What happened
On 25 November 2018, a Bell 429 helicopter, registration M-YMCM, was performing a private flight from Blackpool to Edinburgh. While on short final approach to Edinburgh Airport at a speed of approximately 100 kt, the pilot observed several birds to the left of the aircraft. Although the initial group of birds did not appear to be a threat, a single bird crossed the flight path from right to left directly in front of the aircraft. The pilot attempted an immediate right bank to avoid the collision, but the bird struck the left windscreen.
The impact caused the windscreen to shatter, sending debris into the cockpit. The passenger seated in the left seat sustained one minor injury to their face and hands and required hospital treatment. The pilot declared a MAYDAY and successfully landed the aircraft.
The investigation
Investigators examined the wreckage and found that the left windscreen had shattered, with acrylic fragments distributed throughout the passenger area and cockpit. The bird, identified as a wood pigeon weighing roughly 640g, was found inside the cabin following the impact.
The investigation looked into the certification standards for the aircraft type. It was established that the Bell 429 is certified under the Canadian Airworthiness Manual Chapter 527, which governs Normal category rotorcraft. Unlike Transport category specifications, these requirements do not mandate bird strike resistance, only that windows must not break into dangerous fragments. While the aircraft was equipped with stretched acrylic windscreens intended to provide more protection than standard versions, they were not designed to withstand such impacts.
Findings
- The primary cause of the incident was a bird strike to the left windscreen during the approach phase.
- The aircraft's certification requirements for the Normal category do not include a specific bird strike resistance standard.
- The impact of the 640g wood pigeon at 100 kt was sufficient to shatter the acrylic windscreen and disperse debris into the cabin.