Aviation Accident Summaries

Aviation Accident Summary CHI00LA161

INDIANAPOLIS, IN, USA

Aircraft #1

N7426N

Cessna T210N

Analysis

The airplane's main landing gear collapsed during a precautionary landing following electrical problems. A witness reported that the main landing gear was not fully extended during the approach to the landing runway. The pilot stated that he lowered the landing gear handle and the extension sequence appeared normal except for the fact that at this point the electrical system appeared to be dead and no green 'gear down' light was observed. The alternator circuit breaker was found in the out position. A hand operated hydraulic pump is available in the aircraft for extension of the landing gear in the event of a hydraulic or electrical system failure. Post accident cycling of the landing gear revealed no anomalies.

Factual Information

On June 12, 2000, at 1055 central daylight time, a Cessna T210N, N7426N, piloted by a private pilot, was substantially damaged during a precautionary landing on runway 21 (4,200 feet by 75 feet, asphalt) at the Eagle Creek Airpark (EYE), Indianapolis, Indiana. The main landing gear collapsed upon landing following problems with the airplanes electrical system. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91business flight was not operating on a flight plan. The private pilot reported no injuries. The flight departed EYE, at 1040, en route to the Decatur County Airport, Greensburg, Indiana. The pilot reported the following: "Prior to the accident, I had delivered the plane at Eagle Creek Aviation Services (ECAS) for maintenance work. When landing on a previous flight, I didn't get a gear down green light and had to go around and recycle the gear a couple of times to get a down and locked indication. I asked ECAS to check out the gear problem. ECAS had also installed an electrical tachometer during some previous maintenance work and I had noticed that when I put the gear up or down, the tach would go off and immediately come back on. There appeared to be some sort of electrical problem related to gear deployment. I asked ECAS to also check out this electrical problem." "The week before the accident, I received a call from ECAS stating that they checked the gear and could find no problem. They also could find no reason why the tach would go off and come back on upon gear operation. They told me they contacted Cessna and that Cessna told them the gear motor could be pulling enough current to momentarily shut down other electrical components, and this situation was normal. They said there was nothing further they could do and that I could pick up the airplane..." "...As I departed the pattern I noticed my radio began to flash on and off. The GPS and Loran screens also flashed off and on and kept restarting. I recycled the avionics master switch, but the indicators continued to flash and then went off. I noticed that my stormscope, backup electric attitude indicator, and amber gear up light were also off. I checked the breaker panel, but did not see any breakers popped. I decided to return to EYE and have ECAS check out the electrical problem." "I descended to remain clear of Indianapolis airspace. I continued to troubleshoot and saw that the stormscope would power up momentarily, then go off again. All of the avionics remained off, even with the avionics master on. I concentrated on returning to the airport and scanning for other aircraft since I had no radios to monitor traffic. At a few miles north of the airport I decided to extend the gear so that if the gear motor did not run I would have plenty of time to pump the gear down by hand. When I placed the gear handle down, the gear motor operated and the gear came down. I looked out the left side window and the main gear on the pilot's side appeared to have locked in place. I checked the mirror on the right side and the right main gear and nosewheel appeared to have locked in place. I did not have a green locked indicator, but attributed that to the fact that I had no electrical power to the panel." "Landing approach was normal and at approximately 1615 Zulu I flared normally and began to reduce power for touchdown. Landing was smooth and I felt the main gear, then the nosewheel contact the runway. The airplane began to roll out when all of a sudden the back end dropped down and the plane began to swerve back and forth. I immediately pulled the mixture and the engine shut down. The plane continued down the runway, swerving back and forth as I attempted to keep the plane on the runway centerline..." According to a Federal Aviation Administration (FAA) principal operations inspector (POI), the pilot reported the following: "...[The pilot] explained that after he lowered the landing gear handle, the extension sequence appeared normal except for the fact that at this point the electrical system appeared to be dead and no green "gear down" light was observed. When asked if he had considered utilizing the emergency hand pump to ensure the gear was extended, [the pilot] replied that he could visually inspect the gear position from the left cabin window and with the small convex mirror attached to the underside of the right wing. Additionally, he stated that he felt it was down and locked by the sound of the gear as it came down..." A witness reported the following: "...I was taxiing to the end of runway 21 via the east parallel taxiway when I first observed that aircraft at approximately 50 feet AGL." "The pilot had not made any position reports in the pattern on the CTAF, so I was somewhat surprised when I saw him on short final. I noticed that [his] main landing gear appeared to be not fully extended and was trailing to the rear." "The aircraft continued it's landing, touching down approximately 1,300 feet from the threshold. ..." Inspection of the airplane by the FAA revealed that the landing gear switch was in the down position, the manual gear pump handle was stowed and the alternator circuit breaker was "popped/pulled". Under supervision of the FAA, the aircraft was placed on jacks and the landing gear was retracted with the electrical system/battery under an electrical load and then extended with no anomalies reported. During the second cycle, the extension sequence did not complete fully until the battery recovered. The single green "down and locked" indicator light did not illuminate until the landing gear was lowered manually with two strokes of the emergency pump handle. The Cessna T210N Information Manual, states under Airplane & Systems Description, "A hand operated hydraulic pump, located between the two front seats, is provided for extension of the landing gear in the event of a hydraulic or electrical system failure..."

Probable Cause and Findings

the unlocked main landing gear and the manual gear extension not performed by the pilot. The electrical system failure was a contributing factor.

 

Source: NTSB Aviation Accident Database

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