What happened
On May 3, 2006, an L-2 and 00A Morava, registration OK-PLG, was performing a flight route between LKKB, LKBU, and LKBE. The flight proceeded normally until the approach to LKBE, where the pilot noticed that the nose landing gear down-and-locked indicator was not illuminating. Simultaneously, the pilot observed a drop in hydraulic system pressure.
Due to the loss of pressure and the unreliable gear indication, the pilot aborted the landing at LKBE and decided to return to the home base at LKKB. During the return flight, the pilot visually identified a hydraulic fluid leak on the cowlings of the right engine. Despite several unsuccessful attempts to manually extend the nose gear, the cockpit light indication remained incorrect, even though the mechanical indicators showed the gear was in the proper position.
While flying near the LKKB tower, the pilot requested air traffic control assistance for a visual inspection of the landing gear. Following this inspection, a subsequent attempt at emergency gear extension was successful, resulting in the correct signaling of the nose gear. The aircraft landed on the grass runway 06 at LKKB with increased caution. Emergency services were requested to assist during the landing, and an emergency state was declared. A post-flight inspection confirmed a leak originating from the hydraulic pump in the right engine area.
The investigation
The ÚZPLN investigation focused on the cause of the hydraulic pressure drop and the failure of the landing gear signaling. The commission examined the aircraft's maintenance history, noting that the aircraft had undergone its annual inspection earlier in 2006 and that the landing gear struts had been inspected according to service bulletin L200/128 without findings. The investigation confirmed that the pilot was fully qualified and that the flight procedures followed the L-200 flight manual.
Findings
- The incident was caused by a loss of seal integrity in the hydraulic pump located near the right engine.
- This failure resulted in a hydraulic fluid leak, which caused the pressure drop and the subsequent incorrect landing gear position signaling.