What happened
On 22 April 2021, an AgustaWestland AW10XYSP, registration G-TAAS, was performing a commercial passenger flight while returning from a HEMS mission. As the aircraft was descending through approximately 1,000 ft agl at 140 kt, turning toward East Midlands Airport, a bird—later identified as a crow weighing 1.32 kg—struck the left windshield.
Upon impact, the acrylic windshield shattered, allowing the bird to enter the cockpit. The bird struck the technical crew member on the left side of their helmet before becoming lodged behind the pilot's seat. The impact also sent debris into the main rotor disk, resulting in a hole in the trailing edge of one rotor blade. The pilot immediately notified air traffic control and performed a precautionary landing at East Midlands Airport. There were no injuries to the crew or the passenger on board.
The investigation
The AAIB examined the damage to the aircraft and the regulatory framework governing its certification. The investigation confirmed that the left windshield, constructed of acrylic, had broken into multiple fragments that dispersed throughout the cockpit and passenger cabin. The investigators also noted that the aircraft was certified under EASA CS-27 (Small Rotorcraft) regulations.
Under these specific CS-27 standards, windshields are required to be made of materials that do not break into dangerous fragments, but there is no mandate for the windshield to withstand bird strikes. This differs from the CS-29 standards used for larger rotorcraft, which require the ability to maintain safe flight or landing after an impact with a 1 kg bird.
Findings
- The primary cause of the incident was a bird strike that penetrated the aircraft windshield.
- The aircraft's certification under CS-27 did not require the windshield to be resistant to bird impacts.
- The shattered windshield fragments and bird remains entered the cockpit, causing a noticeable vibration in the airframe.
- The pilot's decision to perform a precautionary landing prevented further incident.