CH146497 Griffon - Epilogue

Report / August 5, 2015 / Project number: CH146485 - E Category

Location: 1 nautical mile south east of the Bell Helicopter facility at Mirabel Airport
Date: 2015-08-05
Status: Investigation Complete

The mission consisted of bringing a CH146 Griffon helicopter from 438 Tactical Helicopter Squadron in Saint-Hubert (CYHU) to the Bell Textron facility located at the Mirabel airport (CYMX) in order to conduct armoured seat fitment trials. The departure was planned for the morning of 5 August 2015. The crew prepared for the mission the day prior, with a confirmatory brief the morning of the mission prior to departure. The weather was better in Saint-Hubert than Mirabel, with the latter being marginal and the crew flew according to Special Visual Flight Rules (SVFR) in the Control Zone. Enroute to their destination, the crew purposefully flew over a known set of high tension power lines that was marked on the Montreal VFR Terminal Area Chart (VTA) and then unexpectedly came across a second set of high tension power lines that was not marked on the map. The crew flew in the 39 foot gap between the top grounding wire and a lower set of wires. There was no contact with the wires and a post occurrence inspection confirmed that there was no damage caused to the aircraft. There were no injuries. Due to the potential for severe damage and injuries, the safety of flight compromise level was assessed as high.

The investigation concluded that there was a breach of orders while the crew was flying in deteriorating weather and that there was likely some confusion amongst the crew with regards to the practical application of Special VFR. The investigation brought to light deficiencies in the CH146 Radalt setting procedures. It was also concluded that there is likely a cultural mentality within the RCAF helicopter communities, particularly within the Griffon community, that reinforces and normalizes the behavior of pushing the weather (flying below minimums) to avoid poor weather in order to accomplish a mission.

The preventive measures include recommendations to improve the current radar altimeter procedures to facilitate crew decision making as well as better Human Performance in Military Aviation (HPMA) training. There are also recommendations to liaise with Transport Canada and Nav Canada in order to document the presence of the second set of high tension power lines.

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