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TSB Recommendation A03-05

Circuit breaker reset philosophy

Regulatory authorities establish the requirements and industry standard for circuit breaker resetting.

Air transportation safety investigation report A98H0003
Date the recommendation was issued 27 March 2003
Date of the latest response June 2006
Date of the latest assessment December 2005
Rating of the latest response Fully Satisfactory
File status Closed

All responses are those of the stakeholders to the TSB in written communications and are reproduced in full. The TSB corrects typographical errors in the material it reproduces without indication but uses brackets [ ] to show other changes or to show that part of the response was omitted because it was not pertinent.

Summary of the occurrence

On 02 September 1998, Swissair Flight 111, a McDonnell Douglas MD-11 aircraft, departed John F. Kennedy Airport in New York, New York, en route to Geneva, Switzerland. Approximately one hour after take-off, the crew diverted the flight to Halifax, Nova Scotia, because of smoke in the cockpit. While the aircraft was manoeuvring in preparation for landing in Halifax, it struck the water near Peggy's Cove, Nova Scotia, fatally injuring all 229 occupants on board. The investigation revealed that the flight crew had lost control of the aircraft as a result of a fire in the aircraft's ceiling area, forward and aft of the cockpit bulkhead.

The Board concluded its investigation and released report A98H0003 on 27 March 2003.

Rationale for the recommendation

TSB's investigation revealed several disparities in the policies and their interpretation regarding circuit breaker reset practices. The TSB believes that, despite initiatives by regulatory authorities to raise awareness, if the existing regulatory environment is not amended to reflect the acceptable circuit breaker reset philosophy, such "best practices" will not be universally applied across the aviation industry and ultimately, the positive changes currently established may not be maintained. Therefore, the TSB recommended that:

Regulatory authorities establish the requirements and industry standard for circuit breaker resetting.
Transportation Safety Recommendation A03-05

Previous responses and assessments

October 2003: Response to A03-05

In response to Recommendation A03-05, Transport Canada (TC) provided the following comments:

  • TC states that it concurs with Recommendation A03-05.
  • TC has requested that the FAA's Transport Airplane and Engine Issues Group (TAEIG) establish the standards for circuit breaker resetting for use by regulatory authorities.
  • TC states that it has adopted the FAA's guidance material regarding circuit breaker resets.
  • By January 2004, TC intends to perform a review of aircraft flight manuals and flight crew operating manuals for those aircraft for which TC is prime authority to ensure that adopted guidance material is included.
  • TC intends to issue advisory material to all operators by the end of September 2003.
  • TC will publish an article in the Aviation Safety Maintainer concerning the resetting of circuit breakers.

October 2003: Board Assessment of the Response to A03-05

TC's response lists a variety of proposed activities, which will raise awareness amongst operators, pilots, and maintainers regarding the appropriate circuit breaker reset procedures. Additionally, a recommendation from the FAA's TAEIG, if adopted, should establish the requirements and industry standards needed to mitigate the risks in the long term. Consequently, the response is assessed as Satisfactory Intent.

Latest response and assessment

December 2005: Response to A03-05

TC advised that it has developed Policy Letter 161, which was issued March 2004 entitled Resetting Tripped Circuit Breakers.

June 2006: Board Reassessment of the Response to A03-05

TC's letter of 14 December 2005 states that it has issued Policy Letter 161 entitled Resetting Tripped Circuit Breakers. This initiative directs that all air operators shall develop training programs intended for crew members, maintenance personnel, and ground servicing personnel that clearly state company policies and procedures with regard to resetting tripped circuit breakers. This action taken will substantially reduce or eliminate the safety deficiency as described in Recommendation A03-05.

Therefore, the assessment is now assigned Fully Satisfactory.

File status

The TSB will monitor TC’s progress on its planned actions.

This deficiency file is Closed.