Gmk Ventures Llc AL18 N17GK accident near Moab, Utah

Probable cause

The pilot’s failure to maintain directional control during a landing attempt, which resulted in a ground loop and collision with terrain. Contributing to the accident was the absence of an airspeed indicator due to an alternator failure.

NTSB analysis

The pilot reported that, he experienced an alternator failure approximately 47 minutes from his destination airport. He switched to a backup battery, but within 2 minutes the entire electrical system shut down, which included a loss of his airspeed and altitude indicators. When he reached the airport, he intentionally flew fast to provide a buffer against stalling the airplane as he was in high density altitude conditions. While over the runway at about 5 ft above ground level, he overflew the runway at the same altitude to bleed off excess airspeed. As the airplane decelerated the pilot was unable to determine when the airplane would touchdown due to the loss of his airspeed indicator. According to the pilot, the right main landing gear touched down first followed by the left main landing gear, at which point the airplane began to ground loop. The left elevator impacted a runway light, which resulted in substantial damage to the airplane. The pilot report no other preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for WPR22LA233 for the full record.