TSB Swissair 111 Report Release and
Summary of Safety Recommendations
Transportation Safety Board of Canada / Bureau de la sécurité des transports du Canada
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TSB no A01/2003

Transportation Safety Board of Canada Releases Final
on Swissair 111, Accident Investigation
Report # A98H0003

Makes Nine Additional Safety Recommendations, Bringing Total to 23

(Halifax, Nova Scotia, 27 March 2003) – The Transportation Safety Board of Canada (TSB) today released its final report on the investigation of Swissair Flight 111 (SR 111), which crashed off the coast of Peggy's Cove, Nova Scotia, on 2 September 1998. All 229 people on board perished.

The report identifies the causes and contributing factors that played a major role in the occurrence, reviews the 14 Aviation Safety Recommendations that have already emerged from the TSB investigation and the impact those recommendations have already had on aviation safety, and makes nine additional Aviation Safety Recommendations.

The nine additional Aviation Safety Recommendations in the final report, include:

  • Two Aviation Safety Recommendations that deal with testing and flammability standards of in-service thermal acoustical insulation materials and one that deals with the application of existing standards for the certification of other materials.

     
  • Two Aviation Safety Recommendations that focus on aircraft electrical systems, including additional measures for certifying supplementary add-on systems and industry standards for circuit breaker resetting.

     
  • Four Aviation Safety Recommendations that propose improvements to the capture and storage of flight data as it relates to cockpit voice recorders, flight data recorders, and cockpit image recording systems.

"This has been the largest, most complex aviation safety investigation the TSB has ever undertaken, and required a significant investment of people, resources and time," said Camille Thériault, Chairman of the Transportation Safety Board. "The efforts of thousands of hardworking people from various countries, industries and regulatory authorities have culminated in a comprehensive report that has changed the face of aviation safety."

The report explains that, at a point along the flight route of SR 111, a failure event occurred that provided an ignition source to flammable materials in the aircraft. This set off an in-flight fire that spread and increased in intensity until it led to the loss of the aircraft and human life.

The SR 111 investigation involved prolonged wreckage recovery operations before technical issues could be addressed. Through detailed examination, reconstruction and analysis of recovered material, the TSB developed potential fire scenarios and identified how and when flammable materials were ignited and how the fire propagated.

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Causes and Contributing Factors

The report notes that the fire most likely started with an electrical arcing event involving one or more wires. The arcing event ignited the metallized polyethylene terephthalate (MPET) covering material on the thermal acoustical insulation blankets above the right rear cockpit ceiling of the McDonnell Douglas MD-11 aircraft.

A segment of the in-flight entertainment network (IFEN) wiring from that area exhibited a region where copper had resolidified, indicating an arcing event. TSB investigators believe that this arcing event on the entertainment system wire was associated with the initial arcing events. However, investigators could not pinpoint this as the lead event, as other wires from that immediate area could not be identified. The circuit breakers in the aircraft were not capable of protecting the wiring against the type of arcing event that occurred.

Aircraft certification standards for material flammability at the time of the SR 111 accident were inadequate, allowing materials to be used in aircraft construction and modification that could ignite, and sustain or propagate a fire. Once ignited, other types of thermal acoustical insulation material with similar flammability characteristics may have contributed to the propagation of the fire.

There were no smoke/fire detection and suppression devices in the area where the fire started, nor did regulations at the time require them. Therefore, the flight crew had very few resources, other than sight and smell, to detect and differentiate between the source of the odours and smoke. The delay in identifying the existence and source of a fire allowed the fire to propagate until it became uncontrollable.

An integrated firefighting plan was not required by regulation. As a result, the flight crew did not have appropriate tools, procedures, or training to locate and eliminate the source of the smoke in a hidden area. For some considerable time, they were not aware of the existence of the fire, or for the need to prepare rapidly for an emergency landing.

In this occurrence, the failure of silicone elastomeric end caps on air conditioning ducts resulted in a continuous supply of conditioned air initially into the space above the forward cabin and then above the cockpit ceiling area. These failures and the flammability of some other materials contributed to the rapid propagation and intensity of the fire.

As conditions deteriorated in the cockpit, the flight crew lost the use of primary flight displays and outside visual references. The heat, smoke and fumes inside the cockpit made it increasingly difficult for pilots to maintain the proper spatial orientation of the aircraft, resulting in a collision with water.

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Safety Issues

"We have already seen profound results stemming from this investigation. That is because we acted immediately to inform the aviation community about safety deficiencies as soon as they were identified," said Mr. Thériault. "Our focus is—and always has been—to put our key findings to use as soon as they become known to us, to improve aviation safety."

The TSB's comprehensive approach to the investigation enabled it to identify important safety deficiencies related to a wide range of issues. These have been addressed in a series of Aviation Safety Recommendations (ASRs), Aviation Safety Advisories (ASAs), and Aviation Safety Information Letters (ASILs), which have been issued by the Board since the start of the investigation.

  • In December 1998, an Aviation Safety Advisory, regarding wiring issues, was sent to the U.S. National Transportation Safety Board (NTSB). The NTSB then made a recommendation to the Federal Aviation Administration (FAA) requiring an inspection of all MD-11 aircraft for wiring discrepancies.

     
  • In March 1999, four Aviation Safety Recommendations were issued regarding flight recorder duration and electrical power supply.

     
  • In August 1999, two Aviation Safety Recommendations were issued regarding thermal acoustical insulation materials and flammability test criteria.

     
  • In March 2000 and December 2000, an Aviation Safety Advisory and an Aviation Safety Information Letter, respectively, were issued regarding concerns about deficiencies in the design and installation of flight crew reading lights.

     
  • In December 2000, five Aviation Safety Recommendations were issued regarding regulatory standards for in-flight firefighting.

     
  • In August 2001, an Aviation Safety Advisory was issued regarding air traffic controller training with respect to emergency procedures.

     
  • In August 2001, three Aviation Safety Recommendations were issued regarding deficiencies in aircraft materials flammability standards, including one dealing with the testing of wire failure characteristics.

     
  • In September 2001, an Aviation Safety Advisory was issued concerning the need to review the regulatory requirements for standby (secondary) instruments.

Action has been taken by various regulatory authorities and others to address the recommendations, advisories and observations made by the TSB during the course of this investigation, significantly improving aviation safety worldwide. Several of these recommendations have already been adopted by regulatory authorities, airlines and aircraft manufacturers. For example, flight crew reading lights have been re-designed; the IFEN system was removed voluntarily from Swissair aircraft, and subsequently that design was de-certified.

New FAA policies are in place for the certification of such entertainment systems. The MPET insulation used on thermal acoustical insulation blankets was ordered removed from aircraft.

Flammability standards for materials used in aircraft are being upgraded. In-flight firefighting procedures have been subjected to intense review. Other safety measures stemming from TSB recommendations are currently being implemented.

The TSB also identified in the final report some safety concerns that require additional follow-up. The TSB will continue to work with regulatory authorities and the aviation industry to help ensure that the recommended safety improvements are carried out as effectively as possible.

The accident victims' families were briefed earlier today about the content of the SR 111 report. In the coming weeks, representatives from the TSB, including investigators and Mr. Thériault, will travel to cities in the United States and Europe for in-person meetings with those families wishing to attend.

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Accident Summary

On 2 September 1998, SR 111 departed John F. Kennedy Airport, New York, with 215 passengers and 14 crew members on board on a scheduled flight for Geneva, Switzerland. Less than an hour after departure, the flight crew noted an abnormal odour in the cockpit and assessed that smoke was present. They decided to divert, ultimately selecting Halifax International Airport as their destination. About 13 minutes after the flight crew detected an unusual odour in the cockpit, SR 111 experienced a rapid succession of aircraft system failures. The flight crew declared an emergency and indicated the need to land immediately. About one minute later, radio communications and secondary radar contact with the aircraft were lost, and the flight recorders stopped functioning. About five and one-half minutes later, the aircraft crashed into the ocean southwest of Peggy's Cove, Nova Scotia. The aircraft was destroyed and there were no survivors.

The Transportation Safety Board of Canada is an independent agency, operating under its own Act of Parliament. Its sole aim is the advancement of transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.

- 30 -

For additional information, see the following documents:

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Summary of Safety Action Taken in Response to TSB SR 111 Investigation Safety Communications

Legend

                   
No. Released Type
(TSB file number)
Title
(A98H0003 Section 4.1 reference)
NTSB TC FAA Boeing Swissair Additional
1 22-Dec-98 Aviation Safety
Advisory
(980031-1)
MD-11 Wiring
(4.1.1)
issued recommendation to FAA nil 1. issued numerous ADs as part of Wiring Corrective Action Plan

2. established Enhanced Airworthiness Program for Airplane Systems (EAPAS)

3. enhanced its .Aircraft Wiring Practices. interactive training

4. produced an Internet-based training aid entitled, "Aircraft Wiring Practices (Job Aid)"

1. generated wire related service bulletins

2. developed improved wire inspection and practices training course

3. revised Standard Wire Practices Manual

1. conducted wiring related inspections on MD-11 fleet

2. conducted special inspection of MD-11 avionics compartment

3. developed new wire maintenance (best practices) concept and training program

Swiss FOCA reviewed and reissued FAA ADs as Swiss Ads

Swiss AAIB concurs with TSB Advisory Letter

                   
2 09-Mar-99 Aviation Safety
Recommendations
(A99-01 thru A99-04)
Flight Recorder Duration
and Power Supply (4.1.2)
issued similar recommendations to FAA 1. harmonize regulations with FAA/JAA

2. FAA NPRMs to be tabled at CARAC

3. Issued NPA

drafting NPRMs in line with NTSB recs published SB to power MD-11 recorders on separate buses intends to comply with recorder SB Swiss AAIB concurs with TSB recommendations
                   
3 11-Aug-99 Aviation Safety
Recommendations
(A99-07 & A99-08)
Thermal Acoustic Insulation
Materials
(4.1.3)
concur with TSB recommendations 1. harmonize regulations with FAA/JAA

2. surveyed Canadian registered aircraft

1. issued two NPRMs

2. issued ADs requiring MPET removal

3. issued NPRM regarding new flammability test criteria for thermal acoustic insulation material

providing engineering support to operators for AD compliance 1. Immediately removed MPET insulation blankets from selected areas in Swissair MD-11s

2. started full replacement of MPET in Nov 2000 in compliance with FAA AD

Swiss FOCA reviewed and reissued FAA AD as Swiss AD

Swiss AAIB concurs with TSB recommendations

                   
4 03-Mar-00 Aviation Safety
Advisory
(A000008-1)
MD-11 Flight Crew Reading
Light (Map Light)
(4.1.4)
forwarded TSB letter to FAA for action nil Issued ADs to incorporate Boeing ASB 1. Issued ASB detailing map light recurrent inspections

2. Coordinated maplight redesign with Hella Aerospace resulting in maplight SB

complied with FAA ADs Swiss FOCA reviewed and reissued FAA ADs as Swiss Ads

FCRL manufacturer (Hella Aerospace) redesigned FCRL and issued SB

Swiss AAIB concurs with TSB Advisory Letter

                   
5 04-Dec-00 Aviation Safety
Recommendations
(A00-16 thru A00-20)
In-Flight Firefighting
(4.1.5)
concur with TSB recommendations concur with TSB recs, working to harmonize regulations with FAA/JAA 1. concurs with recommendations: reviewing existing programs

2. intends to harmonize changes with TC/JAA

Conducted in-depth review of existing designs and in-flight firefighting procedures instituted "MD-11 Modification Plus" program which improved in-flight firefighting checklists, procedures, training, incorporated improved detection and suppression systems, replaced some materials with more heat tolerant materials UK CAA taking active measures

Swiss AAIB concurs with TSB recommendations

UK AAIB concurs with TSB recommendations

                   
6 29-Dec-00 Aviation Safety
Information Letter
(A000061-1)
Flight Crew Reading Light
(4.1.4)
agreed with the TSB, encouraged the FAA to take appropriate action nil issued AD mandating recurring inspections which will remain in force until the unsafe condition has been eliminated in cooperation with Hella Aerospace, a redesigned maplight has been developed to address the unsafe condition raised in the FAA's AD incorporated Hella's SB which improves the maplight's short-circuit protection Swiss FOCA reviewed and reissued FAA AD as a Swiss AD

Hella Aerospace, the maplight manufacturer, worked with Boeing on maplight redesign

                   
7 29-Dec-00 Aviation Safety
Information Letters
(A000062-1, -2)
MD-11 Overhead Aisle and
Emergency Lights
(4.1.6)
nil nil reviewed MD-11 Overhead Aisle and Emergency Lights installation and determined that no unsafe condition existed Boeing determined that the fixture met existing certification standards nil  
                   
8

 

01-Aug-01 Aviation Safety
Advisory
(A010020-1)
Air Traffic Controller Training
(4.1.11)

 

nil

 

Liaised with ATS service providers to ensure TSB's concerns are addressed nil nil nil Nav Canada has revised Air Traffic Controller training and amended its Air Traffic Control Manual of Operations accordingly
No. Released Type
(TSB file number)
Title
(A98H0003 Section 4.1 reference)
NTSB TC FAA Boeing Swissair Additional
9 28-Aug-01

Aviation Safety
Recommendations
(A01-02 thru A01-04)

Material Flammability Standards
(4.1.10)

 

concur with TSB recommendations concur with TSB recs, working to harmonize regulations with FAA/JAA 1. FAA is confident that previously announced initiatives (e.g. Improved Flammability Requirements for Thermal/Acoustic Insulation) will address the deficiencies raised in TSB recommendations A01-02 and A01-03.

2. FAA believes that current regulations coupled with existing programs such as the Arc-Fault Circuit Breaker initiatives will address the deficiency raised in TSB's A01-04 recommendation.

Boeing issued SB to inform MD-11 operators of an FAA-approved modification procedure that uses steel vice aluminum components in the crew oxygen system as a fire-hardening measure.

 

incorporated SB replacing aluminium components as part of its .MD-11 Modification Plus. program  

 

                   
10 28-Sep-01 Aviation Safety
Advisory
(A010042-1, -2)
Standby Instrumentation
(4.1.9)

 

nil

 

nil will address TSB's emergency instrumentation issues at its Aviation Rulemaking Advisory Committee reviewed their current standby instrumentation equipment to identify any areas that could be optimized As part of its .MD-11 Modification Plus. program, installed a secondary flight display system with a layout similar to the primary flight display in the MD-11 aircraft which also incorporates an auxiliary battery  
                   
11

 

N/A N/A In-Flight Entertainment/
Supplemental Type Certificate
(4.1.7)
nil

 

 

nil conducted an SCR of STC ST00236LA-D resulting in the withdrawal of its IFEN certification. Additionally, the FAA has acted to enhance its STC process. conducted a design review of its installations to confirm that no unsafe conditions existed. disabled then removed the IFEN systems in both its MD-11 and Boeing 747 fleets FOCA cancelled validations of the IFEN STCs
            sections.      
12

 

 

N/A N/A Circuit Breaker Reset Philosophy
(4.1.8)
nil

 

published an article in the its Aviation Safety Letter

 

 

 

 

 

 

 

 

issued a Joint Flight Standards Information Bulletin which summarizes the FAA.s position on the issue of resetting tripped CBs states that no CB reset is allowed in-flight except under emergency conditions as duly authorized by the pilot-in-command. Additionally, it stipulates that no CB resets associated with fuel pump circuits were to be carried out under any circumstances. 1. Issued an AOM Bulletin regarding a revision to CB reset procedures

2. after a review of its CB reset policy, Swissair's maintenance provider revisited the subject as part of continuation training for its technician

Airbus issued a CB reset policy which only allows a CB reset in flight under emergency conditions when authorized by the pilot-in-command.
                   


 

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Legend
AD   Airworthiness Directive
AOM Aircraft Operations Manual
ASB Alert Service Bulletin
Boeing The Boeing Company
CARAC Canadian Aviation Regulation Advisory Council
CB circuit breaker
FAA United States Federal Aviation Administration
FCRL Flight Crew Reading Light
FOCA Swiss Federal Office for Civil Aviation
Hella Hella Aerospace GmbH
JAA Joint Aviation Authorities
MPET metallized polyethylene terephthalate
NPA Notice of Proposed Amendment
NPRM Notice of Proposed Rulemaking
NTSB United States National transportation Safety Board
SB service bulletin
SCR Special Certification Review
Swissair Swiss Air Transport Company Limited
Swiss AAIB Swiss Aircraft Accident Investigation Bureau
TC Transport Canada
TSB Transportation Safety Board of Canada
UK AAIB United Kingdom Air Accidents Investigation Branch

UK CAA

United Kingdom Civil Aviation Authority

from this link

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