Casualties unknown

2018-05-16: Piper PA-32R-301T Saratoga (N517FD) — Fair Isle Airfield, Shetland Islands, GB

Fair Isle Airfield, Shetland Islands, GB

On May 16, 2018, a Piper PA-32R-301T Saratoga (registration N517FD) was involved in an aviation accident near Fair Isle Airfield, Shetland Islands, GB. Investigators recorded the probable cause as: The pilot observed that the accident was caused by unexpected windshear. This summary draws on records from the UK Air Accidents Investigation Branch (AAIB).

Sourcesthe UK Air Accidents Investigation Branch (AAIB)Primary reportUpdated 1785658417Data APIEditorial standards

On 16 May 2018, a Piper PA-32R-301T Saratoga (N517FD) encountered windshear on short final at Fair Isle, Shetland, leading to a faster-than-intended touchdown. The aircraft slid off the gravel runway during a turn, causing damage to the right main landing gear, stabilator, and rear fuselage. No injuries occurred.

History of the Flight

The aircraft, a Piper PA-32R-301T Saratoga (N517FD), departed Retford/Gamston Airfield at close to maximum takeoff weight for a 400 nm flight to Fair Isle, a small island between Orkney and Shetland. The pilot, holding a Commercial Pilot's Licence with 3,372 total hours (2,270 on type), was familiar with the airfield's single gravel runway (06/24) which slopes upward from both thresholds toward the midpoint.

Wind was from 330° at 15 kt, and the pilot chose Runway 24 due to unobstructed terrain on the east side. He planned to touch down near the start of the 486 m available landing distance, confident from previous experience that the landing could be completed in less than 400 m, aided by an expected headwind component and the runway's upslope.

During the approach, a steady crosswind was manageable until near the threshold, where sudden windshear produced a large updraught and headwind, causing the aircraft to balloon. The pilot reduced power but then encountered a downdraught that required significant power to regain altitude. The aircraft accelerated as he exited the downdraught, but he focused on touching down at his aiming point, which he achieved.

The touchdown felt normal; the pilot raised flaps and applied normal braking while climbing the runway slope. He realized his groundspeed was higher than intended and briefly considered a go-around but decided to continue. However, he had not accounted for the downslope toward the upwind threshold, preventing a stop. Attempting a 180° turn at the end, he encountered loose gravel and a sloping surface; the aircraft slid sideways off the prepared surface at low speed. The right main landing gear partially collapsed, and the right stabilator and lower rear fuselage struck the ground. None of the six occupants were injured.

Pilot's Assessment

The pilot attributed the accident to unexpected windshear but acknowledged he could have performed a go-around. He noted being "lulled into a false sense of security" after a relaxed transit to a familiar destination. He believed that greater alertness would have led to a go-around upon encountering the updraught or downdraught, and that anticipating the downslope would have prompted a go-around when high groundspeed became apparent.

AAIB Comment

The pilot planned using only the POH performance graph for landing ground roll, disregarding the graph for landing distance from 50 ft above threshold, which indicated a required distance of approximately 500 m—exceeding the available 486 m for Runway 24. The UK AIC 127/2006 recommends a 43% safety factor, which would have increased the required distance to 718 m. The AAIB highlighted that this accident illustrates how variables can substantially increase unfactored distances from the POH.

Probable cause

The pilot observed that the accident was caused by unexpected windshear.