Amateur-built LANCAIR IV-TP N66HL accident near Sisters, Oregon

Probable cause

The pilots’ inability to maintain control of the airplane and arrest a steep spiral dive while maneuvering for reasons that could not be determined because postaccident examination could not identify any anomalies that would have precluded normal operation prior to the inflight breakup.

NTSB analysis

The purpose of the flight was for the flight instructor to conduct a flight review of the private pilot in his high-performance, experimental, amateur-built airplane. On-board data recovered from the airplane indicate that after departure, the airplane maneuvered for about 25 minutes before making a series of turns while gradually climbing. After reaching the highest altitude attained during the flight, the airplane began to descend and continued in an increasingly tightening right turn, creating a hook-type shape at the end of the radar track. This hook occurred over 15 seconds, with the airplane's pitch dropping from level to -68 degrees. This coincided with a vertical speed change from about -300 ft per minute (fpm) to a peak of -22,000 fpm, and a g-load increase to 7G, while the indicated airspeed peaked about 310 kts. The airplane broke apart in flight and the wreckage debris was scattered over an estimated 1,600-ft area of flat terrain.

The instructor was experienced in the airplane and had flown with the private pilot before. The private pilot did not hold a current medical, although he always flew with an instructor onboard. The private pilot built the airplane about 4.5 years before the accident. The autopsy reports for both pilots revealed that the cause of death was blunt force trauma and no medical events likely occurred while in flight.

A performance study of the airplane's flight revealed that the accident sequence only required about 79 percent of the available lift from the wing until well after the descent was established; consequently, the sequence was unlikely to have been precipitated by an aerodynamic stall. A postaccident examination of the airframe and engine revealed no evidence of a preimpact mechanical malfunction or failure that would have precluded normal operation. Flight control system continuity could not be confirmed due to the extensive damage incurred during the inflight break up. Accordingly, the reason for the steepening spiral dive, with increasing roll angle and speed, could not be established.

Twenty-six percent of Lancair airplanes have been involved in accidents, and 19 percent have been involved in fatal accidents. In 2008 and 2012, the FAA convened two safety groups specifically to address the airplane's "unusually high accident and fatality rate compared to other amateur-built aircraft." The study noted that based on the statistics, the kit was involved in fatal accidents at "a rate that is disproportionate to their fleet size." As a result of studies developed by these safety groups, the FAA acknowledged that accidents would continue to occur if no action was taken. Thus, the FAA issued a notice that Lancair pilots should "review and thoroughly understand all information regarding stall characteristics and obtain specialized training regarding slow flight handling characteristics, stall recognition, and stall recovery techniques;" install an angle-of-attack indicator to better predict a stall; and have their airplane evaluated by an experienced type-specific mechanic to ensure proper rigging, wing alignment, and weight and balance. The notice was recalled shortly after its release and another notice was released later to include other high-performance experimental amateur-built aircraft.

Text from the NTSB. Open the NTSB docket for WPR12FA180 for the full record.