Accident Details
On 25 May 1999, at 1823 hours UTC, a de Havilland DH 82A Tiger Moth (registration G-BXMN), powered by a single De Havilland Gipsy Major 1H piston engine, was on a private local flight from a farm strip near Whalley, Lancashire. The aircraft carried a pilot and one passenger. At an altitude of 1,100 feet, the engine began to run roughly and lose power. The pilot decided to carry out a forced landing on a golf course adjacent to a wooded area. As he positioned the aircraft for landing, the engine appeared to recover. The pilot completed a 360° turn, but the engine then again lost power, leaving him no choice but to land in the trees.
During the landing, both Sutton type harnesses failed. The pilot sustained minor injuries, while the passenger suffered serious injuries. There was no fire. The weather conditions, obtained from Blackpool Airport at the time, indicated a temperature of +12°C and a dew point of +6°C, conditions considered favourable for the formation of carburettor icing at cruise power. The pilot and his passenger opined that the symptoms of the power loss were consistent with such icing.
Harness Safety Background
The Sutton harnesses fitted to the aircraft failed during the accident. The AAIB noted that over the years, many Tiger Moth aircraft have been fitted with replacement harnesses made from modern synthetic materials, particularly in Australia, where Sutton harnesses have been prohibited for almost 30 years.
A previous accident involving a Tiger Moth (G-AOBJ) at Cardiff Airport on 20 August 1997, in which both occupants sustained serious injuries, led the AAIB to publish Safety Recommendation 98-40. This recommendation called for mandatory action by the CAA to equip affected aircraft, including the de Havilland Moth series, with improved modern harnesses, citing that most Sutton harnesses in service were likely in deteriorated condition.
The CAA responded to this recommendation on 1 August 1998, accepting it and stating that the aircraft Type Design Organisation would issue a Service Bulletin requiring the fitting of either life-limited Sutton harnesses or new improved modern harnesses for all affected de Havilland aircraft, with mandatory action intended to be completed by 31 December 1998 for de Havilland types and by 31 December 1999 for other affected types.