Into the Winds of Angel Fire: Mooney M20E, N3484X

By N.T.S.B. — January 27, 2014

On March 3, 2013, about 1320 Mountain Standard Time (MST), a Mooney M20E, N3484X, impacted terrain after departing the Angel Fire Airport (KAXX), Angel Fire, New Mexico. The private pilot and three passengers were fatally injured. The airplane was substantially damaged and a post-impact fire ensued. The aircraft was registered to and operated by Verhalen Flyers LLC, Scottsville, Texas, under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which operated without a flight plan. The flight was departing KAXX at the time of the accident, destined to the Dallas-Fort Worth area.

When the pilot arrived at the fixed base operator (FBO), an employee from the FBO questioned the pilot’s intent to fly in the windy weather. The pilot indicated that he planned to fly and that the winds would not be a problem. The FBO employee relayed the current wind and altimeter to the pilot when he radioed on universal communications (UNICOM) that he was taxiing to runway 17. The pilot repeated this information.

Due to snow piles on the airfield, the FBO employee could not see the takeoff and next saw the airplane airborne with a significant crab angle into the wind, about 40 degrees right of the runway heading. The airplane rose and fell repeatedly as its wings rocked. Then the employee saw the airplane’s right wing rise rapidly. The airplane rolled left, and descended inverted with the airplane’s nose pointed straight down.

An eyewitness riding in a car along Highway 434, west of the airport, saw the airplane take off from the runway. The witness perceived that the airplane was struggling to gain altitude. When the airplane climbed between 75 to 150 feet above the ground, the airplane appeared to momentarily hover before the left wing dipped quickly and the airplane descended nose first to the ground.

Personnel Information

The pilot, age 33, held a private pilot certificate for airplane single-engine land. On October 13, 2011, he was issued an unrestricted third class medical certificate. On his medical certificate application, the pilot reported having accumulated 380 total hours. The pilot’s logbook was not available for review by the investigator. Paperwork filed with the pilot’s insurance company reported that as of October 2012, the pilot accrued 459 hours, with 384 hours in the same make and model as the accident airplane.

The pilot reported to the FBO manager that he had flown the accident airplane for five years. He added that KAXX was the highest airport that he had landed at, although he had flown to some lower-elevation airports in Colorado and Wyoming on previous flights. The pilot’s experience flying out of airports with high-density altitude is not known. A cousin of the pilot who lived in the local area reported that the night before the accident he had discussed airplanes and the airplane accidents in the Angel Fire area. The pilot reported to him that flying in wind did not bother him.

Airplane Information

The four-seat, low-wing, single-engine airplane, serial number 1156, was manufactured in 1966. It was powered by a 200-horsepower, fuel-injected, Lycoming IO-360-A1A engine, which drove a two-blade, metal, constant speed Hartzell HC-2YK-1BF propeller. The airplane’s logbooks were almost completely consumed in the post-impact fire. Information retrieved showed that the airplane’s most recent annual in  85 hours, with 1,736.75 hours since major overhaul. At the accident site, the airplane’s tachometer read 4,785.84 hours.

Meterological Information

At 1315, an automated weather reporting facility located at KAXX reported wind from 250 degrees at 33 knots gusting to 47 knots, visibility 10 miles, a clear sky, temperature 47F, dew point 17 F, and a barometric pressure of 29.93 inches of mercury. Utilizing this weather, the density altitude was calculated at 9,549 feet.

KAXX and the accident site are located in a basin nearly encompassed by mountainous terrain. Mountains to the west and northwest of the airport have peaks between 10,470 and 13,160 feet. A weather study was compiled for the accident site. An upper air sound for 1400 MST depicted an unstable vertical environment, which would allow mixing of the wind on the lee side of the terrain. Winds as high as 55 knots could occasionally reach the surface. Satellite imagery between 1300 and 1400 MST recorded a large amount of standing lenticular cloud near all of the mountainous terrain around the accident site. These clouds indicated the presence of a mountain wave environment. At 0322 and 1134, the National Weather Service issued wind advisories for the accident area that warned of a west of southwest wind between 25 and 35 miles per hour with gusts to 50 mph.

A Weather Research and Forecasting (MRF) model was created to simulate the accident’s weather conditions. The WRF model indicated that the accident site at the accident time was located within a turbulent mountain wave environment, with low-level wind shear, updrafts and downdrafts, downslope winds, and an environment conducive for rotors. The pilot did not receive a weather briefing and it is not known what weather sources the pilot referenced prior to takeoff.

Airport Information

The Angle Fire Airport is located at an elevation of 8,380 feet. It has one asphalt runway, 17-35, which is 8,900 feet long by 100 feet wide. The airfield is non-towered and utilizes a common traffic advisory frequency. The departure runway was runway 17, which has a 0.6 per cent upgrade. An Automated Weather Observing System (AWOS-3) is located on airport property.

Information contained in KAXX’s airport/facility directory contains remarks such as “strong gusty crosswinds possible” and “high density altitude probable.”

Located in the airport’s FBO were posters and literature warning pilots about crosswinds, mountainous terrain, weight and balance, take off performance, density altitude, and runway 17’s upgrade.

Wreckage and Impact Information

The airplane came to rest about 0.2 miles south-southwest of the airport. It was located near the intersection of the runway’s extended centerline and Highway 434. The initial impact point was a crater on the highway’s shoulder. The crater contained acrylic glass, and near the crater was the airplane’s propeller. Fifteen feet east of the crater was the main wreckage, which was inverted. A post-impact fire consumed a majority of the fuselage and empennage. Both wings remained attached to the fuselage and displayed near-symmetric accordion crushing. Both fuel tanks were breached and empty. The left wing’s outboard section remained intact, along with its aileron. The inboard portion of the left wing around the area of the fuel tank was consumed by fire to include a majority of the left flap. The left main gear was thermally damaged and buckled. The right wing remained mostly intact, with its aileron and flap still attached at their respective locations. The right flap appeared set to 15 degrees. The right main gear was extended. The vertical stabilizer and horizontal stabilizers were buckled, torn, and thermally damaged. Flight control continuity was established from the ailerons to the cockpit controls. The rudder and elevator rods remained connected to their control surfaces until just forward of the vertical stabilizer where fire had destroyed and melted a majority of the control rods.

The propeller fractured at the propeller flange, with both blades displaying leading-edge nicks and gouges, deep, chord-wise scratches, and leading-edge polishing.

The airspeed indicator read 81 mph. The attitude direction indicator depicted a left wing low, inverted attitude. The tachometer read 2000 rpm. The altimeter’s Kohlsman window read 29.93.

Medical and Pathological Information

An autopsy conducted by the Office of the Medical Investigator of the State of New Mexico noted the cause of death as a result of multiple blunt force injuries. The manner of death was ruled an accident. The FAA Bioaeronautical Sciences Research Laboratory in Oklahoma City, Oklahoma, performed forensic toxicology on specimens from the pilot. Testing did not detect ethanol or drugs. Specimens from the pilot were not suitable to test for carbon monoxide. However, specimens from a passenger were tested and did not contain carbon monoxide.

Additional Information

An old copy of the airplane’s weight and balance, marked “superseded 6/28/02”, was located in the wreckage. Utilizing the data contained on the form and information on file with the Federal Aviation Administration, an estimated weight and balance was calculated for the accident airplane. Postmortem weights of the airplane occupants were obtained from the Office of the Medical Investigator. These weights were not corrected for clothing or water loss due to thermal injuries. Occupant seats were assumed in the forward positions for better forward centre of gravity (CG). The occupants’ baggage was consumed in the post-impact fire and could not be weighed. An estimate of 10 pounds per bag was given to the six bags reported to be on the airplane. Twenty-eight gallons of fuel were reported to be in the tanks prior to flight. The airplane’s weight was calculated at 2,518.77 pounds with a moment arm of 123.98 inches.

In chapter seven of the FAA Aeronautical Information Manual, section 7-5-6 (“Safety of Flight, Mountain Flying”) deals with hazards to pilots flying in mountainous terrain.

“High density altitude reduces all aircraft performance parameters. To the pilot, this means that normal horsepower output is reduced, propeller efficiency is reduced, and a higher true airspeed is required to sustain the aircraft throughout its operating parameters.” The chapter went on to describe the nature of air movement in mountainous areas.

“Mountain waves occur when air is being blown over a mountain range or even the ridge of a sharp bluff area. As the air hits the upwind side of the range, it starts to climb, thus creating what is generally a smooth updraft, which turns into a turbulent downdraft as the air passes the crest of the ridge. From this point, for many miles downwind, there will be a series of downdrafts and updrafts.”

About The Author

N.T.S.B.

For more information, in the U.S.A. (N.T.S.B.) The NTSB is an independent Federal agency charged by Congress with investigating every civil aviation accident in the U.S. and significant accidents in other modes of transportation-railroad, highway, marine and pipeline. WEBSITE = http://www.ntsb.gov/ For more information, in CANADA (T.S.B.) The Transportation Safety Board of Canada (TSB) is an independent agency that advances transportation safety by investigating occurrences in the marine, pipeline, rail and air modes of transportation. WEBSITE = http://www.tsb.gc.ca/eng/

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