WPR23LA136 · Cessna 177RG

The pilot reported that the landing gear hydraulic pump indicator relay and diode were replaced before he departed on the accident flight. Maintenance personnel performed ground checks and function tests that indicated the landing gear hydraulic pump was operational with no defects. The pilot confirmed that during takeoff and approach for landing all functions of the landing gear indication system were normal. The pilot reported that he moved the flap lever to the 10° down position during the landing roll to prevent the airplane from “dancing around.” Subsequently, the landing gear retracted, causing the airplane’s tail section to skid along the asphalt runway, with the nose landing gear remaining extended and locked. Postaccident examination of the landing gear system revealed no evidence of any preimpact mechanical malfunctions or failures that would have precluded normal operation. The landing gear function check was performed using steps outlined in the manufacturer’s maintenance manual. The function checks revealed normal operating parameters, with no anomalies noted throughout the examination. The pilot reported that, to prevent the airplane from dancing around during the landing roll, he normally retracted the flaps to get more weight on the wheels and better brake effectiveness. The pilot recalled that he raised the flap lever to the 10° flap down position. As the airplane’s speed decreased, the main landing gear retracted, and it is possible that the pilot unintentionally retracted the landing gear during the landing roll.

Verbatim NTSB analysis and probable cause from the NTSB dataset