Accident Overview
On July 2, 2010, about 1930 Pacific daylight time, a Beech E-55, registration N3644A, sustained substantial damage following a landing gear collapse during the landing roll at McCarran International Airport (LAS), Las Vegas, Nevada. The airline transport pilot and four passengers were not injured. Visual meteorological conditions prevailed for the cross-country flight operated under 14 Code of Federal Regulations Part 91; no flight plan was filed. The flight had departed Santa Monica Municipal Airport (SMO), Santa Monica, California, about 1730.
Pilot Report
In a statement to the National Transportation Safety Board investigator-in-charge, the pilot reported that while entering the traffic pattern to land and extending the landing gear, the airplane began vibrating. The pilot confirmed a “GREEN” light indicating gear down; post-accident examination revealed the gear down light is actually BLUE. The pilot also observed a red arrow pointing down, indicating gear extension. Subsequently, the pilot lost complete electrical power, including two GPSs, all gauges, and radio communications, and squawked transponder code 7600. During final approach, full flaps could not be extended. The pilot maintained landing speed and touched down on the runway; the initial rollout appeared normal. Suddenly, the left wing dropped, followed by the right wing, and the airplane skidded to a stop.
Damage and Post-Accident Examination
The airplane sustained substantial damage to the lower fuselage area. Both propellers and the main landing gear doors were also damaged. A post-accident examination by a Federal Aviation Administration (FAA) aviation safety inspector and a certified airframe and powerplant (A&P) mechanic revealed the landing gear was partially extended. The main landing gear struts were folded inboard, with tires contacting the partially open inboard doors. The inboard door outboard edges were rubbed from runway contact. The nose landing gear was folded up into the wheel well, with the nose gear extend rod separated from the actuator’s extend/retract arm. The main landing gear actuator bellcrank arms were at an intermediate position. The landing gear DOWN indicator was operational, but its exact position prior to landing could not be determined.
Detailed Inspection Findings
A subsequent detailed examination of the airplane’s wiring to the landing gear motor, gear indicator, limit switches, and control circuits found no anomalies. However, wiring observed pinched and tangled in the left main landing gear actuating arm was inspected as it routed to the circuit breaker panel and cockpit switches. The inspection concluded the wiring could not have affected wiring behind the panel. The mechanic stated the pinched wire could possibly have become tangled in the left gear rod end during operation, potentially activating the down micro switch prematurely, turning off the landing gear motor, turning on the BLUE down light, and disabling the gear warning horn while the gear was not fully down. A Hawker Beechcraft engineer reported that the landing extend limit switch and position switch are mounted on top of each other; activation of one by the entangled wire could have activated both.
Summary of Findings
No obvious mechanical problems or defects were found that could have led to the gear collapse. It remains unknown whether the pinched wire contributed to a false activation of the gear limit switches. The examination could not determine when the wire broke or the exact sequence of events leading to its lodging between the main landing gear gearbox arm and the rod end. This condition was not observed until the airplane had been relocated to a secured area off the runway.