A93W0204-Marine Power Loss/Loss of Control-Northwest Territories-03 December 1993
Safety Action Taken
(as presented in the TSB Report)
In March 1994, the TSB forwarded an Aviation Safety Advisory to TC regarding magneto inspection and maintenance requirements. In response, TC sent a letter to the FAA querying whether AD 78-09-07 R3 would be amended to include the more stringent periodic inspection requirement of SB 599D. There has been no reply to date. This matter was also featured in TC's Aviation Safety Maintainer newsletter, issues 3/94 and 1/95.
Mandatory Service Bulletin MS645
On 04 April 1994, Teledyne Continental issued Mandatory Service Bulletin MSB 645, which superseded SB599D. The reason for the bulletin was to decrease operational wear rates on impulse couplings and to prevent engine stoppage. The bulletin requires 100-hour inspections of riveted impulse couplings. Couplings which do not meet the detailed coupling inspection criteria are to be replaced with new snap ring assemblies.
Regulatory Audits and Surveillance
Analysis and information from this and 18 other accidents led to the identification of shortcomings in the regulatory overview process of air carriers. In particular, it was found that TC's audits sometimes lacked depth, and that the verification of corrective action following the audits was sometimes inadequate. Therefore, the Board recommended that:
The Department of Transport amend the Manual of Regulatory Audits (MRA) to provide for more in-depth audits of those air carriers demonstrating an adverse trend in its risk management indicators; (A94-23, issued December 1994)
The Department of Transport ensure that its inspectors involved in the audit process are able to apply risk management methods in identifying carriers warranting increased audit attention; (A94-24, issued December 1994)
The Department of Transport develop, as a priority, a system to track audit follow-up actions; and (A94-25, issued December 1994)
The Department of Transport implement both short and long term actions to place greater emphasis on verification of required audit follow-up action and on enforcement action in cases of non-compliance. (A94-26, issued December 1994)
In response to these recommendations, TC has indicated that both recommendations A94-23 and A94-24 will be taken into consideration during amendments to the MRA. Also, TC will ensure that the Audit Procedures training program for inspectors takes into account recommendation A94-24 so that risk management methods are clearly understood and applied.
TC's reply to recommendations A94-25 and A94-26 indicates that the MRA will be reviewed to ensure that clear policy direction is given to ensure that effective audit follow-up systems are in place. Furthermore, TC intends to have an enhanced National Aviation Company Information System (NACIS) operational soon to track audit follow-up on a national basis. In the interim, a policy directive will be issued to regions to require a review of respective regional follow-up systems.
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