Investigation Summary
The accident was caused by a mechanical failure in the tail rotor control system. Specifically, a duplex bearing in the tail rotor assembly seized, which allowed the tail rotor's rotation to be transmitted to the normally stationary actuator control shaft. This unintended rotation caused the shaft to spin against the actuator lever mechanism. The resulting friction caused a castellated nut to weld to its carrier, shear its split pin, and unscrew itself from the shaft. Once the nut detached, the control linkage became disconnected, meaning the pilot's pedal inputs could no longer reach the tail rotor blades to control the aircraft's yaw. The helicopter immediately entered a rapid rotation that the pilot could not counteract. The investigation also highlighted that the bearing had reached a state of 'thermal distress' due to a buildup of ceramic and metallic particles, which led to the seizure.
Final Conclusions
The AAIB published its final report on 6 September 2023, concluding that the crash resulted from a failure of the tail rotor actuator control shaft bearing. The seizure of this bearing led to the disconnection of the tail rotor control linkage, resulting in an unrecoverable loss of yaw control. The report noted that the manufacturer's design and testing processes did not fully account for the specific failure mode of the bearing. The inquest into the deaths concluded in January 2025 with a verdict of accidental death for all five victims.
Photographic Evidence (1)
Video Analysis
No video analysis linked for this case file yet.
Systems & Failure Modes
Tail Rotor Actuator Control Shaft
A component that transmits pilot pedal inputs to the tail rotor blades to adjust pitch and control yaw. In this accident, it became disconnected after a bearing seizure caused a locking nut to unscrew.
Duplex Bearing
A bearing designed to allow the tail rotor assembly to rotate while the control shaft remains stationary. Its seizure was the primary trigger for the mechanical failure chain.
Digital Flight Data Recorder (DFDR)
The device recorded the final moments of the flight, including the sudden onset of the yaw rate, despite sustaining severe fire damage.
Interesting Facts
- 01The crash occurred approximately 200 metres from the stadium in Car Park E.
- 02Four of the five occupants survived the initial impact but died in the subsequent fire.
- 03The pilot, Eric Swaffer, and his partner, Izabela Lechowicz (also a pilot), were among the fatalities.
- 04The helicopter reached a maximum height of approximately 430 feet before the spin began.
- 05Two police officers received Queen's Gallantry Medals for their attempts to rescue the occupants.
- 06Four people on the ground (police and stadium staff) were treated for minor injuries sustained during rescue attempts.
Safety Actions & Advisories
EASA Airworthiness Directives
Source ↗EASA published nine Airworthiness Directives for the continued airworthiness of the AW169 and AW189 helicopter types following findings during the investigation.
Manufacturer Service Bulletins
Source ↗Leonardo Helicopters issued sixteen Service Bulletins addressing the tail rotor system and bearing assembly for the AW169 and AW189 fleets.
AAIB Safety Recommendations
Source ↗The AAIB made eight Safety Recommendations to EASA to address weaknesses in Certification Specification 29, specifically regarding rolling contact fatigue in critical bearings and the validation of supplier design data.
Location
ACCIDENT SITE · Coordinates taken from the official investigation report.