Communiqués - SR 111 Investigation
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
- 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
- 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.
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.
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
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
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.
"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
- 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
- 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
- In September 2001, an Aviation Safety Advisory was issued
concerning the need to review the regulatory requirements for standby
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
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.
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: