What happened
On 19 April 2000, a mid-air collision occurred approximately 2 nm north of North Weald Airfield involving two light aircraft. The first aircraft, a Cessna F150J, registration G-INGR, was performing a local flight with two occupants. The second aircraft, a Yak Aerostar, registration RA0/030, was part of a seven-aircraft aerobatic formation performing a display rehearsal.
The Yak pilot had recently arrived from Little Gransden and announced his intention to perform a 'run and break' manoeuvre, using the term 'initials' to indicate his position. While the Yak pilot reported having the Cessna in sight, the two aircraft subsequently entered a flight path that led to a collision. The Yak was observed performing a low-level dive and a left turn, while the Cessna was transitioning onto the base leg of the circuit. At 16:21 hrs, the aircraft collided in a 'belly-to-belly' manner. The impact caused the Cessna's right wing to detach, leading to a rapid spiral descent into an open field. The Yak also struck the ground heavily near the wreckage of the Cessna. There were three fatalities in total: the pilot and passenger of the Cessna F150J, and the pilot of the Yak Aerostar.
The investigation
Investigators examined radar recordings, radio transmissions, and wreckage from both sites. The examination of the wreckage revealed that the collision was a glancing blow that caused significant structural damage. Specifically, the Cessna's right wing and strut were struck from below and behind by the Yak's tailwheel and rudder. The Yak sustained a propeller slash on its right wing, caused by the Cessna's spinner.
Analysis of the flight paths showed that while the Yak pilot used specific formation terminology ('initials'), this term was not defined in the North Weald Airfield Operations Manual. Furthermore, the Yak pilot's actual manoeuvre—a low-level left turn—deviated from the expected flight path associated with a 'run and break' at that airfield, which would typically involve a right-hand turn to align with the runway.
Findings
- The collision occurred because neither pilot detected the other aircraft in time to perform effective evasive manoeuvres.
- The Yak pilot's execution of a low-level left turn placed the aircraft in an unexpected position relative to the Cessna.
- The use of the term 'initials' by the Yak pilot was not standard civilian phraseology and was not defined in the local airfield documentation, potentially leading to confusion regarding the aircraft's intended path.
- Visual acquisition was hindered by the aircraft's relative headings, which resulted in very low relative movement across the pilots' fields of view just prior to impact.
- The high-wing configuration of the Cessna F150J and the long nose of the Yak Aerostar likely obscured the visibility of the other aircraft during critical phases of the manoeuvre.