History of Flight
On May 9, 2011, at about 0915 mountain daylight time, an Air Tractor AT-802A, registration N8523H, sustained substantial damage when it impacted terrain approximately 11 miles east of Frank Wiley Field Airport (MLS) in Miles City, Montana. The commercial pilot, who was the sole occupant, was fatally injured. The airplane was registered to and operated by Taylor Aviation of Fort Benton, Montana, under Title 14 Code of Federal Regulations Part 91. Visual and instrument meteorological conditions prevailed at the time, and a visual flight rules flight plan had been filed for the repositioning flight. The cross-country flight originated from Aberdeen, South Dakota, at about 0752 central daylight time, with an intended destination of Fort Benton and an intermediate fuel stop at MLS.
According to the Federal Aviation Administration (FAA), the operator contacted them on the evening of May 9 after becoming concerned when the pilot did not arrive at the intended destination. The FAA issued an Alert Notification (ALNOT). The Montana Aeronautics Division, United States Air Force, local law enforcement, and volunteer pilots conducted search and rescue operations. The wreckage was located by aerial units on the afternoon of May 10.
A witness located about 0.3 miles northeast of the accident site reported hearing an airplane flying low and fast from east to west, followed by a "poof" sound. She did not see the airplane or smoke. She noted a cloud layer covering the mountain ridge to the west and light rain mist with good visibility below the clouds.
According to a company representative, the pilot was returning from Wisconsin after completing an aerial firefighting contract and was relocating the airplane to Fort Benton.
Lockheed Martin Flight Service records show the pilot contacted a weather briefer at 0733 central daylight time. The pilot filed a VFR flight plan from Aberdeen to Fort Benton with a fuel stop at MLS, declined a weather briefing, stating he had the weather information. About four minutes later, he activated his flight plan and again declined a weather briefing.
Pilot Information
The pilot, aged 65, held a commercial pilot certificate with ratings for airplane single-engine land, multi-engine land, and instrument airplane. He also held a flight instructor certificate with single-engine land and instrument airplane ratings. He was issued a second-class medical certificate on November 12, 2010, with a limitation requiring corrective lenses. On an Interagency Airplane Pilot Qualifications Approval Record dated February 7, 2011, he reported 18,824 total flight hours, including 73 hours of simulated instrument and 7.7 hours of actual instrument flight. He had 172 hours in the previous 12 months and 80 hours in the previous 60 days. His most recent flight review was on March 8, 2010, in the accident make and model.
Aircraft Information
The single-seat, low-wing, fixed-gear airplane, serial number 802A-0162, was manufactured in 2003. It was powered by a Pratt and Whitney PT6A-67AG engine, serial number PCE-RD0085, rated at 1,350 horsepower, and equipped with a Hartzell model HC-B5MA-3D five-bladed adjustable pitch propeller. The airplane had instruments for visual flight rules only. The most recent annual inspection was completed on February 26, 2011, at an airframe and engine total time of 1,406.6 hours.
Meteorological Information
A National Transportation Safety Board (NTSB) meteorologist prepared a factual report. The National Weather Service (NWS) Surface Analysis Chart issued at 0900 depicted a stationary front just southeast of the accident site. Station models west of the front showed temperatures in the low 50s Fahrenheit, temperature-dew point spreads of 3 degrees or less, northeast winds 5 to 15 knots, overcast skies with light rain and mist. East of the front, temperatures were mid 50s, dew points near 50, east winds 5 to 15 knots, overcast skies, and mist. The accident site was north of the frontal boundary in the cold air sector.
At Frank Wiley Field Airport, the closest weather reporting facility, located 11 miles west of the accident site at an elevation of 2,630 feet msl, the 0853 METAR reported wind from 050 degrees at 11 knots, visibility 2 statute miles, mist, overcast ceiling at 700 feet, temperature 12°C, dew point 11°C, altimeter 29.62 inHg, and variable ceiling from 400 to 1,100 feet. A special unscheduled METAR at 0919 reported wind from 060 degrees at 12 knots, visibility 2 statute miles, mist, temperature 12°C, dew point 11°C.
The amended NWS Terminal Aerodrome Forecast (TAF) valid at 0627 expected wind from 330 degrees at 11 knots, visibility 6 miles with light rain showers, broken ceiling at 1,300 feet, and overcast at 4,500 feet. Temporary conditions between 0600 and 0900 MDT expected visibility of 1 mile with moderate rain and mist, and a broken ceiling at 500 feet.
Wreckage and Impact Information
Examination of the accident site revealed wreckage debris and broken tree limbs scattered along a 368-foot debris path on an approximate 212-degree magnetic heading from a cluster of damaged 50 to 60-foot tall trees. The first identified point of contact (FIPC) was at an elevation of about 3,077 feet msl, where a portion of the left wing tip and red navigation lens were found. The debris path extended to the main wreckage at 3,137 feet msl. All major structural components, including primary flight controls, were located along the path. Numerous trees 18 to 20 inches in diameter were topped and damaged at various heights.
Examination of the airplane showed impact damage to the hopper, forward cockpit, and bottom fuselage. The fuselage was separated just aft of the baggage compartment. The instrument panel was displaced forward into the hopper. The chemical hopper was partially separated. The engine firewall was buckled. The cabin area was mostly intact. The right forward wing spar remained attached but bent aft; the right wing structure was completely separated. The left forward wing spar was curled around the fuselage and bent forward; the left wing structure was also completely separated. Flight control continuity was established from cockpit controls to all primary surfaces, with overload separations observed. An elevator trim actuator was damaged, preventing position determination.
The engine exhibited impact deformation without fire damage. The reduction gearbox forward housing was separated. Circumferential contact signatures were noted on turbine components. The propeller assembly remained attached; blades showed various damage: one blade separated, twisted with trailing edge ripples; another separated with ripple; one attached but bent aft and twisted; another attached and bent 90 degrees; the fifth attached with bend and twist. One counterweight separated. The propeller hub components were separated with impact damage. No preimpact mechanical malfunctions were found.
Medical and Pathological Information
An autopsy conducted by the Custer County medical examiner on May 10, 2011, determined the cause of death as multiple blunt traumatic injuries. Toxicological tests performed by the FAA's Civil Aeromedical Institute were negative for carbon monoxide, cyanide, volatiles, and drugs.
Tests and Research
A Garmin GPSmap 496 hand-held GPS was recovered from the wreckage. The NTSB Vehicle Recorders Laboratory successfully downloaded data from the unit. The data for the accident flight showed departure from Aberdeen, followed by a northwesterly course at altitudes between 1,300 and 5,800 feet msl. About 1 hour 29 minutes later, a left turn to a southwesterly course from 5,869 feet was followed by a descent to about 3,819 feet. Over the next 23 minutes, the flight path turned northwesterly with varying altitudes between 3,805 and 3,054 feet, featuring numerous climbs and descents. A 30-degree right turn from about 3,054 to 3,241 feet was followed by a left turn to westerly heading, then a right turn, and finally a left turn to the southwest at about 3,406 feet. The last recorded data point was at an altitude of about 3,284 feet. The accident site was located about 0.15 miles southwest of that position.