History of Flight
On August 19, 2016, at about 1053 mountain daylight time, an Aero Commander S2R airplane, registration N8870Q, impacted terrain near Center, Colorado, while conducting a low-level agricultural spray flight. The commercial pilot sustained fatal injuries, and the airplane was destroyed. The aircraft was operated by Rocky Mountain Ag under Title 14 Code of Federal Regulations Part 137. Day visual meteorological conditions prevailed, and no flight plan was filed. The flight originated from Monte Vista Municipal Airport (MVI), Monte Vista, Colorado.
The operator's records indicate the pilot departed for his first application flight at about 0645, returned for reloading, and made five additional departures, with the last at about 1025. Cell phone records show the pilot was texting during periods that coincided with flight times; a text message was sent at 1038. Police dispatch received the first 911 call at 1053.
Witnesses reported the airplane was making spray passes over a field and appeared normal. One witness observed the airplane make a turn, "pulled up to the sky," and seemed to "stall at the top of the turn." The engine became quiet, and the airplane spiraled nose-first into the ground. Responders found the pilot unresponsive and assisted in extricating him.
Personnel Information
The 27-year-old pilot held a commercial pilot certificate with a single-engine land rating. According to his logbook, he had flown about 450 hours from December 2013 to July 2015, including 81 hours in an Aero Commander and 53 in the accident airplane. His most recent second-class medical certificate, issued May 19, 2016, had no limitations. On that application, he reported approximately 2,000 total flight hours and 600 hours in the preceding 6 months.
Aircraft Information
The 1969-model Aero Commander S2R was a single-seat, low-wing, fixed-gear airplane designed for aerial agricultural application. It was powered by a Walter Engines M601E-11 turboprop engine (serial number 894047) and equipped with an Avia V 508E-AG/106/A three-bladed propeller. The most recent annual inspection occurred on May 21, 2016, at 11,388 total airframe hours. The most recent 100-hour engine inspection was on July 16, 2016, at an hour meter reading of 4,601 hours. The engine had been overhauled by Walter Engines on March 14, 2006, and installed in the airplane on April 6, 2012, at 3,685 hours.
Wreckage and Impact Information
The airplane impacted a wheat field. Postcrash fire consumed the nose section, fuselage, empennage, and landing gear. About 75% of the outboard wing sections remained, exhibiting impact damage and severe leading-edge crushing. The wreckage was recovered.
On September 15, 2016, the NTSB, FAA, and GE Aviation conducted a wreckage layout. Flight control continuity was established from all surfaces to the cockpit area, but the control stick connection could not be verified due to thermal damage. The engine had significant impact damage and was separated from the airframe. The exhaust case and nozzles were deformed. The fuel pump, fuel control unit, and starter generator were separated; accessory gearbox and fuel control unit showed postimpact fire damage. The fuel filter contained a trace amount of fuel and two nonmagnetic, deformed metal balls; their source could not be determined. The engine generator would not rotate. The power turbine blades were separated at the airfoil, consistent with power at impact. First-stage axial compressor blades showed rubbing against the stator, also consistent with power at impact. The reduction gearbox chip detector was clear. The oil filter appeared dark with small metal debris, consistent with normal operation. The propeller was impact-separated; two of eight attachment bolts had separated heads, and six had sheared threads. The propeller shaft did not rotate. Two of three blades were separated at the hub and bent opposite to rotation direction, consistent with engine power at impact.
Medical and Pathological Information
An autopsy by the El Paso County Coroner determined the cause of death as multiple blunt force injuries, with the manner accidental. The pathologist noted early coronary artery disease (10% to 25% stenosis in the right coronary artery) but no other significant natural disease. Toxicology testing by the FAA detected 0.013 ug/ml of diphenhydramine in iliac blood, below the therapeutic range (0.0250 to 0.1120 ug/ml). Carbon monoxide and alcohol tests were negative. Diphenhydramine is a sedating antihistamine; the level found was low.
The operator's records showed that in the week before the accident, the pilot had applied various agricultural chemicals, including insecticides, fungicides, herbicides, and fertilizers. The pilot's family reported he occasionally managed tank filling, but on the accident day, the operator stated the pilot did not mix or fill the tank. The airplane lacked a ventilation system. No reports indicated the pilot complained or behaved unusually.
Tests and Research
The airplane was equipped with a SATLOC M3 system with a differential GPS receiver and capability to record data to a compact flash card. The device was sent to the NTSB Vehicle Recorder Laboratory, but severe heat damage prevented data recovery.