Piper PA-46-310P N712MK accident near Lake Havasu, Arizona

Probable cause

The failure of the low pressure switch in the normal landing gear system, which prevented normal operation of that system, and the misrigging of the emergency extension gear release valve, which prevented the system from being depressurized to allow for the freefall of the gear.

NTSB analysis

The pilot said that he was descending into the traffic pattern after canceling his instrument flight rules clearance and that he lowered the landing gear; however, there was no response. At that point, he reset the landing gear circuit breaker and tried again to no avail. He then used the emergency checklist and attempted to drop the gear. Again there was no response. He continued to repeat all procedures for about the next 1 1/2 hours until the airplane was at minimum fuel and he was forced to land with the landing gear retracted. Prior to landing, he secured all items in the cabin, feathered the propeller, and shut down the engine and all electrical and fuel controls. The airplane touched down mid-field and slid about 1,200 feet.

During the postaccident examination, the airplane was placed on jacks and supplied electrical power. Both the normal and emergency extension landing gear systems did not work. The examination revealed that a faulty low hydraulic pressure switch prevented the normal gear extension system from operating properly. The examination also revealed that the emergency gear release valve’s control arm was misrigged and would only move 1/4 inch instead of the approximately 2 inches of movement that was required. The misrigged control arm would not allow the system to port hydraulic fluid from the gear-down line to the gear-up line, which is required for the fluid to return to the reservoir and to allow gravity to extend the gear.

Text from the NTSB. Open the NTSB docket for WPR11LA245 for the full record.