CH12428 Sea King - Epilogue

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Report / May 11, 2015 / Project number: CH12428 - D Category

Location: Strait of Juan de Fuca, South of Victoria, British Columbia
Date: 11 May 2015
Status: Investigation Complete

The CH124 Sea King was operating from 443 Squadron, in Pat Bay, BC, with a crew of four.  The crew, consisting of an Aircraft Captain (AC), Maintenance Test Pilot (MTP) Trainee, Air Combat Systems Officer and an Airborne Electronic Sensor Operator, were conducting an MTP training sortie.  The crew flew from Pat Bay to Canadian Military Advisory Area 102, south of Victoria, BC, over the Strait of Juan de Fuca while conducting MTP Training.

During the conduct of the number one engine manual throttle topping check, the MTP Trainee inadvertently bumped the manual throttle slightly forward and had to re-establish hand position on the manual throttle lever. The investigation determined that the AC misinterpreted the motion of the MTP Trainee gaining a better grip on the manual throttle control lever as the MTP Trainee closing the manual throttle.  This perception error led to a cascade of subsequent events, which began with the act of lowering the collective and resulted in engine failure. 

Fatigue was identified as a significant contributing factor leading to the perception error.  The Royal Canadian Air Force (RCAF) is currently in the process of implementing a Fatigue Risk Management System (FRMS), which will be a multi-layered approach to preventing fatigue and managing fatigue-related risk.  Full implementation of the RCAF FRMS is anticipated for mid-2017. Fatigue-modelling capability and FRMS are being developed as components of the RCAF Mission Acceptance / Launch Authorization (MALA) risk management tool.

Although not directly causal to this occurrence, collateral findings and recommendations were also made regarding Aircraft Operating Instruction procedures and cautions for operating the manual throttle.

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