NTSB Identification: LAX97FA143.
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Accident occurred Wednesday, April 02, 1997 in GRAND CANYON, AZ
Probable Cause Approval Date: 02/11/2000
Aircraft: Cessna T210N, registration: N6172C
Injuries: 2 Fatal.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
During an IFR flight at night, the pilot reported to the Air Route Traffic Control Center controller that he lost the alternator and had switched to his standby generator. He then requested a lower altitude because he was in the clouds and had lost his cockpit lighting. He then reported the loss of his compass and was looking for a clear area. As the controller was attempting to provide no-gyro vectors to the nearest airport the pilot reported various problems with his flight instruments, including the altimeter, and stated that he did not know whether he could fly straight and level. He reported that his altimeter was working again but that he was still in instrument meteorological conditions and had now lost his vacuum pump. He then told the controller that he did not know where he was and that his bank indicator, DG, and HSI were providing conflicting information. The pilot subsequently could not maintain headings provided by the controller or consistent altitude profiles over the next several minutes. His last transmission said he was in a descent and was trying to pull up. Radar data showed a series of 360-degree left turns followed by turns to the right. The last turn to the left was computed at a +5.487 g load factor with an 80-degree angle of bank. The first turn to the right was +4.213 g's with a bank angle of 76 degrees. The vertical stabilizer, the horizontal stabilizers, and the outboard section of the right wing separated in flight. The pilot attended recurrent Cessna 210 flight and simulator training the day before the accident and failed to meet course standards for IFR proficiency. He routinely lost control of the aircraft while in training and declined further IFR training. The standby electric generator powers the turn coordinator but not gyro slaving, cabin lights, HSI information, heated pitot tube, or autopilot.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilot's failure to maintain aircraft control due to spatial disorientation and his lack of proficiency in conducting instrument flight. Contributing were the inoperative alternator, cockpit lighting, and vacuum system. Full narrative available
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