Wednesday, July 8, 2015

Probable cause of crash of the glider AIRCRAFT INDUSTRIES A.S. L33 SOLO, registration: N318BA in Bunn, NC

 

 
NTSB Identification: ERA14LA199
14 CFR Part 91: General Aviation
Accident occurred Sunday, April 13, 2014 in Bunn, NC
Probable Cause Approval Date: 07/07/2015
Aircraft: AIRCRAFT INDUSTRIES A.S. L33 SOLO, registration: N318BA
Injuries: 1 Serious.
 
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The glider was towed aloft and then released. Shortly after, the glider pilot radioed the towplane pilot and informed him that he was returning to the airport.

 Because of the short duration of the glider flight, the towplane pilot asked the glider pilot if he wanted to be towed aloft again, and he replied that he did.

Witnesses on the ground reported observing the glider low on the downwind leg and then turning onto the base leg. Based on data from the onboard portable GPS receiver, the glider turned onto final approach and flew in a southerly direction toward the runway with its groundspeed decreasing from 34 to 25 knots during the last few seconds of the flight. The glider impacted the ground in a nose-low attitude, which caused the wing to separate.

Postaccident examination of the glider found no evidence of a preimpact failure or malfunction of the flight controls or air brakes, and the air brakes were retracted. The published stall speed for the glider with the air brakes retracted is about 34 knots indicated airspeed.

Although the indicated airspeed during the final portion of the flight could not be determined, the evidence indicates that the pilot likely failed to maintain adequate airspeed while approaching the airport, which resulted in a stall/mush.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
  • The pilot’s failure to maintain airspeed while approaching the airport, which resulted in a stall/mush.