Investigation Summary
The accident occurred during a routine 'bus service' flight for Amoco gas workers. The commander, Captain Ben Breach, was highly experienced and regarded as one of the most proficient Wessex pilots in the industry. Despite this expertise, the aircraft descended rapidly from approximately 1,500 feet following the distress call. The investigation faced significant hurdles when the wreckage could not be recovered from the seabed in a timely manner, leading to its eventual loss. Without the physical evidence of the engines, drive shafts, or flight controls, the Accident Investigation Branch (AIB) could not definitively confirm the mechanical sequence that led to the crash. Theories considered during the inquiry included a drive-shaft failure between the engines and the main gearbox, or a potential misjudgment during an auto-rotation maneuver, possibly exacerbated by visibility conditions. However, none of these could be proven, leading to an open verdict at the inquest.
Final Conclusions
The investigation by the Accident Investigation Branch (AIB) concluded that there was insufficient evidence to explain the loss of power or the loss of control. The final report (4/1983) was unable to determine a definitive cause due to the lack of recovered wreckage. Following the accident, Bristow Helicopters withdrew the Westland Wessex 60 type from service.
Video Analysis
No video analysis linked for this case file yet.
Systems & Failure Modes
Twin-Engine Powerplant
The Wessex 60 was powered by two coupled turboshaft engines driving a single main rotor; the pilot reported a failure in this system prior to the crash.
Main Gearbox Drive Shaft
Investigators considered a failure in the drive shaft connecting the engines to the gearbox as a potential cause, though this could not be verified without the wreckage.
Interesting Facts
- 01The aircraft was previously used as a Westland Helicopters Company demonstrator before being purchased by Bristow in 1970.
- 02The 11 passengers were all workers for the Amoco gas company.
- 03The wreckage was never recovered for detailed forensic analysis.
- 04The inquest into the deaths recorded an open verdict due to the lack of evidence.
- 05A memorial to the 13 victims was unveiled at Great Yarmouth Minster on the 33rd anniversary in 2014.
- 06The aircraft's Manufacturer Serial Number (MSN) was WA/199.
Safety Actions & Advisories
Type Withdrawal
Bristow Helicopters withdrew the Westland Wessex 60 from its fleet following the accident.