What happened
On 13 June 2016, a Robinson R44 Astro, registration G-BZGO, was conducting a training flight near Manchester Barton Airport. The aircraft was cruising at approximately 1,500 ft with a speed of 90 kt, carrying a commander and a trainee pilot. During the flight, the helicopter struck a bird, which caused the left windscreen to shatter and allowed the animal to enter the cockpit.
Following the impact, the helicopter experienced an altitude loss of roughly 700 ft while the crew managed the situation. The pilot in the right seat took control of the aircraft. The crew declared a MAYDAY and successfully returned to Barton Airport for a landing. There were no injuries to the two crew members.
The investigation
The investigation established that the bird, which was estimated to weigh about 0.6 kg and appeared to be a Herring Gull, entered the cockpit with its wings unfolded. The investigation examined the certification standards for the aircraft, noting that the Robinson R44 was certified under FAA Part 27 regulations.
Under these specific regulations, there are no mandates for the aircraft to withstand bird strikes, though there is a requirement that windows must not break into dangerous fragments. The investigation noted that the windscreen was not designed to resist such impacts. The AAIB also reviewed the regulatory landscape, noting that the FAA and EASA are currently reviewing birdstrike protection requirements for Normal category rotorcraft.
Findings
- The primary cause of the incident was a bird strike that resulted in the penetration of the cockpit windscreen.
- The aircraft's certification standards (FAR Part 27) do not require the windscreen to withstand bird impacts.
- The impact caused a significant loss of altitude during the emergency procedure.