What happened
On the night of 29 November 2013, a Eurocopter EC1s35 T2+ helicopter, registration G-SPAO, was conducting a commercial air transport mission to support police operations. After departing Glasgow City Heliport, the aircraft performed several maneuvers over the Glasgow area and Midlothian before requesting clearance to return to its base. At 2222 hrs, radar contact with the aircraft was lost.
Witnesses near the scene reported hearing a sound similar to a loud misfiring engine, followed by a rapid descent. The helicopter struck the roof of The Clutha Bar, a single-story building in central Glasgow, with high downward force and very little forward momentum. The impact caused the roof to collapse, with the aircraft coming to rest amidst the building's debris. The accident resulted in 9 fatalities—comprising the pilot and eight others (two from the aircraft and six from the bar)—and 32 injuries, of which 12 were serious.
The investigation
AAIB investigators arrived at the site the following morning. Due to the unstable state of the collapsed building, the initial examination was conducted within the wreckage. After structural reinforcements were installed and debris was cleared, the helicopter was removed from the building using a crane.
Preliminary engineering checks performed at the AAIB headquarters in Farnborough revealed that all major components were present upon impact. While the aircraft's structure suffered extensive damage from the collision and the subsequent building collapse, the helicopter remained upright. Investigators also noted that the aircraft was not equipped with flight recorders, though they are analyzing radar data, radio communications, and available CCTV footage.
Findings
- The helicopter struck the flat roof of the building at a high rate of descent and negligible forward speed.
- No evidence of major mechanical failure was found during the initial assessment of the engines.
- The impact forces caused a splined shaft in the drive train from the No 1 engine to disengage, which prevented the main rotor and tail rotor from receiving power from that engine.