Recommendation R20020051

Recommendation issued to: Federal Aviation Administration (FAA)

Recommendation details
Output No: R20020051
Date issued: 11 July 2002
Safety action status:
Background: Why this Recommendation was developed

Output text

Safety Recommendation

The Australian Transport Safety Bureau recommends that the US Federal Aviation Administration review the adequacy of requirements covering protection of the engine fire detector loom wires in engine compartments.

Initial response
Date issued: 22 May 2003
Response from: Federal Aviation Administration (FAA)
Action status: Closed - Accepted
Response text:

The ATSB received the following response from the FAA, dated 9 May 2003.

The FAA has reviewed the incident report and the recommendation and does not agree that the regulations covering the fire detection system need to be amended. In the incident, sited by the ATSB, the detection system indicated a malfunction in the engine compartment and subsequent action by the flight crew to shut the engine down was appropriate.

The regulations applicable to fire detection systems result in robust designs that provide redundant fire loops within the fire zone and indication logic that is biased such that damage to the wiring and fire loops will result in indication of a fire. Current technology fire detection systems do not always have enough fidelity to differentiate between a duct leak, localized fire, wiring damage, or an engine case burn through. For example, engine case burn through can cut wiring and detector loops rapidly before the fire loop would be activated due to heating. It is imperative that the engine is shutdown if this failure occurs. The FAA agrees that it is not desirable to provide misleading information to the flight crew and in the incident noted in this recommendation the flight crew discharged both fire bottles into the fire zone when there was no fire. However, the flight crew actions resulted in safe shutdown of an engine with a high pressure duct leak.

Amendment of the existing regulations to provide protection of the fire detector system wiring would likely result in the introduction of protective heat shields. This feature would not appreciably improve safety and maintenance errors on the engine could significantly be impacted by these devices, reducing the overall level of safety.

After careful consideration of the recommendation, the FAA has concluded that amendment of the regulations affecting fire detector systems is not appropriate.

Last update 03 April 2012