What happened
On May 26, 2005, a Reims Cessna F-337-G, registration EC-DLS, departed Utrera, Spain, for a local familiarization flight before an intended mission to Mallorca. The aircraft was operated by Trabajos Aéreos Martínez Ridao and carried two crew members. Approximately 20 minutes into the flight, the pilot in command attempted to extend the landing gear but noticed the green indicator light for the gear being down and locked failed to illuminate.
After several attempts to retract and re-extend the gear, the crew noticed that the left main gear leg had not fully deployed. The crew then initiated the emergency extension procedure, which involved using a manual pump for approximately 95 strokes. Despite this effort, the left main gear remained partially retracted. Due to the inability to secure the gear, the crew decided to perform an emergency landing with the gear up.
After coordinating with air traffic control, the crew sought an airport capable of covering the runway with foam to mitigate the impact. While Jerez, Seville, and Malaga airports lacked the specific foam type requested, the Rota Naval Base agreed to assist. The aircraft landed at the Rota Naval Base on a runway partially covered with foam. Both occupants were uninjured.
The investigation
Following the incident, the aircraft was lifted by jacks at the runway to test the landing gear. During this process, the gear extended and locked normally. The aircraft was subsequently flown to Utrera for a detailed inspection. Investigators examined the hydraulic fluid, which was found to be normal in volume and appearance, with no foreign particles detected during filtration. The hydraulic power pack, actuators, and all lines were inspected and found to be free of leaks, obstructions, or mechanical interference.
Findings
- The primary cause of the incident was a malfunction in the landing gear extension system, specifically involving the left main gear actuator.
- While an obstruction in the circuit was considered a probable cause, the investigation could not definitively confirm the exact mechanism of failure as all components appeared functional during subsequent testing.
- The crew's management of the emergency was deemed highly effective, ensuring the landing was conducted under the safest possible conditions.
- The difficulty in locating an airport with appropriate foam-covering capabilities reflects a broader industry trend of moving away from using foam for emergency landings due to operational challenges.