Synopsis
On 21 July 2019, a Midget Mustang (registration G-AWIR) was involved in an accident near Spanhoe Airfield, Northamptonshire. The pilot, who was the sole occupant, sustained serious injuries, and the aircraft was destroyed.
History of the Flight
The pilot was en route from Leicester Airfield to Sibson Airfield. During the flight, he flew over Spanhoe Airfield at an altitude of approximately 600–700 ft to observe the windsock and decide whether to land there to visit friends. After the overflight, the pilot executed a pull-up and a left bank. He subsequently lost awareness and the next memory was striking the tree canopy.
Aircraft Information
The aircraft was a Midget Mustang, manufactured in 1973 (serial number PFA 1315). It was powered by a single Continental Motors Corp O-200-A piston engine. The pilot held a Private Pilot’s Licence and had 677 total flying hours, including 10 hours on type. In the 90 days prior to the accident, he had flown 71 hours, with 16 hours in the last 28 days.
Commentary
The AAIB commentary explains the relationship between bank angle, load factor, and stall speed. In level flight, lift equals weight, giving a load factor of 1. When banking, lift must increase to maintain altitude; for example, at 60° of bank, lift doubles (load factor 2), and stall speed increases by a factor of 1.4. At 75° of bank, load factor approaches 4 and stall speed doubles. The Midget Mustang has a published stall speed of 60 mph in the clean configuration at maximum gross weight. A pull-up combined with a steep bank further increases the stall speed due to higher load factor. Additionally, if power is not increased, the aircraft slows due to the pull-up and increased drag from the required lift.
Conclusion
The AAIB concluded that it was most likely that the final manoeuvre increased the aircraft’s stall speed to or beyond its actual airspeed, causing the aircraft to stall. The pilot subsequently lost control with insufficient height available to recover before the aircraft struck trees.