Piper PA-32R-300 N4478F accident near Sevierville, Tennessee

Probable cause

The air traffic controller’s failure to comply with the required vectoring and safety alert procedures, which resulted in the airplane’s flight into rising terrain. Contributing to the accident was the Federal Aviation Administration’s continued practice of using air traffic controllers who were performing required radar operational duties to supervise other controllers and the air traffic control facility’s culture of non-compliance with required procedures.

NTSB analysis

Before departure, the pilot had contacted the air traffic control (ATC) facility and received his instrument flight rules (IFR) clearance, which entailed flying direct to a navigational facility about 22 miles west of the departure airport. Shortly after departure, the pilot contacted ATC, and was given radar vectors toward that navigational facility and toward rising terrain. Because the airplane was in instrument conditions, the pilot was unable to see the surrounding terrain. When the airplane’s global position system's terrain feature alerted the pilot of a possible terrain issue, the pilot queried the air traffic controller. However, before the controller responded, the airplane impacted a pole and trees; a postimpact fire ensued and consumed the airplane.

The Federal Aviation Administration (FAA) defines minimum vectoring altitude (MVA) as the lowest altitude at which an IFR aircraft will be vectored by a radar controller to ensure obstacle clearance. The FAA further states that air traffic controllers are to give first priority to separating aircraft, issuing safety alerts, and providing safety alerts regarding terrain or obstructions.

Despite FAA requirements, a review of accident-related ATC radar and voice data revealed that ATC personnel issued a radar vector without first identifying the accident airplane on radar, provided radar vectors when the airplane was below the MVA, and did not provide safety alerts to the accident airplane or another airplane that had departed just before the accident flight. Interviews with the accident ATC personnel indicated that a facility-wide culture of providing vectors to aircraft below minimum altitudes existed, air traffic controllers supervised other controllers while performing operational duties, and the facility was non-compliant with safety alert requirements. The accident air traffic controller failed to adhere to the required procedures for vectoring and providing appropriate safety alerts, which negated the safety margins afforded by those procedures. This culture of disregard for standard operating procedures among the controller workforce at the ATC facility was indicative of a continuous failure of management at the facility.

Text from the NTSB. Open the NTSB docket for ERA13LA042 for the full record.