On May 30, 1986, a Cessna 177RG (registration N1888Q) was involved in an aviation accident near Jacksonville, FL. Investigators recorded the probable cause as: The inoperative landing gear warning horn, which likely contributed to the pilot's failure to recognize an unsafe landing gear configuration prior to touchdown. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
The aircraft's landing gear collapsed upon touchdown despite the indicator showing down and locked. Post-crash inspection revealed the warning horn was inoperative, contributing to the accident.
What happened
The pilot reported that the landing gear indicator light displayed the gear as being down and locked prior to arrival. Upon contact with the runway surface, the landing gear collapsed, causing the aircraft to slide to a final stop.
The investigation
A post-crash examination of the landing gear assembly was conducted to determine the mechanical status of the system. The inspection revealed that the landing gear operated normally in all modes, indicating no mechanical failure within the gear mechanism itself. However, the landing gear warning horn was found to be inoperative during the inspection.
Findings
The primary contributing factor was the inoperative landing gear warning horn. Although the indicator light showed the gear as down and locked, the lack of an audible warning may have prevented the pilot from identifying a potential discrepancy or unsafe configuration before touchdown. The mechanical integrity of the gear was confirmed to be normal during the post-accident inspection.
Probable cause
The inoperative landing gear warning horn, which likely contributed to the pilot's failure to recognize an unsafe landing gear configuration prior to touchdown.