Cessna 172RG N5284V accident near Okeechobee, Florida

Probable cause

The failure of the main landing gear to lock in the extended position for undetermined reasons and both pilots’ failure to ensure that the landing gear was down and locked prior to landing.

NTSB analysis

According to the flight instructor, he and the pilot-rated student entered the left downwind leg of the traffic pattern to land. The flight instructor read the before-landing checklist, and the pilot-rated student extended the landing gear. The flight instructor put his hand on the landing gear handle to verify that the landing gear was down because he could not see the green light from where he was sitting. According to the pilot-rated student, he extended the landing gear on the downwind leg of the traffic pattern, saw the green landing gear indicator light, and felt the vibrations and heard the sounds associated with the landing gear extension. They continued onto the base and final leg of the traffic pattern and landed the airplane. The pilots described what initially felt like a normal landing roll but then the main landing gear collapsed and the airplane's empennage began scraping the runway. The airplane came to rest on the left side of the runway centerline.

A postaccident examination revealed that the main landing gear had collapsed while the nose gear remained locked in the down position. A postaccident examination of the runway revealed tire marks that were about 5 to 6 feet apart, narrowing to 2 to 3 feet apart leading to the airplane. According to guidance provided by the manufacturer, the distance between the two main landing gear tires with the gear fully extended was 8 feet and 6 inches, indicating that the landing gear was likely not fully deployed at touchdown. A postaccident examination of the landing gear system was performed, and the landing gear, power pack, and emergency landing gear extension, were operated several times. The examination noted no grinding noise and no anomalies with the main landing gear’s operation. Further examination revealed that the landing gear warning horn did not operate, but the landing gear indicator light operated correctly. Although the landing gear indicator light is slightly obscured from the right seat, a slight left head movement while seated would allow the light to be clearly visible from the right seat. Additionally, the before-landing checklist calls for visual verification that the associated gear is down and locked through each pilot’s side window.

Text from the NTSB. Open the NTSB docket for ERA11LA231 for the full record.