What happened
On July 23, 2011, a Cessna 172RG operated by Aeroklub Orląt was conducting a training flight at Dęblin Airport [EPDE] when a landing gear malfunction occurred. Shortly after takeoff at 11:05 LMT, while the pilot was retracting the landing gear for a circuit flight with a student, unusual noises were heard in the rear left side of the cabin. The hydraulic pump indicator light failed to extinguish, and subsequent radio communications confirmed that the landing gear had not fully retracted. While the right main gear appeared retracted, the left main gear remained in an intermediate position.
The pilot attempted both standard and emergency gear extension procedures, as well as maneuvers to use aerodynamic forces to lock the gear, but none were successful. Due to a significant fuel remaining, the crew decided to remain airborne to allow ground emergency services time to prepare. At approximately 11:45, while the student was piloting the aircraft, the instructor performed a high-risk maneuver: leaning out of the open left cabin door while partially secured by seatbelts, the instructor manually pushed the left gear strut into the locked position. This action successfully engaged the downlock, as indicated by the cockpit lights.
The aircraft landed safely at 14:54 without visible damage to the airframe. Emergency services, including fire brigades, ambulances, and a medical helicopter, were on site during the approach.
The investigation
The PKBWL examined the landing gear retraction and extension system of the Cessna 172RG, registration SP-OMD. The investigation focused on the hydraulic components and the mechanical movement of the gear struts. Physical inspection of the left main gear hydraulic actuator (P/N 9882015-2) revealed significant structural damage.
Findings
- The investigation established that the primary cause was the malfunction of the landing gear kinematics due to operational wear.
- The hydraulic actuator for the left main gear suffered a cracked housing.
- This failure was caused by the misalignment of the gear kinematics and was further exacerbated by the physical force applied during the instructor's manual attempt to lock the gear into place.