The non-instrument-rated pilot was conducting a cross-country flight in his homebuilt RV-7A.
GPS data indicated that the plane departed and then proceeded west-southwest at an initial altitude of about 4,500 ft mean sea level (msl). About 20 minutes later, the airplane’s track deviated from its initial heading, and it began to climb.
It continued to climb at a slower groundspeed and reached a maximum recorded altitude of 7,769 ft msl; the groundspeed had slowed to 75 knots.
It then began a descending right turn, during which it reached a maximum groundspeed of 208 knots. During this time, it was descending through 5,364 feet msl, and its descent rate reached more than 3,000 feet per minute (fpm).
The last recorded point showed the airplane descending through 4,094 feet msl. During the last 52 seconds of the recorded data, the airplane lost 3,675 feet of altitude, and the descent rate had increased to more than 4,000 fpm.
The plane hit a field near Russell, Iowa, killing both souls on board.
Examination of the wreckage revealed evidence consistent with a near vertical impact.
A mechanic reported that the airplane’s mechanical fuel pump had been replaced a few days before the accident; however, if the mechanical fuel pump had failed it would not have caused the steep descent during the final portion of the flight.
Additionally, the electric fuel pump was operational and would have supplied the fuel necessary for engine operation.
The pilot was receiving flight-following services from air traffic control during the accident flight. In his last communication, he reported to a controller that he had entered instrument meteorological conditions (IMC) and was trying to get “back on track”; he made this communication about the same time as the GPS data showed the airplane in the steep descending right turn.
The controller advised the pilot to maintain visual flight rules, but he did not respond.
Weather conditions in the area at the time of the accident included overcast ceilings of 1,200 to 1,300 feet above ground level.
No record was found indicating that the pilot received a preflight weather briefing; however, it could not be determined if the pilot obtained weather information using other sources.
The restricted visibility conditions would have been conducive to the development of spatial disorientation, and the airplane’s rapidly descending turn were consistent with the non-instrument-rated pilot inadvertently entering IMC and then losing airplane control due to spatial disorientation.
The NTSB determined the probable cause as the non-instrument-rated pilot’s inadvertent entry into instrument meteorological conditions, which resulted in his spatial disorientation and the subsequent loss of airplane control.
NTSB Identification: CEN14LA424
This August 2014 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.