Incident Overview
On Wednesday, 25 September 2002 at 11:30 local time, a Cessna 402-B aircraft registered EC-EMH, operated by Victor Echo, was landing at Málaga Airport after a flight from Melilla Airport. The aircraft was conducting a non-scheduled commercial cargo operation.
Sequence of Events
During the initial touchdown, the pilot observed that the green indicator light for the right main landing gear leg extinguished. The landing was aborted and the aircraft climbed away. The crew informed air traffic control and proceeded to the Torremolinos area to perform landing gear checks. After several extension and retraction cycles, the right gear indicator light remained off. The crew then used the emergency gear extension procedure, but the green light for the right leg still did not illuminate.
The crew requested a low pass over the runway for a visual inspection by the tower controller, who reported that the landing gear appeared to be extended. The controller alerted the airport fire service, which positioned two vehicles ready for action.
The crew decided to land. As soon as the aircraft contacted the runway, the right main gear began to retract. The right propeller struck the runway surface, and the aircraft veered to the right. The crew shut down the engines. Shortly thereafter, the left main gear collapsed. The aircraft slid on its fuselage and departed the runway to the right, coming to a stop about 30 meters from the runway edge.
Injuries and Damage
Both crew members were uninjured and evacuated the aircraft without assistance. The aircraft sustained substantial damage to both main landing gear legs, both propellers, the fuselage, and the right flap. No other damage was reported.
Investigation Findings
A visual inspection of the landing gear revealed the following damage to the right main gear: the bellcrank pivot bolt (part number NAS 464P4-26) was sheared; one of the two trunnion ears that secure the bellcrank was broken; the push-pull tube end attached to the bellcrank was fractured; and the bellcrank link connecting to the overcenter mechanism was broken. The left main gear exhibited a broken adjusting screw.
The bellcrank pivot bolt was sent to a laboratory for analysis. Fractography showed a static shear fracture, confirmed by the presence of dimples. Chemical composition met specifications. Hardness testing gave an average strength of 195 KSI, slightly above the specified range of 160-180 KSI, attributed to plastic deformation during failure.
Examination of the landing gear actuator revealed it was in an intermediate position between fully extended and fully retracted.
Analysis
The investigation determined that the right gear damage resulted from static overloads. In normal operation, the lateral brace (overcenter link) carries landing loads. The broken components indicated that the lateral brace had not achieved its overcenter position, allowing the gear to fold. This misalignment likely originated from an incorrect adjustment, possibly with the overcenter slightly short, causing gradual wear and eventual failure.
For the left gear, the actuator's intermediate position indicated that the crew had not completed the emergency extension procedure, leaving the gear unlocked. This led to its collapse during the landing.
Probable Cause
The investigation did not provide a single explicit probable cause statement in the provided text.