WEEK 37
H2F brings you the ‘helicopter mayday of the week’ with a short accident report summary. I tell you what happened. You think more about why it happened. We all learn from it. Because that’s what accident reporting is for.
TITLE
Engine failure leads to fatal crash following water bucket entanglement.
WHAT?
A Bell 205 suffered an engine failure during an aerial firefighting flight with a bucket on the cargo hook. While autorotating towards a forced landing site, the suspended water bucket became entangled in trees, leading to loss of control and a fatal collision with terrain.
WHERE?
Alberta, Canada.
WHEN?
19 July 2023. Final report published 27 February 2025.
HOW?
After departing the firebase, the helicopter climbed to approximately 1,400 ft AGL and established level flight. While the pilot was communicating with the dispatcher, the it unexpectedly lost approximately 300 ft in height. The cause of this initial descent was not established, although it preceded a subsequent engine failure.
The pilot advised the dispatcher that he was returning to base because of an unspecified problem and commenced a 180° right turn, but the helicopter continued losing altitude before suffering a complete loss of engine power. The pilot then entered autorotation. At approximately 500 ft age, he made a final, largely unintelligible radio transmission.
During the descent, the water bucket contacted trees and became entangled. The resulting snagging provoked a loss of control. Investigators concluded that the pilot’s attempts to arrest the descent led to a loss of rotor RPM.
The pilot only successfully operated the manual cargo release after the bucket had become entangled. The helicopter subsequently struck the ground nose-down.
CONDITIONS?
The flight was conducted in daylight under VFR. Weather was not considered a factor. The helicopter was configured for single-pilot, left-seat external-load operations. Its weight and centre of gravity were within limits, and the pilot was appropriately qualified and current.
OUTCOME?
The helicopter was substantially damaged. The pilot survived the initial impact and escaped the wreckage but subsequently died from his injuries. There was no post-impact fire.
WHY?
A manufacturing defect in a brazed joint securing the engine air diffuser’s No. 2 bearing support cone produced progressive deterioration in engine performance and eventual engine failure.
During autorotation, the suspended bucket became entangled in trees, preventing a successful forced landing.
The investigation also identified the following human-factors:
Pilots had normalised the selection of the electric cargo-release switch OFF to prevent inadvertent load release. However, this meant that emergency jettison required re-arming a switch on the overhead panel, delaying the release and necessitating a momentarily relinquishing of the primary flight controls. The alternative manual release required removing a foot from an anti-torque pedal. Both arrangements introduced additional demands during an already high-workload emergency. Investigators could not determine why the pilot delayed jettisoning the load.
The electrical release was found OFF, but the pilot ultimately operated the manual release successfully. Following the accident, the operator instructed crews to arm the electrical cargo release during external-load operations and verify both release systems before the first flight.
Furthermore, differences between Bell 205 and Bell 212 cargo-release procedures created a risk negative transfer – applying a familiar procedure to the wrong aircraft type. The accident pilot was qualified on both.
Canadian regulations did not specifically require pilots to practise conventional emergencies, such as engine failure, while carrying external loads. Investigators found that pilots at two comparable operators had rarely practised manual load release in flight, let alone during autorotation.
REFERENCE?
Transportation Safety Board of Canada. (2025). Engine power loss and collision with terrain: Valhalla Helicopters Inc., Bell 205A-1, C-GRUV, Alberta, 19 July 2023 (Air Transportation Safety Investigation Report A23W0082).
Note:
Accident reports selected from the following open source databases: US NTSB; UK AAIB; Flight Safety Foundation’s Aviation Safety Network; Australia’s ATSB. Ireland’s AAIU; Taiwan’s TTSB; France’s BEA; Spain’s CIAIAC. Germany’s BFU.
