WEST MIFFLIN, PA, USA
N3869Z
Beech A-36
The pilot reported that immediately after takeoff, he lost the use of the radios and other electrical equipment. The red landing gear position light remained dimly illuminated, which indicated that the landing gear was neither securely stowed or in the down and locked position. The red alternator-out warning light was also illuminated, and the ammeter registered a discharge. The pilot contacted a 911 dispatcher on his cell phone, reported his landing intentions and proceeded toward the airport. He attempted to manually extend the landing gear with the emergency landing gear extension hand crank located behind his seat, but was unable to engage the hand crank handle. Once at the airport, the pilot flew by the control tower and a controller confirmed that the landing gear were not fully extended. The pilot then flew several traffic pattern circuits before landing on a grassy area next to a runway. Upon touchdown, the airplane continued on a straight path until it collided with a runway marker, veered left, and stopped. Examination of the alternator revealed an open rotor circuit between the F1 and F2 terminals. In addition, alternator disassembly revealed an open rotor between the rotor and slip rings. According to the airplane's pilot operating handbook, an inoperative alternator would have placed the entire electrical system operation of the airplane except engine ignition on the battery, and would have been indicated by the illumination of the ALT OUT warning light and a discharge on the ammeter.
On July 31, 2002, at 2045 eastern daylight time, a Beech A-36, N3869Z, was substantially damaged during an emergency landing at Allegheny County Airport (AGC), West Mifflin, Pennsylvania. The certificated private pilot was not injured. No flight plan was filed for the flight that originated at Arnold Palmer Regional Airport (LBE), Latrobe, Pennsylvania, about 2010. Visual meteorological conditions prevailed for the business flight conducted under 14 CFR Part 91. The pilot stated that immediately after takeoff, he lost use of the radios and other electrical equipment. He noted that the red landing gear position light remained dimly illuminated, which indicated that the landing gear was neither securely stowed or in the down and locked position. The red alternator-out warning light was also illuminated, and the ammeter registered a discharge. The pilot contacted a 911 dispatcher on his cell phone, who then contacted the Allegheny County Airport Control Tower. The pilot reported his intentions of landing at Allegheny County Airport and proceeded toward it. While en route, he attempted to manually extend the landing gear with the emergency landing gear extension hand crank located at the rear of both front seats. However, he was unable to engage the hand crank handle. Once at the airport, the pilot flew by the control tower and a controller confirmed that the landing gear were not fully extended. The pilot then flew several traffic pattern circuits before landing on the grass area next to runway 28. Upon touchdown, the airplane continued on a straight path until it collided with a runway marker, veered left, and stopped. A witness, who flew for a major airline, was standing on the airport ramp when he saw the airplane fly overhead about 200 feet above ground level (agl). He said all three landing gear were "three-quarters" of the way extended. The witness observed the airplane make three more passes over the airport, each time with the landing gear in the same position. On the fifth pass, the airplane approached the grass area next to runway 28 and landed. As the airplane touched down, the left main landing gear collapsed and the airplane turned left. Then, the right main landing gear and nose gear collapsed. The witness said the airplane slid for a few hundred feet before it came to rest perpendicular to the runway. Three Federal Aviation Administration (FAA) inspectors performed an examination of the airplane after the accident. According to an inspector, the fuselage was twisted. External examination of the alternator and voltage regulators revealed that all components were intact and securely installed. According to a mechanic, during the recovery process, the airplane was raised on jacks, and the landing gear was lowered by the manual extension system hand crank. The airplane was then towed to a hangar. The alternator was removed and examined under FAA supervision. Examination of the alternator revealed that there was an open rotor circuit between the F1 and F2 terminals. Additionally, when the alternator was disassembled, there was an open rotor between the rotor and slip rings. A review of aircraft maintenance records revealed that the alternator was last overhauled on April 25, 2002, and had accumulated less than 3 hours since installation. Two voltage regulators were also removed and examined under FAA supervision. Examination of both regulators revealed no anomalies. According to the Beechcraft Bonanza A36 Pilot Operating Handbook (POH), page 3-8, "An inoperative alternator will place the entire electrical system operation of the airplane except engine ignition on the battery. An alternator failure will be indicated by the illumination of the ALT OUT warning light, located on the instrument panel below the flight instruments." "The warning light will not illuminate until the alternator output is almost zero. A verification of alternator malfunction would be a discharge on the ammeter." The pilot reported a total of 1,846 flight hours, of which, 1,134 hours were in make and model. Weather at the time of the accident included winds from 340 degrees at 5 knots, visibility 10 statute miles, scattered clouds at 5,500 feet, and broken clouds at 25,000 feet.
The failure of the alternator. A factor was the pilot's inability to manually extend the landing gear.
Source: NTSB Aviation Accident Database
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