What happened
On 2 October 2011, a Royal Artillery Hermes 450, registration ZK515, crashed at Bastion Airfield, Afghanistan, during a routine ISTAR mission. The flight, operated by 57 Battery, 32 Regiment RA, began as planned at 0600L. However, during the initial climb, the engine air temperature was noted to be higher than normal.
As the mission progressed, the engine air temperature continued to rise. By approximately 0855L, the temperature reached 123°C, prompting the crew to terminate the mission early and return to base. Upon approaching the airfield, the crew faced complications due to work in progress on the runway, which prevented an external pilot from performing a manual landing. The crew instead opted for a GTOLS landing.
During the descent, the engine air temperature entered the red sector at 136° and continued to climb. A self-abort of the approach occurred at 0939L due to an incorrect parameter in the GTOLS setup form. In an attempt to manage the situation, the crew commanded the aircraft back to a holding pattern. During this climb, the engine temperature reached 138°C, resulting in engine failure at 0943L.
The aircraft subsequently struck an unoccupied US Marine Corps hangar, which sheared off the port wing. The Hermes 450 then impacted the ground upside down, sliding approximately 100m before coming to rest on an empty aircraft dispersal pan. There were no fatalities.
The investigation
The investigation examined the sequence of events leading from the initial high temperature readings to the final impact. Investigators reviewed the crew's handling of the engine temperature increases, the technical setup of the GTOLS approach, and the operational constraints imposed by airfield work in progress. The inquiry also looked into the impact of the go-around maneuver on the already stressed engine.