Primary finding
Probable cause
The retraction of the main landing gear for undetermined reasons.
Investigator assessment
Analysis narrative
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.
Source record
Factual narrative
On March 15, 2023, about 1335 mountain daylight time, a Cessna 177RG, N2572V, sustained substantial damage when it was involved in an accident in Spanish Fork, Utah. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that the accident flight was the first flight since the airplane had undergone maintenance to the landing gear pump indication relay and diode to correct an uncommanded gear pump activation. The pilot departed Provo Municipal Airport (PVU), Provo, Utah and retracted the landing gear during the initial climb. After a short cross-country flight to Spanish Fork Municipal Airport/Woodhouse Field (SPK), Spanish Fork, Utah, the pilot was cleared to land. According to the pilot, the extension of the landing gear during the approach was flawless, with all indications and lights operating normally. The pilot reported that the landing was normal. The pilot remarked that, “This airplane normally dances around a little bit after landing, so I usually start retracting the flaps to get more weight on the wheels and better brake effectiveness”. Additionally, the pilot affirmed that he raised the flap lever to the 10° setting during the landing roll and the airplane “started to waller” from side to side. The main landing gear then retracted. With the tail of the airplane dragging on the runway, the airplane skidded to a stop, with the nose of the airplane hanging off the left side of the runway in the dirt. Postaccident photographs of the airplane revealed that the nose landing gear was down and locked, as confirmed during the postaccident examination, but the left and right main landing gear had retracted. 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 the manufacturer’s maintenance manual. The landing gear operational function checks revealed normal operation within parameters, with no anomalies throughout the examination. The diode and relay installed the morning of the accident flight were tested and functioned with no defects noted. Following the postaccident examination, the pilot was asked, "Is it possible that you retracted the landing gear instead of the flaps during the landing roll?" The pilot replied, "Regarding your question, I’m pretty sure that the flap lever was never touched during the landing roll."