Incident Overview
On 7 February 2019 at 1734 UTC, a Socata TB20 Trinidad (registration G-BMIX) experienced a taxiway excursion during night taxi operations at Dundee Airport. The aircraft, operated by a private pilot with one passenger, was preparing for a flight to Aberdeen Airport.
Aircraft and Crew
The aircraft, manufactured in 1985 (serial no. 579), was powered by a single Lycoming IO-540-C4D5D piston engine. The pilot, aged 59, held a Private Pilot's Licence and had 808 total flying hours, including 229 hours on type. His recent flying experience included 5 hours in the last 90 days and 1 hour in the last 28 days.
Accident Sequence
The pilot requested taxi instructions and was cleared by ATC to taxi to the south side of the main apron via Taxiway E. The pilot, familiar with the airport, had used this taxiway on many occasions. As the aircraft approached the main apron, the pilot felt a depression in the taxiway followed by a loud bang, which he attributed to a landing gear oleo bottoming out. He continued to the assigned position, where ATC informed him that they had heard a loud bang. The pilot then stopped and shut down the engine to inspect the aircraft.
Witness marks indicated that the aircraft continued straight instead of following the left curve of Taxiway E where it meets the main apron. The left main landing gear leg sank into the grass beyond the taxiway and then rode over the paved edge of the main apron, causing an overload that burst the left main landing gear oleo, releasing hydraulic fluid. No other damage occurred.
A witness, familiar with night operations on Taxiway E, stated that in his opinion the aircraft's taxiing speed was excessive.
Contributory Factors
According to the pilot, heading toward the brightly-lit main apron at night reduced the conspicuity of the blue taxiway edge lights, contributing to a loss of situational awareness of his position on the curved section of Taxiway E. He noted that in daylight the left turn is clearly visible. The AAIB report lists as contributory factors the possible loss of sight of taxiway edge lights against the brightly-lit apron and possible excessive taxiing speed.
Safety Actions
Dundee Airport investigated the event and plans to insert a taxi speed limit into the warnings section of the AIP for the airport. Additionally, the airport plans to reduce the severity of the lip between the grass and the main apron surface at the junction of Taxiway E and the main apron.