aviation

In-flight Separation of Right Wing

Flying Boat, Inc. (doing business as

Chalk’s Ocean Airways) Flight 101

Grumman Turbo Mallard (G-73T), N2969

Port of Miami, Florida

December 19, 2005

ACCIDENT REPORT

NTSB/AAR-07/04

PB2007-910405

Aircraft Accident Report

In-flight Separation of Right Wing

Flying Boat, Inc. (doing business as

Chalk's Ocean Airways) Flight 101

Grumman Turbo Mallard (G-73T), N2969

Port of Miami, Florida

December 19, 2005

NTSB/AAR-07/04

PB2007-910405 National Transportation Safety Board

Notation 7756D 490 L’Enfant Plaza, S.W.

Adopted May 30, 2007 Washington, D.C. 20594

E PLUR IBUS UNUM

NATIONAL TRA S PORTATION

B OAR D

SAFE T Y

N
National Transportation Safety Board. 2007. In-flight Separation of Right Wing, Flying Boat, Inc. 

(doing business as Chalk's Ocean Airways) Flight 101, Grumman Turbo Mallard (G-73T), N2969, Port 

of Miami, Florida, December 19, 2005. Aircraft Accident Report NTSB/AAR-07/04. Washington, DC.

Abstract: This report explains the accident involving Flying Boat, Inc. (doing business as Chalk’s Ocean 

Airways) Flight 101, a Grumman Turbo Mallard (G-73T) amphibious airplane, which crashed into a 

shipping channel adjacent to the Port of Miami, Florida, shortly after takeoff from the Miami Seaplane 

Base. Safety issues discussed in this report focus on air carrier maintenance programs and practices and 

Federal Aviation Administration (FAA) oversight procedures for air carrier maintenance programs. Safety 

recommendations concerning these issues are addressed to the FAA.

The National Transportation Safety Board is an independent Federal agency dedicated to promoting aviation, railroad, highway, marine, 

pipeline, and hazardous materials safety. Established in 1967, the agency is mandated by Congress through the Independent Safety Board 

Act of 1974 to investigate transportation accidents, determine the probable causes of the accidents, issue safety recommendations, study 

transportation safety issues, and evaluate the safety effectiveness of government agencies involved in transportation. The Safety Board 

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

statistical reviews.

Recent publications are available in their entirety on the Web at <http://www.ntsb.gov>. Other information about available publications also 

may be obtained from the Web site or by contacting:

National Transportation Safety Board

Public Inquiries Section, RE-51

490 L’Enfant Plaza, S.W.

Washington, D.C. 20594

(800) 877-6799 or (202) 314-6551

Safety Board publications may be purchased, by individual copy or by subscription, from the National Technical Information Service. To 

purchase this publication, order report number PB2007-910405 from:

National Technical Information Service

5285 Port Royal Road

Springfield, Virginia 22161

(800) 553-6847 or (703) 605-6000

The Independent Safety Board Act, as codified at 49 U.S.C. Section 1154(b), precludes the admission into evidence or use of Board reports 

related to an incident or accident in a civil action for damages resulting from a matter mentioned in the report. 
iii Aircraft Accident Report

Contents

Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v

Abbreviations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi

Executive Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

1. Factual Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

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

1.2 Injuries to Persons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.3 Damage to Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.4 Other Damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.5 Personnel Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.5.1 The Captain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.5.2 The First Officer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.6 Airplane Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.6.1 Wing Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

1.6.2 Maintenance Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.6.2.1 Company Records of Right Wing Repairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.6.2.2 Major Repairs and Alterations of the Wing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

1.6.2.3 Continuous Airworthiness Maintenance Program . . . . . . . . . . . . . . . . . . . . . . . 11

1.6.2.4 Continuing Analysis and Surveillance System Program . . . . . . . . . . . . . . . . . . 11

1.6.2.5 Aging Airplane Inspection and Records Review . . . . . . . . . . . . . . . . . . . . . . . . 12

1.7 Meteorological Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1.8 Aids to Navigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1.9 Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1.10 Airport Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

1.11 Flight Recorders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

1.11.1 Cockpit Voice Recorder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

1.11.2 Flight Data Recorder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

1.12 Wreckage and Impact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

1.13 Medical and Pathological Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

1.14 Fire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

1.15 Survival Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

1.16 Tests and Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

1.16.1 Additional Grumman G-73T Examinations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

1.16.2 Video and Image Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

1.16.3 Examination for Explosives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

1.17 Organizational and Management Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

1.17.1 Maintenance Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

1.17.1.1 Additional Maintenance Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

1.17.2 Postaccident Actions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

1.17.3 Federal Aviation Administration Oversight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

1.18 Additional Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

1.18.1 Applicable Federal Aviation Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
iv Aircraft Accident Report

1.18.2 Previous Related Safety Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

1.18.2.1 Supplemental Inspections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

1.18.2.2 Cockpit Voice Recorder Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

1.18.3 Postaccident Interviews Regarding Maintenance of 

Chalk’s Ocean Airways’ Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

1.18.3.1 Former and Current Company Pilots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

1.18.3.2 Director of Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

1.18.3.3 Maintenance Supervisor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

1.18.3.4 Designated Engineering Representatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

1.18.4 Grumman Customer Service Bulletin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

1.18.5 Department of Transportation Concerns About the 

Economic Fitness of Chalk’s Ocean Airways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

2. Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

2.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

2.2 In-flight Breakup Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

2.2.1 Fracture Scenario . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

2.3 Chalk’s Ocean Airways Maintenance Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

2.3.1 Ineffective Repairs on the Accident Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

2.3.2 Recurring Discrepancies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

2.3.3 Other Fleet Maintenance Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

2.4 Federal Aviation Administration Oversight of the Chalk’s 

Ocean Airways Maintenance Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

2.4.1 Importance of Program Oversight for Aircraft With

Limited Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

2.4.2 Continuing Analysis and Surveillance System

Program Guidance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

2.4.3 Other Indicators of Potential Safety Deficiencies . . . . . . . . . . . . . . . . . . . . . . . . . . 49

2.5 Certification Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

3. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

3.1 Findings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

3.2 Probable Cause . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

4. Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

4.1 New Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

4.2 Previously Issued Recommendation Reiterated and 

Classified in This Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

4.2.1 Previously Issued Recommendation Resulting 

From This Accident Investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Board Member Statements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

5. Appendixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

A: Investigation and Hearing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Contents
v Aircraft Accident Report

Figures

1. G-73/G-73T Wing Box Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2. Locations of Fractures Near Right Wing Station 34 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

3. External Doubler Adjacent to Right 

Wing Station 34 (Before Removal) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

4. Lower Skin Crack in the Area That Was Covered 

by the Doublers Adjacent to Right Wing Station 34 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

5. Right Wing Rear Z-Stringer Fracture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

6. Right Wing Rear Spar Lower Spar Cap Fracture . . . . . . . . . . . . . . . . . . . . . . . . . . 20
vi Aircraft Accident Report

Abbreviations

AC advisory circular

AD airworthiness directive

ASOS automated surface observing system

CAMI Civil Aeromedical Institute

CAMP Continuous Airworthiness Maintenance Program

CASS Continuing Analysis and Surveillance System

CFR Code of Federal Regulations

c.g. center of gravity

CVR cockpit voice recorder

DER designated engineering representative

DOT Department of Transportation

FAA Federal Aviation Administration

FAR Federal Aviation Regulation

FLL Fort Lauderdale/Hollywood International Airport,

Fort Lauderdale, Florida

FSAW flight standards information bulletin for airworthiness

GMM general maintenance manual

METAR meteorological aerodrome report

MIA Miami International Airport

PMI principal maintenance inspector

POI principal operations inspector

S/N serial number

SAIB special airworthiness information bulletin

SAFO safety alert for operators

STC supplemental type certificate

WS wing station

X44 Miami Seaplane Base, Miami, Florida
vii Aircraft Accident Report

Executive Summary

On December 19, 2005, about 1439 eastern standard time, a Grumman Turbo 

Mallard (G-73T) amphibious airplane, N2969, operated by Flying Boat, Inc., doing 

business as Chalk’s Ocean Airways flight 101, crashed into a shipping channel adjacent to 

the Port of Miami, Florida, shortly after takeoff from the Miami Seaplane Base. Flight 101 

was a regularly scheduled passenger flight to Bimini, Bahamas, with 2 flight 

crewmembers and 18 passengers on board. The airplane’s right wing separated during 

flight. All 20 people aboard the airplane were killed, and the airplane was destroyed by 

impact forces. Flight 101 was operating under the provisions of 14 Code of Federal 

Regulations Part 121 on a visual flight rules flight plan. Visual meteorological conditions 

prevailed at the time of the accident.

The National Transportation Safety Board determines that the probable cause of 

this accident was the in-flight failure and separation of the right wing during normal flight, 

which resulted from (1) the failure of the Chalk’s Ocean Airways maintenance program to 

identify and properly repair fatigue cracks in the right wing and (2) the failure of the 

Federal Aviation Administration (FAA) to detect and correct deficiencies in the 

company’s maintenance program. 

The safety issues discussed in this report focus on air carrier maintenance 

programs and practices and FAA oversight procedures for air carrier maintenance 

programs. Safety recommendations concerning these issues are addressed to the FAA.

1 Aircraft Accident Report

1. Factual Information

1.1 History of Flight

On December 19, 2005, about 1439 eastern standard time,1 a Grumman Turbo 

Mallard (G-73T) amphibious airplane, N2969, operated by Flying Boat, Inc., doing 

business as Chalk’s Ocean Airways flight 101, crashed into a shipping channel adjacent to 

the Port of Miami, Florida, shortly after takeoff from the Miami Seaplane Base (X44). 

Flight 101 was a regularly scheduled passenger flight to Bimini, Bahamas, with 2 flight 

crewmembers and 18 passengers2 on board. The airplane’s right wing separated during 

flight.3 All 20 people aboard the airplane were killed, and the airplane was destroyed. 

Flight 101 was operating under the provisions of 14 Code of Federal Regulations (CFR) 

Part 121 on a visual flight rules flight plan. Visual meteorological conditions prevailed at 

the time of the accident.

On the day of the accident, the accident flight crew flew the airplane from Fort 

Lauderdale/Hollywood International Airport (FLL) in Fort Lauderdale, Florida, to X44 as 

Chalk’s Ocean Airways flight 110. According to the flight log, the airplane departed FLL 

about 1305 and landed at X44 about 1321.4

The airplane departed X44 on the accident flight about 1438 and crashed into the 

water about 1 minute later. Of about 15 witnesses interviewed, most reported that the 

airplane’s right wing separated from the rest of the airplane in flight, that smoke or fire 

came from the wing or a fireball in the sky, and that the airplane subsequently descended 

into the water.5 About one-half of these witnesses reported that they heard an explosion 

associated with the wing separation.6

Most of the wreckage was located in about 30 feet of water. Lifeguards who 

patrolled Miami Beach on foot and on jet skis were the first to respond to the accident 

scene. Miami emergency dispatch notified the Miami Coast Guard and the Miami Beach 

Police Department by telephone about the accident. The Miami Coast Guard log showed 

1 Unless otherwise noted, all times in this report are eastern standard time, based on a 24-hour clock.

2 Of the 18 passengers, 3 were lap-held infants. Eleven of the passengers were citizens of the Bahamas; 

the seven other passengers and the flight crew were U.S. citizens.

3 The G-73T technically has one wing structure. For the purpose of this report, “right wing” generally 

refers to any wing area on the right side of the airplane’s fuselage, and “left wing” generally refers to any 

wing area on the left side of the airplane’s fuselage.

4 During a postaccident interview, the chief pilot of Chalk’s Ocean Airways stated that the accident 

airplane had been scheduled to depart from FLL about 0815 but had been delayed because of weather.

5 Some witnesses provided video and digital still images that captured segments of the accident 

sequence. For more information, see section 1.16.2.

6 An explosives examination performed on the wreckage found no evidence of explosives. For more 

information, see section 1.16.3.
Factual Information 2 Aircraft Accident Report

that the Miami Coast Guard launched an HH-65 helicopter to the accident scene about 

7 minutes after receiving notification of the accident and began recovery efforts about 

6 minutes afterward.

1.2 Injuries to Persons

Table 1. Injury chart.

Injuries Flight Crew Cabin Crew Passengers Other Total

Fatal 2 0 18 0 20 

Serious 0 0 0 0 0

Minor 0 0 0 0 0

None 0 0 0 0 0

Total 2 0 18 0 20

1.3 Damage to Airplane

The airplane was destroyed by impact forces.

1.4 Other Damage

No other damage was noted.

1.5 Personnel Information

1.5.1 The Captain

The captain, age 37, held an airline transport pilot certificate with ratings for 

airplane multiengine land and sea. She held a Federal Aviation Administration (FAA) 

first-class medical certificate dated September 27, 2005, with a limitation that required her 

to wear corrective lenses while exercising the privileges of this certificate. The captain 

received a type rating for the G-73T in May 2005. FAA records indicated no accident or 

incident history or enforcement action, and a search of records at the National Driver 

Register found no history of driver’s license revocation or suspension.
Factual Information 3 Aircraft Accident Report

The captain was hired by Chalk’s Ocean Airways in March 2003.7 The captain’s 

most recent line check occurred on August 14, 2005, and her most recent G-73T 

proficiency check was on May 10, 2005. Company records indicated that the captain had 

accumulated 2,820 hours of total flying time, including 1,330 hours as a 

pilot-in-command, 1,630 hours in the G-73T, and 430 hours as a G-73T 

pilot-in-command. She had flown 723, 203, and 85 hours in the 12 months, 90 days, and 

30 days, respectively, before the accident. In the 24 hours before the accident, the captain 

had flown about 2.5 hours.

On the day of the accident, the captain was scheduled to fly seven flight segments 

for a total of 4.1 hours of flying time. (The accident occurred on the second flight 

segment.) The captain’s first flight was scheduled to depart from FLL about 0815 but was 

delayed by a low fog layer that prevented flying. The captain had to wait in the airport 

terminal. According to the chief pilot, who had also waited at FLL to depart, the captain 

seemed to be upbeat, friendly, smiling, and alert.

 According to company flight logs, on the day before the accident (December 18), 

the captain’s first flight segment began about 0635 and was a repositioning flight to return 

the airplane to FLL. The captain then flew seven additional flight segments, with the last 

one ending about 1730. She accumulated a total of 6.9 hours for the day. 

On December 17, the captain was on duty and flew the accident airplane on 

10 flight segments. The first officer who flew with the captain during those trips stated 

that the captain appeared to be in a good mood. The first officer also stated that, after a 

layover at a hotel, the captain appeared rested when flying resumed early on the morning 

of December 18.

Company records indicated that the captain was off duty from December 12 to 16, 

2005. According to her husband, the captain slept all day on December 16 because they 

had arrived home from a personal trip the night before (December 15), and she was 

exhausted. 

In addition to her flying duties, in August 2005, the captain was appointed as the 

company’s director of safety.8 According to a company representative, the captain spent 

about 2 days per month accomplishing her director of safety activities, which involved 

attending meetings, performing safety audits, and reporting safety concerns directly to the 

general manager. 

According to the captain’s husband, on days when the captain was on duty, she 

awoke about 0430. During the winter, she returned home from work between 2030 and 

7 The captain flew the G-73T as a first officer until receiving her type rating on the airplane.

8 According to 14 CFR 119.65(a)(1), a Part 121 certificate holder must have a qualified person 

“serving full-time” as director of safety. However, according to FAA Order 8400.10, “Air Transportation 

Operations Inspector’s Handbook,” “in a small Part 121 operation, the director of safety functions may be an 

additional function of a current manager. Any request for a management deviation involving a director of 

safety position must be approved by AFS-200.” The company’s FAA-approved operations specifications 

listed the captain as the director of safety.
Factual Information 4 Aircraft Accident Report

2100 and went to bed by 2230. He stated that she was healthy and strong but that, during 

the year before the accident, her health had been affected by the stress of work demands. 

He also stated that, although she felt loyal to the airline and liked the company’s director 

of operations, she had begun applying for another flying job because she was becoming 

physically exhausted, was not enjoying the job any longer, and was interested in a higher 

salary.9 Her husband added that, despite the situation at work, she had a positive frame of 

mind.

Before the captain’s employment with Chalk’s Ocean Airways, she was a flight 

instructor10 for Angel Air Flight Training, Chandler, Arizona, from May 2002 to 

February 2003 and a charter coordinator for Scottsdale Flyers, Scottsdale, Arizona, from 

March 2000 to March 2002.

1.5.2 The First Officer

The first officer, age 34, held a commercial pilot certificate with ratings for 

airplane single- and multiengine land and sea and an FAA first-class medical certificate 

dated January 31, 2005, with no limitations. FAA records indicated no accident or incident 

history or enforcement action, and a search of records at the National Driver Register 

found no history of driver’s license revocation or suspension.

The first officer was hired by Chalk’s Ocean Airways in April 2005. He received 

company ground school training from April to mid-June 2005 then took a 3-month 

break.11 He received company flight training from September to October 2005 and 

completed a G-73T proficiency check on October 19, 2005. He completed his company’s 

initial operating experience on November 21, 2005. Company records indicated that the 

first officer had accumulated 1,420 hours total flying time, including 1,200 hours as a 

pilot-in-command, 100 hours as second-in-command, and 71 hours in the G-73T. He had 

flown 71, 58, and 1.1 hours in the 90 days, 30 days, and 24 hours, respectively, before the 

accident.

Company records indicated that the first officer had been on duty from 

December 15, 2005, to the day of the accident. On the day of the accident, he was 

scheduled to fly seven flight segments for a total of 4.1 hours of flying time. A company 

maintenance manager at FLL observed the first officer about 0620 on the morning of the 

accident as he conducted a preflight inspection of the accident airplane. The maintenance 

manager stated that the first officer looked normal and energetic. The maintenance 

manager also saw the first officer about 1300 and described him as being friendly and 

happy.

9 According to the captain’s husband, she also voiced concerns about the company’s maintenance of its 

airplanes. Additional information from interviews with the captain’s husband and with other company 

personnel regarding the company’s maintenance program appears in section 1.18.3.

10 The captain received her flight instructor certificate with a rating for airplane single-engine land in 

February 2002.

11 According to Chalk’s Ocean Airways personnel, in April 2005, the company hired more first officers 

than it needed and had to postpone the flight training for some because of aircraft availability issues.
Factual Information 5 Aircraft Accident Report

The accident flight was the first officer’s first pairing with the captain. Company 

pilots described the first officer as a likable and helpful person who was happy working 

for the company and who had good piloting skills for his experience.

Before his employment with Chalk’s Ocean Airways, the first officer was a line 

service technician for Reading Flite Academy, Reading, Pennsylvania, from April to 

August 2002 and was pilot/dispatcher for Quest Diagnostics in Reading from June 2002 to 

April 2005.

1.6 Airplane Information

The accident airplane, a Grumman Turbo Mallard (G-73T), serial number 

(S/N) J-27, was a turbine-conversion amphibious airplane equipped with two Pratt & 

Whitney PT6A-34 turbopropeller engines12 and Hartzell HC-B3TN-3D constant-speed, 

three-bladed propellers. The airplane was manufactured by Grumman Aircraft 

Engineering Corporation in May 1947 and was originally certificated as a G-73 model 

equipped with Pratt & Whitney radial piston engines.13 At the time of original 

certification, the airplane’s maximum gross weight was 12,750 pounds, and it was 

configured to carry 2 flight crewmembers and 10 passengers.

Chalks Ocean Airways acquired the airplane in 1980 and modified it to a G-73T 

model in July 1981 by replacing its piston engines with turbopropeller engines in 

accordance with FAA-approved supplemental type certificate (STC) SA2323WE.14 The 

modification to the G-73T model included an increase in the airplane’s maximum gross 

weight to 14,000 pounds. Also, in July 1981, the airplane’s cabin was modified to a 

17-seat passenger configuration in accordance with STC SA4410SW, and its avionics 

were upgraded.

At the time of the accident, the airplane had accumulated 31,226 total flight hours 

and 39,743 total cycles.15 Information about the hours for the powerplants and propellers 

appears in table 2.

12 One engine was a PT6A-34AG model, which has identical specifications and limitations as the 

PT6A-34. “AG” denotes it was originally configured for agricultural aviation.

13 Grumman ended production of the G-73 airplane in 1951.

14 For more information about the STC, see section 1.18.1.

15 An aircraft cycle is one complete takeoff and landing sequence.
Factual Information 6 Aircraft Accident Report

Table 2. Powerplant and Propeller Information for the Accident Airplane

Powerplant Time since new Date of last overhaul Time since last overhaul

Engine

 No. 1 (left) 7,515 hours March 2005 1,154 hours

 No. 2 (right) 9,036 hours July 2004 3,037 hours

Propeller

 No. 1 (left) 11,117 hours March 2005 1,154 hours

 No. 2 (right) 17,995 hours October 2003 2,657 hours

According to the weight-and-balance manifest form for the accident flight, the 

airplane’s takeoff weight was 13,828 pounds,16 which was less than the maximum takeoff 

weight of 14,000 pounds. The takeoff center of gravity (c.g.) was 21.8 percent mean 

aerodynamic chord, which was within the c.g. limits of 17.7 to 26.0 percent. The zero fuel 

weight was 12,488 pounds, which was less than the maximum zero fuel weight of 

12,800 pounds.

The accident captain and another first officer had flown the accident airplane on 

December 17, 2005 (2 days before the accident) for 10 trip segments. According to that 

first officer, the airplane flew normally. He stated that the airplane underwent maintenance 

before these trips and that he and the accident captain conducted a 15- to 20-minute 

operational check flight before beginning passenger service that day. He stated that the 

captain commented that the airplane came out of maintenance in good shape and that, 

during passenger service, he felt no unusual vibrations and observed no fuel, oil, or 

hydraulic fluid leaks.

1.6.1 Wing Structure

The wing structure of G-73 and G-73T airplanes includes a center wing box that 

spans the center of the wing from left wing station (WS) 125 to right WS 125.17 The 

fuselage walls intersect the wing box at left and right WS 34. Portions of the wing box 

structure serve as the left and right fuel tanks. 

16 Chalk’s Ocean Airways did not allow carry-on baggage. The manifest form listed the total passenger 

weight as 2,475 pounds, which was derived from taking the number of noninfant passengers (15) and 

multiplying it by 165 pounds in accordance with the company’s average weight program. The FAA 

approved the program’s 165-pound-per-passenger estimate on the basis of a company survey of actual 

passenger weights. Although Chalk’s Ocean Airways’ operations specifications had been amended to 

require that the company should use only actual passenger weights, on September 7, 2005, the company 

petitioned the FAA to reconsider this requirement. In a letter dated September 26, 2005, the FAA notified the 

company that the effective date of the actual weight requirement was postponed pending the FAA’s review 

and final response to the petition.

17 Each WS is designated “right” or “left,” depending on its location in relation to the airplane’s 

centerline, and WS numbers correspond to the distance in inches outboard from the airplane’s centerline.
Factual Information 7 Aircraft Accident Report

The structural components of the wing box include the front spar, the rear spar, the 

stringers, the ribs, the upper skin, and the lower skin.18 The skin panels are attached by 

fasteners to stringers; the three stringers for the lower skin panel are known as Z-stringers 

because of their shape.19 The vertical surface of each Z-stringer, called a web, has two 

slosh holes20 located just outboard of the wing ribs at WS 34 and WS 48. Figure 1 shows a 

general diagram of some wing box components.

The accident airplane’s wing structure was certificated in accordance with the 

requirements in Part 4aT of the Civil Air Regulations, dated November 1, 1943, and 

amended March 8, 1944. The certification requirements included a static strength analysis, 

which is performed using loads that do not vary with time and have a constant magnitude, 

such as a steady 1 G flight condition.21 No requirements for a fatigue analysis existed at 

the time the G-73T was originally certificated as a G-73. A fatigue analysis is performed 

using loads that vary in amplitude and frequency; these loads are referred to as dynamic, 

cyclic, or repetitive loads. Examples of these loads include taxiing on a rough runway, 

taxiing on rough water, taking off and landing, and encountering turbulence during 

flight.22 

18 Spars are beam-like structures that are the principal structural members of the wing. The spars are 

oriented parallel to the airplane’s lateral axis, which runs wingtip to wingtip. The vertical surfaces of each 

spar are called webs, and the top and bottom of each spar are called spar caps. Wing ribs are the structural 

crosspieces of the wing that are oriented forward to aft. Ribs give the wing its cambered shape. Ribs for the 

wing box are located at the centerline and at 18 wing stations (9 on the right and 9 on the left). Skin is the 

smooth outer covering of an aircraft. The skin panels discussed in this section are sheet metal panels that 

make up the upper and lower surfaces of the wing and wing box structure.

19 Stringers are also structural components of the wing but are much smaller than spars. The wing box 

stringers are oriented parallel to the airplane’s lateral axis, and, like spars, their vertical surfaces are called 

webs. The top and bottom of each Z-stringer’s web have horizontal flanges that face in opposite directions. 

Thus, in cross-section, the stringer has the shape of the letter “Z.”

20 The slosh holes are the round openings in the vertical surface of each Z-stringer that allow fuel inside 

the tank area of the wing to move forward and aft.

21 G is a unit of measurement that is equivalent to the acceleration caused by the earth’s gravity 

(32.174 feet/second2

). A 1 G flight condition is represented by wings-level, steady-state flight.

22 Fatigue failure is the sudden and catastrophic separation of a part into two or more pieces under 

normal operating loads as a result of a crack that grows due to repeated variations in load over a period of 

time. Failure takes place after a fatigue crack reaches a critical length then propagates suddenly.
Skin

Ribs

Stringers

Front spar

Web

Rear spar

lower spar cap

Rear spar

Wing station 34

Wing station 125

Factual Information 8 Aircraft Accident Report

Figure 1. G-73/G-73T Wing Box Components

Note: For illustrative purposes only. For figure clarity, some components are shown not to scale, and others are not 

depicted.

1.6.2 Maintenance Information

1.6.2.1 Company Records of Right Wing Repairs

National Transportation Safety Board investigators reviewed Chalk’s Ocean 

Airways’ flight log sheets for the accident airplane from January 1995 to December 1999 

and February 2001 to December 18, 2005 (the day before the accident); Chalk’s Ocean 
Factual Information 9 Aircraft Accident Report

Airways could not provide the flight log sheets from January 2000 to January 2001. No 

open maintenance items appeared on the log sheets that were reviewed.

During July 2005, three flight log maintenance record entries for fuel leaks in the 

right wing root area were recorded. These entries stated the following: “fuel leak right 

wing root,” “fuel leaking in ... right wing root,” and “fuel leaking from ... right aft 

bottom.” Also, during September 2005, three flight log maintenance record entries noted a 

“fuel leak from right [wing] dry bay.”23 Maintenance records indicated that the July and 

September 2005 fuel leak discrepancies were corrected by removing the existing sealant 

and applying new sealant.24

Safety Board investigators also reviewed routine and nonroutine work cards25 for 

the accident airplane’s C checks26 from 2001 to 2005 and found eight references to fuel 

leaks on the right wing. A nonroutine work card from an August 2005 check indicated 

“fuel leak ... lt [left] & rt [right] wing tanks ...” and a corrective action of “cleaned lt & rt 

fuel tanks, repaired as req’d [required] and sealed ... re-fueled ... no leaks noted at this 

time.” Also, while the airplane was undergoing its December 2005 C1 check, a fuel leak 

discrepancy was noted, and the nonroutine work card indicated “rt fuel tank bottom aft 

corner has leak” and a corrective action of “rt wing fuel tank bottom aft corner leak repair 

and sealed.”

1.6.2.2 Major Repairs and Alterations of the Wing

A review of FAA records for the accident airplane indicated that an FAA form 337, 

“Major Repair and Alteration,”27 was on file for a major repair that was made on April 13, 

1992, to the rear spar upper spar cap at right WS 34. According to the engineering 

information submitted with the form, this repair was made because of structural corrosion 

under the skin and popped rivets that were discovered during inspections on the right wing 

at WS 34. The information indicated that, when the skin was removed, light-to-moderate 

corrosion was also found on the top aft spar.

23 The dry bay is a compartment that contains electronic, hydraulic, and mechanical components. The 

dry bay for the G-73T is located inside the center wing box between left and right WS 34 and is adjacent to 

the wing fuel tanks.

24 The flight logs also documented numerous discrepancies regarding elevator flutter, elevator 

vibration, and elevator trim. For some of these discrepancies, the flight logs showed that maintenance 

personnel tried to resolve the problem several times before it was eventually corrected.

25 According to FAA Advisory Circular 120-16D, work cards, although not required by regulations, are 

often used in air carrier maintenance programs to comply with regulations for performing maintenance and 

for maintenance recordkeeping. 

26 C checks are scheduled maintenance visits designed to ensure a complete inspection of the airplane 

over the course of 20 calendar months. The C checks are divided into six categories of work, C1 through C6, 

to be performed at 80-day intervals. For more information, see section 1.6.2.3.

27 According to FAA Order 8300.10, “Airworthiness Inspector’s Handbook,” a major repair is a repair 

that “might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight 

characteristics, or other qualities affecting airworthiness” or a repair that “is not done according to accepted 

practices or cannot be done by elementary operations.”
Factual Information 10 Aircraft Accident Report

Another FAA form 337 showed that a major repair to the rear Z-stringer at right 

WS 50.5 was made on July 6, 2000. Chalk’s Ocean Airways could not provide the Safety 

Board with corresponding company maintenance records or a description of the 

discrepancy that resulted in this repair. During visual examination of the airplane 

wreckage, investigators observed that the rivets used in the repair were not installed in 

accordance with Advisory Circular (AC) 43.13-1B, section 4, figure 4-6, “Riveting 

Practice and Rivet Imperfections.”28 Specifically, some rivets used in the repair had 

undersized shop heads and were overdriven, and one rivet through the skin and stringer 

flange at the slosh hole was of a larger size and different head type than specified. 

Evidence of additional maintenance work, which involved the use of angles and blind 

rivet fasteners at the rib-to-stringer interface, was observed; however, this type of work 

was not documented in the engineering drawing or on FAA form 337.

Examination of the wreckage also discovered evidence that a major repair was 

made to the lower right wing skin at the location where the wing separated from the 

fuselage. Maintenance records provided by Chalk’s Ocean Airways did not contain any 

entry for this major repair, which consisted of one external and three internal doublers29

applied in the area of a long chordwise skin crack just outboard of right WS 34. Company 

maintenance records contained an entry indicating that, on May 6, 1992, the lower wing 

skin at left WS 34 received a major repair; examination of the wreckage showed that this 

repair had characteristics similar to the repairs observed near right WS 34. The areas with 

the repair doublers observed during the examinations would not have been visible on the 

exterior of the airplane because a fairing30 between the wing and fuselage covered each 

area. The fairings also covered a fuel sump drain on each wing.

Examination of both the repair to right WS 34 (date of repair unknown) and the 

May 6, 1992, repair to left WS 34 revealed evidence that the rivet installation for each was 

not in accordance with AC 43.13-1B, section 4, paragraph 4-57c, “Rivet Edge Distance”; 

figure 4-5, “Rivet Hole Spacing for Single-Lap Sheet Splices”; figure 4-6, “Riveting 

Practice and Rivet Imperfections”; and figure 8, “Holes.” Specifically, some fastener holes 

were observed at edge distances less than specified, rivet-hole spacing was less than 

specified, and some holes did not meet specifications because they were double-drilled.31

28 The engineering drawing for this repair indicated that the riveting needed to be performed in 

accordance with AC 43.13-1B. Technical data referenced in such drawings become approved data.

29 A doubler is material that is intended to relieve load in the structural element to which it is attached.

30 Fairings are shaped and rounded panels on the exterior of the airplane that are typically installed in 

areas where the wing or other structural units meet the fuselage at angles. The purpose of fairings is to 

smooth out the airflow in these areas during flight.

31 A double-drilled hole is a hole consisting of two intersecting, nonconcentric-drilled holes in which a 

portion of the hole from the first drilling remains after the second hole is drilled.
Factual Information 11 Aircraft Accident Report

1.6.2.3 Continuous Airworthiness Maintenance Program

The Flying Boat, Inc., operations specifications for Chalk’s Ocean Airways 

indicated that the air carrier was authorized to use a continuous airworthiness maintenance 

program (CAMP),32 the latest revision of which was approved by the FAA on 

November 21, 2005. Basic CAMP requirements include aircraft inspection, scheduled and 

unscheduled maintenance, overhaul and repair, structural inspection, required inspection 

items, a continuing analysis and surveillance system (CASS) program,33 and outsourcing 

maintenance. The company’s CAMP included the following maintenance items:

• Transit service, which was to be performed overnight every 48 hours or less at 

bases where maintenance personnel are available. Company records showed 

the last transit service on the accident airplane was performed on 

December 19, 2005 (the day of the accident).

• Engine service, which was to be performed every 250 flight hours. Company 

records showed the last engine service on the accident airplane was performed 

on October 19, 2005 (No. 1 engine) and November 12, 2005 (No. 2 engine); 

both occurred within the 250-hour requirement.

• C checks, which were divided into six scheduled maintenance visits, C1 

through C6. These visits, which were to be completed at 80-day intervals, were 

designed to completely inspect the airframe, components, systems, and 

appliances within 20 calendar months. Company records showed the airplane’s 

most recent C check was completed December 17, 2005.34 In accordance with 

the Grumman Service Manual, the airplane’s external components were 

washed with fresh water during each of the C checks to minimize the effects of 

corrosion on those components.35

1.6.2.4 Continuing Analysis and Surveillance System Program

As part of its FAA-approved CAMP, Chalk’s Ocean Airways was required to 

maintain a CASS program that identified and corrected deficiencies in the company’s 

maintenance program. As part of a CASS, operators are required to monitor the 

mechanical performance of the flying fleet by collecting and analyzing operational data. 

This includes the day-to-day monitoring and long-term monitoring of each airplane. To 

accomplish this task, operators typically set repair thresholds by establishing the number 

of times a discrepancy may reoccur in a given period, usually specified in days or hours. If 

32 A CAMP combines the maintenance and inspection functions used to fulfill an operator’s total 

maintenance needs. 

33 For more information about the company’s CASS program, see section 1.6.2.4.

34 The most recent C check for the right wing, which was maintenance visit C3, was completed 

March 23, 2005. According to the C3 checklist, the inspection covered right WS 34 to 400 and included 

preliminary inspection/corrosion control, lubrication, avionics check/inspection, and main landing gear 

inspection.

35 Company maintenance personnel stated that the airplane’s external components were also washed 

with fresh water during transit service maintenance, but the transit service cards did not show this task.
Factual Information 12 Aircraft Accident Report

a discrepancy recurs within the established repair threshold, further troubleshooting, such 

as maintenance and/or engineering, would be needed, and, at times, grounding of the 

airplane would be necessary.

Chalk’s Ocean Airways conducted monthly CASS meetings to review the previous 

month’s maintenance discrepancies. Records indicated that FAA representatives, 

including the air carrier’s principal maintenance inspector (PMI), attended the January, 

October, and November 2005 meetings.36 Minutes from the CASS meetings for January 

through November 2005 included mechanical interruption reports, logbook information, 

airplane discrepancies, and minimum equipment list information for each company 

airplane.37 The minutes for the July and September 2005 CASS meetings referenced fuel 

leaks on the accident airplane. The July 2005 minutes referenced six fuel leaks on either 

the accident airplane’s left or right wing during a 5-day period; the September 2005 CASS 

meeting minutes referenced a fuel leak from the accident airplane’s right wing dry bay 

area for 3 consecutive days.38 None of the 2005 CASS meeting minutes directly 

referenced any of the accident airplane’s wing box structural fractures.

1.6.2.5 Aging Airplane Inspection and Records Review

The operations specifications for Chalk’s Ocean Airways also indicated that the air 

carrier must have an aging aircraft inspection and records review. Title 14 CFR 121.368, 

“Aging Airplane Inspections and Records Reviews,” paragraph (b)(1), requires initial and 

repetitive inspections and records review of airplanes operating under Part 121 (except for 

those airplanes operating entirely within the state of Alaska) and exceeding 24 years of 

service on December 8, 2003. The regulation requires that the initial inspection and 

records review take place no later than December 5, 2007, and that the repetitive 

inspections occur at intervals thereafter not to exceed 7 years. According to 

14 CFR 121.368(b), the purpose of the regulation is for the operator to demonstrate to the 

FAA that “the maintenance of age-sensitive parts and components of the airplane has been 

adequate and timely enough to ensure the highest degree of safety.”

On October 7, 2005, Chalk’s Ocean Airways’ PMI conducted the company’s aging 

airplane inspection and records review. At the time, the accident airplane had accumulated 

31,012 flight hours and 39,404 flight cycles. The review included the April 13, 1992, 

major repair to the rear spar upper spar cap at right WS 34 and the May 6, 1992, major 

repair to the lower wing skin at left WS 34. The review found that no further action was 

required for these repairs. The review did not include the doubler repair that was observed 

on the chordwise skin crack just outboard of right WS 34 and for which Chalk’s Ocean 

Airways did not have records. On November 4, 2005, the PMI sent a letter to Chalk’s 

Ocean Airways indicating that the aging airplane inspection and records review had been 

36 Chalk’s Ocean Airways could not provide CASS meeting attendance records for March and 

May 2005, so there was no record of whether FAA representatives attended those meetings.

37 The December 2005 CASS meeting had not been held at the time of the accident.

38 As mentioned previously, maintenance records showed that the repair methods used to address these 

fuel leaks involved removing and replacing the sealant in the fuel tank.
Factual Information 13 Aircraft Accident Report

completed. The PMI noted that paperwork discrepancies found during the review were 

corrected by the air carrier during the C5 and C6 inspections.

The accident airplane, because of its size and the date of its type certificate, would 

not be subject to the additional inspection requirements of 14 CFR 121.370a, 

“Supplemental Inspections,” which apply to transport-category, turbine-powered airplanes 

(except for those airplanes operating entirely within the state of Alaska) that were type 

certificated after January 1, 1958, and had a maximum passenger seating capacity of 30 or 

more or a maximum payload of 7,500 pounds. Title 14 CFR 121.370a(c) requires that, 

after December 20, 2010, the maintenance programs of the affected airplanes must include 

“FAA-approved damage-tolerance-based inspections and procedures for airplane structure 

susceptible to fatigue cracking that could contribute to a catastrophic failure. These 

inspections and procedures must take into account the adverse affects repairs, alterations, 

and modifications may have on fatigue cracking and the inspection of this airplane 

structure.” On July 24, 2006, the Safety Board issued Safety Recommendation A-06-52 to 

address the exemptions contained in this regulation; see section 1.18.2.1 for more 

information.

1.7 Meteorological Information

The nearest weather reporting station is located at Miami International Airport 

(MIA), Miami, Florida, which is about 8 nautical miles from X44. MIA has an automated 

surface observing system (ASOS) that is maintained by the National Weather Service and 

records continuous information on wind speed and direction, cloud cover, temperature, 

precipitation, and visibility.39 The ASOS transmits an official meteorological aerodrome 

report (METAR) each hour. A METAR at 1443 on the day of the accident indicated the 

following: wind from 340o at 7 knots, visibility 4 miles, ceiling overcast at 1,200 feet, 

temperature 23o C, dew point 18o C, and altimeter 30.09 inches of mercury.

1.8 Aids to Navigation

No problems with any navigational aids were reported.

1.9 Communications

No communications problems were reported.

39 Cloud cover is expressed in feet above ground level. Visibility is expressed in statute miles.
Factual Information 14 Aircraft Accident Report

1.10 Airport Information

X44 is located on Watson Island and about 2 miles east of Miami. X44 has a water 

runway that is 15,000 feet long and 600 feet wide and is oriented northwest/southeast. The 

water runway has an elevation of 0 feet mean sea level. X44 has no published instrument 

procedures. Chalk’s Ocean Airways’ terminal was built in 1926.

1.11 Flight Recorders

1.11.1 Cockpit Voice Recorder

The airplane was equipped with a Fairchild model A-100A solid-state cockpit 

voice recorder (CVR), S/N 52969. The CVR did not sustain any heat or structural damage, 

but the recorder was wet because of its immersion in the water. The tape was removed 

from the recorder and was cleaned and dried. The audio information was extracted without 

difficulty.

The CVR recording contained channels of audio data for the pilot and copilot 

stations and the cockpit area microphone.40 Although audio was recorded on each of these 

channels, the audio was unintelligible. The Safety Board noted, specifically, that the 

characteristics of the audio were similar to that of the tape having been recorded over 

multiple times without being erased between recordings.

The CVR chassis was sent to L3 Communications41 for evaluation of its 

functionality. According to the L3 Communications evaluation report, testing revealed a 

failure of the electronic circuit card for the erase head. The evaluation report indicated that 

this condition was most likely the reason for the failure of the erase-head functionality of 

the recorder and that, on the basis of the Safety Board’s finding of multiple overwriting on 

the CVR-recorded channels, this failure most likely occurred sometime before the 

accident. 

The evaluation report further indicated that the CVR “push to test” operation 

would not likely identify a failure of the erase head because the recorded test tone 

amplitude would be detected despite the presence of previously recorded audio.42 On 

March 24, 2006, the Safety Board issued Safety Recommendation A-06-23, which 

addressed this and other issues related to CVR functionality. Section 1.18.2.2 provides 

information about this recommendation.

40 The CVR was equipped with another channel for a third flight crewmember. Because the G-73T was 

not configured for a three-person flight crew, that CVR channel was unconnected.

41 L3 Communications is the owner of Fairchild model CVRs.

42 L3 Communications stated that one way to ensure correct operation of the erase-head function was a 

service check of the CVR. With regard to the accident airplane, Chalk’s Ocean Airways’ operations 

specifications did not require CVR service checks.
Factual Information 15 Aircraft Accident Report

1.11.2 Flight Data Recorder

The airplane was not equipped with a flight data recorder (FDR). The FAA stated 

that 14 CFR 121.344a, “Digital Flight Data Recorders for 10-19 Seat Airplanes,” applied 

to the accident airplane and that the regulation excludes 10-to-19 seat, turbine-powered 

airplanes that were brought onto the U.S. registry on or before October 11, 1991. 

1.12 Wreckage and Impact Information

The right wing separated from the fuselage in flight, and the remainder of the 

airplane broke up on impact with the water. Most of the main wreckage was scattered 

within a debris field of about 200 feet by 200 feet and was oriented along a 122o magnetic 

heading. The fuselage, left wing, left engine, landing gear, and empennage were located 

within the main debris field. All of this wreckage was submerged in the water along a rock 

jetty. The separated right wing with the right engine attached was located about 160 feet 

northwest of the main debris field. The center wing box structures were fractured where 

the wing intersected the fuselage at right WS 34, allowing the right wing to separate.

Examination of the wreckage found that the right wing fuel tank was breached and 

that fire damage was evident on the right wing. Fire damage and soot were also present on 

fuselage skins and empennage skins aft of the right wing. The left wing showed no 

evidence of fire damage.

Safety Board investigators documented and reconstructed the airplane’s center 

wing box. The reconstruction consisted of locating and identifying the right and left wing 

front and rear spars and upper and lower stringers and skins from about right WS 60 to left 

WS 60. Detailed examination of the wreckage fractures revealed areas of fatigue on 

multiple elements of the wing box structure, including the lower skin panel aft Z-stringers 

at right and left WS 34 (emanating from the fuel slosh holes), the skin at the edge of the 

doubler repairs at right and left WS 34, the rear spar lower spar cap at right WS 34, and the 

forward spar lower spar cap near left WS 53.

The recovered fracture surfaces from the wing box were sent to the Safety Board’s 

Materials Laboratory in Washington, D.C., for visual and fractographic examinations. To 

facilitate the examination, the internal and external repair doublers that were located near 

right and left WS 34 were removed from the lower skin. 

The upper part of figure 2 shows an overall view of right WS 34, including the 

locations of the rear spar lower spar cap, rear Z-stringer, the chordwise fracture in the 

lower skin, the crack (approximately parallel to and outboard of the chordwise lower skin 

fracture) in the lower skin, and the external and internal doublers. The lower part of 
Factual Information 16 Aircraft Accident Report

figure 2 shows a view with the doublers detached. Fatigue fracture features were found in 

the rear spar lower spar cap, rear Z-stringer, skin fracture (inboard), and skin crack 

(outboard).43

Figure 2. Locations of Fractures Near Right Wing Station 34

43 Overstress fracture features were found on the entire fracture surfaces of the middle Z-stringer, 

forward Z-stringer, and forward spar lower spar cap at right WS 34.
Factual Information 17 Aircraft Accident Report

Figure 3 shows a photograph of the external doubler that was adjacent to right 

WS 34 before it was removed from the lower skin for examination. The lower skin crack 

that was observed in the area that had been covered by this external doubler was about 

16 inches long. The aft end of the crack extended from the skin trailing edge to a point 

near the aft side of the middle Z-stringer lower flange.

Figure 3. External Doubler Adjacent to Right Wing Station 34 (Before Removal)

The skin crack under the doublers at right WS 34 (see figure 4) intersected three 

unfilled machined holes in the skin that exhibited features consistent with stop drill 

holes.44 These holes were located about 7, 9, and 16 inches forward of the skin trailing 

edge. Several fasteners at the inboard end of the doubler were inserted through hard green 

sealant around the fuel sump drain.

44 A stop drill hole is made at the tip of a fatigue crack to temporarily retard the propagation of a fatigue 

crack until a more permanent repair can be made.
Factual Information 18 Aircraft Accident Report

Figure 4. Lower Skin Crack in the Area That Was Covered by the Doublers Adjacent to 

Right Wing Station 34

Note: The yellow arrows show the direction that each segment of the crack propagated.

The fractographic examination at right WS 34 found that fatigue in the rear 

Z-stringer initiated from the slosh hole in the Z-stringer located about 1.5 inches outboard 

of right WS 34, as shown in figure 5. Sanding marks were observed under the sealant 

around the edge of the slosh hole, and sealant was observed on the fracture surface. In the 

sanded area, deformed material was observed curled over onto the edges of the fracture 

surface.
Factual Information 19 Aircraft Accident Report

Figure 5. Right Wing Rear Z-Stringer Fracture

The skin crack under the doublers at right WS 34 had an aft segment with fatigue 

features emanating from the area of corrosion around the fuel sump drain and a longer 

forward segment with fatigue features that initiated from a fastener hole adjacent to the 

rear Z-stringer fracture. 

The lower skin chordwise fracture (inboard of the skin crack) at the separated area 

intersected the fastener holes at the inboard edge of the doublers. Regions of fatigue 

emanated from several of the fastener holes. Sliding contact marks consistent with 

repeated opening and closing of the chordwise skin fracture were observed on the surface 

of the external doubler between several fastener locations in the inboard fastener row for 

the doubler.

Fatigue in the rear spar lower spar cap initiated from a double-drilled hole for a 

threaded fastener in the horizontal flange of the spar cap located about 1 inch inboard of 

right WS 34, as shown in figure 6. Multiple fatigue origins were observed along the 

double-drilled hole through the thickness of the horizontal flange. Relatively flat regions 

with large numbers of crack arrest positions, indicating slower growth fatigue cracking, 

emanated from the fatigue origin areas both forward and aft of the hole. The remainder of 

the fatigue regions had a mixture of curving flat regions (indicating areas of relatively 

slow crack growth) with crack arrest positions separated by rougher regions without crack 

arrest positions (indicating relatively fast crack growth or overstress regions). The portion 
Factual Information 20 Aircraft Accident Report

of the crack aft of the hole propagated from a length of 0.07 to 0.44 inch in about 

11 increments of rapid crack growth.

Figure 6. Right Wing Rear Spar Lower Spar Cap Fracture

Examination of the left wing indicated that fatigue fracture features were found in 

the rear Z-stringer, middle Z-stringer, front spar lower spar cap, and lower skin fractures 

near left WS 34. One external and two internal doublers were attached to the lower skin 

panel at the aft side of the wing box at left WS 34. The lower surface of the external 

doubler showed evidence around the fuel sump drain that was consistent with corrosion in 

that area.
Factual Information 21 Aircraft Accident Report

The left wing front spar lower spar cap had a transverse fracture about 5 inches 

outboard of left WS 34. This area had not been repaired and did not have adjacent 

structural element failures. A portion of the horizontal flange of the spar cap had fatigue 

features that emanated from a hole for a threaded fastener to attach a wing leading edge 

panel. The aft portion of the fatigue region contained multiple relatively rough regions, 

which was indicative of an overstress fracture that was progressing fairly rapidly. These 

fracture regions were interspersed between regions with crack arrest positions.

1.13 Medical and Pathological Information

Toxicology tests were performed by the FAA’s Civil Aeromedical Institute 

(CAMI) on specimens from the captain and first officer. The specimens were tested for 

ethanol and a wide range of drugs, including major drugs of abuse. All specimens tested 

negative, except that diphenhydramine was detected in urine specimens from the captain 

and quinine was detected in tissue specimens from the first officer.45

1.14 Fire

Postcrash examination of the wreckage indicated the occurrence of an in-flight fire 

on the separated right wing and on exterior skin surfaces of the fuselage and empennage 

aft of the right wing. The left wing showed no evidence of fire damage.

1.15 Survival Aspects

The Miami medical examiner performed autopsies of the airplane occupants, and 

the autopsy reports indicated the cause of death for each was “plane crash.” A review of 

the reports revealed the main pathologic findings for each occupant were multiple blunt 

force injuries.

1.16 Tests and Research

1.16.1 Additional Grumman G-73T Examinations

Safety Board investigators examined other G-73T airplanes following the 

accident. One airplane, N142PA, was also owned by Chalk’s Ocean Airways and was used 

for passenger service at the time of the accident. Like the accident airplane, N142PA was 

built in 1947 as a G-73 model and was subsequently modified to a G-73T. Also, N142PA 

45 Diphenhydramine, commonly known by the trade name Benadryl, is an over-the-counter 

antihistamine with sedative effects, often used to treat allergy symptoms or as a nighttime sedative. It is not 

quantified in CAMI results unless a substantial quantity is present. Diphenhydramine was not detected in the 

captain’s blood specimens. Quinine is found in tonic water and is not quantified in CAMI results, unless a 

substantial quantity is present.
Factual Information 22 Aircraft Accident Report

had a similar number of flight hours and cycles as the accident airplane. The left wing aft 

spar attachment point on N142PA showed evidence of grinding in some areas, and the 

right wing aft spar attachment point had corrosion. Extensive corrosion was present on 

other areas of the airplane.

In August 2005, N142PA’s right wing lower skin was replaced from the centerline 

to the nacelle. The designated engineering representative (DER)46 who provided 

engineering approval for this major repair stated that Chalk’s Ocean Airways informed 

him in June 2005 that fuel was leaking from the right wing-to-body fairing. The DER also 

stated that his subsequent inspection47 found that fuel was leaking out of a lower skin 

crack on the right wing and that his analysis showed that the crack, which was about 

22 inches in length, had reduced the load-carrying capacity of the right wing box by about 

50 percent.48 The DER stated that he recommended that the wing be removed for repair 

but that Chalk’s Ocean Airways did not want to remove the wing. As a result, the fuselage 

skin was pulled away from the area of the skin crack so that the lower wing skin could be 

replaced. The DER stated that, when the skin was removed, he noticed that all of the 

stringers were corroded and cracked, so they were removed and replaced. He also noticed 

that many of the repairs that had previously been made on the rest of the wing appeared to 

be “quite old.”

Although fatigue- and damage-tolerance requirements were not part of the G-73’s 

original certification (which was the certification basis for the G-73T), a fatigue- and 

damage-tolerance-based approach was employed in the August 2005 repair to the right 

wing on N142PA. The repair included instructions for continued airworthiness,49 which 

indicated that the repair should be inspected every 24 months or 6,020 flight hours, 

whichever occurred first. These inspections were intended to detect cracks before they 

reached their critical crack length (that is, the point at which fracture occurs rapidly 

without increased load).

In July 1999, a repair was made to N142PA’s lower left wing skin, which extended 

across the wing-to-fuselage junction. According to the structures DER who designed this 

repair for Chalk’s Ocean Airways, an area of corrosion around the fuel sump drain was 

removed, a 14-inch crack (emanating from the forward edge of the corrosion to a point 

46 A DER is a qualified technical person who is authorized by the FAA to perform certain examinations, 

testing, and inspections necessary to determine compliance with applicable airworthiness standards and who 

offers technical expertise with state-of-the-art knowledge. A DER completes FAA form 8110-3, “Statement 

of Compliance with the Federal Aviation Regulations,” to indicate that the engineering changes are in 

accordance with regulations. The company is responsible for implementing the changes stated on the form 

and completing FAA form 337 after the repair has been accomplished. 

47 During this inspection, the DER noticed a doubler on the left wing lower skin with a 17-inch crack. 

(The DER provided the Safety Board with a photograph showing this crack.) According to the DER, he 

asked Chalk’s Ocean Airways if he should provide the engineering for the repair of the left wing, but the 

company indicated that it would take care of the repair.

48 The DER’s analysis showed that the skin and stringers carried about 70 percent of the load and that 

the spar caps carried 30 percent of the load.

49 Instructions for continued airworthiness are a series of maintenance actions that help to ensure the 

continued airworthiness of a repair. DERs can include these instructions as part of FAA form 8110-3.
Factual Information 23 Aircraft Accident Report

that was 9 inches forward) was stop-drilled and slotted, and a doubler was placed over the 

top of the wing skin in this area. This repair was designed with a static strength analysis 

only.

Safety Board investigators also examined a privately owned G-73T airplane, 

N632SS. That airplane was undergoing restoration at Mirabella Aviation, Jupiter, Florida. 

Chalk’s Ocean Airways had owned the airplane briefly beginning in November 2005 and 

had maintained it as a spare parts airframe before selling it. Like the accident airplane, 

N632SS was built in 1947 and was subsequently modified to a G-73T. N632SS had fewer 

flight hours (about 16,000) and cycles (about 30,000) than the accident airplane.

In July 1977, N632SS was substantially damaged when it crashed and sank during 

an attempted takeoff from Great Bear Lake in Canada. The airplane was recovered, 

rebuilt, and used during the 1980s for revenue operations. According to Mirabella staff, 

the airplane was again damaged in 1989 when it was subjected to flooding during a 

hurricane.

At the time of the examination of the airplane, the left wing had been removed, the 

outboard wing sections had been separated from the center wing box, and the lower wing 

skin was removed from the center wing box. Investigators found that, although corrosion 

was present on the wing structure, the corrosion was generally not as severe as that found 

on the airplanes in the Chalk’s Ocean Airways fleet and that only one rear Z-stringer had a 

similar amount of corrosion.

The rear Z-stringer was sent to the Safety Board’s Materials Laboratory for 

examination. The examination found that the rear Z-stringer had a fatigue crack that was 

located about 1.5 inches outboard of the rib at left WS 48. The examination also found that 

the fatigue emanated from the slosh hole in the web of the Z-stringer. In addition, the 

examination found that the corrosion was particularly severe in the web and flange areas 

above the slosh hole.

1.16.2 Video and Image Study

Segments of the accident flight were captured by witnesses with personal video 

and still cameras and by a U.S. Coast Guard video surveillance security camera. Copies of 

the video and still images were submitted to the Safety Board’s Vehicle Recorder 

Division, Washington, D.C., for review.

One video from a personal video camera was recorded by a witness on the deck of 

a cruise ship that was located across the main channel from X44. The video does not show 

the accident but contains footage of the accident airplane arriving and departing from X44. 

The only noise heard on the video that is associated with the airplane is that of the 

powerplants after the airplane’s departure.

Another video from a personal video camera was recorded by a witness on a beach 

north of the accident site. The video does not show the right wing separating but captures 
Factual Information 24 Aircraft Accident Report

the airplane in a nose-down attitude of between 35o and 45o after the separation. The video 

shows no obvious smoke or debris coming from the airplane, but, in the upper right corner 

of view, a cloud of fire and black smoke appears behind the airplane. The airplane and the 

cloud of fire and smoke follow a similar trajectory and impact the water behind a rock 

jetty.

The digital surveillance video was recorded by a U.S. Coast Guard station camera 

located near the east end of the main channel. The video shows the accident airplane 

passing over Miami Harbor toward the ocean and traveling away from the camera. About 

the time that the airplane moves into the center of the camera’s view, it has become too 

small to be seen. About 9 seconds after the airplane disappears, a bright flash appears in 

the area where the airplane was last seen. Black smoke then begins emanating from the 

flash, and the trail of smoke falls toward the water.

A digital still image taken by a witness in a vehicle traveling on a nearby causeway 

shows the accident airplane in the water during its takeoff roll. Both propellers appear to 

be in motion. A bright streak located outboard of the right engine appears to be a flashing 

light. A second digital image, which was taken by a witness in a vehicle traveling on the 

same causeway, shows the airplane shortly after liftoff above the main channel.

1.16.3 Examination for Explosives

Specimens from the accident airplane were sent to the Federal Bureau of 

Investigation’s laboratory in Quantico, Virginia, to determine whether explosives or 

explosive residues were present. None of the explosives or explosive residues for which 

the laboratory screens was found on the specimens.

1.17 Organizational and Management Information

Flying Boat, Inc., held an air carrier certificate to conduct Part 121 passenger 

operations originally issued on December 10, 1990, and reissued on March 19, 1997, by 

the FAA Southern Region. The company’s operating certificate was managed by the FAA 

South Florida Certificate Management Office, and the Miami, Florida, Flight Standards 

District Office was responsible for oversight. Flying Boat began operating passenger 

service under the business name Chalk’s Ocean Airways in July 1999, in reference to the 

original airline, Chalk’s Flying Service, which was founded in 1919. Since 1919, Chalk’s 

Flying Service was owned and operated by various owners under various business 

names.50 At the time of the accident, Chalks Ocean Airways had 82 employees, including 

10 pilots, 12 mechanics, and 5 mechanic assistants.51

50 Chalks Flying Service was purchased in the 1980s by a hotel and casino development company. That 

company then sold the airline to several south Florida business investors, who operated the airline under the 

name Pan Am Air Bridge. In July 1999, the airline was bought by a Florida businessman and began 

operating on the Flying Boat certificate as Chalk’s Ocean Airways.

51 According to a company representative, the other employees represented functions such as 

reservations, dispatch, and station personnel.
Factual Information 25 Aircraft Accident Report

Also, at the time of the accident, Chalk’s Ocean Airways’ flights were based at 

X44 and flew to destinations in the Bahamas. Most of the flights were over open water, 

and most of the destination airports were seaplane bases. Chalk’s Ocean Airways operated 

three G-73T airplanes for revenue service, all of which had the same configuration.52 The 

airplanes would typically fly six to eight cycles each day.

On the day after the accident, Chalk’s Ocean Airways flew one more scheduled 

flight (in N142PA) from Bimini to Fort Lauderdale. Afterward, the airline ceased flight 

operations.

1.17.1 Maintenance Organization

Flying Boat, Inc., also held a Part 145 repair station certificate issued on 

August 24, 1993. The Chalk’s Ocean Airways General Maintenance Manual (GMM) 

contained an organizational chart of the maintenance organization and described the duties 

of company maintenance and inspection personnel.

As outlined in the GMM, the general manager was in charge of the entire 

maintenance organization. The director of maintenance and the chief inspector/director of 

quality control reported to the general manager. According to the GMM, the director of 

maintenance was responsible for “maintaining Company aircraft in an airworthy condition 

at all times, including all maintenance, repairs, and modifications performed.” The 

director of maintenance was also responsible for reviewing daily status sheets to ensure 

efficient and smooth coordination of maintenance tasks, verifying that assigned work 

packages were completed, ensuring that parts were ordered, overseeing the scheduling of 

airplanes to ensure dispatch reliability, and serving as the vice chairman at the monthly 

CASS meetings. In addition, the production manager (also referred to as the maintenance 

supervisor), lead mechanics, and mechanics reported directly to the director of 

maintenance.

The chief inspector/director of quality control was responsible for the inspection of 

all work performed. The chief inspector/director of quality control was also responsible 

for ensuring that maintenance, inspections, airworthiness directives (AD), repairs, and 

modifications were conducted according to FAA and company policy; accepting or 

rejecting all work that was accomplished on company airplanes by company shops, 

maintenance contractors, or vendors; inspecting all incoming parts; maintaining training 

records of all company inspection and maintenance personnel; maintaining all company 

manuals; and serving as the chairman during the monthly CASS meetings. The inspectors 

52 At the time of the accident, one revenue service airplane, N130FB, was not operable because its 

engines had been removed for maintenance. In addition, Flying Boat, Inc., had another G-73T, N2974, and a 

G-73, N1208, listed on its certificate that were not airworthy at the time of the accident. Besides the 

airplanes in Chalk’s Ocean Airways’ fleet, only three other G-73/G-73T airplanes were in revenue service at 

the time of the accident and were being operated as sightseeing airplanes in Australia. The remaining 

airplanes in the G-73/G-73T fleet were operated by personal or corporate owners, most of whom maintained 

their airplanes as showpieces.
Factual Information 26 Aircraft Accident Report

(including those designated as required inspection item inspectors) and the CASS/aircraft 

records technician reported directly to the chief inspector/director of quality control.

Chalk’s Ocean Airways did not have an engineering department to oversee 

structural airplane issues. As a result, the company contracted with DERs for major 

repairs of the airplane’s structure. 

Section 3 of Chalk’s Ocean Airways GMM, volume 5 (dated May 24, 2005), 

contained the maintenance policies and procedures used to ensure the airworthiness of 

company airplanes. Page 53006, paragraph a, stated that each corrective action was to 

include “a reference to FAA approved data, such as repaired in accordance with GMM, 

chapter, sec[tion], page or any other FAA approved document applicable to corrective 

action signoff.”

1.17.1.1 Additional Maintenance Information

In March 1981, Frakes Aviation in Cleburne, Texas, purchased the G-73 type 

certificate from Grumman. As a result, Chalk’s Ocean Airways did not have engineering, 

maintenance, and operating support from the original aircraft manufacturer. Also, a 

structural repair manual was not issued for the G-73 because it was not required at the 

time the airplane was manufactured.53 According to Frakes Aviation personnel, the 

company had no involvement with G-73/G-73T repairs and no formal interaction with 

Chalk’s Ocean Airways for at least the 15 years that preceded the accident.

1.17.2 Postaccident Actions

In December 2005, after the accident, the Department of Transportation’s (DOT) 

Air Carrier Fitness Division suspended Chalk Ocean Airways’ economic authority to 

operate under the Flying Boat, Inc., Part 121 certificate.54 The DOT stated that the air 

carrier had 1 year to “prove to [the DOT] that the public interest is best served if they 

[Chalk’s Ocean Airways] re-start their operation.” As of the 1-year target date, Chalk’s 

Ocean Airways was not operating its own airplanes; the Part 121 certificate remained 

suspended, and the company had entered into a wet lease55 arrangement with another 

certificated carrier to provide transportation. Flying Boat, Inc., retained its Part 145 repair 

station authorization for Chalk’s Ocean Airways; however, according to an FAA 

inspection on December 14, 2006, there was little activity.

53 For operators of airplanes for which no structural repair manual was issued, AC 43-13 provides 

information on typical structural repairs that have been approved by the FAA. The AC contains methods, 

techniques, and practices “for the inspection and repair of ... civil aircraft, only when there are no 

manufacturer repair or maintenance instructions.”

54 For more information about the history of the DOT’s concerns about the economic fitness of Chalk’s 

Ocean Airways, see section 1.18.5.

55 According to the FAA, a wet lease is a leasing agreement whereby a certificate holder agrees to 

provide an aircraft and at least one crewmember to another direct air carrier.
Factual Information 27 Aircraft Accident Report

On December 23, 2005, the FAA issued Special Airworthiness Information 

Bulletin (SAIB)56 NM-06-18, which advised G-73 and G-73T operators of the 

circumstances of this accident. The SAIB stated, in part, the following: “FAA is 

considering the need for mandatory detailed inspections of parts or all of the wing 

structure on the fleet of G-73 airplanes. If FAA determines that the accident airplane 

wing’s pre-separation condition is potentially manifest in other G-73 airplanes, the FAA 

will take appropriate action.”

On December 30, 2005, the FAA issued Emergency AD 2006-01-51, which 

directed operators of G-73 and G-73T airplanes to do the following: 

Before further flight, perform a detailed visual inspection to detect repairs, 

cracking, or corrosion of the wings from wing station (WS) 77L to WS 77R, front 

spar to rear (main) spar; remove any repair that is found, to allow for inspection of 

the wing structure underneath the repairs; and remove the sealant from the interior 

of the wet bays to allow for inspection of the skins, stringers, and both spars. 

This visual inspection was to be performed in accordance with a method that has 

been approved by the FAA. Because no such method existed at the time that the AD was 

issued, the AD effectively grounded all G-73/G-73T airplanes. At the time, there were 31 

U.S.-registered G-73/G-73T airplanes, about 15 of which were considered airworthy. The 

AD also required that an FAA aircraft certification office approve reports of any findings, 

repairs performed, or alternate methods of compliance.

Since the time that the AD was issued, the FAA approved, on a case-by-case basis, 

six privately owned G-73/G-73T airplanes to fly for an interim period of 200 flight hours. 

At least two other privately owned airplanes were undergoing evaluation. Also, the FAA 

recently approved a private owner’s alternate means of compliance for the AD, and work 

has begun on the airframe of that airplane. That airplane and the rest of the G-73/G-73T 

fleet remain prohibited from further flight until individually approved by the FAA to be in 

compliance with AD 2006-01-51 or an approved alternate method.

1.17.3 Federal Aviation Administration Oversight

As stated previously, the Flying Boat, Inc., operating certificate for Chalk’s Ocean 

Airways was managed by the FAA’s South Florida certificate management office. At the 

time of the accident, the Chalk’s Ocean Airways PMI had been in that position for about 

5 years. He was also responsible for overseeing two other Part 121 air carriers.

During a postaccident interview, the Chalk’s Ocean Airways PMI stated that the 

number of times he visited the company each month varied depending on his workload 

and that he attempted to be at each monthly CASS meeting. The PMI also stated that his 

work included inspections of the maintenance facility, vendors, and airplane records; ramp 

inspections; and the aging aircraft inspection and records review program. The PMI 

indicated that he was “comfortable” with the maintenance being conducted on the 

56 SAIBs are informational in nature and are not mandatory.
Factual Information 28 Aircraft Accident Report

company’s airplanes. He added that the maintenance program met all Federal Aviation 

Regulation (FAR) requirements.

1.18 Additional Information

1.18.1 Applicable Federal Aviation Regulations

As stated previously, the accident airplane was modified from a G-73 model to a 

G-73T model in accordance with STC SA2323WE, and its seating configuration was 

modified in accordance with STC SA4410SW. A review of the STCs showed that both 

were held by Frakes Aviation. In August 1968, Frakes Aviation applied to the FAA for the 

STC to replace the piston engines with turbopropeller engines and to increase its 

maximum gross weight from 12,750 to 14,000 pounds. The FAA issued STC SA2323WE 

to Frakes Aviation in April 1971. In October 1979, Frakes Aviation applied to the FAA for 

an STC to increase the number of passenger seats in the cabin from 10 to 17. The FAA 

issued STC SA4410SW to Frakes Aviation in July 1981.

Title 14 CFR 21.19, “Changes Requiring a New Type Certificate,” had been in 

effect since February 1965, more than 3 years before Frakes Aviation applied for the 

engine modification STC. The version of the regulation that was current at the time of the 

STC application stated in paragraph (b)(2) that a new application for a type certificate was 

required for transport-category airplanes if the proposed change included engines using 

different principles of propulsion. However, the FAA granted Frakes Aviation the option 

to use the airplane’s original type certificate (which was issued in September 1947) as the 

basis for the analysis required for the modifications, instead of requiring Frakes to apply 

for a new type certificate for the G-73T airplane.57 The practice of applying former 

regulations instead of new regulations is known as grandfathering.

As a result of the FAA’s decision, Frakes Aviation performed the analysis for the 

engine modifications58 in accordance with Part 4aT of the Civil Air Regulations, dated 

November 1, 1943, and amended March 8, 1944. As mentioned previously, this regulation 

required a static strength analysis, which is performed using loads that do not vary with 

time and that have a constant magnitude. The regulation did not include any provisions for 

a fatigue strength analysis for an expected service life for the airplane’s structural 

components.

Because the FAA allowed Frakes Aviation to perform the analysis per the 

airplane’s original type certificate, the G-73T airplane was not made subject to 

14 CFR 25.571, “Fatigue Evaluation of Flight Structure,” which had been in effect since 

57 An STC applicant can request to negotiate the certification basis with the applicable FAA aircraft 

certification office, and all decisions are made at the discretion of the FAA Administrator.

58 Frakes Aviation used STRATO Engineering Company, Inc., of California to perform the engineering 

analysis.
Factual Information 29 Aircraft Accident Report

February 1965. The version of 14 CFR 25.571 that was in effect at the time that Frakes 

applied for the STC was dated October 1966 and required, in part, the following:

(a) Strength, detail design, and fabrication. Those parts of the structure 

(including wings, fixed and movable control surfaces, the fuselage, and 

their related primary attachments), whose failure could result in 

catastrophic failure of the airplane, must be evaluated under the 

provisions of either paragraph (b) or (c) of this section.

(b) Fatigue strength. The structure must be shown by analysis, tests, or both, 

to be able to withstand the repeated loads of variable magnitude expected 

in service.

(c) Fail safe strength. It must be shown by analysis, tests, or both, that 

catastrophic failure or excessive structural deformation, that could 

adversely affect the flight characteristics of the airplane, are not probable 

after fatigue failure or obvious partial failure of a single principal 

structural element.

1.18.2 Previous Related Safety Recommendations

1.18.2.1 Supplemental Inspections

According to 14 CFR 121.370a, “Supplemental Inspections,” the maintenance 

programs of certain airplanes are required to include damage-tolerance-based 

supplemental inspections and procedures in addition to the aging airplane inspection and 

records review required by 14 CFR 121.368. The FAA issued the final rule for 

14 CFR 121.370a in February 2005; however, the final rule differed substantially from the 

December 2002 interim final rule by exempting certain airplanes from the supplemental 

inspection requirements. The supplemental inspection requirements in the final rule for 

14 CFR 121.370a apply only to transport-category, turbine-powered airplanes that were 

type-certificated after January 1, 1958, and that have a maximum passenger seating 

capacity of 30 or more seats or a maximum payload of 7,500 pounds.59 The final rule also 

changed the compliance date from December 5, 2007, to December 10, 2010. In addition, 

both the December 2002 interim final rule and the February 2005 final rule exempted 

airplanes that are operated entirely within the state of Alaska. 

In a July 24, 2006, letter to the FAA, the Safety Board referenced this accident and 

stated that it was concerned that the exemptions allowed certain airplanes, including the 

G-73T airplane, to carry passengers under Part 121 without having to undergo 

59 The December 2002 interim final rule required supplemental inspections for all airplanes operated 

under 14 CFR Part 121, all U.S.-registered multiengine airplanes operated under 14 CFR Part 129, and all 

multiengine airplanes used in scheduled operations under 14 CFR Part 135 (with the exception of certain 

Alaska and smaller airplane operations mentioned later in this section).
Factual Information 30 Aircraft Accident Report

supplemental inspections. Because of these concerns, the Board issued Safety 

Recommendation A-06-52 on July 24, 2006, which asked the FAA to do the following:

Require records reviews, aging airplane inspections, and supplemental inspections 

for all airplanes operated under 14 Code of Federal Regulations (CFR) Part 121, 

all U.S.-registered airplanes operated under 14 CFR Part 129, and all airplanes 

used in scheduled operations under 14 CFR Part 135. This would include those 

airplanes operated under 14 CFR Part 135 that carry nine or fewer passengers and 

those that are operated in scheduled cargo service.

On November 20, 2006, the FAA stated that airplanes that were type-certificated 

before 1958 and that had a maximum passenger seating capacity of less than 30 seats were 

not included in the final rule requiring damage tolerance-based supplemental inspections 

because it would be cost prohibitive to do so. The FAA estimated that fewer than 

80 aircraft operated under Part 135 would be in scheduled operation in 2010, the 

compliance date for the supplemental inspections. The FAA stated that it would address 

the discovery of any age-related problems or unsafe conditions for these airplanes through 

continued operational safety programs and ADs. The FAA further stated that, if operators 

of small airplanes wanted to voluntarily develop supplemental inspections programs, they 

could refer to AC 91-60, which was being revised and would be completed in 2007. 

On March 21, 2007, the Safety Board issued a response letter and asked that the 

FAA reconsider its position regarding the exemption of aircraft from the supplemental 

inspection requirements. In the letter, the Board stated that, until such reconsideration, 

Safety Recommendation A-06-52 is classified “Open—Unacceptable Response.”

1.18.2.2 Cockpit Voice Recorder Functionality

During its investigation of the March 23, 2004, accident involving a helicopter that 

crashed into the Gulf of Mexico,60 the Safety Board found that the CVR data recovered 

during that investigation were of limited use because of a CVR anomaly that was not 

detected during the functional check of the CVR after installation. As a result, on 

March 24, 2006, the Board issued Safety Recommendation A-06-23, which asked the 

FAA to do the following:

Require all operators of aircraft equipped with a cockpit voice recorder (CVR) to 

(1) test the functionality of the CVR before the first flight of each day as part of an 

appoved aircraft checklist and (2) perform a periodic maintenance check of the 

CVR as part of an approved maintenance check of the aircraft. The CVR preflight 

test should be performed according to procedures provided by the CVR 

manufacturer and should include listening to the recorded signals on each channel 

to verify that the audio is being recorded properly, is intelligible, and is free from 

60 National Transportation Safety Board, Controlled Flight into Terrain, Era Aviation, Sikorsky 

S-76A++, N579EH, Gulf of Mexico, About 70 Nautical Miles South-Southeast of Scholes International 

Airport, Galveston, Texas, March 23, 2004, Aviation Accident Report NTSB/AAR-06/02 (Washington, DC: 

NTSB, 2006).
Factual Information 31 Aircraft Accident Report

electrical noise or other interference. The periodic maintenance check of the CVR 

should include an audio test followed by a download and review of each channel 

of recorded audio. The downloaded recording should be checked for overall audio 

quality, CVR functionality, and intelligibility.

In response, the FAA issued Safety Alert for Operators (SAFO) 06019 on 

November 8, 2006, advising operators to test CVR functionality before the first flight of 

the day and to add this test to their approved checklists. The SAFO emphasizes the 

importance of operators ensuring they have procedures and training for the functional test 

of the CVR. The SAFO also recommends that operators ensure that training requirements 

for testing of CVRs are emphasized during initial and recurrent training and that all pilots 

of aircraft equipped with a CVR test the function of the CVR before the first flight of each 

day as part of an approved aircraft checklist. 

According to the FAA, the release of the SAFO was to be accompanied by a flight 

standards information bulletin for airworthiness (FSAW) that would instruct airworthiness 

aviation safety inspectors to ensure that operators perform periodic CVR maintenance 

checks, including checks of all possible combinations of intercom and microphone audio 

selections. These checks would ensure that all permutations of these selections were 

connected to the appropriate CVR channels and did not inhibit normal selectable functions 

or create loss in fidelity or intelligibility. As of April 2007, the FAA had not yet issued the 

FSAW.

In a letter to the FAA dated April 12, 2007, the Safety Board noted that the SAFO 

did not provide the specific guidance for the CVR preflight test included in the 

recommendation. The Board also reminded the FAA that the FSAW should include 

sufficient detail to ensure that nonfunctional CVR systems are identified and repaired as 

quickly as possible. On April 12, 2007, the Board classified Safety Recommendation 

A-06-23 “Open—Unacceptable Response,” pending the FAA’s revision of the SAFO and 

issuance of an appropriate FSAW. 

1.18.3 Postaccident Interviews Regarding Maintenance of 

Chalk’s Ocean Airways’ Airplanes

The Safety Board interviewed Chalk’s Ocean Airways pilots, the husband of the 

accident captain, the company’s director of operations, the company’s maintenance 

supervisor, and two DERs regarding Chalk’s Ocean Airways’ maintenance policies and 

practices. Their interviews are summarized in sections 1.18.3.1 through 1.18.3.4, 

respectively.

1.18.3.1 Former and Current Company Pilots

The Safety Board interviewed four pilots who were employed by Chalk’s Ocean 

Airways at the time of the accident, the husband of the accident captain, and three pilots 

who had left the company before the accident. According to some pilots, in August 2004, 

all of the company captains had met with their director of operations to discuss shared 
Factual Information 32 Aircraft Accident Report

pilot concerns about the maintenance of company airplanes, including concerns about 

visible cracks and degraded rivets on some airplanes. Some pilots recalled that, during the 

meeting, the pilots had stated that they wanted to know that actions would be taken to 

ensure their safety and that the director of operations seemed to be concerned and told 

them that the airplanes would be examined.61 

Some of the pilots stated that they were concerned about the amount of time 

maintenance items on company airplanes were deferred and that the director of 

maintenance and the maintenance supervisor told them that that skin cracks in the 

airplanes were superficial. Some of the pilots stated that they voiced concerns about fuel 

leaks, most of which occurred near the location where the wing meets the fuselage, and 

that the company told them that the leaks involved sealant in the fuel tanks and that the 

tanks would be resealed. One current company captain stated that fuel leaks had to be 

written up multiple times before they were fixed and that, in 2004, the same fuel leak was 

written up between 10 and 15 times. 

Two current company first officers stated that company maintenance was “great” 

and that, when any problems were found with the airplanes, they would be fixed or 

grounded.

One former captain stated that, in November 2004, he experienced an in-flight 

emergency when he lost elevator control of the airplane during climbout because of an 

elevator cable that failed. He stated that he landed the airplane without incident using 

elevator trim. This captain stated he resigned from his job at Chalk’s Ocean Airways on 

the day of the event because he had a job offer from another company.

Another former captain stated that he experienced loss-of-engine-power events 

during flights in January and February 2005. The flight crews were able to land the 

airplane each time without incident. This captain stated he resigned after the 

February 2005 engine failure because of his concerns with company maintenance issues.

Another captain stated that he resigned from the company solely because of his 

concerns with maintenance issues. This captain stated that, just before submitting his 

resignation letter (dated January 28, 2005) to the company, he provided the company’s 

director of maintenance with a five-page letter (dated January 13, 2005) outlining his 

concerns.62 The captain’s letter stated that the most common reaction to a maintenance 

problem that could not be fixed quickly was for the mechanic to ask the captain of that 

airplane if he would fly it anyway; the letter stated that the second most common reaction 

was for the mechanic to sign off that the airplane was fixed when it actually was not fixed. 

The letter further indicated that “delayed maintenance, ignored maintenance, and lack of 

maintenance on our aircraft has caused an alarming trend to develop that has been all but 

61 The accident captain’s husband stated that the captain was concerned that company airplanes were 

not well maintained and that she would speak daily about problems with the airplanes.

62 This captain stated that he submitted this letter and tendered his resignation after being informed by 

the director of maintenance that he would be receiving disciplinary action (either a downgrade to first officer 

or time off) because of his difficulties in dealing with maintenance personnel.
Factual Information 33 Aircraft Accident Report

ignored by the maintenance department and management altogether.” In addition, in the 

letter, the captain suggested that the company “fix the aircraft when they do break, and 

improve our preventative maintenance, which is obviously sadly lacking.”

1.18.3.2 Director of Operations

The Chalk’s Ocean Airways director of operations has been in that position since 

August 2001.63 He was an active pilot who conducted most acceptance flights after 

maintenance because he wanted to personally confirm that the airplanes were safe before 

other pilots flew them.64 He stated that the company responded seriously to the comments 

expressed by its former captain by systematically checking airplane logbooks to confirm 

that all of his maintenance concerns had been addressed and fixed. The director stated that 

he was satisfied that these issues had been resolved and that the airplanes were safe to fly.

The director of operations stated that he did not agree with the former captain’s 

assertion that, among pilots, there was a general concern with airplane maintenance. The 

director pointed out that only two captains left the company because of maintenance 

concerns and that several other captains could provide a more favorable view of the 

company. He also pointed to the company’s 86-year “unblemished” safety record before 

the time of the accident.65

The director of operations stated that fuel leak concerns raised by pilots were 

“always a company concern” and that they were addressed before a flight was released. 

He also stated that every crack reported by pilots was corrected. He stated that the accident 

captain, as director of safety, was responsible for the safety aspect of flight and ground 

operations. He indicated that she discussed routine items during monthly meetings. He 

stated that he did not recall any time during these meetings in which she raised a concern 

about maintenance. The director further indicated that each captain could decide not to fly 

an airplane if a problem, including maintenance, existed.

63 The director of operations has also been the company’s general manager since February 2005.

64 The director of operations stated that he had to limit his flying after August 2005 because of medical 

issues.

65 A review of Safety Board accident and incident data revealed that on March 18, 1994, two Chalk’s 

Ocean Airways crewmembers were killed when the G-73T they were piloting crashed on takeoff. The Board 

determined that the probable cause of the accident was the “failure of the pilot-in-command to assure that 

the bilges were adequately pumped free of water (adequately preflighted), which resulted in the aft center of 

gravity limit to be exceeded, and the failure of the aircrew to follow the checklist. A factor related to the 

accident was the water leak.” For more information about this accident, see MIA94FA097 on the Board’s 

web site at <http://ntsb.gov>. Other Chalk’s Ocean Airways accidents and incidents include a hard landing 

in 2002; a landing-gear fatigue failure in 2001 due to unserviceable parts installed on an airplane; a control 

yoke overload separation in 2000; a nose landing-gear failure in 1984; and an elevator-trim actuator failure 

in 1984. For more information about these events, see MIA02WA063, MIA01IA144, MIA00IA186, 

MIA84IA147, and MIA84IA077, respectively. Also, the previously mentioned November 29, 2004, event, 

in which a pilot reported he lost elevator control due to a broken elevator cable but landed the airplane 

safely, is reflected in a service difficulty report that Chalk’s Ocean Airways submitted to the FAA.
Factual Information 34 Aircraft Accident Report

1.18.3.3 Maintenance Supervisor

The Chalk’s Ocean Airways maintenance supervisor at the time of the accident 

had been employed with the company for about 28 years and had been in that position for 

26 years. He stated that he attended the yearly recurrent training on the company’s GMM 

and the Grumman service manual66 and was present at most of the monthly CASS 

meetings.

The maintenance supervisor stated that Chalk’s Ocean Airways management gave 

him all of the resources, including airplane parts and personnel, to maintain the airplanes 

in an airworthy condition and that he did not sense “any pressure from upper management 

to keep the airplanes flying no matter what.” He also stated that sometimes it took several 

attempts to determine the cause of a discrepancy and implement a fix to solve the problem. 

The maintenance supervisor further stated that he was not involved with any of the DER 

structural repairs.67

The maintenance supervisor did not recall accomplishing, or instructing one of the 

company’s mechanics to accomplish, the doubler repair at right WS 34 on the accident 

airplane. He recalled seeing the repair several times during the C3 (right wing) inspection 

but thought that the repair “must have been done prior to Chalk’s getting the airplane.” 

The maintenance supervisor stated that he did not recall seeing any paperwork for this 

repair.

During the postaccident interview, the Safety Board showed the maintenance 

supervisor a picture of stop drill holes in the area of the doubler repair at right WS 34 on 

the accident airplane. The maintenance supervisor stated that he had not previously seen 

the stop drill holes and that he did not recollect instructing any of the mechanics to 

accomplish a stop drill repair in the area. He further stated that the repair was not 

accomplished using best maintenance practices.68

1.18.3.4 Designated Engineering Representatives

A structures DER stated that he worked with Chalk’s Ocean Airways during the 

5 to 6 years that preceded the accident. He indicated that most of the work performed for 

the company was the reverse engineering69 of parts that were affected by corrosion. To 

accomplish this work, he prepared a design drawing and a stress report, along with FAA 

form 8110; this form provided approval for the replacement parts, which were made of 

modern materials whose design properties were equivalent to those of the former 

66 The chief inspector provided this and all other recurrent training at the company.

67 Either a company mechanic or an outside mechanic recommended by the DER would accomplish 

these repairs.

68 As mentioned in section 1.6.2.2, several characteristics of the repair were not in accordance with 

AC 43.13-1B.

69 Reverse engineering is the process of recreating a drawing or specification for a component by 

analyzing a manufactured product for which a drawing or specification is unavailable.
Factual Information 35 Aircraft Accident Report

materials. The DER stated that the August 2005 right wing repair on N142PA was the first 

time he had worked on the wing structure of an airplane in Chalk’s Ocean Airways’ fleet.

Another structures DER stated that he had worked with Chalk’s Ocean Airways on 

four or five repairs since 1999, including the July 1999 lower left skin repair to N142PA. 

He also worked with the company on the July 2000 rear Z-stringer repair (right WS 50.5) 

to the accident airplane. The DER stated that this repair, which was needed because of a 

fatigue crack in one of the slosh holes, consisted of nesting two angles on the stringer in 

the region of the crack. The DER further stated that this repair was accomplished when the 

airplane was having major maintenance performed and that he did not recall any other 

damage or corrosion on the rest of the airplane at that time.

1.18.4 Grumman Customer Service Bulletin

Grumman issued Customer Service Bulletin No. 89 in May 1963. The bulletin 

stated that corrosion was the “greatest maintenance problem” for watercraft and that, for 

G-73 airplanes operating in a saltwater environment for most of their service life, 

corrosion might occur in the lower skin of the wings in the fuel tank areas. The bulletin 

also stated that corrosion might be occurring if one or all of the following conditions were 

present: chronic leakage of fuel; looseness of sealant in the tanks; and/or blisters, swelling, 

or visible corrosion in the skin in the tank areas.

The bulletin further stated that local repairs would probably correct the corrosion, 

but, if the aircraft had much saltwater operation in the past or if extended saltwater 

operations were anticipated in the future, the lower wing skin should be completely 

removed for a thorough cleaning, inspection, and resealing. In addition, the bulletin stated 

that wing skin removal and resealing of the fuel tanks would improve the fuel tightness 

and corrosion resistance of the tanks.

1.18.5 Department of Transportation Concerns About the 

Economic Fitness of Chalk’s Ocean Airways

As part of the DOT’s informal continuing fitness review of Chalk’s Ocean 

Airways, the Air Carrier Fitness Division sent the company a letter dated April 14, 2004, 

that expressed its concerns about the company’s “weak” financial position and what it 

considered to be excessive subservicing.70 The DOT notified the FAA of its concerns by 

sending copies of the correspondence to the principal operations inspector (POI) assigned 

to Chalk’s Ocean Airways. In a four-page attachment to the fitness review letter, the DOT 

also noted that, during discussions with the POI, the POI indicated that “his overall 

impression of the air carrier’s operations was that it seems to be run more like a Part 135 

air taxi operation rather than the Part 121 operator it is.” The DOT review also indicated 

that the POI expressed concerns “that the management team may be too busy with their 

70 Subservicing is the practice of transferring passengers to other carriers.
Factual Information 36 Aircraft Accident Report

flight duties to effectively attend to their administrative and oversight duties on the 

ground.”

In a follow-up e-mail on August 11, 2004, the DOT asked the POI, “Aside from 

the subservice issue, do you have any concerns with the carrier’s operations and/or 

management?” In an e-mail reply that day, the POI stated, “I do not.”

In a letter dated November 4, 2004, Chalk’s Ocean Airways responded to the DOT 

that it used subservicing when fleet maintenance requirements prevented it from using its 

own airplanes. These maintenance events included both scheduled and unscheduled 

maintenance items. In a January 5, 2005, letter to the company’s general manager, the 

DOT reiterated its concerns about the company’s economic viability and its subservicing 

arrangements.
37 Aircraft Accident Report

2. Analysis

2.1 General

The captain and the first officer were properly certificated and qualified under 

Federal regulations. No evidence indicated any medical or behavioral conditions that 

might have adversely affected their performance during the accident flight. There was no 

evidence of flight crew fatigue. 

The accident airplane was certificated and equipped in accordance with Federal 

regulations. The recovered components showed no evidence of any system or powerplant 

failures but showed evidence of multiple failures of wing structural components. 

The fire damage to the fuselage and empennage was a result of the failure of the 

right wing and the subsequent breach in the wing fuel tank. The accident was not 

survivable. The emergency response was timely. 

This analysis discusses the in-flight separation of the accident airplane’s right 

wing, Chalk’s Ocean Airways’ maintenance of the accident airplane and other airplanes in 

its fleet, the FAA’s oversight of the Chalk’s Ocean Airways maintenance program, and 

certification issues pertaining to aging aircraft.

2.2 In-flight Breakup Sequence

On the basis of the accident airplane’s takeoff weight and airspeed, the wing 

structure developed normal aerodynamic loads during takeoff, and these loads, in turn, 

created normal internal loads. However, the right wing separated from the airplane at 

WS 34 while the airplane was operated within its certificated design envelope, rendering 

the airplane uncontrollable. The airplane departed on the accident flight with preexisting 

damage to some wing structural components, however, the damaged components were not 

visible to the flight crew. The Safety Board concludes that there was no evidence from the 

performance or appearance of the airplane that would have provided warning to the flight 

crew of the right wing’s imminent failure and that there was nothing that the crew could 

have done to regain control of the airplane after the in-flight separation of the right wing. 

Section 2.2.1 discusses the fracture scenario and the right wing’s structural performance.

2.2.1 Fracture Scenario

Examination of the right wing revealed preexisting fatigue fractures and cracks in 

the rear Z-stringer, lower skin, and rear spar lower spar cap, each of which contributed to 

reducing the wing structure’s ability to carry load. An analysis of each component’s 

fracture characteristics, rub evidence and other characteristics observed on some 
Analysis 38 Aircraft Accident Report

components and on some maintenance repairs, and evaluation of the typical load-bearing 

characteristics of the wing structure design were performed to produce a general timeline 

and likely sequence for the respective failure of each fractured component. Section 2.3 

discusses the importance of this sequence as it relates to opportunities for repairing each 

damaged component before they cumulatively resulted in wing failure. 

The analysis revealed that the airplane’s right rear Z-stringer (as shown in figure 5) 

likely fractured first. Several features indicated that the right rear Z-stringer had been 

fractured for some time, most likely years, before the accident.71 Fatigue initiated at the 

slosh hole in the web of the Z-stringer just outboard of right WS 34. No anomalies, such as 

material defects, mechanical damage, or corrosion, were identified as factors to cause 

fatigue initiation at the slosh hole. It is likely that fatigue initiated at the slosh hole because 

the number of load cycles on the stringer exceeded its fatigue life.72

After the right rear Z-stringer fractured, the lower skin developed a fatigue crack 

(as shown in figure 4). Because of the load-bearing characteristics of the wing structure 

design, initiation of a skin-fatigue crack in this location would be unlikely unless the rear 

Z-stringer was already fractured.73 The skin crack, which was about 16 inches in length, 

consisted of two segments that initiated from two areas. Both segments of the skin crack 

propagated forward and aft of the initiation sites. The aft segment of the crack initiated 

from an area of corrosion and missing skin material around the fuel sump drain near right 

WS 34. The forward segment of the skin crack (the longer of the two segments) initiated 

from a rear Z-stringer fastener hole (the first fastener hole outboard of the fracture). 

Several features observed on this crack and on maintenance repairs associated with the 

crack suggest that the crack also likely developed over a period of months to years.

For example, three stop drill holes were observed in the crack path forward of the 

initiation site at the rear Z-stringer fastener hole (about 7, 9, and 16 inches forward of the 

skin trailing edge), indicating that the skin crack was detected by maintenance personnel 

on at least three occasions, likely over the course of months to years, and that crack 

extension beyond the previous stop drill hole was detected at least twice. The external and 

internal doublers were likely applied after the third stop drill hole had been drilled and 

after the skin crack propagated forward up to the middle Z-stringer. Missing skin material 

replaced with hard green sealant was observed between the doublers around the fuel sump 

drain. In this area, several fasteners at the inboard edge of the doublers went through the 

71 These features included the following: the overstress region on the upper flange was worn, which 

was consistent with rubbing of mating fracture surfaces over time; sanding marks were observed around the 

slosh hole that deformed the edges of the fracture face, and sealant was present in the fracture surface, 

indicating that the flange was cracked or fractured at the time the sanding and sealant procedures were 

performed; and one of the three internal doublers was covering the lower flange of the Z-stringer at the 

fracture location.

72 Fatigue life is the number of load cycles that a component experiences before failure is expected due 

to fatigue fracture.

73 If the rear Z-stringer were intact, it would carry most of the load, thereby reducing the load on the 

skin at the stringer fastener row. However, the right rear Z-stringer on the accident airplane was broken, 

causing the load to shed to the skin and leading to fatigue of the skin emanating from a fastener hole adjacent 

to the fracture.
Analysis 39 Aircraft Accident Report

sealant instead of skin material and, thus, would not provide load transfer across the skin 

crack in that area.

Multiple-site fatigue damage was observed on the skin fracture surface (inboard of 

the stop-drilled crack) at the inboard fastener row for the external doubler adjacent to right 

WS 34. At some time before the accident, several of these sites linked up in overstress to 

form a fracture through the skin at the rear Z-stringer and, most likely, several inches 

forward and aft of the Z-stringer.74

After the lower skin fractured, fatigue cracks initiated in the rear spar lower spar 

cap (as shown in figure 6). The initiation of these fatigue cracks was likely late in the 

overall sequence of events because the fracture features indicated relatively rapid growth 

under relatively high stresses. Fatigue in the rear spar lower spar cap initiated from a 

double-drilled hole in the horizontal flange of the spar cap for a threaded fastener 

attaching the wing to the fuselage.75 Although a double-drilled hole could be considered 

an initiating defect in many cases, in this case, fatigue initiated from multiple sites through 

the thickness of the horizontal flange (including both the narrow and wide areas of the 

double-drilled hole) indicating that stresses in the spar cap were high enough to cause 

fatigue initiation from any fastener hole in the area, with relatively few load cycles.

Further, fatigue in the rear spar progressed rapidly from a relatively small, slow 

growth region. The portion of the crack aft of the hole propagated from a length of 0.07 to 

0.44 inch in about 11 increments of rapid crack growth; each increment was most likely 

associated with an individual flight cycle. Also, more than one-half of the rear spar lower 

spar cap fractured in overstress. The relatively small size of the slow growth region and 

the limited overall size of the fatigue region indicated that stresses on the rear spar lower 

spar cap were relatively high as the crack propagated under normal flight loads, and the 

high stresses were most likely a result of the shedding of load from the fatigue-fractured 

and cracked rear Z-stringer and lower skin.

The Safety Board’s residual strength and fatigue analyses76 of the right wing 

structure revealed that the fatigue cracks grew to their critical crack length and that the 

remaining wing structure could no longer sustain the applied loads. The Safety Board 

74 Evidence of relative movement between the inboard side of the skin fracture and the doubler at its 

inboard fastener row, which was consistent with the fracture opening and closing, was observed on the 

surface of the doubler between several fastener locations, including the fastener for the right rear stringer 

and the adjacent two fasteners aft of the stringer.

75 The age of the double-drilled hole could not be determined. It is possible that both holes could have 

been drilled at the time the airplane was manufactured, and it is also possible that the second hole was drilled 

during maintenance.

76 The residual strength and fatigue analyses assumed 1 G flight loads that were obtained with and 

without fuel and were applied to the wing structure. The resulting reaction forces and associated stresses 

were computed for the undamaged wing. The stresses were then recomputed with certain elements either 

completely removed or their cross-sectional areas reduced, based on the amount of fatigue damage present 

in the wing structure. Stress concentration factors were then applied, and new stresses were computed and 

compared with the material yield and ultimate stresses. A crack-growth analysis was performed for the spar 

cap and the wing skin to determine the number of cycles required for the fatigue fractures to reach their 

critical crack length.
Analysis 40 Aircraft Accident Report

concludes that the right wing separated from the accident airplane at WS 34 because of 

preexisting fatigue fractures and cracks in the rear Z-stringer, lower skin, and rear spar 

lower spar cap and that this multiple-element fatigue damage reduced the residual strength 

capability of the wing structure and caused the fatigue failure of the wing during normal 

flight operations. 

2.3 Chalk’s Ocean Airways Maintenance Program

The Chalk’s Ocean Airways maintenance program was ineffective in identifying 

and correcting the longstanding structural problems that led to the in-flight separation of 

the accident airplane’s right wing near WS 34. Because several of these problems occurred 

over months and years, company maintenance and inspection personnel had multiple 

opportunities to identify and correct the individual damaged components and, thus, could 

have prevented the wing failure. 

2.3.1 Ineffective Repairs on the Accident Airplane 

Although maintenance personnel detected some problems and attempted repairs, 

many of the repairs were ineffective in that they did not properly restore the load-carrying 

capability of the wing structure. Ineffective repairs observed on the accident airplane 

included documented repairs performed by company maintenance personnel and some 

undocumented repairs. Also, company inspection personnel failed to identify that the 

repairs were ineffective. The ineffective repairs observed on the accident airplane included 

the following:

• Sanding marks were observed around the rear Z-stringer slosh hole and 

fracture lips at right WS 34, suggesting that the sanding was an attempt to 

remove cracking that had been detected in the Z-stringer. The cracking, 

however, was not completely removed, and the crack continued to propagate 

over time.

• One of the three internal doublers at right WS 34 had a portion that covered the 

lower flange of the rear Z-stringer, suggesting that the portion of the doubler 

covering the Z-stringer was an attempt to reinforce the fractured Z-stringer. 

Doubling only the lower flange did not restore the strength of the fractured 

Z-stringer.

• Multiple-site fatigue damage at the inboard fastener row for the doublers at 

right WS 34 linked up in the area of the rear Z-stringer before the wing 

separated, indicating that repairs in this area did not restore the strength of the 

rear Z-stringer.
Analysis 41 Aircraft Accident Report

• Several fasteners in the inboard row of fasteners for the doubler repair at right 

WS 34 were inserted through sealant near the fuel sump drain instead of the 

lower skin.77 This resulted in ineffective load transfer between the skin and the 

doublers in that area.

• Three stop drill holes were located in the area of the doubler repair to the lower 

skin at right WS 34. The stop drill holes showed that the skin crack was 

detected at least three times before the doublers were applied and that the crack 

had extended twice from the location of a previous stop drill hole. Continued 

crack growth from a stop drill hole is indicative of an underlying structural 

problem that was not properly addressed in previous maintenance actions.

On July 6, 2000, a major repair to the accident airplane’s rear Z-stringer was 

performed at right WS 50.5 using a DER drawing that indicated that the riveting was to be 

performed in accordance with AC 43.13.78 This repair was not part of the fracture scenario 

but was, nonetheless, ineffective because the rivets used in the repair did not meet the 

standards described in the AC. Some rivets had undersized shop heads and were 

overdriven, and a rivet through the skin and stringer flange at the slosh hole was of a larger 

size and different head type than specified, which was not in compliance with the 

engineering drawing for the repair. A fatigue crack in the skin emanated from the hole 

with the large rivet.

In addition, flight logs documented numerous fuel leak discrepancies involving the 

accident airplane that occurred over several months before the accident. Many of these 

discrepancies occurred near the area where the right wing separated from the airplane. The 

Chalk’s Ocean Airways director of maintenance stated that fuel leaks reported by pilots 

were addressed before a flight was released. However, the flight logs showed that the fuel 

leak discrepancies often took several attempts to resolve but would then recur. Because the 

wing skin and other wing box structures make up the wing fuel tanks, wing fuel leaks can 

be indicative of discrepancies with the wing box structure. The Safety Board concludes 

that the repetitive fuel leaks near the area where the accident airplane’s right wing 

separated from the fuselage were indicators of structural damage inside the right wing. 

This issue is further discussed in section 2.3.2.

Other maintenance-related problems existed with the accident airplane. For 

example, during postaccident metallurgical examinations, corrosion was observed in 

many locations throughout the airplane’s structure,79 with some areas showing significant 

pitting and thinning. Also, the metallurgical examinations showed significant fatigue 

77 AC 43.13 shows typical structural repair methods for aluminum structure, but the repairs described in 

this and the preceding two bulleted items were not included as examples of typical structural repair methods. 

Also, AC 43.13 does not include any reference to indicate that cracks can be removed by sanding, as 

described in the first bulleted item.

78 Technical data referenced in engineering drawings are considered to be approved data, and Chalk’s 

Ocean Airways GMM requires that all maintenance be performed in accordance with approved data.

79 The Safety Board could not determine whether Chalk’s Ocean Airways had received and 

implemented Grumman Service Bulletin No. 89, which addressed the problem of corrosion for airplanes that 

operated in a saltwater environment (see section 1.18.4).
Analysis 42 Aircraft Accident Report

cracks on the left wing, including one crack on the left wing front spar lower spar cap that 

had extended from an area of corrosion damage and had begun to progress fairly rapidly. 

The crack was located in an area that had not been repaired and did not have adjacent 

structural element failures. If the accident airplane had not experienced a catastrophic 

failure at right WS 34, the crack in the left wing front spar lower spar cap likely would 

have eventually led to a catastrophic failure.

In addition, Chalk’s Ocean Airways’ maintenance records did not contain any 

entry for the doubler repair to the accident airplane’s lower skin at right WS 34. During a 

postaccident interview, the company’s maintenance supervisor stated that he did not recall 

accomplishing, or instructing one of the company’s mechanics to accomplish, the repair. 

The maintenance supervisor stated that he recalled seeing the repair several times during 

the C3 (right wing) inspection but thought that the repair “must have been done prior to 

Chalk’s getting the airplane.” The company’s maintenance records showed that, on May 6, 

1992, a doubler repair was made to the accident airplane’s lower skin at left WS 34. 

Metallurgical examination showed a substantially greater amount of corrosion damage in 

the left wing doubler repair compared to corrosion damage in the right wing doubler 

repair. Thus, the right wing repair appeared to be more recent than the May 1992 left wing 

repair. 

As a result, the Safety Board concludes that Chalk’s Ocean Airways most likely 

performed the doubler repair to the accident airplane’s lower skin at right WS 34 and that 

this repair should have been reflected in the company’s maintenance records. It is possible 

that this repair was accomplished between January 2000 and January 2001, the time 

period for which the company was unable to provide flight log sheets. The Safety Board 

further concludes that the doubler repair to the accident airplane’s lower wing skin at right 

WS 34 was ineffective because the doublers did not restore the load-carrying capability of 

the skin in the area of the fuel sump drain and the repair did not properly address the 

underlying cause of the skin cracking, which was the cracked or fractured rear Z-stringer. 

2.3.2 Recurring Discrepancies 

As previously stated, Chalk’s Ocean Airways’ flight logs documented numerous 

fuel leak discrepancies involving the accident airplane. Minutes from the July 2005 CASS 

meeting showed that the accident airplane had a fuel leak from either the left or right wing 

near the fuel tank six times during a 5-day period. Also, the minutes from the 

September 2005 CASS meeting showed that the accident airplane had a fuel leak in its 

right wing dry bay for 3 consecutive days. The repair methods used to address these fuel 

leaks involved removing and replacing the sealant on the fuel tank.

As mentioned previously, the Chalk’s Ocean Airways’ repair methods to resolve 

the fuel leak discrepancies were not effective, as demonstrated by the recurring leaks in 

the same areas. As part of its CAMP and CASS program, Chalk’s Ocean Airways was 

required to monitor the mechanical performance of the flying fleet by collecting and 

analyzing operational data. However, the company’s evaluation of the recurring leaks was 

inadequate because it failed to recognize that the leaks were repeated indicators of 
Analysis 43 Aircraft Accident Report

structural damage inside the right wing. A thorough evaluation of the leaks should have 

recognized that, because the leaks recurred after repeated skin repairs, the skin repairs 

were not effective. This should have prompted further evaluation to determine a more 

effective repair; in the case of the accident airplane, further evaluation should have 

detected the structural damage inside the wing that led to skin cracks and the recurring 

leaks. Correction of that structural damage not only would have corrected the leaks but 

also would have prevented the accident. 

If Chalk’s Ocean Airways had established a repair threshold that limited the 

number of times such a discrepancy may recur in a given period, the recurrence of the 

leaks following multiple repairs may have prompted further troubleshooting, 

maintenance, engineering, and/or grounding of the airplane. The Safety Board concludes 

that the establishment of repair thresholds in all maintenance programs would help ensure 

that repeated occurrences of a specific discrepancy are sufficiently evaluated. Therefore, 

the Safety Board believes that the FAA should verify that the maintenance programs of 

commercial aircraft operators include stringent criteria to address recurring or systemic 

discrepancies to include, if necessary, further analysis of the discrepancies through a 

comprehensive engineering evaluation. 

2.3.3 Other Fleet Maintenance Issues

Maintenance-related problems also existed with another G-73T airplane in Chalk’s 

Ocean Airways’ fleet, N142PA. According to the structures DER who provided 

engineering approval for the August 2005 major repair to the lower right wing skin of that 

airplane, Chalk’s Ocean Airways informed him 2 months earlier that fuel was leaking 

from the right wing-to-body fairing. The DER inspected the airplane and found that fuel 

was leaking from a 22-inch crack in the right wing lower skin; the crack was covered by 

the fairing and reduced the load-carrying capacity of the right wing box by about 

50 percent. The DER also found that all of the stringers on the right wing were corroded 

and cracked and that many of the other repairs visible on the rest of the wing appeared to 

be “quite old.”80 As a result of the DER’s findings, the wing repairs involved replacing all 

of the stringers (including lower Z-stringers) and the lower wing skin from the centerline 

to the nacelle. The Safety Board concludes that, on the basis of the repetitive nature of the 

fuel leaks on the accident airplane and the structural damage that was found during the 

fuel leak inspection of another company airplane that led to the August 2005 replacement 

of that airplane’s lower right wing skin and stringers, Chalk’s Ocean Airways should have 

performed a comprehensive inspection of and maintenance on the wing structures of the 

airplanes in its fleet. 

80 In addition, the DER noticed that a doubler on the left lower wing skin had a 17-inch crack. The 

Safety Board confirmed the existence of the right wing lower skin crack and the left wing lower skin doubler 

crack in photographs provided by the DER. In addition, the DER who designed the July 1999 major repair to 

N142PA’s lower left wing skin stated that N142PA had an area of corrosion around the fuel sump drain and a 

14-inch crack that emanated from the forward edge of the corrosion to a point that was 9 inches forward. He 

also stated that the left wing aft spar attachment point showed evidence of grinding in some areas, the right 

wing aft spar attachment point had corrosion, and extensive corrosion was present on other areas of the 

airplane.
Analysis 44 Aircraft Accident Report

Even though the airplanes in Chalk’s Ocean Airways’ fleet were not subject to the 

fatigue evaluation requirements in 14 CFR 25.571,81 and the aging aircraft inspection and 

records review performed under 14 CFR 121.368 was not designed to detect fatigue 

cracking, the company was still responsible for maintaining its airplanes in an airworthy 

condition. The Chalk’s Ocean Airways maintenance supervisor stated that he was given 

all of the resources (parts and personnel) that he needed to maintain the company’s 

airplanes in an airworthy condition and that he did not sense “any pressure from upper 

management to keep the airplanes flying no matter what.” However, in a January 2005 

letter to the company’s director of maintenance, a former company captain stated that the 

most common reaction to a maintenance problem that could not be quickly fixed was for 

the mechanic to ask the captain of that airplane if he would fly it anyway and that the 

second most common reaction was for the mechanic to sign off that the airplane was fixed 

when it was not actually fixed.

The Safety Board concludes that the failure of Chalk’s Ocean Airways to identify 

and properly repair fatigue cracks in the accident airplane’s wing structure and the 

numerous maintenance-related problems found on the accident airplane and another 

company airplane demonstrate that the company’s maintenance program and practices 

were deficient, and these deficiencies were causal to the accident. 

2.4 Federal Aviation Administration Oversight of the 

Chalk’s Ocean Airways Maintenance Program

The Chalk’s Ocean Airways PMI was responsible for overseeing the company’s 

maintenance program plan and the maintenance performed on the airplanes in the 

company’s fleet. During a postaccident interview, the PMI stated that he was 

“comfortable” with the maintenance being conducted on Chalk’s Ocean Airways’ 

airplanes, and he did not convey any concerns about the quality of the maintenance 

program. The PMI also noted that the company’s maintenance program plan met all FAR 

requirements. 

As part of his oversight duties, the PMI conducted the 14 CFR 121.368 aging 

aircraft inspection and records review for Chalk’s Ocean Airways on October 7, 2005. A 

review of the paperwork for the PMI’s aging aircraft inspection and records review 

indicated that, for the accident airplane, major repairs to the rear spar upper spar cap at 

right WS 34 and to the lower wing skin at left WS 34 were accomplished on April 13 and 

May 6, 1992, respectively. However, the paperwork did not include the July 6, 2000, 

major repair to the rear Z-stringer at right WS 50.5, even though maintenance records for 

this repair were available. Also, the paperwork did not include the major repair to the 

lower wing skin at right WS 34. 

81 As mentioned in section 1.16.1, the Safety Board notes that Chalk’s Ocean Airways electively 

employed a fatigue- and damage-tolerance-based approach for the August 2005 repair to the right wing on 

N142PA.
Analysis 45 Aircraft Accident Report

Because 14 CFR 121.368 does not specifically include requirements for inspecting 

airplane structures that are susceptible to fatigue cracking, a thorough aging aircraft 

inspection alone would not likely detect the multiple-element fatigue cracking on the 

accident airplane’s right wing and the significant fatigue crack on the airplane’s left wing 

front spar lower spar cap. However, the Safety Board is concerned that the PMI’s aging 

aircraft inspection and records review for Chalk’s Ocean Airways did not include a repair 

that was undocumented in the maintenance records but was known to company 

maintenance personnel.

As previously discussed, the purpose of Chalk’s Ocean Airways’ CASS program 

was to identify and correct deficiencies in the company’s maintenance program plan, and 

the PMI was responsible for monitoring the company’s CASS program. Records showed 

that the Chalk’s Ocean Airways PMI did not attend the July and September 2005 CASS 

meetings, each of which included discussions of fuel leak issues on the accident airplane. 

However, according to the PMI’s annual work plan, he was responsible for reviewing all 

information related to the company’s CASS program, including the CASS meeting 

minutes, so he should have been aware of the repetitive fuel leaks on the accident airplane. 

As stated previously, the fuel leak discrepancies on the accident airplane were 

repeated indicators of wing structural damage issues that the Chalk’s Ocean Airways 

maintenance program did not effectively address. Because the PMI had information that 

the fuel leaks were recurring and that a DER’s evaluation of leaks on N142PA led to 

extensive structural repairs of that airplane’s wing structure in August 2005, the PMI 

should have realized that the skin and sealant repair methods being applied to the accident 

airplane were not sufficient. However, no evidence indicated that the PMI investigated the 

cause of the repetitive fuel leaks or discussed these issues with company management. 

2.4.1 Importance of Program Oversight for Aircraft With

Limited Support 

The Safety Board has long recognized that effective FAA oversight of air carriers 

serves as an important safety function to help prevent accidents. For example, during its 

investigations of the May 11, 1996, ValuJet Airlines accident82 and the August 7, 1997, 

Fine Airlines accident,83 the Board noted that FAA oversight activities did not detect 

systemic deficiencies at each airline that were related to the circumstances of each 

accident. As a result, the Board issued Safety Recommendation A-98-51 on July 10, 1998, 

which asked the FAA to determine why certain oversight procedures failed to detect 

82 National Transportation Safety Board, In-flight Fire and Impact With Terrain, ValuJet Airlines Flight 

592, DC-9-32, N904VJ, Everglades, Near Miami, Florida, May 11, 1996, Aircraft Accident Report 

NTSB/AAR-97/06 (Washington, DC: NTSB, 1997).

83 National Transportation Safety Board, Uncontrolled Impact With Terrain, Fine Airlines Flight 101, 

Douglas DC-8-61, N27UA, Miami, Florida, August 7, 1997, Aircraft Accident Report NTSB/AAR-98/02 

(Washington, DC: NTSB, 1998).
Analysis 46 Aircraft Accident Report

systemic safety problems at ValuJet Airlines and Fine Airlines and to modify those 

procedures.84

The Safety Board has also long recognized the value of engineering services in 

assisting operators to periodically evaluate and improve their maintenance practices. For 

example, on July 21, 1989, the Board issued Safety Recommendation A-89-61,85 which 

asked the FAA to require that air carrier maintenance departments use the engineering 

services available from the manufacturer or other sources to periodically evaluate their 

maintenance practices.86 In response to the recommendation, the FAA stated, “present 

association between the manufacturers’ engineering organizations and the air carriers’ 

maintenance organizations is adequate,” and “air carrier engineering departments 

maintain a close liaison with their counterparts in the manufacturers’ organizations and 

their maintenance department liaison with the manufacturers’ service representatives.”

However, in the case of Chalk’s Ocean Airways, neither the airplane’s 

manufacturer nor the current type certificate holder provided engineering services, and 

Chalk’s Ocean Airways did not have an engineering department. Engineering support for 

Chalk’s Ocean Airways was provided by individual contracts with multiple DERs. This 

type of support does not provide the comprehensive understanding of the operator’s fleet 

that sole-source engineering support could provide. In addition, a structural repair manual 

was not issued for the G-73 because one was not required at the time the airplane was 

manufactured. 

The Safety Board notes that, because of the limited availability of engineering 

services and manufacturer support for the G-73T airplanes, effective FAA oversight of the 

Chalk’s Ocean Airways maintenance program plan was important to ensure that the 

program addressed the airworthiness issues of such a fleet. However, although the 

program plan met FAR requirements and the PMI performed his required oversight 

activities, these activities did not result in the detection and correction of the systemic 

84 Safety Recommendation A-98-51 specifically asked that the FAA do the following: “Review its 

national aviation safety inspection program and regional aviation safety inspection program inspection 

procedures to determine why inspections preceding these accidents failed to identify systemic safety 

problems at ValuJet and Fine Air[lines] and, based on the findings of this review, modify these inspection 

procedures to ensure that such systemic indicators are identified and corrected before they result in an 

accident.” On March 12, 2001, the Safety Board classified Safety Recommendation A-98-51 “Open—

Unacceptable Response” because the FAA did not answer why the inspections failed to identify systemic 

safety problems at ValuJet and Fine Airlines and did not address how the program modifications ensure that 

such systemic indicators are identified and corrected before they result in an accident.

85 Safety Recommendation A-89-61 was issued as part of the Safety Board’s final report on the 

April 28, 1988 Aloha Airlines flight 243 accident. The airplane experienced an explosive decompression 

and structural failure at 24,000 feet while en route from Hilo to Honolulu, Hawaii. About 18 feet of cabin 

skin and structure aft of the cabin entrance door and above the passenger floorline separated from the 

airplane. For more information, see National Transportation Safety Board, Aloha Airlines, Flight 243, 

Boeing 737-200, N73711, Near Maui, Hawaii, April 28, 1988, Aircraft Accident Report NTSB/AAR-89/03 

(Washington, DC: NTSB, 1989).

86 On September 22, 1992, the Safety Board classified Safety Recommendation A-89-61 “Closed—

Acceptable Alternate Action” as a result of the implementation of several FAA initiatives to reinforce the 

requirements of the existing regulation (14 CFR 121.373) and to provide assurance that operator 

maintenance programs were satisfactory.
Analysis 47 Aircraft Accident Report

deficiencies in the maintenance program that led to this accident. Thus, the Safety Board 

concludes that the Chalk’s Ocean Airways maintenance program plan was inadequate to 

maintain the structural integrity of its aircraft fleet. Further, the Safety Board concludes 

that the FAA’s procedures for maintenance program oversight, when applied to 

commercial operators of aircraft with limited manufacturer or engineering support, such 

as Chalk’s Ocean Airways, are insufficient to ensure the adequacy of such programs’ 

structural airworthiness plans and, thus, the safety of such aircraft operations and that the 

FAA’s failure to identify the inadequacy of the Chalk’s Ocean Airways maintenance 

program was causal to the accident. Therefore, the Board believes that the FAA should 

identify the systemic deficiencies in the maintenance program oversight procedures that 

led to this accident and modify those procedures to ensure that the maintenance program 

plans for commercial operators are adequate to ensure the continued airworthiness, both 

structural and otherwise, of the operator’s fleet. 

2.4.2 Continuing Analysis and Surveillance System

Program Guidance

Inspector guidance for ensuring that an operator’s CASS meets the necessary 

requirement for certification or revision is currently found in FAA Order 8300.10, 

Airworthiness Inspector’s Handbook, volume 2, chapter 65, “Evaluate Continuing 

Analysis and Surveillance Program.” Inspector guidance for monitoring the CASS 

program is currently found in FAA Order 8300.10, volume 3, chapter 37, “Monitor 

Continuing Analysis and Surveillance Program.” These handbook sections were 

developed in the early 1990s.

In March 2003, the FAA issued AC 120-16D, “Continuous Airworthiness 

Maintenance Programs,” which indicated that an air carrier’s CASS program should 

detect and correct air carrier maintenance program deficiencies through a closed-loop, 

continuous cycle of surveillance and investigations, data collection and analysis, 

corrective actions, and monitoring and feedback. AC 120-16D stated that an air carrier’s 

CASS program should include detailed policy and procedures for determining whether an 

air carrier needed to amend its maintenance program and for making such amendments. In 

addition, the guidance stated, “proactive surveillance and analysis forecasts faults in your 

[the air carrier’s] maintenance program ... through the collection and analysis of a wide 

variety of data. It corrects those faults, including human factors issues, in advance of any 

specific event, accident, or incident.”

In April 2003, the FAA published AC 120-79, “Developing and Implementing a 

Continuing Analysis and Surveillance System,” which was a comprehensive guide for the 

development of CASS programs. The AC provided information on many CASS-related 

topics and described model CASS programs for air carriers in three different size ranges.
Analysis 48 Aircraft Accident Report

On March 5, 2004, the Safety Board issued Safety Recommendation A-04-14 as 

part of its investigation into the January 2003 Air Midwest flight 5481 accident in 

Charlotte, North Carolina.87 Safety Recommendation A-04-14 asked the FAA to “include 

the Continuing Analysis and Surveillance System guidance from Advisory Circular 

(AC) 120-16D, ‘Continuous Airworthiness Maintenance Programs,’ and AC 120-79, 

‘Developing and Implementing a Continuing Analysis [and] Surveillance System,’ in 

Federal Aviation Administration Order 8300.10, Airworthiness Inspector’s Handbook.”

On June 18, 2004, the FAA stated that it would include a reference to AC 120-16D 

and AC 120-79 in FAA Order 8300.10 and that it anticipated that the order would be 

revised by October 2004. On October 12, 2005, the Safety Board stated that a May 2005 

check of FAA Order 8300.10 on the FAA’s Web site did not find this revision. The Board 

stated that, pending issuance of a revised FAA Order 8300.10 that incorporates the 

reference to the ACs, Safety Recommendation A-04-14 was classified “Open—

Acceptable Response.”

In December 2006, the FAA notified the Safety Board that the Airworthiness 

Inspector’s Handbook had been revised in October 2005 to include references to 

AC 120-16D and AC 120-79. However, the Board’s review of the handbook found that 

the references to both ACs only appeared in a chapter that discussed outsourcing 

maintenance (volume 2, chapter 69). In addition, the Board found that (1) a reference to 

only AC 120-79 was added to volume 2, chapter 95 of the handbook, which discusses an 

operator’s use of a Coordinating Agencies for Supplier Evaluation audit to satisfy the 

operator’s surveillance requirement under 14 CFR 121.373 and that (2) a reference to only 

AC 120-16D was added to volume 3, chapter 134 of the handbook, which discusses the 

evaluation of an outsource maintenance organization’s facility.

For the handbook chapters that discuss evaluating and monitoring a CAMP 

(volume 2, chapter 64, and volume 3, chapter 36, respectively), a reference to only 

AC 120-16D appears. Also, for the handbook chapters that discuss evaluating and 

monitoring a CASS program (volume 2, chapter 65, and volume 3, chapter 37, 

respectively), a reference to only AC 120-16D appears. To effectively assess the adequacy 

of an operator’s CASS program, a PMI needs to consider the guidance in AC 120-79 in 

addition to the guidance in AC 120-16D. Also, for all of the CASS guidance references, 

only the AC number and the AC title appear. The handbook contains no specific 

information to inform the PMI of the purpose and contents of each AC. Such information 

would help PMIs to evaluate and monitor a company’s CASS.

The Safety Board concludes that updating FAA Order 8300.10, Airworthiness 

Inspector’s Handbook, with the latest CASS guidance and an explanation of this guidance 

would help FAA aviation safety inspectors ensure that CASS programs are being 

effectively implemented at 14 CFR Part 121 air carriers. Therefore, the Board reiterates 

87 National Transportation Safety Board, Loss of Pitch Control During Takeoff, Air Midwest 

Flight 5481, Raytheon (Beechcraft) 1900D, N233YV, Charlotte, North Carolina, January 8, 2003, Aircraft 

Accident Report NTSB/AAR-04/01 (Washington, DC: NTSB, 2004).
Analysis 49 Aircraft Accident Report

Safety Recommendation A-04-14. Further, the Board classifies Safety 

Recommendation A-04-14 “Open—Unacceptable Response.”

2.4.3 Other Indicators of Potential Safety Deficiencies

During the investigation of this accident, a number of cues from several sources 

served as indicators of potential safety deficiencies at Chalk’s Ocean Airways. In 2004 

and 2005, Chalk’s Ocean Airways received and responded to repeated correspondence 

from the DOT regarding the DOT’s concerns with the economic fitness of the air carrier. 

The DOT sent copies of this correspondence to the POI. Although the DOT Air Carrier 

Fitness Division’s role does not include assessing air carrier safety, the correspondence 

served to notify the POI that Chalk’s Ocean Airways was exhibiting financial difficulties. 

The Safety Board notes that the financial distress of an operator can be an indicator that 

additional surveillance may be warranted.88

In addition, the DOT correspondence indicated that the POI expressed concerns 

that company managers were too busy with their flight duties to effectively attend to their 

compliance and management duties. The accident captain was a full-time line pilot but 

also served as the company’s director of safety, a position that required FAA approval for 

her to perform. During postaccident interviews, the husband of the accident captain 

reported that, in the year before the accident, she was becoming exhausted and stressed by 

work demands.

 Also, for an airline with a small fleet, there were a number of maintenance-related 

events that compromised flight safety. In November 2004, an in-flight emergency 

occurred on a company airplane when an elevator cable failed in flight. Chalk’s 

documented this event and informed the FAA by means of a service difficulty report. 

Also, a landing-gear fatigue failure incident in 2001 was attributed to unserviceable parts 

installed on the airplane by Chalk’s maintenance personnel. Further, through the CASS 

meetings and minutes, the PMI was made aware of repetitive maintenance issues, such as 

wing fuel leaks on the accident airplane. These leak issues continued to persist, even after 

the FAA was made aware that another company airplane received a major structural wing 

repair to fully address its fuel leak issues.

The Safety Board is concerned that the FAA received cues from a number of 

sources that, when looked at in aggregate, served as indicators of potential safety 

88 On December 28, 1988, the Safety Board issued Safety Recommendation A-88-155, which asked 

that the FAA provide POIs of operators under 14 CFR Parts 135 and 121 with similar indicators of financial 

distress and rapid growth; these indicators suggest when increased surveillance of those operations is 

warranted. On May 23, 1989, the Safety Board classified Safety Recommendation A-88-155 “Closed—

Acceptable Action” after the FAA responded that it issued an action notice and guidance materials for POIs 

with regard to requested action. Subsequently, the FAA incorporated a “Financial Condition Assessment 

Decision Aid” into FAA Order 8300.10. The recommendation resulted from the Board’s investigation of the 

February 19, 1988, fatal accident involving a Fairchild Metro III operated as AvAir, Inc., flight 3378. For 

more information, see National Transportation Safety Board, AvAir Inc., Flight 3378, Fairchild Metro III, 

SA227 AC, N622AV, Cary, North Carolina, February 19, 1988, Aircraft Accident Report NTSB/AAR-88/10 

(Washington, DC: NTSB, 1988).
Analysis 50 Aircraft Accident Report

deficiencies at Chalk’s Ocean Airways. However, there is no evidence that the FAA 

conducted any meaningful increase in surveillance in response to the aggregate 

information. In fact, the FAA principal inspectors expressed no concerns with the 

company’s operations and maintenance. Therefore, the Safety Board concludes that the 

FAA received sufficient cues from a number of sources to alert it of potential safety 

deficiencies at Chalk’s Ocean Airways and that these cues should have prompted 

heightened vigilance and additional surveillance of the operator. 

2.5 Certification Issues

The accident airplane’s right wing was designed in accordance with the applicable 

certification requirements in Part 4aT of the Civil Air Regulations, dated November 1, 

1943, and amended March 8, 1944. The Safety Board’s review of certification documents 

revealed no faulty methods or invalid assumptions for the wing structure certification 

basis. However, the Board notes that the certification requirements included a static 

strength analysis but not a fatigue analysis. No requirements for a fatigue analysis existed 

at the time of the G-73’s original certification because such an analysis had not yet been 

developed.

In August 1968, when Frakes Aviation applied for the STC to increase the gross 

weight of the G-73 and replace its piston engines with turbopropeller engines, 

14 CFR 21.19, “Changes Requiring a New Type Certificate,” was in effect. 

Paragraph (b)(2) of the regulation stated that a new application for a type certificate was 

required for transport-category airplanes if the proposed change involved engines using 

different principles of operation. However, the FAA granted Frakes Aviation the option to 

perform the analysis for the modifications according to the original type certificate, which 

was issued more than 20 years earlier.

As mentioned in section 1.18.1, the practice of applying former regulations instead 

of new regulations is known as grandfathering. This practice is generally employed when 

a type certificate or STC applicant is developing derivative aircraft (those for which 

changes in the type design are considered minor)89 as long as the omission of current 

regulations does not have a negative impact on structural integrity, continued 

airworthiness, or safety of flight. A major change in type design may, in some cases, be 

accomplished without applying the most recent requirements at the time of type certificate 

or STC application (as demonstrated by the G-73’s increase in gross weight and 

conversion from piston to turbopropeller engines).

Because the FAA allowed Frakes Aviation to use the original certification basis for 

the modifications, the analysis to support the modifications for the STC considered only 

static loading. A review of the Frakes Aviation STC, as approved by the FAA and applied 

to the accident airplane, revealed that, on the basis of the static strength analysis 

performed in support of the STC, the increase in gross weight and the conversion from 

89 A minor change is one that has no appreciable effect on the weight, balance, structural strength, 

reliability, operational characteristics, or other characteristics affecting the airworthiness of the product.
Analysis 51 Aircraft Accident Report

piston to turbopropeller engines for the accident airplane did not contribute to the 

circumstances of the accident. The accident airplane’s wing structure did not fail because 

of static loading but rather because of multiple-element fatigue damage that reduced the 

residual strength capability of the wing structure.

However, had the FAA not allowed Frakes Aviation to use the original certification 

basis for the STC modification, Frakes Aviation would have had to apply for a new type 

certificate in 1968. As part of that process, Frakes Aviation would have most likely90 been 

required to perform a fatigue analysis, according to 14 CFR 25.571, “Fatigue Evaluation 

of Flight Structure,” which was enacted more than 3 years earlier. Such a fatigue analysis 

would have included an evaluation of the strength, design, and fabrication of those parts of 

the structure, including the wings, whose failure could result in catastrophic failure of the 

airplane. Also, this analysis likely would have included a determination of a safe operating 

life for the wing structure that would have been used as the basis for inspection and 

retirement requirements.

Because no fatigue analysis was performed, no information is available for the 

dynamic loading experienced by the G-73 wing before or after the incorporation of the 

Frakes Aviation STC. Without the results of a complete fatigue analysis of the wing before 

and after the time of the STC, it is not possible to determine whether the fatigue damage 

and locations of fatigue cracks in the accident airplane’s wing structure were what could 

have been expected. Also, without a fatigue analysis, there was no existing information for 

the safe operating life of the G-73T wing structure that could have been used as the basis 

for inspection and retirement requirements. Therefore, the Safety Board concludes that the 

FAA missed an opportunity to recertify the Grumman Mallard G-73T airplane with a new 

type certificate that would likely have included a fatigue analysis of the airplane. Such a 

fatigue analysis likely would have included a determination of a safe operating life for the 

wing structure that would have been used as the basis for inspection and retirement 

requirements that could have prevented the accident. The Board notes that, according to 

the current FARs pertaining to type certificates and STCs, an operator can no longer 

accomplish such major modifications of primary structural elements without first 

conducting a detailed assessment of the certification basis and the analysis necessary to 

support such design changes, including, but not limited to, static, fatigue, and/or 

damage-tolerance analyses. 91

The Safety Board further notes that the accident airplane was not subject to the 

supplemental damage-tolerance-based inspections and procedures required by 

90 Although fatigue requirements were in place at the time, applicants could negotiate the certification 

basis with the FAA.

91 The current version of 14 CFR 25.571 was revised when damage-tolerance regulations were enacted 

in December 1978; the section’s name changed to “Damage-Tolerance and Fatigue Evaluation of Structure.” 

The regulation requires, in part, that an applicant must perform a damage-tolerance evaluation to include a 

determination of the probable locations and modes of damage due to fatigue, corrosion, or accidental 

damage; repeated load and static analyses supported by test evidence and (if available) service experience; 

and special consideration for widespread fatigue damage. The regulation also states that an applicant must 

demonstrate with sufficient full-scale fatigue test evidence that widespread fatigue damage will not occur 

within the design service goal of the airplane.
Analysis 52 Aircraft Accident Report

14 CFR 121.370a, “Supplemental Inspections,” because of FAA exemptions.92 As a result, 

Chalk’s Ocean Airways was not required to account for the adverse effects that repairs, 

alterations, and modifications might have on fatigue cracking and the inspection of the 

airplane structure.

Because of its concerns about the FAA exemptions to 14 CFR 121.370a, on 

July 24, 2006, the Safety Board issued Safety Recommendation A-06-52 to recommend 

that the FAA require records reviews, aging airplane inspections, and supplemental 

inspections for all airplanes operated under Part 121.93 The Board notes that the actions 

proposed by the safety recommendation would identify potential failures of structures in 

airplanes, like the G-73T, that are not currently subject to 14 CFR 121.370a. In its 

November 20, 2006, response to this recommendation, the FAA stated that it would not 

include, in the final rule requiring damage-tolerance-based supplemental inspections, 

airplanes that were type-certificated before 1958 and had a maximum passenger seating 

capacity of fewer than 30 seats because it would be cost prohibitive to do so. The Board 

strongly encourages the FAA to reconsider its position and take expeditious action on 

Safety Recommendation A-06-52.

92 According to the February 2005 final rule, 14 CFR 121.370a applies only to transport-category, 

turbine-powered airplanes that were type-certificated after January 1, 1958, and that had a maximum 

passenger seating capacity of 30 or more seats or a maximum payload of 7,500 pounds. 

93 In addition to all airplanes operated under Part 121, the safety recommendation included all 

U.S.-registered airplanes operated under Part 129 and all airplanes used in scheduled operations under 

Part 135. This would include those airplanes operated under Part 135 that carry nine or fewer passengers and 

those that are operated in scheduled cargo service.
53 Aircraft Accident Report

3. Conclusions

3.1 Findings

1. The captain and the first officer were properly certificated and qualified under Federal 

regulations. No evidence indicated any medical or behavioral conditions that might 

have adversely affected their performance during the accident flight. There was no 

evidence of flight crew fatigue.

2. The accident airplane was certificated and equipped in accordance with Federal 

regulations. The recovered components showed no evidence of any system or 

powerplant failures but showed evidence of multiple failures of wing structural 

components.

3. The fire damage to the fuselage and empennage was a result of the failure of the right 

wing and the subsequent breach in the wing fuel tank.

4. The accident was not survivable. The emergency response was timely.

5. There was no evidence from the performance or appearance of the airplane that would 

have provided warning to the flight crew of the right wing’s imminent failure, and 

there was nothing that the crew could have done to regain control of the airplane after 

the in-flight separation of the right wing.

6. The right wing separated from the accident airplane at wing station 34 because of 

preexisting fatigue fractures and cracks in the rear Z-stringer, lower skin, and rear 

spar lower spar cap, and this multiple-element fatigue damage reduced the residual 

strength capability of the wing structure and caused the fatigue failure of the wing 

during normal flight operations.

7. The repetitive fuel leaks near the area where the accident airplane’s right wing 

separated from the fuselage were indicators of structural damage inside the right 

wing.

8. Chalk’s Ocean Airways most likely performed the doubler repair to the accident 

airplane’s lower skin at right wing station 34, and this repair should have been 

reflected in the company’s maintenance records.

9. The doubler repair to the accident airplane’s lower wing skin at right wing station 34 

was ineffective because the doublers did not restore the load-carrying capability of 

the skin in the area of the fuel sump drain and the repair did not properly address the 

underlying cause of the skin cracking, which was the cracked or fractured rear 

Z-stringer.
Conclusions 54 Aircraft Accident Report

10. The establishment of repair thresholds in all maintenance programs would help 

ensure that repeated occurrences of a specific discrepancy are sufficiently evaluated.

11. On the basis of the repetitive nature of the fuel leaks on the accident airplane and the 

structural damage that was found during the fuel leak inspection of another company 

airplane that led to the August 2005 replacement of that airplane’s lower right wing 

skin and stringers, Chalk’s Ocean Airways should have performed a comprehensive 

inspection of and maintenance on the wing structures of the airplanes in its fleet.

12. The failure of Chalk’s Ocean Airways to identify and properly repair fatigue cracks in 

the accident airplane’s wing structure and the numerous maintenance-related 

problems found on the accident airplane and another company airplane demonstrate 

that the company’s maintenance program and practices were deficient, and these 

deficiencies were causal to the accident. 

13. The Chalk’s Ocean Airways maintenance program plan was inadequate to maintain 

the structural integrity of its aircraft fleet.

14. The Federal Aviation Administration’s (FAA) procedures for maintenance program 

oversight, when applied to commercial operators of aircraft with limited manufacturer 

or engineering support, such as Chalk’s Ocean Airways, are insufficient to ensure the 

adequacy of such programs’ structural airworthiness plans and, thus, the safety of 

such aircraft operations, and the FAA’s failure to identify the inadequacy of the 

Chalk’s Ocean Airways maintenance program was causal to the accident.

15. Updating Federal Aviation Administration (FAA) Order 8300.10, Airworthiness 

Inspector’s Handbook, with the latest Continuing Analysis and Surveillance System 

(CASS) guidance and an explanation of this guidance would help FAA aviation safety 

inspectors ensure that CASS programs are being effectively implemented at 14 Code 

of Federal Regulations Part 121 air carriers.

16. The Federal Aviation Administration received sufficient cues from a number of 

sources to alert it to potential safety deficiencies at Chalk’s Ocean Airways, and these 

cues should have prompted heightened vigilance and additional surveillance of the 

operator.

17. The Federal Aviation Administration missed an opportunity to recertify the Grumman 

Mallard (G-73T) airplane with a new type certificate that would likely have included 

a fatigue analysis of the airplane. Such a fatigue analysis likely would have included a 

determination of a safe operating life for the wing structure that would have been used 

as the basis for inspection and retirement requirements that could have prevented the 

accident.
Conclusions 55 Aircraft Accident Report

3.2 Probable Cause

The National Transportation Safety Board determines that the probable cause of 

this accident was the in-flight failure and separation of the right wing during normal flight, 

which resulted from (1) the failure of the Chalk’s Ocean Airways maintenance program to 

identify and properly repair fatigue cracks in the right wing and (2) the failure of the 

Federal Aviation Administration to detect and correct deficiencies in the company’s 

maintenance program.
56 Aircraft Accident Report

4. Recommendations

4.1 New Recommendations

As a result of the investigation of this accident, the National Transportation Safety 

Board makes the following recommendations to the Federal Aviation Administration:

Verify that the maintenance programs of commercial aircraft operators 

include stringent criteria to address recurring or systemic discrepancies to 

include, if necessary, further analysis of the discrepancies through a 

comprehensive engineering evaluation. (A-07-39)

Identify the systemic deficiencies in the maintenance program oversight 

procedures that led to this accident and modify those procedures to ensure 

that the maintenance program plans for commercial operators are adequate 

to ensure the continued airworthiness, both structural and otherwise, of the 

operator’s fleet. (A-07-40)

4.2 Previously Issued Recommendation Reiterated and 

Classified in This Report

The Safety Board reiterates the following recommendation to the Federal Aviation 

Administration:

Include the Continuing Analysis and Surveillance System guidance from 

Advisory Circular (AC) 120-16D, “Continuing Airworthiness Maintenance 

Programs,” and AC 120-79, “Developing and Implementing a Continuing 

Analysis [and] Surveillance System,” in Federal Aviation Administration 

Order 8300.10, Airworthiness Inspector’s Handbook. (A-04-14)

Further, Safety Recommendation A-04-14 (previously classified “Open—

Acceptable Response”) is classified “Open—Unacceptable Response” in section 2.4.2 of 

this report.
Recommendations 57 Aircraft Accident Report

4.3 Previously Issued Recommendation Resulting From 

This Accident Investigation

As a result of the investigation into this accident, the Safety Board issued the

following recommendation to the FAA on July 24, 2006:

Require records reviews, aging airplane inspections, and supplemental

inspections for all airplanes operated under 14 Code of Federal

Regulations (CFR) Part 121, all U.S.-registered airplanes operated

under 14 CFR Part 129, and all airplanes used in scheduled operations

under 14 CFR Part 135. This would include those airplanes operated under

14 CFR Part 135 that carry nine or fewer passengers and those that are

operated in scheduled cargo service. (A-06-52)

For more information about this recommendation, see sections 1.18.2.1 and 2.5 in

this report.

Member Hersman filed the following concurring statement on June 6, 2007, joined

by Vice Chairman Sumwalt and Member Higgins. Member Higgins filed the following

statement on June 6, 2007, and was joined by Member Hersman.

BY THE NATIONAL TRANSPORTATION SAFETY BOARD

MARK V. ROSENKER

Chairman

ROBERT L. SUMWALT

Vice Chairman

DEBORAH A. P. HERSMAN

Member

KATHRYN O. HIGGINS

Member

STEVEN R. CHEALANDER

Member

Adopted: May 30, 2007
58 Aircraft Accident Report

Board Member Statements
Board Member Statements 59 Aircraft Accident Report
Board Member Statements 60 Aircraft Accident Report
Board Member Statements 61 Aircraft Accident Report

63 Aircraft Accident Report

5. Appendixes

Appendix A

Investigation and Hearing

Investigation

The National Transportation Safety Board was initially notified of this accident 

during the afternoon of December 19, 2005. A go-team was assembled, which departed 

for Miami about 1900 and arrived on scene about 2200. Accompanying the team to Miami 

was Acting Chairman Mark Rosenker.1

The following investigative teams were formed: Aircraft Operations, Human 

Performance, Aircraft Structures, Aircraft Systems, Powerplants, and Maintenance 

Records. While the investigative team was in Miami, a specialist was assigned to 

transcribe the cockpit voice recorder at the Safety Board’s laboratory in Washington, D.C. 

Also, specialists in the areas of survival factors and witnesses, video/imaging, and 

materials assisted in the investigation.

Parties to the investigation were the Federal Aviation Administration, Chalk’s 

Ocean Airways, Frakes Aviation, Grumman Mallard Owners Association, and Hartzell 

Propellers. In accordance with the provisions of Annex 13, paragraph 5.18, to the 

Convention on International Civil Aviation, the Transportation Safety Board of Canada 

participated in the investigation as the representative of the State of Design and 

Manufacture of the powerplants. Accordingly, Pratt & Whitney Canada participated in the 

investigation as a technical advisor to the Transportation Safety Board of Canada. In 

accordance with the provisions of Annex 13, paragraph 5.27, to the Convention on 

International Civil Aviation, the Bahamas Ministry of Transport participated in the 

investigation as the representative of the State with special interest in the accident by 

virtue of fatalities to its citizens.

Public Hearing

No public hearing was held for this accident.

1 Mark Rosenker served as acting chairman from March 2005 until August 11, 2006, when he was 

sworn in as the 11th chairman of the National Transportation Safety Board.