Incident Summary
On 26 April 2006, a Beech 60 Duke, registration D-INAZ, was involved in an accident during landing at Grottaglie Airport (TA), Italy. The aircraft touched down with the right main landing gear retracted, resulting in damage to the right wing, right propeller, right engine, and a distance marker signboard adjacent to the runway. The pilot, the sole occupant, was not injured, and no third parties were harmed.
Aircraft and Pilot Information
The Beech 60 Duke is a twin-engine, low-wing, pressurized aircraft with retractable tricycle landing gear, manufactured in 1980 (serial number P532). It was equipped with two Lycoming TIO-541-E1C4 piston engines and Hartzell HC-F3YR three-blade constant-speed propellers. At the time of the accident, the airframe had accumulated 3,594 total flight hours, with 8 hours and 43 minutes since the last annual inspection on 13 January 2006. The pilot, a 69-year-old male, held a valid private pilot license with multi-engine and instrument ratings, and had logged 4,343 total flight hours, including 4 hours 13 minutes on type in the previous 90 days.
Sequence of Events
The flight departed Grottaglie Airport at 10:00 UTC for a tourist flight to Brindisi. During the landing approach at Brindisi, when the pilot extended the landing gear, he heard unusual noises and noted that the right gear indicator light did not illuminate, while the circuit breaker for the electric gear actuator popped out. The pilot aborted the landing, performed a low pass for a visual check, and was informed that the right gear was not fully extended. He decided to return to Grottaglie. On the return flight, he reset the circuit breaker, retracted the landing gear successfully (with normal indications), but the circuit breaker popped out again. Approaching Grottaglie, he attempted to extend the gear, but the circuit breaker popped before the sequence began. He then manually extended the gear using the hand crank, encountering significant resistance. The right gear indicator still showed unsafe, confirmed by the control tower. After burning off fuel, the pilot declared an emergency and landed on runway 17 with engines shut down. The aircraft touched down on the left main and nose wheels. During deceleration, the right wing dropped and scraped the runway for about 150 meters, shearing two runway lights and striking a distance marker signboard before coming to a stop near the signboard base. No fire occurred.
Examination Findings
Post-accident examination revealed that the right main landing gear was fully retracted with its doors closed. When the inner door was removed, the gear leg automatically extended about one-third of its travel, restrained by the control rod. Further inspection of the gear mechanism found: fracture and deformation of the microswitch support plate on the gearbox; deformation of the right gear leg control rod attachment at the gearbox; absence of safety lock wire on the adjustment terminal for the uplock lever cable; complete seizure of the uplock roller bearing on the knuckle joint; and almost no lubrication in all gear mechanism joints, whereas the left gear joints were well lubricated.
Maintenance Findings
Maintenance records showed annual inspections on 27 October 2004 (at 3,495 hours) and 13 February 2006 (at 3,578 hours), both recorded as 100-hour checks despite only 83 flight hours between them. The inspections should have included tasks such as uplock block adjustment. Notably, during the 2004 annual inspection, the uplock roller bearing on the right gear was removed, cleaned, and lubricated as an extraordinary task. During the 2006 inspection, the downlock cable was adjusted for slackness. In the 98 hours before the accident, the landing gear system had undergone at least two control and adjustment interventions by the maintenance organization.