What happened
On 10 July 1998, a Cessna F177RG, registration G-AYSY, departed Woodford for Meppershall, Bedfordshire. Shortly after takeoff, the pilot observed that the electro-hydraulically operated landing gear failed to retract as expected. The cockpit indicators failed to show either red or green lights, and the gear could not be confirmed in the down position.
Following the aircraft's operating procedures, the pilot attempted to manually extend the gear using the onboard hand pump. However, the pump provided no resistance, even after extended use. Realizing the gear would not lock down, the pilot declared an emergency with East Midlands Approach. After evaluating several options, the pilot chose to land at Cranfield Airfield to utilize the available grass runway and the Airfield Fire Service.
Prior to touchdown, the pilot shut down the engine, fuel, and electrical systems. While the nose gear remained extended, both main gear legs collapsed rearwards upon contact with the grass runway. The incident resulted in no injuries to the pilot, though the aircraft sustained minor damage to the underfuslamage skin and the stabilator.
The investigation
Investigators examined the aircraft's maintenance history and the hydraulic system. Approximately ten flying hours prior to the accident, the aircraft had experienced intermittent low voltage warnings. A previous maintenance action had replaced the hydraulic pump's pressure switch, as the pump was believed to be running continuously and draining the battery.
Post-accident inspections by the maintenance organization revealed that the hydraulic system was entirely devoid of fluid. Upon replenishing the system, a leak was identified at a flared pipe connection located just downstream of the pump. Further inspection found a crack in the flared end of this pipe, which had led to the total loss of hydraulic fluid.