NTSB Identification: WPR12CA288
14 CFR Part 91: General Aviation
Accident occurred Sunday, June 24, 2012 in Richland, WA
Probable Cause Approval Date: 10/04/2012
Aircraft: DG-FLUGZEUGBAU GMBH DG-500MB, registration: N505JL
Injuries: 1 Minor.

NTSB investigators used data provided by various entities, including, but not limited to, the Federal Aviation Administration and/or the operator and did not travel in support of this investigation to prepare this aircraft accident report.

In a written statement, the pilot reported that the accident flight was his second flight of the day. After conducting a series of practice maneuvers, he was returning to the airport. The pilot entered a right traffic pattern and configured the glider for landing. With the landing gear extended and the flaps set at 10 degrees, he opened and tested the spoilers. While on the base leg of the traffic pattern, he noticed that the glider was low, and, as he maneuvered onto final approach, he closed the spoilers (forward activation of the lever). The glider’s sink rate was excessive and he observed that the spoilers visually appeared to be deployed although the control lever was in the full-forward (closed) position. He manipulated the lever back and forth, which had no effect on the spoiler position. The glider impacted railroad tracks about 1,000 feet from the approach end of the runway and sustained substantial damage to the fuselage and wings in the accident sequence.

A postaccident examination of the glider revealed that the right wing spoiler’s lower plate appeared to have been rubbing the aft spoiler bay wall until it scraped off the resin. It appeared to have scraped enough material off that it caught on a fabric seam (once sealed in the resin) and would not retract. In other words, the spoiler’s lower plate would not push past the catch due to the exposed fabric edge. The location of the scrape marks and the fabric seam put the spoilers at half extension, which is consistent with the lack of performance the pilot reported. The left wing spoiler’s lower plate bushings were tight, with no play.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The failure of the spoilers to retract because the right wing spoiler’s lower plate became jammed, which resulted in the glider not having enough lift to make it to the runway surface.

Full narrative available

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