ALBUQUERQUE, NM, USA
N79NL
Cessna P210N
The pilot reported a dual vacuum pump failure while flying IFR at FL220. Despite having a standby electric artificial horizon, aircraft control was lost during the pilot's attempt to descend to 13,000 feet (reported cloud base). The airframe was overstressed and the right wing failed. Laboratory examination of the vacuum-driven gyroscopes disclosed no evidence of high rotation at impact. Both vacuum pumps bore signatures indicative of failure prior to impact. Not enough of the check valve manifold remained to determine its operational status.
HISTORY OF FLIGHT On January 20, 1999, at 1527 mountain standard time (mst)*, a Cessna P210N, N79NL, was destroyed when it broke up in flight and collided with terrain in the Sandia Mountain Wilderness Area, near Albuquerque, New Mexico. The instrument rated private pilot and two passengers were fatally injured. Visual meteorological conditions prevailed at the accident site, but the pilot reported being in instrument meteorological conditions. An IFR flight plan had been filed for the personal flight being conducted under Title 14 CFR Part 91. The flight originated in Scottsdale, Arizona (SDL), at 1243 Pacific standard time (Pst), and was en route to Wichita, Kansas (ICT). According to a spokesman for Advanced Industries, Inc., to which the airplane was registered, the pilot and his passengers had flown to Scottsdale on January 15, 1999, to participate in a golf tournament. They were returning to Wichita when the accident happened. According to the Federal Aviation Administration, the pilot telephoned the Wichita, Kansas, Automated Flight Service Station (AFSS) at 0606 Pst, and began filing an IFR flight plan. The cellular telephone connection was lost but reestablished a minute later, and the pilot finished filing his flight plan. He then asked for an "outlook" weather briefing. The pilot was told there was an area of high pressure along his route, and that a weak trough would be moving across Kansas, Oklahoma, and Texas. Across the northern half of Arizona, the forecast was for scattered clouds at 15,000 feet; across New Mexico, scattered to broken clouds at 12,000 to 14,000 feet, with a chance of an isolated snow shower across the mountains; across Kansas, scattered clouds around 15,000 feet, becoming broken to scattered cirrus by the afternoon. Winds aloft at FL (flight level) 230 over Arizona were forecast to be from 300 degrees at 70 to 75 knots; over Albuquerque, 300 degrees at 60 knots; over western Kansas, 250 degrees at 30 knots; at Wichita, 250 degrees at 40 knots. The briefing was terminated at 0611 Pst. At 0729 Pst, the airplane was serviced with 38 gallons of 100LL fuel. According to Corporate Jets' fuel invoice, both wing tanks were filled to capacity, and 15 gallons were put in the baggage compartment fuel tank. At 1235, the pilot was issued his IFR clearance. At 1237, he was cleared to taxi to runway 21. He was cleared for takeoff at 1243, and told to contact Phoenix Departure Control. Communications with Phoenix TRACON (terminal radar control) were routine, and the pilot was subsequently instructed to fly a 090 heading and intercept J (jet route) 18. The flight proceeded without incident until 1519:10, when the Albuquerque controller told the pilot, "Verify you're level at [flight level] two three zero, [I'm] showing you four hundred feet low." The pilot replied, "We've just figured out we've had a dual vacuum pump failure. We've lost both our vacuum pumps, so we're gonna need to look for someplace. We've got electric back up systems here, but we're having a little trouble holding altitude and everything." The pilot then asked, "What's the bottom of the cloud layer? We're IFR at this time." When told cloud bases in the area were "around 13,000 [feet agl]," the pilot advised he wanted to descend and "get below the bases." He was cleared to descend and maintain 14,000 feet. At 1521:47, the controller asked the pilot if he wanted to "continue on to Wichita or [if he wanted to] land early [at Albuquerque]." The pilot answered, "If we can get down below the cloud layer, we'd like to get to Liberal, Kansas, if we could." (It was later learned that the airplane was scheduled to undergo an annual inspection the next day at a maintenance facility in Liberal, Kansas.) The controller acknowledged and instructed the pilot to contact a different air route traffic control center (ARTCC) sector. Before the pilot could do so, at 1524:35, he reported, "We're having trouble. I think we're in a spin." Fifteen seconds later the pilot reported, "We're back with you," and said he was at 18,000 feet. He was then instructed to contact Albuquerque Approach Control. When the pilot contacted Albuquerque Approach Control at 1526:06, he verified that he was at 17,600 feet, and added, "We've lost both our vacuum pumps, and I think we just went through a roll. We've got electric driven backup systems -- electric horizon and electric compass -- and they're not agreeing with each other at this time. We're gonna need some help." The controller asked the pilot is he was "stable there at one seven thousand four hundred," to which the pilot replied, "Negative. . .we're not necessarily stable." At 1526:48 the pilot said, "Nine November Lima, we're going to need some help!" At 1527:07 the pilot said, "We're at one four thousand four hundred [feet]." At 1527:20 the pilot radioed, "Nine November Lima, we're going down. We're dead." Eleven witnesses, six of whom submitted written statements, reported seeing a wing separate from the airplane, then observed the airplane spiral vertically to the ground. Three witnesses were at the bottom of the Sandia Peak Aerial Tramway (see WITNESS LOCATION MAP). Their attention was drawn to the sound of an airplane engine "racing, as if it was pulling out of a stall or dive." The airplane "was already in a pure vertical spin" when one of the three witnesses saw it emerge from the cloud base. "There was no spiral component to its attitude." After the airplane made a couple of revolutions, he saw a "puff" at one of the wing roots, followed by the wing separation. The airplane continued to spin "in the pure vertical. . .traveling approximately 300 knots straight down." He added that the engine sounded like it was at full throttle. Another of the three witnesses said the airplane "broke over the top of a loop" when he first saw it. "As I watched it go over it started straight down and it was somewhere at this time I saw something come off the plane." The airplane continued "straight down." The engine "sounded like it was running." Two witnesses were at a home located at 1063 Red Oaks (see WITNESS LOCATION MAP) when they heard and saw the airplane. One witness said the engine sounded "stressed out." The other witness said the plane "spiraled clockwise, at a tremendous speed, vertically into the ground. . .The left wing was missing. . ." Another witness was working on the roof of house at 1179 Laurel Pl., S.E. (see WITNESS LOCATION MAP) when he heard what sounded like "a plane diving at full power." The sound subsided momentarily, then returned. The witness looked up and saw the airplane in a vertical dive. The plane rotated and he could see only one wing. The accident took place during the hours of daylight at a location of 35 degrees, 10.255 minutes north latitude, and 106 degrees, 26.422 minutes west longitude, or about 20 DME miles out on the 055 degree radial from the Albuquerque VORTAC (Very high frequency omnidirectional radio range tactical air navigation). PERSONNEL (CREW) INFORMATION The pilot, age 42, held a private pilot certificate, dated July 13, 1994, with airplane single-engine land and instrument ratings. He also held a repairman certificate, dated July 13, 1994, and a third class airman medical certificate, dated May 27, 1998, with the restriction that the holder shall wear corrective lenses. Two pilot logbooks were recovered at the accident site. The first logbook contained entries from May 3, 1980, to January 21, 1998. The second logbook contained entries from January 21, 1998, to December 23, 1998. The pilot had logged 1,345.4 total hours, of which 491.3 hours were in the Cessna P210N. An additional 98.9 hours were accrued in the Cessna T210, and 5.9 hours were logged in a Cessna 210 simulator at Flight Safety International in Wichita, Kansas (a summary of the pilot's flight time is attached as an exhibit to this report). According to Flight Safety International (FSI) training records, the pilot attended Cessna 210 Pilot Proficiency Training Courses in May 1993, January 1996, and December 1998. In each case, he satisfied the requirements of FAR 61.56 (flight review) and FAR 61.57 (instrument competency check). Each course consisted of 8 to 16 hours of classroom instruction, written tests, and training sessions in the flight simulator and the Cessna P210N airplane. The FSI instructor said that during one of the training sessions, he failed the Cessna 210 simulator's vacuum system to test the pilot's "partial panel" skills. He said that the pilot recognized the failure and resorted to partial panel without difficulty. The FSI simulator differs from N79NL in that the directional gyro (heading indicator) is electrically driven as opposed to being vacuum driven. Thus, when the vacuum system was failed in the simulator, only the artificial horizon (attitude indicator) was disabled. AIRCRAFT INFORMATION N79NL (s.n. P21000260), formerly N4690K, was manufactured by the Cessna Aircraft Corporation in 1979. It was equipped with a Continental TSIO-520-P engine (s.n. 278702-R), rated at 310 horsepower, and a McCauley D3A34C402C propeller (s.n. 971982). The last annual inspection was performed on January 8, 1998, when the airframe had accrued 2,705.5 total hours (tachometer 1,305.5 hours). The rebuilt engine, which had been installed on December 9, 1994, had accrued 570.6 hours. At the time of the annual inspection, a new McCauley propeller was installed. The recording tachometer was not found in the wreckage but, based on the pilot's logbook, the airplane flew another 151.7 hours from the time of the annual inspection until December 23, 1998, the date of the last logbook entry. It is estimated that at or near the accident date, the airframe, engine, and propeller had accrued 2,857.2, 722.3, and 151.7 total hours, respectively. Both altimeters, the static system, altitude reporting system, and transponder were recertified for IFR operations on December 12, 1997. The airplane maintenance records were reviewed, concentrating on those items pertaining to the vacuum pumps, vacuum gauge, filters, associated plumbing, and instruments used for flight in instrument meteorological conditions, to wit: 08/29/87 Installed Cessna Kit SK210-103B, dual vacuum pump kit. TACH 60.8, ATT 1,452.2. 03/24/94 Replaced vacuum pump p/n 212CW, s/n 08AH003048, and filter. TACH 580.9. 08/03/94 Replaced left side vacuum pump with p/n 212CW, s/n 03AK001308 unit, replaced vacuum filter. HOUR METER 668.0 08/28/96 Replaced central vacuum filter p/n C294502-0201. Found vacuum pump inop. Removed old pump p/n 212CW, s/n 08AH003048, and installed new pump p/n 212CW, s/n 3AM000830. Ops check OK. RECORDER 1,097.6. 10/02/96 Repaired electric turn coordinator C661003-0506, s/n 803-446. 11/01/96 Installed standby electric gyro horizon. TACH 1,108. 01/08/98 Vacuum gauge not working. Sent out for repair. L/R source button full of carbon. Overhauled by Kelley Instruments. Reinstalled. RECORDER 1,305.5, ATT 2,505.5. 06/19/98 Installed new Sigma-Tek vacuum pump m/n 1U128B, s/n T31443H, new filter C294502-0201, and two new B3-5-1 regulator filter bands. TACH 1,426.2. METEOROLOGICAL INFORMATION The following are the weather conditions that were observed at Albuquerque International Airport two minutes before and three minutes after the accident: 1525 MST: Wind 220 degrees at 14 knots; visibility 10 statute miles; ceiling broken 6,500 feet; temperature 14 degrees C. (57.2 degrees F.); dew point 0 degrees C. (32 degrees F.); altimeter 29.85 inches of mercury. 1530 MST: Wind 230 degrees at 10 knots; visibility 10 statute miles; ceiling broken 6,000 feet; temperature 14 degrees C. (57.2 degrees F.); dew point 0 degrees C. (32 degrees F.); altimeter 29.86 inches of mercury. At the time of the accident, SIGMET (Significant Meteorological Advisory) Whiskey 6, AIRMETs (Airmen's Meteorological Information) Sierra Update 4 and Zulu Update 4, and a PIREP (Pilot Report) were in effect (see exhibits). SIGMET Whiskey 6, which included New Mexico and was valid at the time of the accident, called for "moderate occasional severe turbulence below FL 180 due to strong low level and mid level winds over mountainous terrain." It is not known whether the pilot was aware of this SIGMET. AIRMET Sierra Update 4, which included Arizona and New Mexico and was valid at the time of the accident, called for "mountains occasionally obscured in clouds, precipitation, mist." It is not known whether the pilot was aware of this AIRMET. AIRMET Zulu Update 4, which included New Mexico and was valid at the time of the accident, called for "occasional moderate mixed icing in clouds and precipitation between freezing level at FL 2000. Freezing level 8,000 to 12,000 feet." It is not known whether the pilot was aware of this AIRMET. The PIREP was filed at 1519 by a Cessna 172 pilot flying at 12,500 feet and 56 miles southwest of the Albuquerque VORTAC. He reported an 8,000 foot broken cloud layer, a west-southwesterly wind at 30 knots, light turbulence, and scattered rain showers. WRECKAGE AND IMPACT INFORMATION Access to the accident site was gained on January 21, 1999. Light snow had fallen during the previous 24 hours. The wreckage was spread out in a fan-shaped pattern on a heading of 155 degrees. The propeller blades were buried in the ground underneath the engine. Next to the engine was the instrument panel. Nearby lay the wing carry-through spar with the left portion lying to the left of the flight path. Just beyond were portions of the left wing. The fuselage, horizontal stabilizer, elevator, and vertical stabilizer lay nearby. Parts of the left wing containing the stall warning vane were identified. The engine was turned over and the Parker Hannifin vacuum pump was removed from its left mounting pad which remained attached to the engine case. The second vacuum pump, a Sigma-Tek, was broken off the right mounting pad and was buried underneath the instrument panel. The right wing could not be accounted for and it was determined that it had separated from the airplane during the breakup sequence. It was later found by hikers and recovered by the salvage company on April 15, 1999. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed on the pilot by the New Mexico State Medical Examiner's Office. A toxicological screen was not possible due to the paucity of remains and identification difficulties. TESTS AND RESEARCH Radio transcripts were collated with the airplane's flight path and encoded altitude as derived from NTAP (National Track Analysis Program) data and studied. The data showed N79NL departing runway 21 at Scottsdale, making a right turn to a 090 heading, then joining J 18 (the filed flight plan route was Scottsdale direct Wichita). Shortly after 1500, the airplane began to make slight heading and altitude deviations (from FL 230). It was at 1519:10 when the airplane was just north of the Albuquerque VORTAC that the controller asked the pilot to verify his altitude. The pilot replied he had lost both vacuum pumps. At that time, N79NL's altitude varied between FL 228 and FL 229 feet. At 1520:38, the pilot was cleared to descend to 14,000 feet. He acknowledged the clearance. Yet at 1522:32, while just north of Albuquerque International Airport, the airplane was still at FL 220. At 1523:27, it was at FL 214. At 1524:28, it was at FL 193, a loss of 2,100 feet. Seven seconds later and 1,300 feet lower (a calculated descent rate of 11,143 feet per minute, or 110 knots vertical velocity), when the airplane was at FL 180, the pilot said: "I think we're in a spin." At 1524:50, at an altitude of 17,100 feet msl (above mean sea level), the pilot said: "We're back with you." At 1526:06, the controller asked the pilot to verify that he was at 17,600 feet and the pilot replied, "That's affirmative (NTAP data also showed an encoded altitude of 17,600 feet). . .we've lost both our vacuum pumps, and I think we just went through a roll. We've got electric driven backup systems -- electric horizon and electric compass -- and they're not agreeing with each other
Total failure of the vacuum system, and failure of the pilot to maintain aircraft control, resulting in wing spar failure. Factors were the pilot's spatial disorientation, and his exceeding the design stress limits of the airplane.
Source: NTSB Aviation Accident Database
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