N3644ABeech E-55 · 1969

On August 2, 2012, about 1028 central daylight time, a Beech E-55, N3644A, sustained substantial damage when it struck a road embankment following an aborted takeoff after a loss of engine power on the left engine at the West Houston Airport, Houston, Texas. The pilot and his passenger were not injured. The airplane sustained substantial damage to the left wing. The aircraft was owned and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which was not operated on a flight plan. The local flight was originating at the time of the accident.

The pilot reported that during the initial portion of the takeoff, the engines accelerated smoothly and the systems and gauges indicated normal operation. As the airplane accelerated the pilot noticed a roughness in performance and verified that the throttle, mixture, and propeller controls for both engines were forward. Due to the roughness and a perceived loss of engine power on one engine, the pilot aborted the takeoff. There was insufficient runway remaining to stop the airplane and it went off the end of the runway and struck an embankment that bordered the airport perimeter road.

Postaccident examination of the airplanes left engine revealed damage to two of the six spark plug leads. The engine was mounted on a test stand and during a subsequent test run the engine exhibited rough operation. The damaged ignition harness was replaced with the harness from the right engine and the test run repeated. During the second test run the engine started immediately and ran through various power settings with no hesitations, stumbling or interruptions in power. The reason for the damage to the ignition harness could not be determined. The most recent annual inspection of the airplane was completed on July 16, 2012.

On July 2, 2010, about 1930 Pacific daylight time, a Beech E-55, N3644A, was substantially damaged following a landing gear collapse during landing roll out at the McCarran International Airport (LAS), Las Vegas, Nevada. The airline transport pilot and his four passengers were not injured. Visual meteorological conditions prevailed for the cross-country flight, which was operated in accordance with 14 Code of Federal Regulations Part 91, and a flight plan was not filed. The flight departed the Santa Monica Municipal Airport (SMO), Santa Monica, California, about 1730.

In a statement submitted to the National Transportation Safety Board investigator-in-charge (IIC), the pilot reported that upon entering the traffic pattern to land and while extending the landing gear, the airplane started vibrating. The pilot stated that he confirmed that the "GREEN" light was on, which indicated to him that the landing gear was down and extended; a post accident examination of the landing gear system revealed that the color of the gear down light is BLUE. The pilot reported that he also confirmed that the red arrow indicator was pointing down, which indicated the landing gear was down and extended. The pilot further reported that "all of a sudden” he lost the complete electrical system, which included two GPSs, “all gauges” and radio communications, after which he squawked transponder code 7600. The pilot stated that after turning final [approach] he tried to add full flaps but they did not extend. The pilot added that he maintained landing speed and touched down on the runway, and during the initial roll out everything appeared normal. The pilot added further that “all of a sudden” the left wing dropped, followed by the right wing dropping. The pilot reported that the airplane then skidded on the runway and came to a full stop. The airplane sustained substantial damage to the lower fuselage area. Both propellers and the main landing gear doors were also damaged.

At the request of the IIC, a postaccident examination of the airplane was conducted by a Federal Aviation Administration (FAA) aviation safety inspector, assisted by a certified FAA airframe and powerplant (A&P)mechanic. The examination revealed that the landing gear was found partially extended. The main landing gear struts were folded inboard with the landing gear tires contacting the partially open inboard landing gear doors. The inboard landing gear door outboard edges were rubbed from contacting the runway surface. The nose landing gear was folded up into the wheel well, and the nose landing gear extend rod was separated from the landing gear actuator nose landing gear extend/retract arm, which is located at the base of the landing gear actuator. The main landing gear actuator extend/retract bellcrank arms were positioned at an intermediate landing gear extend/retract position. The FAA inspector also reported that while the landing gear DOWN indicator was operational, its exact position could not be determined prior to the aircraft landing.

In a subsequent and more detailed examination of the airplane conducted by both the FAA inspector and the A&P mechanic, it was revealed that all wiring to the landing gear motor, gear indicator and limit switches and control circuits were inspected for integrity and routing, with no anomalies noted. There was wiring that was observed to be pinched and tangled in the left [main landing] gear actuating arm, which was inspected as it routed through the left side wall and up to the circuit breaker panel and cockpit switches. The inspection also revealed that the wiring could not have affected the wiring behind the circuit breaker panel. The mechanic stated that the pinched wire could possibly have gotten tangled in the left gear rod end during operation of the landing gear. The mechanic stated further that it was possible that the wire could have activated the down micro switch prematurely, turning off the landing gear motor, turning on the BLUE down light and disabling the gear warning horn, when in fact the gear was not all the way down, which may have caused the gear to collapse on landing. A Hawker Beechcraft engineer reported that the landing extend limit switch and the landing gear extend position switch are mounted on top of each other, and that activation of one by the entangled wire could have activated both switches.

The examination revealed that no obvious problems or defects were found that could have lead to a mechanical failure and collapse of the landing gear. Further, with respect to the wire that was found lodged between the main landing gear gearbox arm and the left main actuating rod end, it is unknown if this wire might have contributed to a possible false activation of the gear limit switches. The examination concluded that no determination could be made as to when the wire may have broken, or to the exact sequence of events that led to the wire becoming lodged between the main landing gear gearbox arm and the left main [landing] gear rod end. This condition was not observed until after the airplane had been relocated to a secured location off of the active runway where the airplane came to rest.