Incident Overview
On 20 July 2018 at 1215 UTC, a Cessna 182T Skylane, registration G-ORDM, was involved in a serious incident at RAF Brize Norton, Oxfordshire, when it was caught in the propwash of a stationary Lockheed Martin Hercules C130J C Mk 4, registration ZH878. The Cessna was being positioned for pre-takeoff engine checks at Holding Point Golf when the encounter occurred.
Sequence of Events
G-ORDM had taxied behind ZH878 to Holding Point Golf, maintaining an assessed separation of 50 to 100 m. No adverse propwash effects were encountered during the taxi. Upon arrival, the Cessna began turning into wind for engine power-up checks. At that time, ZH878 was stationary with its crew completing pre-takeoff checks, the last item being a Propeller Overspeed Check requiring increased engine power from Ground to Flight Idle.
Midway through its turn, the Cessna pilot heard the C-130J's engine note increase and immediately felt violent buffet from its propwash. The turbulent airflow lifted the Cessna's nosewheel off the ground, and the wings rocked violently. The pilot attempted to clear the area by turning right, but despite left aileron input, the aircraft was briefly lifted off the ground before tipping onto its right wing. It pivoted on the right mainwheel and nosewheel and was blown sideways approximately 8 m before coming to rest upright on all three wheels.
During the sideways movement, the propeller struck the ground multiple times before the engine failed. The pilot, uninjured, transmitted a Mayday call and vacated the aircraft unaided.
Aircraft and Personnel
The Cessna 182T (2003, serial no. 18281206) was powered by a single Lycoming IO-540-AB1A5 piston engine. It sustained airframe and engine damage. The Hercules C-130J (year of manufacture not known) had four AE2100D3 turboprop engines and sustained no damage.
The Cessna pilot, aged 39, held an Airline Transport Pilot's Licence with 3,567 total hours (3 on type). The Hercules commander, aged 48, also held an ATPL with 6,057 total hours (679 on type). Both aircraft carried only crew: one on the Cessna, three on the Hercules. No passengers were aboard.
Human Factors and Investigation Findings
The Cessna pilot had extensive experience on large aircraft, including the C-130J, and had recently renewed his Single Engine Piston class rating. He used visual cues based on the size of the C-130J to assess spacing, believing he maintained 50–100 m. However, post-accident analysis indicated actual separation was approximately 25 m at the time of the propwash encounter. The pilot was surprised by the intensity and extent of the propwash; he noted that Flight Idle thrust was significantly higher than breakaway thrust for a fully laden C-130J.
The Hercules commander considered the propeller overspeed check normal at the holding point and did not perceive it as a high-power ground run, thus did not pre-warn ATC or other aircraft.
The joint investigation by the Cessna's operator and the pilot's employer noted no promulgated data for C-130J propwash intensity or warnings in the Aircrew Manual. The investigation determined that the accident resulted from insufficient separation between the two aircraft at Holding Point Golf.