Language selection

Air transportation safety recommendation A03-05

Reassessment of the responses from Tranport Canada to Aviation Safety Recommendation A03-05

Circuit breaker reset philosophy

 Recommendation A03-05 in PDF [100 KB]


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.

Board Recommendation A03-05 (27 March 2003)

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

Response to A03-05 (29 October 2003)

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

Board Assessment of the Response to A03-05 (29 October 2003)

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.

Response to A03-05 (14 December 2005)

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

Board Reassessment of the Response to A03-05 (23 June 2006)

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.

Next TSB action

As the safety deficiency associated with Recommendation A03-05 is considered rectified, no further action is necessary.

This deficiency file is assigned an Closed status.