What happened
On 16 February 2001, a Piper PA-28R-201, registration G-OARA, was conducting a training flight at Cranfield airport. The flight, involving a flying instructor and a student, was focused on circuit flying using a right-hand pattern on runway 04. Following a standard circuit and landing, the instructor requested a 'high glide' approach.
During the downwind leg, the student pilot struggled to determine the appropriate point to reduce throttle for the glide. Consequently, the student failed to complete the necessary pre-landing checks, prompting the instructor to make the downwind call. As the aircraft progressed on the glide approach, the instructor noted the aircraft was too low and applied power to correct the path before returning to flight idle. The aircraft was cleared for a touch-and-go, and landing flaps were deployed.
Crucially, the landing gear remained retracted during the approach. Although the tower controller observed the retracted undercarriage and issued a warning to check the gear status and subsequently instructed a go-around, the crew did not hear these transmissions. The aircraft subsequently landed with the gear up. There were no fatalities and no injuries to the two occupants. The aircraft sustained damage to the propeller due to engine shock loading, along with minor damage to the lower fuselage.
The investigation
The investigation focused on why the crew failed to identify that the undercarriage was not extended. The aircraft was equipped with an undercarriage warning system designed to trigger a horn and a red warning light if the gear was up while the throttle was reduced below 14 inches of manifold pressure, or if flaps were extended beyond 10 degrees without the gear being locked down.
Post-accident testing on jacks at Cranfield revealed that the warning horn failed to activate under the specific conditions of gear up, flaps in the landing position, and throttled-back power. While subsequent repairs and maintenance at Elstree Aerodrome restored the system to a serviceable state, the initial failure was confirmed. Additionally, investigators noted that unlike other aircraft in the operator's fleet, this specific Piper PA-28R-201 was not equipped with an automatic gear lowering system.