What happened
The incident occurred during the final phase of flight as the aircraft approached the runway for landing. The pilot reported that he had selected the landing gear down position and audibly confirmed that the gear was extending. However, just prior to touchdown, he observed that the gear selector switch remained in the down position but did not see the green light indication typically associated with a locked and extended gear configuration.
Despite the lack of visual confirmation that the gear was securely locked down, the pilot proceeded with the landing. The aircraft touched down on its belly, resulting in substantial damage to the airframe due to the absence of wheel support.
The investigation
Following the accident, investigators conducted a thorough post-crash inspection of the aircraft systems. The examination focused on the landing gear mechanism and associated warning systems to determine why the pilot was unaware of the gear status.
The inspection revealed two critical mechanical failures:
- The gear selector switch was found to be functioning intermittently, meaning it failed to provide a consistent electrical signal indicating the gear position.
- The gear warning horn, which is connected to the throttle controls to alert the pilot when power is reduced with the gear up, was found to be inoperative and did not sound during the approach.
Findings
The investigation concluded that the accident was caused by a combination of system failures that prevented the pilot from verifying the landing gear status. The intermittent operation of the gear selector switch meant that the visual indicators were unreliable. Furthermore, the inoperative gear warning horn failed to provide an auditory alert when the throttle was retarded for landing with the gear potentially up.
These mechanical defects deprived the pilot of the necessary cross-checks to confirm that the landing gear was down and locked, leading to a gear-up landing.