request and current status

Action 2: wreckage analysis EIT requests the elevators PCA’s vendor (Parker 

Hannifin) to review the contents of Boeing letters 

B-H200-17066-ASI and B-H200-17082-ASI for 

concurrence relative to remarks made by Parker 

representative (Steve Weik) during the June 28th

Systems Group meeting at the NTSB about the 

hypothetical position of the spring coil adjacent to 

the outside diameter of the spring guide.

 EIT requests Boeing to evaluate Page 15 photo 

marks relative to the scenarios considered in the 

referenced letters. Also, the EIT would like to know 

if these marks are consistent with a bellcrank shear 

for number 3 PCA?

To support the analysis of the anomalies observed 

with one of the recovered PCA’s.

EIT did not receive Boeing answer yet.
15

Reference Egyptian Investigation Team Requests Reason of request and current status

Action 4: autopilot 

disconnect

EIT in its response on the Boeing submission to 

NTSB dated 31 October 2000, showed its 

disagreement with Boeing conclusion regarding 

elevator behavior in the events of auto pilot 

disengagement.

Refer to B.1 Exhibit #10 Flight Data Recorder, B

Action 5: elevator failure 

scenario

EIT requests clarification of the conditions causing 

elevator pogo deflection during both single and dual 

valve jams (reference Boeing letter B-H200-17032-

ASI).

To support the analysis of possible mechanical 

failure.

Boeing presented the letter “Column forces 

required to deflect elevator input pogo”, B-H200-

17030-ASI, dated 11-Aug-2000

Action 7: inner marker EIT requests Boeing to study the reason for having 

“inner marker bit” appearing in the FDR at the end 

of the dive. Boeing indicated that it would confirm 

this condition by checking the CVR for marker aural 

warning associated with this condition.

Refer to B.1 Exhibit # 10 Flight Data Recorder

Action 10: Air Data System For the purpose of verifying instruments behavior 

during the dive, EIT requested Boeing to perform 

pitot static test using FDR data on a B767 airplane. 

Boeing refused to perform this test at Boeing 

claiming that it has not a similar Boeing 767-300 

airplane. EIT offered to perform the test on the MS 

sistership airplane on condition that Boeing would 

provide the test plan, pitot static test equipment, and 

that the test should be supervised by Boeing. 

EIT did not receive Boeing answer yet.

Action 12: elevator failure 

scenario

EIT requests an explanation of the reason why the 

elevator model presented by Boeing (Boeing report 

B-H200-17026-ASI-R1, dated 14 Sept 2000, 

767Elevator System Operation with Regard to 

Column Splits, Aft Quadrant Splits, and Column 

Jams), does not accurately predict the effects of 

single and dual PCA failures.

 Boeing is also requested to provide an explanation 

for the large deflection of the elevator surface 

associated with the column being held at neutral and 

how it is consistent with normal column sweep test 

data in the Failure Analysis Report.

Refer to B.1 Exhibit #9 systems, split elevator

Action 14: high rate column 

inputs

EIT requests the tabular data (e-fi1e) that support 

Boeing study regarding the effect of high rate 

column inputs (letter B-H200-17065-ASI)) 

EIT did not receive Boeing answer yet.
16

Reference Egyptian Investigation Team Requests Reason of request and current status

Action 18: ailerons 

behavior

EIT repeats request for Boeing to study the behavior 

of the inboard and outboard ailerons using highspeed data. EIT also requests the control surfaces 

hinge moment at speeds near sonic speed as derived 

from wind tunnel tests. EIT did not receive Boeing 

answer yet.

Refer to B.1 Appendix #13, Performance, 

Addendum #1

Action 20: elevator failure 

scenario

Regarding Boeing failure scenario (Boeing report BH200-17027-ASI, dated 4 August 2000, Explanation 

of Two767 Elevator System

Characteristics Observed During Dual PCA Fault 

Ground Testing)

Egyptian Investigation Team requests the following:

- Explanation for the mismatch in the elevators/ 

Columns gearing ratio.

- The reason for ignoring the three factors 

inf1uencing the elevator surface def1ection 

mentioned in Boeing relevant study, with regard 

to Boeing study concerning Split Elevator 

Failure Scenario (B-H200-16968.ASI.R1, dated 

21 July 2000), and its impact on the study when 

these factors are included.

- Explanation for the variation in the left-to-right 

elevator difference with regard to the Failure 

Analysis Report

To acquire more precise information for the 

possible mechanical failure. EIT did not receive 

Boeing answer yet.

Action 21: elevator system 

friction and hysteresis

With regard to 767 Elevator System Friction and 

Hysteresis (Boeing report B·H200-17028-ASI, dated 

7August 2000), EIT requests Boeing to provide a 

study showing the impact of the conclusion in the 

above mentioned report on its failure analysis report.

To support the analysis of possible mechanical 

failure.

Boeing presented the letter “767 elevator control 

friction and Hysteresis “ B-H200-17028-ASI 

dated 7-Aug-2000 

Action 22: elevator 

response with power On

EIT requests the tabular data (e-file) that supports 

Boeing letter concerning elevator system response to 

hydraulic power On (letter B-H200-17076-ASI) 

To support the analysis of possible mechanical 

failure. EIT did not receive Boeing answer yet.

Action 23: elevator failure 

scenario

EIT requests documentation of the expected 

tolerances of the analytically-developed elevator 

traces for the dual PCA valve jam scenario and a 

comparison of these tolerances with the tolerances 

of the FDR elevator traces.

To establish the match criteria between the 

analytically predicted results and the FDR data. 

EIT did not receive Boeing answer yet.
17

Reference Egyptian Investigation Team Requests Reason of request and current status

Action 24: elevator 

hysteresis

EIT requests an example of a hysteresis curve for an 

autopilot driven elevator

To support the analysis of possible mechanical 

failure. 

EIT did not receive Boeing answer yet.

Action 25: elevator failure 

scenario

With regards to Elevator System Friction and 

Hysteresis (Boeing letter B-H200-17028.ASI), EIT 

requests Boeing evaluation of the impact of the 

contents of this letter with Boeing letter concerning 

Split Elevator Failure Scenario (letter B-H200-

16968-ASI-R2)

To support the analysis of possible mechanical 

failure. 

 EIT did not receive Boeing answer yet.

Action 26: elevator split EIT requests Boeing to evaluate the aileron required 

to match the bank angle during the elevator split.

To support the analysis of possible mechanical 

failure. 

EIT did not receive Boeing answer yet.
18

III.Specific Comments Regarding The NTSB’s Draft Report, Which Is 

Based Upon an Incomplete Investigation, Unverified Data, and 

Unsupported Conclusions

As stated previously, the ECAA prepared a separate report: 

a) Pursuant to section 5.3 of Annex 13, it was anticipated that the investigation would be 

conducted as a partnership between equals. However, it soon became apparent that the NTSB 

leadership did not regard the Egyptian delegation as an equal partner and shared its processes, if 

at all, on a selective and seemingly random basis. Often the Egyptian delegation read about the 

NTSB’s views in the press without prior communication.

b) Because of the flawed and biased NTSB investigation; and because the NTSB draft 

report is specifically dedicated to proving the deliberate act (suicide) theory. Under these 

circumstances, the ECAA’s “comments” on the draft could never be adequate to correct all of the 

deficiencies of the NTSB draft or to provide input for meaningful revisions to the report. The 

draft NTSB report would require a major revision to include an expanded analysis of critical 

issues and, most importantly, an objective assessment of the evidence. 

Consequently, the ECAA was compelled to develop a separate report concerning the 

EgyptAir Flight 990 accident. However, it is important to underscore the following major 

deficiencies in the draft NTSB report in order to highlight those shortcomings which hampered 

the accident investigation, and which now are incorporated into the draft NTSB report.

• The draft NTSB report selectively uses the facts of the investigation to develop, support 

and “prove” the findings of the deliberate act scenario which appears to have been 

predetermined since November 1999. The NTSB’s most glaring omission is its failure to 

discuss any evidence of the motive or intent that would have caused the relief First 

Officer to take the “deliberate act” that the NTSB alleges. Similarly, the NTSB fails to 

account for specific facts in the record that refute the possibility of an intentional act by 
19

the First Officer. In addition, the NTSB ignores the significance of critical internal PCA 

damage, which it admits, “might or might not have been impact-related.”

• The NTSB uses airplane performance data, often supplied by Boeing, and performance 

data developed in the Boeing E Cab simulator, to reach conclusions about the 

performance of EgyptAir Flight 990 without addressing the proven inaccuracies and 

errors in the data. Additionally, the NTSB does not account for the absence of airplane 

performance data or characteristics for the flight regime of Flight 990 in the areas above 

.91 Mach. The NTSB draft report, nevertheless, reaches specific findings about the 

Boeing 767 and Flight 990. The fact that many of these conclusions are either 

speculative or are based upon data that has not been validated, supports the view that the 

NTSB’s conclusions were predetermined. 

• The NTSB downplays and ignores critical safety issues related to the Boeing 767 elevator 

system. In part, the draft NTSB report uses its analysis of performance data to discount 

the existence of safety deficiencies that were illustrated by the two FAA Airworthiness 

Directives related to the Boeing 767 elevator system, while ignoring the ongoing 

incidents of failed components in the bellcrank assembly and a recently reported incident 

of a jammed elevator on an American Airlines Boeing 767.

As shown in the comments below, because of these general errors and shortcomings, the 

NTSB draft report creates a false view of the evidence and an inaccurate determination of 

probable cause. The following comments, set forth with reference to the page numbers in the 

draft report, must be addressed by the NTSB before the issuance of any final report. Each 

comment is separately numbered, with the page numbers of the draft report set forth in

parentheses at the beginning of each comment. 

1. (Pages 3-5) The NTSB’s deliberate act theory is based, in part, on establishing 

that the Relief First Officer (RFO) took various unusual means to “clear the cockpit” so that he 

alone would be in control of the airplane. The implication in the quoted statements from the 

CVR is that the RFO “ordered” the Command First Officer (CFO) out of his seat and off the 
20

flight deck. In making this argument, however, the NTSB failed to account for the literal nature 

of the CVR translation and failed to interpret the literal translation with appropriate Egyptian 

cultural nuances and references. Although the NTSB quotes a substantial portion of the CVR 

transcript, several facts and statements are omitted. In light of the apparent bias of the NTSB’s 

draft report, it is not possible to conclude that these omissions were either unintentional or 

inadvertent.

After some discussion of changing places, the CFO told the RFO at 0140:35 “... if you 

want to sit here, there’s no problem.” The RFO then said, “I’ll come back to you, I mean, I will 

eat and come back, all right?” Out of the entire CVR transcript on the subject, the NTSB omitted 

this exchange. In doing so, the NTSB left the reader without the critical evidence that the CFO

advised that changing places would be “no problem” and that the RFO offered to eat and come 

back later -- an offer that the CFO refused, suggesting, instead, that the RFO eat his meal in the 

cockpit.

Moreover, without considering either the tone or cultural context of the discussion, the 

NTSB created the erroneous impression that the RFO was improperly “pulling rank.” According 

to the Egyptian Team investigators who listened to the CVR, the RFO was not ordering the CFO 

out of the cockpit, but rather, was simply asking to take an early turn on the flight deck -- a 

procedure that is not contrary to any EgyptAir policy or ECAA regulation. Presumably, if any 

adverse inference should be drawn from the RFO’s conduct, the Captain would have intervened 

and made his views known. The fact that the Captain did not intervene is the best evidence that 

the RFO’s request was not improper.2

The draft report also highlights the RFO’s statement at 0147:55 “Look here’s the new 

first officer’s pen. Give it to him. God spare you.” The only conceivable purpose in picking 

this one statement from the otherwise normal, routine cockpit conversation is, again, to imply 

 

2 Further, the CFO’s subsequent comments at 0140:57 and 0141:09 that the RFO “does whatever he pleases” 

indicated that the RFO’s request to work early was in keeping with his past actions and was not part of a plan to 

crash the airplane.
21

that the RFO was trying to make others leave the cockpit. More important, however, is that the 

NTSB report does not reflect that at the time the RFO asked that the pen be returned, the CFO 

was still in the cockpit, and that he was still present at 0147:03 -- seven minutes after he agreed 

to change seats with the RFO. 

The draft report fails to point out that the RFO never asked the CFO or anyone else to 

leave the cockpit. In fact, the transcript identifies a number of different voices in the cockpit and 

numerous times when the cockpit door is “operating,” suggesting that there was substantial 

traffic in and out of the cockpit. Consequently, it would have been extremely difficult for a crew 

member seeking to be alone to be sure that would occur when others were so freely -- and 

frequently -- present in the cockpit. Further, there is no evidence even if the RFO were alone --

as the NTSB contends -- that he took any action, such as locking the door, to prevent other 

crewmembers from entering the cockpit.

These facts neither reflected in nor commented upon in the draft report present a picture 

of a busy cockpit with people coming and going in response to their own desires and not as part 

of the RFO’s coordinated plan.

2. (Page 5, footnote 10) The meaning of “Tawakkalt ala Allah” is critical to the 

investigation. The Egyptian Team presented a substantial report about the cultural and religious 

meanings of this statement, and specifically made the point that this statement would never be 

used by a person who was about to do an evil deed. This aspect of the CVR and the cultural 

basis for the explanation of the actions of the RFO were generally ignored in the draft report. 

The NTSB should include in its report the cultural evidence regarding the circumstances when 

this expression would and would not be used.

3. (Pages 6-10) This section of the draft report addresses the actions of the RFO and 

the Captain and the manner in which the airplane maneuvered up until the end of the CVR and 

FDR recordings. The section is replete with the selective use of FDR data and CVR statements. 

The following points either are not raised or are minimized:
22

• The draft NTSB report does not discuss the important fact that there was no 

argument between the Captain and the RFO when the Captain re-entered the 

cockpit at 0150:06 after the accident event started. The Captain did not say to the 

RFO “What are you doing?” “Why are you pushing the controls of the airplane 

forward?” “Let go of the controls.” There is absolutely no indication that the 

Captain thought the RFO had any part with the condition of the airplane. None of 

this is addressed in the draft report. Instead, the Captain said five times, “What’s 

happening?” There is no indication from the Captain’s words that he believed the 

RFO was acting improperly.

• The cockpit door was left open. The RFO would have closed and locked the door 

if he had a plan to deliberately place the airplane into a dive.

• There is no mention of the following FDR data:

− Only 6 degrees of TED elevator was used even though 15 degrees of TED 

elevator were available;

− The computed control column position was less than 4 degrees forward 

although 11 degrees of forward movement was available;

− Throughout the maneuver, the airplane was never rolled more than 10 

degrees, and each time a roll started, it was corrected back toward a wings 

level attitude;

• The engines were not cut off as part of the initial dive;

• The FDR contains 25 hours of data detailing the airplane’s performance prior to 

the accident. In particular, this data shows an unusual pattern of 11 autopilot 

disconnects. These autopilot disconnects shed light on the unique behavior of 

EgyptAir 990. Of special note is that most of the time the autopilot was 

disengaged, there was an obvious downward movement of elevators, with the 

right elevator showing a greater deflection than the left. 

To analyze this data, EgyptAir test flew another 767 and performed a series of 

autopilot disconnects and reviewed the FDR data from those test events. This set 
23

of test autopilot disconnects was performed during cruise on a flight from Cairo to 

Rome. As was expected, the data recording these disconnects showed no 

significant movement of the elevator between autopilot and manual operation at 

the moment the autopilot disconnected. This is in contrast to the data for the 

EgyptAir 990 airplane where there ware downward elevator deflections when the 

autopilot was disengaged.

4. (Page 9, footnote 22) This footnote is devoted to asserting that during the dive 

as reproduced on the simulator, the airplane’s controls could be worked without difficulty. The 

NTSB notes, however, that the zero g loads recorded on the FDR could not be duplicated in the 

simulator. This is typical of the NTSB’s approach in other areas -- identify a potential problem 

and then totally ignore it.

The inability to simulate zero g may be critical in any evaluation of the potential 

recoverability of the airplane; yet, the NTSB suggests that identifying the problem is all that it 

must do. The issue is important where, as here, the control column force needed to recover the 

airplane is much higher than normal and must be sustained by the crew for longer than normal. 

Under zero g conditions, it may be difficult, if not impossible, for an unrestrained crewmember 

to exert sufficient force on the controls to affect the same recovery demonstrated in the 

simulator. Consequently, no conclusions as to probable cause should be based on the purported 

recoverability of the airplane.

5. (Page 15, footnote 32) The routing of the cable in Figure 1a appears to be the 

opposite of the routing described in the footnote.

6. (Page 21-22) The NTSB mischaracterizes the report of the EgyptAir Captain on 

the outbound flight to Los Angeles regarding the operation of the autopilot. The important fact 

is not that the autopilot could not be reengaged, but rather why Captain Arram disconnected the 

autopilot in the first place. With respect to that question, Captain Arram reported that he 

observed movement in the control column, as if the autopilot was “hunting.” Because of the 

abnormal movement in the control column, he disengaged the autopilot. It is entirely possible 
24

that the RFO also observed unusual movement in the control column and, like Captain Arram 

before him, decided to disconnect the autopilot.

7. (Page 22) The NTSB states that all of the previous elevator movements on 

autopilot disconnect -- which were “primarily in the trailing-edge-down (TED) direction” --

were consistent with “normal operation.” The ECAA is not aware of any Boeing supplied data 

that shows a TED movement is expected consistently upon autopilot disconnect and has not been 

shown any data or studies to confirm that movement of .88 degrees or less is “normal.”

8. (Page 23) The discussion of Boeing 767 bellcrank anomalies minimizes the 

critical safety aspects represented by these findings and is presented in such a way as to convince 

the reader that these types of failures never happened on EgyptAir Flight 990. The report does 

not point out that the Egyptian Team was responsible for the identification of the possibility of 

bellcrank assembly failures due to rivet shears and PCA jams. The NTSB Systems investigation 

refused to address these issues or to bring the safety deficiencies to the attention of the FAA. 

The draft report does not discuss the cumulative findings that were developed which suggest that 

there was a similar bellcrank/PCA failure associated with EgyptAir Flight 990.

The facts are that, as a result of the safety issues raised during the EgyptAir Flight 990 

investigation, the FAA issued two Airworthiness Directives concerning the Boeing 767 bellcrank 

assemblies. More than 152 bellcrank assembly rivets were found defective. Of this number, 52 

had to be replaced before the airplanes were allowed to fly again. The FAA determined that the 

approved Boeing inspection procedure for the rivets was inadequate. Boeing is evaluating 

design changes, as the potential terminating action, of the system. 

The sheared elevator bellcrank rivets on an AeroMexico Boeing 767 (a fact 

acknowledged only in a footnote on page 23), along with the discovery of numerous defective 

rivets as a result of the FAA’s August 2000 Emergency AD, are ample proof of unusual and 

unexplained forces acting within the Boeing 767 elevator system. These anomalies may well be 

related not only to the Flight 990 accident, but also to three other incidents involving the 

improper functioning of the Boeing 767 elevator system.
25

In particular, the NTSB’s assertion that there is no relevant FAA Service Difficulty 

Reports (SDR) is incorrect. The following incidents involving the Boeing 767 elevator system 

are included in the SDR's:

i. On September 12, 1994, United Airlines reported that a B767-300 airplane (serial 

number 27159) experienced a frozen elevator condition (while descending 

through 11,000 feet), which took 30 pounds forward pressure to pop the elevator 

free. A post-landing inspection revealed no discrepancies in the elevator control 

system.

ii. On June 20, 1996, the same airplane reported that it was “unable to hold altitude 

at 10,000 feet on autopilot which was disconnected and the elevator was stiff. 

After 5 to 10 minutes of using stabilizer trim, while pushing up and down on the 

control column, something let go at 4,000 feet and the airplane flew normal 

since.” A post-landing inspection, once more, revealed no discrepancies in the 

elevator control system.

Finally, on March 27, 2001, American Airlines reported that one of its B767-300 

airplanes experienced pitch control difficulties when descending through 6,000 feet on approach 

to Paris, France. A post-incident evaluation of the FDR confirmed that one of the elevators was 

frozen (believed to be the right elevator) in response to both autopilot and manual inputs. This 

event was described in the NTSB letter to the ECAA dated April 19, 2001 as a binding of the 

elevator aft quadrant. The pilots used the stabilizer trim to land the airplane. On the ground, the 

crew applied a higher force on the control column to break the elevator free. The post-landing 

inspection also revealed no discrepancies in the elevator system and the airplane was ferried back 

to Dallas, Texas. The incident is still under investigation by the NTSB, FAA, and Boeing.

Not only are these incidents significant because they provide documented evidence of 

malfunction in the Boeing 767 elevator system, they also conclusively demonstrate that such 

malfunctions can occur without leaving any obvious physical evidence. The NTSB’s five-year 

investigation of the USAir 427 accident was made all the more difficult and prolonged precisely 
26

because the suspect valve left no physical evidence of a malfunction. In light of this evidence of 

previous incidents and of the physical anomalies found in the Flight 990 wreckage, the NTSB’s 

contention that there is no evidence of a possible mechanical malfunction is neither accurate nor 

credible.

9. (Page 23, footnote 40) The footnote refers to the February 2000 incident 

involving an AeroMexico Boeing 767. The airplane experienced two failed bellcrank shear 

rivets. This prompted a March 15, 2000, Boeing letter to Boeing 767 operators which discussed 

the findings and explained that the bellcrank assembly rivets are designed to shear in the event of 

a jam of a PCA. Efforts by the NTSB and the Egyptian Team to examine components of the 

AeroMexico airplane were unsuccessful because the parts were not retained by Boeing. 

Consequently, the statement that the “examination of the elevator PCA’s revealed no evidence of 

a PCA jam” is an unsubstantiated report from Boeing -- which has its own interest in the 

outcome of this investigation -- and was not verified by the NTSB. It would be helpful to 

describe exactly what Boeing examined and what it observed rather than simply repeat the 

conclusory statement that there was “no evidence of a PCA jam.” Moreover, the NTSB should 

point out that the absence of evidence of a valve jam is not determinative as to whether or not a 

jam occurred.

10. (Page 25) There actually have been more than 152 reports of damaged shear 

rivets. The draft report understates the magnitude of this issue and the safety implications of the 

sheared rivets and the elevator control system failures.

11. (Page 25) Given the critical nature of the bellcrank assembly rivet issue and its 

possible involvement in the Flight 990 accident, it is irresponsible for the draft report to dismiss 

this issue with nothing more than the statement that “although the cause of the bellcrank shear 

rivet failures has not yet been determined, Boeing and the FAA are continuing to study the 

failures to identify the cause.” What is not mentioned is that the FAA is discussing an elevator 

system design change with Boeing. Given the documented safety problems with the elevator 

control system and the ongoing, unresolved deficiencies, the dismissive treatment by the NTSB 
27

in the draft report is surprising. This lack of emphasis potentially could be justified if the cause 

of the sheared rivet failures were known and had been thoroughly analyzed. However, without 

knowing the cause of the failures, the NTSB cannot dismiss the issue as unrelated to the 

EgyptAir Flight 990 accident and still expect to maintain high standards of accident investigation 

credibility.

12. (Page 25) This section states that the airplane is controllable with a dual 

bellcrank failure. However, there is no discussion of the increased control forces a pilot would 

experience or the fact that there is no pilot training for this failure. This information is critical to 

a proper analysis of pilot actions.

13. (Page 30) Speech Pattern Information -- This entire section was developed 

without consideration to how a person would react if he were so shocked or ill-prepared by an 

unexpected airplane system failure that he reverted to a state of inaction. This behavior has been 

documented by the NTSB in the past, but is not accounted for here.

14. (Page 32) The purportedly “unintelligible” comment was interpreted by some in 

the CVR group as “control it.” If “control it” was uttered by a crewmember in response to 

observed, unexplained, movement of the control column or the control wheel, it explains both 

the comment and the decision to disconnect the autopilot. Again, this comment is not included 

or discussed in the draft, especially within the context of the statement of the EgyptAir captain 

who observed this activity on the outbound flight.

It is puzzling that the NTSB repeatedly describes this phase as “unintelligible” when five 

of the nine CVR Group members were able to understand the words -- with four believing it to 

be “control it” and one thinking it was “hydraulic.” In fact, it was only a minority of the group 

that found the speech “unintelligible.” In light of these facts, it is wrong for the NTSB to label 

the utterance as unintelligible. The comment that these words “might have been an isolated 

declaration” of the RFO is sheer speculation. In fact, given the RFO’s reported lack of comfort 

using English, it is highly unlikely that he was the speaker.
28

15. (Page 34) Here, the NTSB describes its review of the transcripts of other 

accidents and states that it “did not observe instances on these CVR recordings in which a pilot 

failed to exhibit surprise, alarm, or increased stress . . . .” The NTSB’s purpose in making this 

comparison with Flight 990 obviously is to suggest that the absence of exclamations from the 

RFO indicates he was in control of the events and, therefore, was not surprised. First, the NTSB 

fails to note that the instances it uses for comparison all involved circumstances where there 

were two or more crewmembers in the cockpit at the beginning of the accident sequence. 

Consequently, many of the comments appear to have been made as part of the communication 

from one crewmember to another. Although there is no evidence to prove that the RFO was 

alone in the cockpit, the NTSB assumes this to be a fact. Therefore, the circumstances of Flight 

990 are unlike any of those studied by the NTSB. Second, and more important, the NTSB 

provides no data or studies to show that the absence of an excited utterance is in any way 

meaningful, much less that it is indicative of an intent to crash an airplane. Consequently, there 

is no evidence in the record to support a view that the RFO was acting improperly.

In contrast to the lack of evidence concerning the meaning of the absence of an excited 

utterance, there is specific, expert evidence in the record that the NTSB ignores completely. An 

Egyptian psychiatrist, Dr. Adel Fouad, listened to the entire CVR tape and provided a detailed 

report substantiating his conclusion that the RFO was acting normally and interacted 

appropriately with the Captain. The NTSB surpressed this evidence in its report and provided no 

explanation as to why Dr. Fouad’s opinion -- the only expert medical opinion obtained during the 

investigation -- was completely ignored.

16. (Page 37) The report should be clarified to reflect that it could not be determined 

if portions of either the right or left elevator surfaces were recovered or were present at either 

wreckage site.

17. (Page 39) Although the NTSB notes the unusual characteristics of the internal 

mechanisms of one of the right-side PCA’s, nowhere does the NTSB discuss the fact that in the 

entire course of the five-year USAir Flight 427 investigation, it did not find any anomalies on the 
29

internal mechanisms of any of the PCA slides that it examined. In fact, the EgyptAir PCA slide 

anomaly is probably the first ever found by the NTSB. The absence of this background stands in 

stark contrast to the extensive historical context that the NTSB devotes to the review of CVR 

transcripts to show the uniqueness of the RFO’s response compared to other flight crews. 

In most NTSB reports the metallurgical investigation is reported in a separate section to 

provide detailed information about the metallurgical findings of the investigation. In the draft 

report, however, the NTSB puts the metallurgical work in the wreckage information section and 

provides virtually no detail about any findings. This is a critical oversight, since the 

metallurgical work is tied directly to the FAA Airworthiness Directives on the sheared bellcrank 

rivets, and is related to the Boeing inspection procedure for the rivets which was proved to be 

unsatisfactory. 

Additionally, if the FAA and Boeing have not found the cause of the rivet shears, it is 

irresponsible for the NTSB to provide anything less than a full accounting of the EgyptAir 990 

PCA and bellcrank rivet examinations. In fact, the findings were that two of the three bellcrank 

rivets on the right elevator sheared in a direction different from the third bellcrank assembly rivet 

on the same side. The draft report fails to identify the right elevator as the location of these 

conflicting shear patterns and makes only a very general (and vague) statement that some 

assemblies sheared in a direction opposite to the others.

18. (Page 39) The statement that there were no scrapes or abrasions on the bias 

spring is misleading and incomplete. The bias spring is composed of a metal that is harder than 

other PCA components and, therefore, would naturally resist any physical evidence of a jam. 

Moreover, in the USAir 427 accident investigation, the NTSB concluded that a jam could occur 

in a similar PCA without leaving any physical mark.

19. (Page 40) The statement that the fracture surfaces “were consistent with failures 

generated by high-speed impact” is misleading and incomplete. This statement is written not just 

to advise that the fracture surfaces are consistent with high-speed impact, but also to suggest that 

high-speed impact caused the fractures. There is no evidence that these fractures were, in fact, 
30

caused by a high-speed impact. In fact, the fractures are stress fractures that are just as 

consistent with low-speed forces as with high speed. This statement in the report needs to be 

corrected.

20. (Page 41) The NTSB states that the U.S. Air Force determined that unidentified 

radar returns “were caused by radio interference.” For over 18 months, the Egyptian Team has 

been seeking the technical data that would either support or refute this conclusion and has 

consistently been refused access to this information. The data on which the Air Force relies 

should be disclosed and delivered to the Egyptian Team.

21. (Page 44, footnote 70) This note suggests that even a small sideslip angle or roll 

rate could produce large changes in the aerodynamic forces acting on the ailerons when 

approaching 1.0 Mach. If the NTSB believes that these same forces do not affect the elevators in 

a similar way, the difference must be explained.

22. (Page 45, footnote 71) The NTSB advises that for performance numbers higher 

than .91 Mach (the highest number for which Boeing has verified data), “the simulator’s 

database was adjusted to reflect extrapolations . . . .” This reflects the inexact methodology 

relied upon by the NTSB to arrive at its conclusions. With respect to the use of extrapolated data 

to predict transonic airplane performance, the Egyptian Team is not aware of any study or 

analysis that validates this approach. The reason is that airplane performance and aerodynamic 

forces change in radical ways as the airplane’s speed approaches 1.0 Mach as it did here. 

Consequently, without technical evidence that extrapolation produces valid results, none of the 

simulator results above .91 Mach can be considered reliable.

Furthermore, the validity of many of the simulator results is questionable for an even 

more fundamental reason. The simulator runs were based on published Boeing performance data 

and predictions. Various ground tests, using an actual Boeing 767, however, demonstrated that 

many of Boeing’s predicted results did not reflect real-world airplane behavior. Nevertheless, 

Boeing refused to use the ground test results in the simulator experiments. Thus, there is 

empirical evidence that demonstrates the inherent unreliability of conclusions based solely on 
31

simulator results and Boeing’s calculated predictions. Without further study, it is not possible to 

determine the margin of error. It is, however, clear that many of the NTSB’s factual assertions 

are derived from faulty simulator tests.

23. (Page 48) The assertion that “calculations” showed that there would initially be 6 

degree nose-down elevator deflection is accurate, but misleading. As noted above, this number 

was derived from Boeing calculations -- not from testing -- that could not be replicated on a real 

airplane, thus raising a significant question as to their validity. The simulator was then 

programmed to produce a 6 degree nose-down deflection as shown in NTSB figure 2. The clear 

implication of the NTSB’s text and its charts is that the dual PCA jam testing produced certain 

results that did not “match” the FDR. This is simply not the case because the test parameters 

were nothing more than Boeing’s calculations. Consequently, none of the testing confirmed 

Boeing’s calculations. Indeed, it was just the opposite as shown by the ground tests. Therefore, 

the NTSB’s assertions that a dual PCA jam would produce a deflection of 6 degree nose-down 

on the failed side and 4 degree nose-down on the non-failed side suggests a degree of precision 

not warranted by any of the tests conducted during the investigation. The error built into the 

simulator testing along with normal variations in airplane performance make it impossible to 

conclude (with any reasonable scientific certainty) that Flight 990 was not affected by a dual 

PCA jam.

24. (Page 50) In an effort to convince the reader that the simulation results were 

valid, the NTSB states (a) that the simulator reflected the flight characteristics “to the maximum 

extent possible,” (b) that all flight conditions “were calculated correctly,” and (c) that the outthe-window view replicated the visual cues during actual flight. Again, these statements are both 

misleading and inaccurate. Even if the simulator reflected the EgyptAir 990 characteristics “to 

the maximum extent possible,” the NTSB has omitted any discussion of the inaccuracies in the 

modeling and whether those inaccuracies affected the test results. As noted previously, the 

ECAA believes that there were sufficient inaccuracies in the data used in the simulator which, 

when combined with the limitations of the simulator, produced inaccurate results. In particular, 
32

these inaccuracies do not support a definitive conclusion as to the amount of elevator deflection 

in the various failure scenarios. The degree of precision represented in the NTSB draft report is 

simply not a valid product of the simulator testing and misrepresents the reliability of the data 

obtained.

25. (Page 50) The NTSB acknowledges that in recovering the airplane during the 

dive, “additional forces” would be required beyond those necessary for recovery if a failure had 

not occurred. However, the NTSB omits any discussion the magnitude of those “additional 

forces” and of the impact that such forces have in the recovery of the airplane. Again, there was 

a marked difference in the additional forces demonstrated through ground testing and those 

predicted in the simulator -- with the ground testing forces being much higher. The actual 

demonstrated forces were never used in the simulator, making the NTSB’s comments concerning 

recoverability speculative. Rather than simply identify an issue and then ignore it, the NTSB 

must discuss the additional forces needed for recovery, the duration that such forces must be 

applied, and the effect of zero or negative g on the crew’s ability to apply such forces. Unless 

these issues are fully developed, there can be no meaningful conclusion regarding the 

recoverability of the airplane. 

The numerous references in the draft report to the recoverability of the airplane reveal 

another “backdoor” through which the NTSB arrives at its probable cause determination. 

Presumably, the NTSB’s logic is that if an airplane suffering a dual PCA jam can be recovered in 

the simulator, then the failure to recover Flight 990 means that it did not experience a dual PCA 

jam. The obvious flaw in this logic is that no matter how good the simulator is, it cannot 

reproduce the feelings, sensations, and emotions triggered by an unexpected upset, at night, over 

the ocean, during which the airplane and its contents experience a 40 degree nose down pitch and 

the crew and passengers experience negative g forces.

Further, in none of its references to “recoverability” does the NTSB ever define what it 

means by that term. If recovery were defined as a point at which an uncommanded descent has 

been arrested, the wings are level, and the pitch has almost reached zero, then the Flight 990 
33

crew recovered the airplane because those were the flight characteristics when the FDR stopped 

recording. Precisely what happened after Flight 990 recovered is unknown because both the 

CVR and FDR stopped recording. It does appear, however, from the location and condition of 

the left engine, that pieces of the airplane, including the left engine, departed the airplane prior to 

the beginning of the second, fatal dive toward the ocean. The loss of the left engine -- likely due 

to an overstress of the airplane during the ascent back to 24,000 feet -- created an asymmetrical 

load on the airplane from which recovery was virtually impossible. Consequently, regardless of 

the reason that the airplane initially departed cruise flight, there is a substantial argument that the 

reason that Flight 990 crashed was because it lost a major component -- the left engine -- which 

rendered the airplane unstable and unrecoverable.

26. (Page 58) As a result of the EgyptAir’s January 12, 2001 response to the Boeing 

submission, the NTSB was compelled to conduct further simulator tests and bench tests of the 

pressure relief valves of the elevator control assembly. These additional tests were required 

because of the incorrect data -- identified by EgyptAir -- that Boeing had submitted to the NTSB. 

The inaccuracies in the Boeing submission resulted in incorrect blowdown data for the elevator 

which was subsequently used as the basis for some of the airplane performance analysis. These 

facts should be included in the report to document the inaccuracies of the Boeing performance 

data relied upon by the NTSB. The variances in Boeing data demonstrate how easy it is to move 

the FDR flight profile towards, or away from, the E Cab simulator profile for a dual actuator 

failure. This aspect of the investigation underscores the manner in which the factual record and 

the subsequent analysis was selectively developed in the draft report.

27. (Page 59) The NTSB’s assertion that there was “no evidence of any ATC 

problems or issues” is incorrect. The ATC transcript included in the docket shows that Flight 

990 was “lost” in the ATC system during the handoff from New York TRACON to New York 

ARTCC. Further, the controller did not attempt to contact Flight 990 until six minutes after the 

accident sequence began and almost four minutes after the airplane crashed into the ocean. It 

appears that the light early morning air traffic may have lulled the controller into a period of 
34

inattention. It is neither acceptable nor explainable that an ATC controller does not notice the 

disappearance of an aircraft for more than four minutes after the last possible transponder radar 

return -- particularly when there are only a few airplanes in the air.

28. (Page 60) The analysis does not address in any way the reports of unexplained 

movements of the control column or the control wheel. These events on the outbound flight are 

possibly the reason the RFO disconnected the autopilot on EgyptAir Flight 990.

29. (Page 60) The discrepancy between the left and right elevators as recorded on the 

FDR prior to the event are not cited or analyzed. The position differences are indicative of an 

anomaly in the elevator control system and are critical to the analysis of the PCA jam/failure 

scenario

30. (Page 61) This sweeping generalization does not at all address the likelihood or 

possibility that the right elevator separated from the airplane about 0150:21. EgyptAir 

previously provided the NTSB with detailed calculations regarding the expected roll rate that 

would have occurred if the elevator were attached and in fact split from the left elevator to the 

extent indicated on the FDR. The NTSB must explain why the expected roll did not occur.

31. (Pages 62-63) The discussion of the recovered PCA’s and the bellcrank 

assemblies provides no in-depth analysis or a description of the anomalies that have been 

documented. The Board again fails to note that the one PCA from EgyptAir Flight 990 with a 

sheared rivet, sheared slid pin and an improperly positioned coil spring is the only PCA ever 

examined by the NTSB with any observable anomalies. The NTSB’s analysis does not address 

the shear patterns of the recovered elevator bellcrank assemblies except to attribute them in 

general to “high speed water impact and under water recovery.” There are no facts in the docket 

to support, much less prove, this conclusion. This analysis is inadequate and speculative and, 

more importantly, appears intended solely to support the deliberate act scenario.

Further, the analysis completely avoids any discussion of the NTSB’s statement on page 

39 that the internal anomalies of the right elevator PCA “might or might not have been impactrelated.” If those anomalies were not impact-related, then they indicate a serious problem in 
35

Flight 990’s elevator system. Unless the NTSB can exclude non-impact causes for this observed 

damage, it is not correct to state that there is no evidence of a mechanical defect, and it is not 

appropriate to assert a probable cause based on purported flight control inputs by the RFO.

32. (Page 63) The shear rivets in the recovered elevator bellcrank assemblies were 

sheared in different directions; however, “the Safety Board considers it likely that the rivets 

sheared as a result of impact or recovery-related forces.” The NTSB continues to ignore the 

history of the bellcrank shear rivets since this accident. The unexplained rivet failures have 

resulted in two FAA Airworthiness Directives, new airline inspection procedures for the rivets, 

and possible design changes of the system by Boeing. In addition, there was an unexplained 

elevator jam on an American Airlines Boeing 767 in March 2001. It is irresponsible for the 

NTSB to summarily dismiss this issue with a “considers it likely” assessment in the accident 

analysis. The existence of uncontroverted evidence of deformed rivets, suggesting a defect in the 

Boeing 767 elevator system, makes opinion “evidence” highly speculative and inappropriate. 

There is significant physical evidence that suggests that this type of failure was a factor in the 

accident.

As a relevant factor, however, the issue is not so much whether sheared rivets caused the 

uncommanded dive, but whether such shearing -- potentially evidenced by the opposing shear 

patterns on the recovered bellcranks -- is indicative of as yet unidentified problems elsewhere in 

the elevator control system. If nothing else, this investigation has shown that the Boeing 767 

elevator system is extremely complex and that there is relatively little certainty as to its precise 

operation under various failure scenarios. Consequently, the mere existence of examples of rivet 

shearing and deformation, the cause of which is unknown, should be adequate evidence of the 

possibility of a mechanical malfunction relating to Flight 990. This possibility is all the more 

likely where, as here, the rivets in question are designed and intended to give way in the event of 

a PCA jam. It is hardly farfetched or speculative to suggest that the rivet defects that have been 

observed are attributable to intermittent PCA jams, which are sufficiently transient as to leave no 

direct evidence and are sufficiently random as to defy predictability. The ECAA also notes that 
36

there was no physical evidence observed on the PCA’s of the USAir Flight 427 or United Flight 

585 where the NTSB concluded that the PCA caused a malfunction of the rudder. In the 

EgyptAir accident, the NTSB has physical evidence of an anomaly with the PCA yet concludes 

that “... the absence or presence of a jammed or disconnected impact linkage or a jam in the 

servo valve in one of the airplanes elevator PCA’s could not be established.”

33. (Page 64) The centerpiece of the NTSB’s argument that there was no evidence of 

a mechanical failure is that the elevators did not move to 6? TED at the beginning of the dive. As 

discussed previously, there are substantial reasons to question whether the calculated -- not 

demonstrated -- value of 6 degrees is accurate. Moreover, there is no discussion of whether this 

initial deflection value could be less if the crew were exerting back-pressure on the control 

column or if the failure were intermittent -- or at least not total -- at the beginning of the dive. 

Finally, there is no data in the docket showing the range of deflection that could be expected in 

the case of a dual PCA jam. Because the 6 degrees is a calculated number, it does not reflect 

real-world variances. If such variances were accounted for, the deflections observed on the 

Flight 990 FDR would likely be far closer to the NTSB’s calculations for a dual PCA jam. 

Again, the NTSB’s emphasis on the precise amount of deflection is misleading, not only because 

the testing did not validate that degree of precision, but also because it tends to obscure the 

physical evidence of a possible jam -- the oppositely sheared rivets, the sheared servo slide pin, 

and the differential bending in the PCA connecting rods. This physical evidence cannot be 

dismissed as impact damage when there is no evidence to prove it was impact-related.

34. (Page 65) Figure 2 shows a close correlation during the first 13 seconds between 

the accident aircraft FDR elevator profile and the dual jam failure scenario. Figure 2 also shows 

a close correlation between the accident aircraft elevator profile and all three failure scenarios if 

the RFO makes some limited control inputs once the accident sequence starts. However, the 

draft report does not address these issues and simply dismisses the possibility that any of the 

failure scenarios are consistent with the accident aircraft FDR data. Again, the NTSB’s failure to 

include any discussion of the forces necessary to move the flight control surfaces creates a 
37

misleading impression. The NTSB’s claim that “the nonfailed surface would have responded 

immediately to any nose-up flight control inputs” is not correct. The nonfailed surface would not 

respond to “any” nose-up input; it would only respond to nose-up input of a sufficient force to 

overcome the failed condition. As demonstrated in the ground testing, this force is considerably 

higher than the normal force. Whether the crew would immediately apply sufficient force to 

overcome a failure for which they were not trained is a matter of conjecture.

This same comment applies to the NTSB’s wholly conclusory assertion that the lack of 

demonstrated nose-up movement proves that there was no attempt to recover the airplane (see p. 

66). There is no evidence whatsoever to support this statement, which is made solely for the 

purpose of placing blame for the accident on the RFO. The fact is that the RFO could have been 

attempting a recovery, but failed -- or was not able -- to exert sufficient force to move the 

elevators in a failed condition. The question of the RFO’s ability to exert the necessary force is 

significant when Figure 4 is examined. Figure 4 shows that the downward deflection of the 

elevators tracked exactly the decrease in load factor. This may indicate that as the load factor 

decreased, the RFO became less able to exert the force necessary for recovery and, thus, the 

force of the PCA failure overcame the force of recovery. Figure 4 also shows that when the load 

factor began to increase, the elevators also began to move TEU -- possibly in response to the 

increasing ability of the crew to gain the leverage necessary to exert recovery level forces.

35. (Page 67) The draft report seriously understates the limitations of the E Cab 

simulator and the Boeing aircraft performance data with the simple statement that “the Board is 

well prepared to take those limitations into account ... In this case the Board determined that the 

differences were not significant ....” This sweeping conclusion again indicates a preconceived 

conclusion by the Safety Board to not involve the airplane in the accident scenario. More 

importantly, the draft report omits any discussion explaining exactly how the NTSB took the 

simulator limitations into account, what differences were considered, and why those differences 

were deemed “not significant” in the context of this investigation.
38

36. (Pages 67-68) As part of its conclusion that there was no mechanical failure, the 

NTSB argues that the RFO “exhibited no audible expression of anxiety or surprise.” This fact --

even if true -- does not mean that there was no PCA jam or that the elevator bellcrank rivets did

not shear. By making this argument in the mechanical defect analysis section of the draft report, 

the NTSB illustrates the biased and predetermined nature of the report. Clearly, there are no 

scientific or behavior studies that link the existence of a surprised utterance with proof of a 

mechanical defect in an airplane.

In its apparent haste to place blame on the RFO, the NTSB has overlooked three other 

important considerations. First, when the Captain returned, he asked several times, in an excited 

way, “What’s happening?” Presumably, if an excited utterance were the hallmark of the 

existence of a mechanical defect, the Captain’s statements would tend to support that theory --

particularly when made under circumstances where it should have been obvious to the Captain if 

the RFO were trying to crash the airplane. 

Second, the NTSB’s contention that the RFO showed no audible anxiety fails to account 

for the rapid repetition of the phrase, “I rely on God.” That repetition in itself is likely an 

indicator of stress. Moreover, the NTSB has failed to offer any evidence to support its theory 

that the lack of discernable stress or anxiety means that the RFO was intentionally diving the 

airplane. Without such evidence, the RFO’s “passive behavior” is just that -- passive behavior. 

At worst, the RFO’s behavior is unexplained -- a vastly different conclusion than that his 

behavior proves he intentionally dove the airplane.

Third, the NTSB’s assessment that the RFO did not exhibit undue anxiety is based, in 

part, on its analysis of fundamental frequency characteristics, described on pages 29-30 of the 

draft report. The NTSB’s assessment of the RFO was that he exhibited a 25 percent increase in 

fundamental frequency -- below the 30 percent threshold the NTSB identifies as the indication of 

“stage 1 level of stress.” Interestingly, a similar study of the Captain when he returned to the 

cockpit and asked “What’s happening?” showed an increase of only 29 percent -- still below the 
39

NTSB’s 30 percent threshold. Thus, neither the Captain nor the RFO met the NTSB’s criteria 

for a stage 1 level of stress.

The relative comparability of the fundamental frequency increases for both the Captain 

and the RFO show that it is unfair to characterize only the RFO as purportedly failing to exhibit 

an audible indication of anxiety. Even at the most extreme point in the accident sequence, the 

NTSB attributes only a 47 to 65 percent increase in fundamental frequency to the Captain. This 

equates to a range of stress from stage 1 to a very low level of stage 2 (50 to 150 percent 

increase). Given the cascading problems aboard Flight 990, including a 40 degree nose-down 

pitch and zero g, it is remarkable that the Captain barely broke into stage 2 -- and, in fact, did so 

only toward the end of the descent.

These facts suggest that the NTSB’s reliance on a change in fundamental frequency may 

not, in this case, be an accurate predictor of anxiety and stress. At a minimum, the NTSB must 

describe the range of variances from the norm that may be attributable to personality, training, 

and culture. In particular, the NTSB must validate its measurement techniques and analytical 

assessments for Egyptian persons speaking Arabic.

Finally, the NTSB provides no evidence to show the RFO’s intent or motive or otherwise 

to explain his behavior. It is extraordinary to conclude that the evidence is so strong that it 

supports a determination of probable cause, yet fail to include any explanation for the allegedly 

intentional human action that had such tragic consequences. In fact, the total lack of any cogent 

explanation for the RFO’s actions -- in contrast to the detailed scenario established in the Silk 

Air investigation -- is itself evidence that calls into question the validity of the NTSB’s deliberate 

act theory. In spite of the crucial role that such evidence has in establishing the probable cause 

set forth by the NTSB, the draft report is silent on the subject. This alone is cause for the NTSB 

to withdraw its probable cause determination.

37. (Page 68) The ECAA maintains that the FDR shows that the crew did recover the 

airplane -- or, at a minimum, substantially recovered the airplane -- by the time the FDR stopped 

recording. While it is evident that the recovery could not be maintained, the NTSB draft report 
40

fails to discuss the reasons that such recovery was not ultimately successful. Again, without any 

analysis, the NTSB asserts that a successful recovery was possible. Not only does this 

conclusory statement substitute speculation for fact, it ignores the real possibility that the 

airplane, in passing through a range of g forces and approaching 1.0 Mach, experienced shock 

waves and aerodynamic forces that led to structural damage, including the loss of the right 

elevator and the left engine. Under those circumstances, the airplane would have been out of 

control and -- contrary to the NTSB’s claim -- unrecoverable.

38. (Page 69) The entire Pilot Action Scenario is developed by selectively using 

information developed during the investigation to prove that the RFO deliberately crashed the 

airplane. The same information could be presented in a different manner to prove that the RFO 

had no idea what was happening and that the Captain did not suspect that the RFO was 

performing any actions that were contributing to the airplane dive. See comments in No. 36 

above.

39. (Page 70) See previous comment No. 1. 

40. (Page 72) The RFO could have disconnected the autopilot in response to 

unexplained movements of the control wheel or column. Further, all radar targets have not been 

adequately resolved. The Pilot Action Scenario does not account for the fact that the airplane 

maintained an essentially wings level attitude which would be unexplained if the RFO was trying 

to dive/crash the airplane or if a struggle was underway with the Captain. Further, the NTSB 

fails to note that if the RFO were intending to dive the airplane, he could have used an additional 

9 degrees of nose down elevator authority. The fact that full elevator authority was not used 

indicates that the RFO was not intending to dive the airplane.

Similarly, the NTSB implies that retarding the throttles at the beginning of the dive 

indicates that the RFO intended to dive the airplane. The NTSB is wrong; this action implies 

precisely the opposite conclusion. If he had intended to crash the airplane, the RFO would have 

increased power to enhance the dive, rather than slowing the dive by retarding the throttles.
41

It is readily apparent from a comparison of Flight 990 data with that from Silk Air that 

the NTSB has manipulated the facts and corresponding analysis to fit its predetermined result. In 

Silk Air, the NTSB wrote that “physical evidence of a high engine power setting, a horizontal 

stabilizer trim setting positioned for maximum nose-down attitude, and the absence of any 

indication of an attempt to reduce the airplane’s speed ... strongly suggest the [diving] maneuver 

was intentional.” In the case of Flight 990 where all of these factors are the opposite of those in 

Silk Air -- where the engines were throttled back to a low power setting, less than full elevator 

authority was used, there was no nose-down stabilizer trim, and various steps, including 

extended the speed brakes, were taken to reduce speed -- the NTSB still concludes it was an 

intentional act. It is impossible to believe that the NTSB conducted an objective and unbiased 

investigation of Flight 990 when it is plain that completely opposite data concerning key factors 

in two accidents, nevertheless, produced the same NTSB conclusion.

41. (Page 74) The NTSB makes several speculative statements without explanation 

or support. The NTSB hypothesis that the RFO was gripping the control column when he 

supplied “significant nose-down control column inputs” and that action also provided some input 

to the ailerons. First, the FDR does not record either control column movement or the forces 

exerted; consequently, control column movement is only implied from other parameters. There 

is no FDR data that confirms what action was taken by the RFO. Second, input to the ailerons 

could also be supplied when pulling on the control column in response to a dual PCA jam.

The NTSB also states that the RFO increased forward pressure on the control column 

“when he heard the captain returning to the cockpit.” This statement demonstrates that the 

NTSB’s intention to avoid an objective evaluation of all of the evidence extends to making up 

evidence. There is no evidence whatsoever that the RFO heard the Captain returning to the 

cockpit. The only reason to include this fabricated claim is to place the blame for the accident on 

the RFO and to provide an explanation for an event that the NTSB finds otherwise 

unexplainable.
42

42. (Page 75) The NTSB concludes that the Captain made the nose-up elevator 

movements when he returned to the cockpit. Once again, this statement reflects more the 

NTSB’s conjecture than any supportable facts. Because there is no FDR record of control 

column movement or force, there is absolutely no basis to claim that the Captain rather than the 

RFO, or that the Captain alone and not along with the RFO, provided nose-up elevator inputs. 

As previously pointed out, the RFO could have tried to move the elevator nose-up, but those 

efforts may not have shown up on the FDR if the force applied was insufficient to overcome a 

dual PCA failure. The NTSB’s failure to provide an objective analysis of the evidence shows its 

intent to support a predetermined probable cause.

43. (Pages 75-76) The contention that the elevators would be minimally affected by 

aerodynamic forces at .99 Mach is not supported by any validated test data. As noted previously, 

the extrapolation of airplane performance is not appropriate for the transonic speeds experienced 

by Flight 990. Consequently, the conclusion that the elevator split was caused by different 

inputs to each elevator surface is not supported by reliable evidence. More importantly, 

however, even if differing inputs were the cause of the split, there is no basis other than shear 

speculation to conclude that the different inputs were the result of a struggle between the Captain 

and the RFO. In fact, it is just as reasonable (and even more likely) that different control inputs 

were in response to differing perceptions as to the airplane’s attitude and the input necessary to 

affect a recovery. If the RFO believed that the pitch was increasing too much, he would push the 

column forward. A split would occur if, at the same time, the Captain believed that the 

increasing pitch needed to be sustained, and he pulled back. Remarkably, within just a few 

seconds of the split, the Captain reversed course and reduced the nose-up deflection of the left 

elevator. It seems reasonable that this action was due to the Captain perceiving, as the RFO had, 

that the pitch needed to be moderated. There is no indication that the Captain’s decreasing noseup input was because the alleged struggle was “over.”

44. (Page 76) The NTSB’s statement that the Captain’s actions just after the split 

“were consistent with an attempt to recover the airplane, and the relief first officer’s were not” is 
43

totally unsupported opinion and not factual analysis. If the NTSB insists on this reasoning, then 

it must add that during the last 10 seconds of the recording, when the Captain moved the left 

elevator TED and the RFO moved the right elevator TEU, the RFO’s actions were consistent 

with an attempt to recover the airplane, and the Captain’s were not. In fact, the Captain’s action 

is completely contrary to his request to the RFO to “pull with me.”

45. (Pages 80-81) The NTSB provides an unnecessary summary of its analysis, 

based on the same erroneous facts and unsupported conclusions addressed by the comments set 

forth above. 

CONCLUSION

In summary, it is obvious that the NTSB has not done the type of professional accident 

investigation expected by the Egyptian Government when delegation was convened in 

November 1999. Pursuant to section 5.3 of Annex 13, it was anticipated that the investigation 

would be conducted as a partnership between equals. However, it soon became apparent that the 

NTSB leadership did not regard the Egyptian delegation as an equal partner and shared its 

processes, if at all, on a selective and seemingly random basis. Often the Egyptian delegation 

read about the NTSB’s views in the press without prior communication. 

Therefore, the responsibility of the Egyptian Government for the integrity of air safety 

and to underscore the work the Egyptian Investigation Team has done in the past 17 months, 

obliges the Government of Egypt to prepare a comprehensive and objective report of accident. 

This report is an accurate, technical document for use by an aviation industry that is truly 

concerned with air safety and addressing the safety issue of the EgyptAir Flight 990 accident on 

October 31, 1999.