FTW97FA067

The airplane collided with rugged, mountainous terrain while on a VFR cross country flight. According to all available information, the airplane was en route at an altitude between 9,000 and 13,000 feet MSL. Mountain peaks along the route of flight were in the 9,000 to 13,000 foot range. Area Pilot Reports (PIREPS) 16 for light airplanes, and weather observations confirmed that the airplane had flown into about 50-55 knot upper level headwinds, and through moderate to severe turbulence. One PIREP indicated that 'up' and 'down' drafts exceeded 1,000 feet per minute. Another PIREP indicated that 'stacked lenticular clouds were observed at a magnitude that he had not seen before.' According to the NTSB Meteorology Factual Report, the airplane was in severe to extreme turbulent air, and that mountain wave conditions may have been present at the time of the accident. The 8,200 hour pilot was familiar with the route of flight, and no condition of incapacitation was found during the autopsy. Examination of the airframe, engine, and propeller did not reveal any evidence of pre-impact failure(s).

History of flight

On December 21, 1996, approximately 1300 mountain standard time, a Beech A36 single engine airplane, N3869A, was destroyed upon impact with terrain and a post impact fire near Chacon, New Mexico. The instrument rated private pilot and 5 passengers (one of which was pilot rated) were fatally injured. Visual meteorological conditions prevailed, and a flight plan was not filed for the Title 14 CFR Part 91 personal cross country flight. After departing from the Raton Municipal Airport, Raton, New Mexico, approximately 1200, the airplane was en route on a 427 nautical mile flight to the Glendale Municipal Airport, Glendale, Arizona. The airplane was owned and operated by the pilot.

According to family members, the pilot flew the airplane from Glendale to Raton earlier in the day to pick up 5 family members for a return flight back to Glendale for the holidays. An airport worker at the Raton Airport reported that when the pilot arrived at Raton, he checked the weather for the return flight to Glendale. He also reported that the pilot commented that the flight from Glendale was "rough", and said that if it was that bad going back, he was going to "head south along I-25", then cut back to the west to avoid going directly over the mountains. The airport worker did not have any further contact with the pilot other than this brief conversation, and to the best of his recollection, the airplane departed Raton about 1200 for the return flight to Glendale.

The pilot's wife reported that the airplane was overdue on the afternoon of December 21st, and a search was initiated. That same afternoon (approximately 1330), a local resident reported that he saw "smoke" coming from a remote area in the Sangre de Cristo mountain range [this person reported this information after the wreckage had been located]. The wreckage was located in heavily wooded, steep terrain (elevation: approximately 9,200 feet MSL) by search and rescue aircraft from Kirkland Air Force Base, Albuquerque, New Mexico, in the early morning hours of December 22nd. A law enforcement officer from the New Mexico State Police, aided by an ELT signal, was able to reach the site by helicopter to attempt a rescue; however, no survivors were found.

Heavy snowfall in the early morning hours of December 22nd covered the mountain and adjacent valleys. Local mountain rescue authorities and the NTSB investigation team reached the accident site by foot about 1200 on December 22nd.

Personnel information

The 72 year old, 8,200 hour pilot held a private pilot certificate with a single engine land rating, originally issued on June 19, 1956. He added an instrument rating on April 30, 1971. According to all available records, the pilot had about 2,300 hours of flight time in the "V" tail Beech Bonanza (V35B), and about 5,800 hours in the Beech A36. He had completed Phase II of the FAA Professional Pilot Program, and according to family members, flew the accident airplane on a "regular" basis, and that he always was "safe and careful" about flying.

Aircraft information

The Beech model A36 airplane, serial number E-1853, was manufactured in 1981 and had a valid normal category airworthiness certificate. According to all available records, the airplane's total time was about 3,739 hours. The last annual inspection on the airplane was accomplished on August 8, 1996, at a time of 3,689 hours.

The fuel injected engine, a Continental model IO-520-BB, serial number 274506-R, was taken out of service for overhaul on March 11, 1996. According to a copy of the original work order [No. 5879] for the overhaul, the engine had a tachometer time of 3,609.7 hours at the time of overhaul. After the overhaul work was completed the engine was reinstalled in the airplane, and was returned to service on April 30, 1996.

According to annotations on the aforementioned work order No. 5879, the following engine accessories were also overhauled at the time of the engine overhaul:

[1] Starter, part number 646275, serial number Z1886233 [2] Alternator, part number 646843, serial number C058716 [3] Magneto-Left, part number 10-349350-4, serial number 646958 [4] Magneto-Right, part number 10349350-5, serial number 646957

Meteorological information

The following information is a summary of findings in the NTSB's Meteorology Group Chairman's Factual Report, dated April 15, 1997. The full detailed report is attached to this document.

The nearest surface weather reporting facility to the accident area was Las Vegas, New Mexico, elevation 6,873 feet MSL, located about 34 miles southwest of the accident site. The observations from this facility at 1250 were:

Wind, 280 degrees at 23 knots gusting to 30 knots, wind variable from 240 degrees to 320 degrees; Visibility-35 miles; Present Weather, none; Sky Condition, few 7,000 feet, overcast 15,000 feet; Temperature 46 degrees F; Dew Point 10 degrees F; Altimeter Setting, 29.72 inches hg; Remarks, peak wind 290 degrees at 38 knots, breaks in overcast.

A resident of Mora County, New Mexico, who was located about five miles from the accident site, stated his local weather observations of December 21, 1996, in a letter to the NTSB. The following is an excerpt of the letter: "The weather all day had been mostly clear to scattered clouds, with very strong winds [of] 40 to 60 knots or higher, a few showers of light snow in the late afternoon, visibility 1/4 to 1/2 miles in [the] showers."

Another local resident, a rancher on whose property the accident occurred, stated that "heavy winds were shaking" their family's mobile home [located in the valley directly below the mountain peak where the accident occurred] during the afternoon of the accident. The rancher further stated that strong winds were typical for that time of year, "but the wind on this particular day was more than usual." The rancher's wife also added that their screen porch door was caught by the wind "and torn off."

A pilot, who was flying a Piper Warrior on the west side of the Sangre De Cristo mountain range at about 1400 on December 21st, reported that he observed "stacked lenticular clouds of a magnitude that he had never seen before." The reported clouds were oriented northeast-southwest along the eastern edge of the Sangre De Cristo range. He reported that the cloud bases were approximately 15,000 feet. In addition, the pilot said that "it was very difficult to maintain altitude, with up and down drafts of 1,000 feet, and wing rolls of 45 to 60 degrees." After experiencing the turbulence, he elected to not cross over the range directly, and re-planned his route to go around the range. He further stated that he had been flying in mountainous areas for "many" years and had about 4,000 hours of flight time in light airplanes.

Sixteen (16) light airplane pilot reports (PIREPS) were referenced in the Meteorology Factual Report. These PIREPS indicated that moderate to severe turbulence was being encountered in New Mexico and Colorado on December 21st, between 8,000 and 13,000 feet MSL.

Winds and temperatures aloft, numerical model forecasts, upper wind observations, and PIREPS showed evidence that the 9,000 to 12,000 foot MSL winds (mountain top) in the accident area were generally from the west at 50-55 knots. In addition, surrounding radiosonde soundings showed either isothermal or temperature inversion layers in the range from around 9,000 to 13,000 feet MSL. The accident occurred just downwind from a mountain range with peaks exceeding 10,000-11,000 feet MSL.

In summary, data that was compiled in the Meteorology Factual Report showed evidence that meteorological conditions could have been present for the airplane to have encountered severe to extreme turbulence at the time of the accident. Also, the data show evidence that low level wind shear could have been present in the range of altitudes (9,000 to 13,000 feet MSL) that the a