Accident Overview
On 31 August 2018 at approximately 8:00 am, a private Fly Synthesis Catalina NG 582 amphibian aircraft, registration 9H-UTA, was on a leisure flight from Malta International Airport. The aircraft had taken off from Runway 23. During flight, the pilot observed that of three undercarriage indicator lights, two were green and one was red. In this amphibious aircraft, green indicates fully retracted landing gear (safe for water), while red indicates gear partially or fully extended. The pilot returned to the airport and performed a low pass over the control tower. Flight control personnel visually confirmed that one wheel on the main undercarriage was stuck midway.
The pilot subsequently executed an emergency-controlled crash landing on Runway 05. The left main wheel and nose wheel were fully extracted, while the right main wheel remained partially retracted. After touching down, the aircraft skidded approximately 107 meters along the runway before coming to a stop. The landing resulted in minor damage to the undercarriage and superficial scratch marks on the runway surface. The two occupants sustained no injuries.
Aircraft and Operational Conditions
The accident occurred at Malta International Airport (Luqa), coordinates N 35°51’ / E 014°28’, on Runway 05. Weather conditions were good: visibility was excellent, temperature up to 30°C, wind from the north at about 6 km/h. The aircraft was certified to fly over Malta, and the pilot held a valid license. The aircraft was an amphibian, model Fly Synthesis Catalina NG 582, with registration 9H-UTA. It was private, and the nature of the flight was leisure.
Investigation Findings
The investigation determined that a tyre change had been performed the night before the flight. During the maintenance, a brake cable became entangled, restricting movement of the wheel. This impeded the full retraction of the right main wheel. The aircraft manual included an emergency procedure to bypass the hydraulic pressure control and force gear extraction using an emergency switch, but the pilot did not follow that procedure due to concern about causing further damage.
While the manual contained contradictory wording regarding emergency operation between Chapter 5 (suggesting activation for more than 10 seconds) and Appendix A (suggesting activation for no more than 10 seconds), the investigation noted that this wording was not the cause of the accident. A full pre-flight check could have detected the restricted wheel, but the manual lacked detailed guidelines and diagrams for such checks, particularly for maintenance processes like avoiding brake cable entanglement with landing gear kinematics.
Conclusions
The probable cause of the accident was a brake cable that restricted movement of the wheel, thereby impeding full retraction of the wheel. The investigation made three safety recommendations: (1) correct the contradictory emergency procedures in the manual; (2) expand maintenance instructions to include step-by-step diagrams and warnings, and require a ground extraction/retraction check after any landing gear maintenance; (3) emphasize that flight and maintenance procedures must be followed to avoid damage, injuries, or death.