What happened
On 25 June 2003, a Piper PA-3ually-200T Seneca II, registration G-BFLH, was conducting a public transport flight from Blackpool Airport back to Wycombe Air Park. The flight was intended to return two passengers to their origin following an earlier successful outbound leg. Shortly after departing Blackpool, the pilot observed the 'GEAR UNSAFE' red warning light. Believing the indication was merely a signal that the hydraulic pump was running and fearing potential pump damage, the pilot elected to pull two circuit breakers related to the landing gear system.
The aircraft returned to Wycombe Air Park after the airfield had officially closed for the day. Upon entering the circuit for Runway 07, the pilot attempted to extend the landing gear while on the base leg. However, because the circuit breakers had been previously pulled, the gear failed to deploy. Distracted by other aircraft in the area and preparing for a landing on a grass area south of the runway, the pilot failed to verify the gear position. Consequently, the aircraft struck the runway surface, causing the propellers, flaps, and fuselage skin to make contact with the ground. The aircraft slid approximately 300 metres before stopping. There were no injuries to the single crew member or the two passengers.
The investigation
The investigation established that the pilot did not follow the recommended troubleshooting procedures outlined in the Pilot's Operating Handbook, which suggest recycling the gear if the unsafe light remains illuminated. Instead, the pilot's decision to pull the circuit breakers disabled the hydraulic motor and the warning systems.
It was also discovered that a previous incident involving this specific aircraft had led to a practice of pulling circuit breakers to silence a malfunctioning warning horn. While a training organisation had previously instructed pilots not to pull these breakers, the landing gear indication system on G-BFLH had not been tested or repaired following the earlier issue. The investigation suggested an intermittent fault in the up-position switch was likely the cause of the initial warning light.
Findings
- The primary cause of the accident was the failure to extend the landing gear due to the manual removal of the landing gear circuit breakers.
- The pilot's decision to pull the circuit breakers was based on a mistaken belief that the 'GEAR UNSAFE' light indicated the gear was already retracted.
- A lack of final gear verification during the approach was exacerbated by distraction from nearby traffic.
- The landing occurred at an airfield that was closed, meaning no emergency or fire services were immediately available.
- An intermittent fault in the landing gear up-position switch likely triggered the initial warning light.