Incident
On 23 July 2011, a Cessna 172RG (registration SP-OMD) operated by Aeroklub Orląt was performing circuit training from Dęblin Airport (EPDE). The aircraft was crewed by an instructor pilot and a student. Shortly after takeoff at 11:05 local time, while retracting the landing gear, the instructor heard unusual noises from the left rear area of the cabin. The red hydraulic pump warning light remained illuminated. During the first turn, radio communication informed the crew that the landing gear had not fully retracted. The right main gear appeared retracted, but the left main gear leg was hanging in an intermediate position.
Attempts to extend the gear using the normal and emergency systems, as well as further retraction attempts, were unsuccessful. After evaluating the situation and consulting ground services, the crew performed in-flight maneuvers to try to lock the gear, which also failed. With ample fuel remaining, the instructor decided to consume fuel before attempting a landing, allowing ground emergency services—including fire brigade, ambulance, medical helicopter, and a recovery team—to prepare. The helicopter arrived from Lublin-Radawiec airport. At 14:15, the instructor made a final attempt to lock the left main gear: he opened the left cabin door, leaned out (partially restrained by harnesses), and manually pushed the gear leg into the locked position. The landing gear indicator showed three green lights. During this operation, the student was piloting the aircraft. The instructor subsequently performed an uneventful landing at 14:54, with no visible damage to the aircraft. The Polish State Commission for Aircraft Accident Investigation (PKBWL) had been notified by telephone approximately 2.5 hours before landing.
Examination
A post-incident inspection of the landing gear retraction and extension system revealed damage to the hydraulic actuator (P/N 9882015-2) for the left main landing gear leg. The actuator cylinder was found to be cracked and worn.
Findings
The investigation identified two causes for the event: 1. Misadjustment of the landing gear retraction mechanism kinematics due to operational wear. 2. Wear and cracking of the left main landing gear hydraulic actuator cylinder resulting from the kinematics misadjustment as well as from attempts to forcefully manually lock the gear.
No safety recommendations were issued.