N8870QAero Commander S2R · 1969

**This report was modified on 8/2/2018.**

On August 19, 2016, about 1053 mountain daylight time, an Aero Commander S2R airplane, N8870Q, impacted terrain near Center, Colorado, during a low-level agricultural spray flight. The commercial pilot was fatally injured, and the airplane was destroyed. The airplane was registered to Air Care Leasing LLC and operated by Rocky Mountain Ag under the provisions of Title 14 Code of Federal Regulations Part 137 as an agricultural application flight. Day visual meteorological conditions prevailed for the flight, and no flight plan was filed. The flight originated at Monte Vista Municipal Airport (MVI), Monte Vista, Colorado.

A review of the operator's agricultural application records showed that the pilot departed for his first application flight of the day about 0645. The pilot returned to base, waited while the airplane was reloaded with chemical, and departed five additional times, with the last departure about 1025. According to the pilot's cell phone records, the pilot was texting during periods of time coinciding with flight times. During the accident flight, the pilot sent a text message at 1038. Police dispatch records indicated that the initial call to 911 to report the accident was received at 1053.

According to witness statements, the airplane was making spray passes over a field, and the flight appeared to be "normal." One witness reported that the airplane made a turn, "pulled up to the sky," and appeared to "stall at the top of the turn." The airplane "got quiet" and then spiraled toward the ground hitting nose first. Witnesses who responded immediately to the scene found the pilot unresponsive and assisted in removing him from the wreckage.

The pilot, age 27, held a commercial pilot certificate with an airplane single-engine land rating. According to the pilot's logbook, he had flown about 450 hours between December 4, 2013, and July 26, 2015. Of the 450 hours, 81 hours were in an Aero Commander airplane and 53 of those hours were in the accident airplane. His most recent second-class medical certificate was issued May 19, 2016, with no limitations. On the application for this medical certificate, the pilot reported about 2,000 total hours of flight experience and 600 hours in the prior 6 months.

The 1969- model-year, single-seat, low-wing, fixed-gear airplane was designed for aerial agricultural application flights. It was powered by a Walter Engines model 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 was completed on May 21, 2016, at 11,388 hours total airframe time. The most recent 100-hour engine inspection was completed on July 16, 2016, at an hour meter reading of 4,601 hours. Maintenance records indicated that the engine was overhauled at Walter Engines on March 14, 2006. The engine was installed in the airplane on April 6, 2012, at an hour meter reading of 3,685 hours.

The 1969- model-year, single-seat, low-wing, fixed-gear airplane was designed for aerial agricultural application flights. It was powered by a Walter Engines model 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 was completed on May 21, 2016, at 11,388 hours total airframe time. The most recent 100-hour engine inspection was completed on July 16, 2016, at an hour meter reading of 4,601 hours. Maintenance records indicated that the engine was overhauled at Walter Engines on March 14, 2006. The engine was installed in the airplane on April 6, 2012, at an hour meter reading of 3,685 hours.

The airplane impacted the ground in a wheat field. Examination at the wreckage at accident site exhibited the nose section, fuselage, empennage, and landing gear were consumed by postcrash fire. About 75% of the outboard sections of both wings remained and exhibited impact damage with severe leading edge crushing along their wingspans. Following the on-scene examination, the wreckage was recovered to a secure storage facility.

On September 15, 2016, the National Transportation Safety Board (NTSB) investigator-in-charge and personnel from the Federal Aviation Administration (FAA) and GE Aviation (the current owner of the Walter M601 type certificate) conducted a layout of the wreckage. Flight control continuity was established from all flight control surfaces to the cockpit area. The flight controls to the control stick could not be verified due to the extensive thermal damage to the cockpit.

The engine sustained significant impact damage and was separated from the airplane. The engine mounts and mounting ring were separated. The exhaust case and exhaust nozzles were deformed and pressed inward towards the aft end of the engine. The fuel pump, fuel control unit, and starter generator were found separated from the accessory gearbox. The accessory gearbox, fuel pump, and fuel control unit showed signs of postimpact fire.

The fuel filter was removed from the fuel pump. A trace amount of fuel was found inside the fuel pump. Two nonmagnetic, metal, deformed balls were found in the fuel filter cavity. No internal, metallic engine components showed signs of wear, spalling, or deformation that would indicate the metallic balls were from a source internal to the engine. The source of these metallic balls could not be determined.

The engine generator would not rotate. The air breather valve was found in the open condition. The power turbine (PT) blades were separated at the airfoil area, consistent with the engine producing power at impact. The first stage axial compressor blade showed signs of rubbing against the stator, consistent with the engine producing power at impact. The reduction gearbox chip detector was clear of metal chips.

The oil filter was discolored; it appeared dark with small metal debris. According to GE Aviation, the condition of the filter was consistent with normal operation of the engine.

The propeller was impact-separated from the engine propeller shaft; two of the eight propeller attachment bolts were separated with the head portions still in the engine propeller shaft. The other six bolts were found on the engine propeller flange, but the threads were sheared from the bolt shanks. The propeller shaft did not rotate. Two of the three propeller blades were separated at the hub area and bent opposite to the direction of propeller rotation, consistent with the engine producing power at the time of impact.

The El Paso County Coroner, Colorado Springs, Colorado, performed an autopsy of the pilot. The cause of death for the pilot was multiple blunt force injuries, and the manner of death was accident. In addition, the pathologist noted early coronary artery disease with 10% to 25% stenosis in the right coronary artery. No other significant natural disease was identified.

The FAA Bioaeronautical Research Laboratory, Oklahoma City, Oklahoma, performed toxicology testing on samples taken from the pilot during the autopsy. The pilot's toxicology results were negative for carbon monoxide and alcohol; 0.013 ug/ml of diphenhydramine was detected in iliac blood. Diphenhydramine is a sedating antihistamine available over the counter in a number of cold and allergy products. It carries a warning about causing drowsiness, and it is commonly the active ingredient in over-the-counter sleep aids. Its therapeutic range is between 0.0250 and 0.1120 ug/ml, significantly above the amount found in this pilot.

According to the operator's agricultural application records, in the week prior to the accident, the pilot was applying a combination of agricultural spray products that included:

Warrior II - a lambda-cyhalothrin insecticide. (Side effects: minor skin irritation, facial paresthesias.)

Bravo Ultrex - a chlorothalonil fungicide. (Side effects: contact dermatitis, conjunctivitis.)

Bravo Weather Stik - a chlorothalonil fungicide. (Side effects: same as Bravo Ultrex.)

Reglone - diquat herbicide that produces pre-harvest desiccation and defoliation. (Side effects: upper respiratory irritation, fingernail changes, skin irritation, delayed wound healing, nosebleeds. May also cause parkinsonism days after exposure.)

Compradre - contains deposition aid product, drift control agent, antifoaming agent, and a defoaming agent (Side effects: skin irritation.)

Perm-Up - permethrin insecticide (Side effects: stinging, burning, paresthesias, skin irritation.)

Fertilizer finisher ("hot mix")

Hot Mix ingredients from Stone Chemical:

1 Gallon/Acre of 7-25-5

1 Gallon/Acre of Convert 0-0-3

10.66 liquid ounces of Defender 15-0-0

The pilot's family reported that the pilot, on occasions, managed the filling of the airplane's spray tank with chemicals. It is unknown what, if any, personal protective equipment he used on these occasions. According to the operator, on the day of the accident, the pilot did not mix or fill the airplane's spray tank with chemicals. The airplane was not equipped with a ventilation system. There were no reports that the pilot complained of anything or displayed any unusual behavior on the day of the accident.

The airplane was equipped with a SATLOC M3 system that included a differential GPS receiver and had the capability to record historical information to an internal, compact flash card. The SATLOC M3 was sent to the NTSB's Vehicle Recorder Laboratory, in Washington, DC, for readout. However, examination of the device revealed that the unit had sustained severe heat damage that precluded recovery of any data.