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N8HU accident description

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Tail numberN8HU
Accident dateAugust 23, 2001
Aircraft typeAviat A-1
LocationMontrose, CO
Near 38.215278 N, -108.218889 W
Additional details: None

NTSB description

HISTORY OF FLIGHT

On August 23, 2001, at 1530 mountain daylight time, an Aviat Aircraft Inc. A-1, N8HU, was destroyed by impact with terrain during a landing attempt at Flying M&M Ranch Airfield (known locally as Sanborn Park) near Montrose, Colorado. The two airline transport certificated pilots aboard received fatal injuries. The flight was being operated under Title 14 CFR Part 91. Visual meteorological conditions prevailed for the local flight that was originating at the time of the accident. The pilot had not filed a flight plan.

A witness a Montrose Regional Airport said that the airplane departed at approximately 1420, and performed approximately six touch-and-go landings. He said the pattern altitudes they flew appeared abnormal: cross wind was at approximately 200 feet (normally 400 feet), and downwind was at approximately 500 feet (normally 800 feet). The airport operations manager watched the airplane taxi by him on its initial takeoff; he said Stephen Downs was the pilot in the front seat. At approximately 1450, the airplane departed the area, flying to the southwest.

Several witnesses observed the airplane flying in the traffic pattern at the Flying M&M Ranch Airfield. It was unclear, from the witness statements, if the airplane had made one or two landings. One witness said he saw the airplane land to the north (runway 02) and taxi to the end. He said he thought the airplane stopped, but he was not sure for how long. He said he couldn't see it very well [because of vegetation]. A second witness said the airplane departed to the south (runway 20), and began a "very low, very steep turn to the right." He said, "the airplane was not going very fast, and the wings were straight up and down." He said the airplane disappeared from view, due to terrain features, and few minutes later he observed a column of smoke. Upon investigation, he found the aircraft on fire at the approach end of runway 10.

The Montrose County coroner's office determined that Marvon Hoge was in the front seat.

PERSONNEL INFORMATION

The pilot, Marvon Hoge (front seat occupant), was trained to fly in the United States Air Force, and then flew in the airlines. On his last Federal Aviation Administration (FAA) flight medical application, dated January 24, 2000, he reported that he had 20,585 hours. His personal flight logbook was never located; it was not determined when he took his last FAA flight review. The investigator-in-charge found no documentation to indicate that he had flown this make or model aircraft before. He had been trained to be a flight instructor, but his certificate expired on August 31, 1963. He was the owner of the Flying M&M Ranch Airfield.

The owner of the airplane, Stephen Downs (back seat occupant), had documented in his personal flight logbook that he had approximately 3,591 hours of flight experience. He purchased the airplane on April 9, 1993. His flight records indicate that he had approximately 343 hours in make and model, and over 10 hours in the previous 90 days. He was trained to be a flight instructor, but his certificate expired on October 31, 2000. Stephen Downs completed a Flight Safety King Air recurrency training on August 1, 2001; he took a Part 135 check ride on the same day.

AIRCRAFT INFORMATION

The airplane was a single engine, propeller-driven (constant-speed), fix landing gear (tail wheel), two seat airplane (tandem), which was manufactured by Aviat Aircraft Inc., in 1991. It was powered by a Lycoming O-360-C1G, four cylinder, reciprocating, horizontally opposed, direct drive, air cooled, normally aspirated engine, which had a maximum takeoff rating of 180 horsepower at sea level. The airplane manufacturer's representative that the engine would produce approximately 120 horsepower at 11,000 feet density altitude. The last annual inspection was completed on August 23, 2001, and the documented engine and airframe time was 494 hours.

The airplane was certified with a maximum gross weight of 1,800 pounds. The last weight and balance determination, that could be located, was made on June 4, 1992. The empty weight was 1,250 pounds, and the useful load was 550 pounds. The two pilot's FAA medical applications indicate that their combined weight was 380 pounds. The aircraft held 50 gallons for usable fuel, or a potential weight of 300 pounds. The owner of the airplane had the fuel tanks topped off with 24.3 gallons when he returned from a six day trip to Wichita, Kansas, ending August 2, 2001. His personal flight logbook indicated that he had not flown the aircraft again until the accident flight. The airplane manufacturer’s representative calculated that the airplane was approximately 83 pounds over weight at the time of the accident.

The airplane's flight load factors were limited to the following: Flaps up, positive flight to +3.8 Gs; negative flight to -1.5 Gs.

METEOROLOGICAL CONDITIONS

At 1453, the weather conditions at the Montrose Regional Airport, Montrose, Colorado (elevation 5,759 feet), 040 degrees 22 nautical miles (nm) from the accident site, were as follows: wind 340 degrees at 5 knots; visibility 10 statute miles; clear of clouds; temperature 84 degrees Fahrenheit; dew point 39 degrees Fahrenheit; altimeter setting 30.23 inches. The calculated density altitude was 11,155 feet.

AERODROME INFORMATION

The Flying M & M Ranch Airfield (elevation 8,000 feet), Norwood, Colorado, is a private airfield. It is located on a mesa, and has two turf runways. Runway 2-20 is 4,500 by 150 feet, and has a 15 degree curve in it; runway 10-28 is 4,000 by 150 feet. The indigenous population referred to the area as Sanborn Park.

WRECKAGE AND IMPACT INFORMATION

The airplane was found (N38 degrees, 12.92'; W108 degrees, 13.13'; elevation 7,862 feet) on the end of runway 10 (a turf surface runway). It was found upright and consumed by postimpact fire. An 85 foot ground scar, on an orientation of 93 degrees, lead to the wreckage. At the beginning of the ground scar was found green position light lens material. Approximately 30 feet down the ground scar was found two propeller slashes in the soil, and approximately 25 feet further was found red position light lens material. The Montrose Count Sheriff's deputy said the airplane appeared to cart wheel to its final resting place; its fuselage was on a 265 degree orientation.

All of the airplane's major components were accounted for at the accident site. The flight control surfaces were all identified. Postimpact fire and impact damage precluded flight control cable continuity check, and any cockpit instrumentation or avionics documentation. The right wing was broken aft, rotated back, and partially separated from the fuselage. The left wing was swept aft, but in place. The engine was substantially thermal damaged. The spark plugs were removed and revealed a low service life; their color was consistent with normal combustion. The number three-cylinder intake valve push rod was bent and it was removed prior to engine rotation. When the engine was rotated, cylinder compression was verified by "thumb" testing and valve train continuity was verified. Both propeller blades displayed leading edge gouging, and rotational scoring. One blade exhibited "S" type bending.

No preimpact engine or airframe anomalies, which might have affected the airplane's performance, were identified.

MEDICAL AND PATHOLOGICAL INFORMATION

Autopsies were performed on the two pilots by the Division of Forensic Pathology, Montrose Memorial Hospital, Montrose, Colorado, for the Montrose County coroner, on August 28, 2001.

The FAA's Civil Aeromedical Institute (CAMI) in Oklahoma City, Oklahoma, performed toxicology tests on the two pilots. According to CAMI's report (#200100255001), Marvon Hoge's tissue samples were not tested for carbon monoxide or cyanide; the tests for volatiles (ethanols), and drugs, were negative. CAMI's report (#200100255002) on Stephen Downs indicates that tests for carbon monoxide, cyanide, and volatiles (ethanol's) were negative. His blood and liver samples were found to contain amlodipine (also known by the trade name Norvasc) and metoprolol (also known by the trade name Toprol). Both medications are approved by the FAA for high blood pressure control.

TESTS AND RESEARCH

Medical records on Stephen Downs indicate that in 1988, he had a transient ischemic attack, also referred to as a "mini-stroke." The FAA issued him a restricted third-class medical certificate for the year following the incident, and a restricted second-class medical certificate the year after that. Thereafter, he was issued an unrestricted second-class medical certificate. His toxicological analysis revealed two medications that he was taking for high blood pressure. The one medication, metoprolol, is in the same class as medications that have been reported to reduce G-tolerance, and these medications are not permitted for military aircrew flying high-performance aircraft.

The Flight Theory For Pilots, by Charles Dolo, indicates that a 60 degree bank maneuver requires 2 Gs of back pressure; a 75 degree bank maneuver requires a 3.86 Gs of back pressure.

ADDITIONAL DATA

The airplane, including all components and logbooks, was released to a representative of the owner's insurance company on January 23, 2003.

(c) 2009-2011 Lee C. Baker. For informational purposes only.