N73000Cessna 140 · 1946

On September 8, 2019, at an undetermined time, a Cessna 140 airplane, N73000, sustained substantial damage when it was involved in an accident near Lakeview, South Dakota. The student pilot and passenger sustained fatal injuries. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 aerial observation flight.

Local law enforcement reported that according to family members, the purpose of the flight was for the student pilot and his son to fly around the local area for the aerial observation of various large water towers stationed on farms on the Rosebud Indian Reservation. It was unknown what time the airplane departed for the flight from the student pilot's private airstrip.

The student pilot would normally fly the airplane low, over the water towers, and look down into the water towers to determine the water level. He would then report the water level to the farmers. It was unknown if the pilot was compensated by the farmers for performing the aerial observation work.

After not hearing from the student pilot and his son for several hours, concerned family members contacted local law enforcement officers, who then initiated a search for the missing airplane. The wreckage was located about 0800 central daylight time on September 9, 2019, as shown in the figure.

Figure. View of the airplane looking to the south. The student pilot's private airstrip is shown in the upper right corner of the photograph near the trees.

A review of the Federal Aviation Administration (FAA) electronic airmen registry for the student pilot revealed that he held a student pilot certificate. The limitation listed on the student pilot certificate states, "carrying passengers is prohibited." Title 14 CFR 61.89 discusses the limitations for student pilots and states that a student pilot may not act as a pilot-in-command of an aircraft that is carrying a passenger. It was undetermined if the passenger was manipulating the flight controls during the flight.

A review of the student pilot's logbook showed that he started logging flight time in August 2007 and that the last logged flight was in November 2015. The student pilot had received an endorsement to conduct solo flights in a Cessna 150 airplane. The endorsement was dated October 29, 2015, and expired in July 2016. No further endorsements were found. No solo flight endorsements were found listed for a Cessna 140. Title 14 CFR 61.87(n) discusses the limitations for student pilots operating an aircraft in solo flight and states the following:

A student pilot may not operate an aircraft in solo flight unless that student pilot has received an endorsement in the student's logbook for the specific make and model aircraft to be flown by an authorized instructor who gave the training within the 90 days preceding the date of the flight.

The flight instructor who provided the initial solo endorsement for the student pilot described the student pilot as a "safe pilot" except that he flew with his son and wasn’t supposed to as a student pilot. The flight instructor reported that the student pilot was taught to fly by his grandfather, who was not a certificated pilot. He further reported that the student pilot knew he was not supposed to fly with passengers as a student pilot.

The amount of fuel in the airplane before the flight departed was undetermined. The airframe and engine were modified to use automotive fuel (referred to as MOGAS) in accordance with

FAA supplemental type certificates.

The airplane was not equipped with a carburetor temperature system or a stall warning indicator, nor was it required to be.

A review of the airplane's maintenance records revealed no evidence of any uncorrected mechanical discrepancies with the airframe and engine.

A review of weather data from 1652 to 2152 from the Miller Field Airport (VTN), Valentine, Nebraska, showed temperatures between 16°C (60.8°F) and 19°C (66.2°F), along with dew points between 11°C (51.8°F) and 12°C (53.6°F). The reported conditions for those times indicated a probability of serious icing at either cruise or glide power settings per the carburetor icing probability graph from the FAA Special Airworthiness Information Bulletin CE-09-35 Carburetor Icing Prevention.

The amount of fuel in the airplane before the flight departed was undetermined. The airframe and engine were modified to use automotive fuel (referred to as MOGAS) in accordance with

FAA supplemental type certificates.

The airplane was not equipped with a carburetor temperature system or a stall warning indicator, nor was it required to be.

A review of the airplane's maintenance records revealed no evidence of any uncorrected mechanical discrepancies with the airframe and engine.

The airplane came to rest on a heading of 24° and at an elevation of 2,910 ft above mean sea level on grass. The airplane was about 825 ft to the northwest of the approach end of runway 17 at the student pilot's private airstrip.

The airplane sustained substantial damage to both wings, the fuselage, and the empennage. Evidence was consistent with the airplane impacting terrain in a near-vertical, nose-down, left-wing-low attitude. The tail was bent slightly up and over the fuselage. The left- and right-wing leading edges sustained significant impact compression damage. All components of the airframe and engine were located at the accident site. Flight control continuity was established for the airframe. Control continuity was established for the engine.

A flap impact-related witness mark was observed on the right side of the fuselage indicating the flaps were extended at the time of impact.

Due to impact damage, the position of the carburetor heat control at the time of the accident was not determined.

The two wing fuel tanks were breached from the accident sequence, and the fuel level at the time of impact was undetermined. A small amount of fuel was obtained from both fuel tanks. The fuel had unknown debris in it and was a slight yellow color.

The propeller remained attached to the engine. One propeller blade remained relatively straight and exhibited paint burnishing with diagonal scratches on the cambered side. The other propeller blade was bent aft around the engine cowling at approximately midspan and did not exhibit rotational impact signatures.

The examination revealed no preimpact mechanical malfunctions or failures with the airframe and engine that would have precluded normal operation.

The Sanford Health Pathology Clinic, Sioux Falls, South Dakota, conducted an autopsy of the pilot. The cause of the death was attributed to multiple blunt force injuries.

The FAA's Forensic Sciences Laboratory, Oklahoma City, Oklahoma, performed toxicology tests on specimens from the pilot; testing was negative for carbon monoxide and ethanol.

FAA Special Airworthiness Information Bulletin CE-09-35 Carburetor Icing Prevention informs pilots of the potential hazards associated with carburetor icing. This document does not include information about the probability of carburetor icing occurring with MOGAS. The FAA reported it has not published any information or disclaimers for the public about MOGAS and the formation of carburetor icing.