GRAND CANYON, AZ, USA
N6172C
Cessna T210N
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.
HISTORY OF FLIGHT On April 2, 1997, at 2016 hours mountain standard time, a Cessna T210N, N6172C, collided with snow covered mountainous terrain in a wilderness area on the north rim of the Grand Canyon in Arizona. The airplane was destroyed and the certificated private pilot/owner and his passenger received fatal injuries. The airplane was being operated by the pilot/owner as a personal flight under 14 CFR Part 91 when the accident occurred. The flight originated in Las Vegas, New Mexico, and was en route to North Las Vegas, Nevada, at the time of the accident. Night instrument meteorological conditions were reported by the pilot at cruise altitude and an IFR flight plan was filed. At 1956, the pilot reported to the Los Angeles Air Route Traffic Control Center (ARTCC) controller that he lost his alternator (malfunction) and that he was switching to his standby generator. At 1958, the pilot called requesting a lower altitude and stated that he was in the clouds without any (cockpit) lighting. He was cleared from flight level (FL) 190 down to 15,000 feet mean sea level (msl). He was advised that the Grand Canyon airport was open and would remain open beyond its scheduled closing time if he chose to land there. He was told that Grand Canyon was reporting 6,000 feet overcast; however, the controller did not know if there is a clear layer between FL 190 and 6,000 feet. The pilot replied that he was "looking for it" (a clear layer). There was no discussion about the possibility of a climb to an "on top" FL. At 2002, the pilot called and told the controller that he had problems. The controller asked him if he wanted to go to Grand Canyon which was then about 10 miles away. He replied in the affirmative and asked for a radar vector, adding that his gauges were all messed up. The controller then asked him for his heading and he replied that his magnetic compass showed 070 degrees. He was then told that Grand Canyon airport was 240 degrees at 8 miles. The controller asked him if his compass was working properly, to which the pilot replied no, everything was out, adding that he did not know whether or not he could fly straight and level. The controller told him to maintain his present heading and that he should expect a non-gyro vector. At 2003, the controller asked the pilot to turn left. A few seconds later the pilot informed the controller that he was "descending pretty bad." At 2004, the controller told the pilot to stop his turn. The pilot acknowledged the instruction to stop the turn and added that his altimeter was not working. The controller attempted to confirm the pilot's statement concerning his altimeter. The pilot replied that he did not trust his altimeter and that he smelled something strange. The controller suggested that he check his pitot heat. The pilot replied that the pitot heat was on but that there was a funny smell. The controller told the pilot that he showed him at 18,400 feet and suggested that he start a shallow descent. The pilot acknowledged and told the controller that he was using his alternate static source. At 2005, the controller told the pilot to start a left turn. The pilot acknowledged and informed the controller that his altimeter was working again. The controller advised the pilot that his transponder was indicating 17,400 feet and then 18,000 feet. The pilot confirmed the latter altitude. At 2006, the controller asked the pilot to make another left turn but to try to make the turn not as steep. The pilot acknowledged and said that he would turn slower. The controller told the pilot to stop his turn and, again, the pilot acknowledged. At 2008, the controller asked the pilot to make another shallow left turn. The pilot acknowledged. The controller told him to stop his turn and, again, the pilot acknowledged. The controller then asked the pilot to say his altitude. The pilot replied 17,700 feet. At 2009, the controller told the pilot that 17,700 feet was the same altitude that he was receiving and asked him to descend and maintain 15,000 feet. The pilot acknowledged that he was to descend. The controller told the pilot that he was headed toward the Grand Canyon airport. The pilot replied that he was instrument meteorological conditions (IMC) and that he thought he had lost his vacuum pump. He also told the controller that he smelled something burning, he was on his standby generator and that he did not know where he was. The controller told the pilot to make a right turn. The pilot acknowledged that he was to turn right. At 2010, the controller told the pilot to stop his turn and to fly straight and level. The pilot replied that he would try but that his bank indicator said one thing, the DG said another thing, and the HSI said another thing. At 2011, the pilot told the controller that his magnetic compass was walking all over the place so he knew that he was turning. At 2012, the controller told the pilot that because of the weather minimums at Grand Canyon, he would not be able to get him down low enough to cancel. The pilot then asked if he could be vectored directly to North Las Vegas. The controller agreed and asked the pilot to remain on his present heading, commenting that it appeared he was in a slight left turn. The pilot acknowledged his left turn and then commented that he was in a significant descent. At 2013, the controller told the pilot that he was on course for North Las Vegas and he should try to hold his altitude and heading steady. The pilot replied that he would try. At 2014, the controller told the pilot that he was now showing that his altitude was 16,000 feet. The pilot replied that he was showing all kinds of stuff and that he was going to lose control of the aircraft. The controller told the pilot that the Grand Canyon was 15 miles due south of his position and asked him if he wanted a radar vector to the airport. The pilot said he would try something since his gauges were going all over the sky. The controller asked if the aircraft was still flying all right. The pilot replied that the aircraft was flying all right. However, he could not control it because one gauge said one thing and another gauge said another, as well as being unable to stay on a compass heading. About 10 seconds later, the pilot reported that the aircraft seemed to be flying halfway decent. At 2015, the controller acknowledged the pilot's comment, adding that he was still in a left turn. The pilot replied that he would turn to the right. About 33 seconds later, the controller told the pilot to remain steady on his present heading. About 4 seconds later the pilot replied that he would try to pull up. That was the last recorded transmission from the pilot. The airplane was last observed on radar making a series of 360-degree turns with fluctuations in airspeed and altitude before disappearing from radar about 19 minutes after the pilot first reported an alternator failure. PERSONNEL INFORMATION The pilot was issued his private pilot certificate with a single engine land rating on September 13, 1991. He was issued an airplane instrument rating on April 5, 1992. A review of the pilot's No. 3 logbook revealed that he had received a biennial flight review on November 30, 1996. The entry states "biennial flight review (BFR) slow flight steep turns, etc." and is signed by a certified flight instructor (CFI). The entry shows that the BFR was conducted at night; however, there was no simulated or actual instrument time logged during the flight. The BFR was conducted in a Cessna 172. According to the pilot's logbook; however, the majority of his total and most recent flight time was logged in his own aircraft, a Cessna T210N. On March 31, 1997, through April 2, 1997, the pilot attended Flight Safety's CE-210 Pilot Proficiency Training Course in Wichita, Kansas. His training record was annotated "Training completed to visual flight rules (VFR) standards only." His pilot logbook contained an entry "Initial CE-210 Course, Wing I," and was signed by a CFI-airplane and instrument (A&I). The training was conducted in a simulator and consisted of 7 hours of instrument and 0.9 hours of VFR. In the "remarks" section of the grade sheet, an entry dated April 2, 1997, states "Completed course to VFR standards only. Customer did not want to do any non-precision approaches because he said he does not need them." His grade sheet showed that he needed additional training in the following IFR procedures: A. Holding B. Non-precision (approach) C. Missed approach D. Communication/Navigation procedures E. Approach/landing His grade sheet showed that he needed additional training in the following navigation items: A. VOR holding B. VOR approach C. DME arc D. Localizer E. Localizer back course Electrical emergencies, including alternator failure, were demonstrated on day No. 2 of training. AIRCRAFT INFORMATION The aircraft was equipped with a standby electric generator. Upon the loss of the aircraft alternator, the aircraft battery automatically powers the electrical system when the master switch is in the "on" position. The pilot is notified of an alternator failure by means of an annunciator light, which is mounted on the upper left corner of the instrument panel just below the eyebrow. He may then switch to the standby electric generator by activating the two-position toggle-type off-on switch located on the left sidewall circuit breaker panel. The battery is 28 volts and is rated at 480-amp minutes. There is no requirement for the battery to power the electrical system for a minimum time period after the loss of the alternator. If electrical demands on the battery continue, the battery's electrical charge will be depleted as the electrical components dim/weaken and ultimately cease to function. The aircraft manufacturer stated that the alternator annunciator light is designed to illuminate at 24.5 volts. He also stated that at 24.5 volts the electrical output to the autopilot is already below that required for full function. The length of the battery's useful charge depends on factors such as the age and/or condition of the battery as well as the overall demands being placed on it. The aircraft manufacturer's stated that this could vary from about 30 minutes to less than 2 minutes. Once the pilot switches from alternator to the standby electric generator, the electrical system delivers power to the following only: A. Landing gear warning system B. Stall warning system C. Fuel quantity indicators D. Turn coordinator E. Engine oil and cylinder head temperature indicators F. Circuit breakers labeled radio 1 or radio 2 as selected by switch NC1/NC2 G. Circuit breaker labeled radio 3 normally the transponder and encoding altimeter The electrical components that are offline during standby electric generator operation include: A. Electric landing gear motor B. Electric wing flaps C. Cabin and external lights D. Gyro slaving E. Heading situation instrument (HSI) heading information F. Distance measuring equipment (DME) G. Marker beacon receiver H. Auto pilot I. Heated pitot tube J. Propeller electric anti-ice According to an employee at Yingling Aircraft, Inc., in Wichita, Kansas, the pilot's aircraft developed an oil leak prior to his departure on April 2, 1997. They found the left magneto had a broken flange and replaced it with a customer-supplied magneto in order to correct the oil leak. An engine run-up was performed to verify that the repair had been successful. During the aircraft run-up, mechanics observed both magnetos and the alternator to operate without any apparent discrepancies. The employee stated that the pilot said the aircraft and engine logbooks were in his office, therefore no logbook entry was made for the repair. Yingling Aircraft, Inc. also serviced the aircraft's oxygen system before departure. The aircraft was last refueled at an unknown FBO in Las Vegas, New Mexico, with an unknown quantity of fuel. Assuming that the aircraft was topped off, the aircraft would have departed with a total of 90 gallons of fuel (89 gallons usable). The pilot's operating handbook (POH) states that the aircraft's operating limitations prohibit flight into known icing conditions. METEOROLOGICAL INFORMATION Prior to departure from Las Vegas, New Mexico, the pilot requested a weather briefing from Albuquerque Flight Service Station (AFSS) which he limited to an update of significant weather along his route of flight. He was told to expect IFR conditions with turbulence and mountain obscuration along the remainder of his route. He was also advised to expect precipitation with level 1 and level 2 thunderstorms over Arizona changing to level 3 and level 4 beyond Peach Springs, Arizona and then continuing to his North Las Vegas, Nevada, destination. The Grand Canyon airport (KGCN) METAR special at 2013 reports that snow began at 1959 and ended at 2013. AIDS TO NAVIGATION The pilot was in radar and radio contact with Los Angeles ARTCC while on a radar vector direct to North Las Vegas, Nevada. His progress was being monitored by ARTCC controllers. Subsequent no-gyro turns and headings were also provided by the ARTCC controller. COMMUNICATIONS The pilot was in constant radio contact with Los Angeles ARTCC until radar and radio contact was lost at 2016, the presumed approximate time of the accident. WRECKAGE AND IMPACT INFORMATION The airplane was found on April 6, 1997, after an extensive search by the National Park Service (NPS), which had been impeded by inclement weather conditions. The site was located at 36 degrees 17 minutes north latitude and 112 degrees 1 minute west longitude at an elevation of approximately 8,880 feet msl. The terrain was wooded and mountainous, with 5 to 6 feet of snow. Safety Board investigators went to the accident site on April 7, 1997. Upon their arrival, NPS personnel informed investigators that they were still looking for the passenger. During this inspection, investigators noted that the left wing, roof, and the butt of the right wing had rotated. The left wing was now nearly parallel to the fuselage with the tip pointing in the same direction as the nose. Control cables and wiring to the separated empennage exhibited multiple twisting. On April 8, 1997, the Safety Board investigator decided that, due to the depth of the snow, the logistical limitations for tools and equipment, and the projected limited available time for the on-site phase of the investigation, they would continue the inspection after the aircraft had been recovered. On April 20, 1997, the right front seat and passenger were located by recovery personnel, about 100 yards from the main wreckage. On May 28, 1997, Safety Board investigators reconvened at the accident site. The stand-by power switch was found in the "off" position. This switch is guarded and when the guard is closed, the switch is repositioned to off. The NC1/NC2 switch was in the NC1 position. The alternator circuit breaker appeared open. The engine and propeller both remained attached to the airframe. Drive train continuity was established from the propeller through the accessory section by hand rotation of the crankshaft. The No. 1, 2, 3, 4, 5 and 6 top and bottom spark plugs were removed and examined. The plugs all exhibited some degree of rust-colored deposits. According to Champion Spark Plugs Check-a-Plug chart, the plugs showed normal wear patterns. The fuel manifold was removed and disassembled. The screen was found to be clean and free of contamination. The engine driven fuel pump was removed and inspected. The drive was found to be intact. The engine oil pump was disassembled and inspected. It was noted that the gears rotated freely on both the scavenge and pressure sides. The alternator remained attached to the engine. According to the representative of the aircraft manufacturer, the external wiring appeared to have been modified with the addition of Silastic 732 RTV high temperature adhesive sealant at the attachment of the wire from the capacitor to the noise filter. The alternator was removed from t
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.
Source: NTSB Aviation Accident Database
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