Schleicher ASK-21
Tehachapi, CA — May 10, 2008
Event Information
| Date | May 10, 2008 |
| Event Type | ACC |
| NTSB Number | SEA08CA129 |
| Event ID | 20080603X00777 |
| Location | Tehachapi, CA |
| Country | USA |
| Coordinates | 35.10139, -118.42722 |
| Airport | Mountain Valley Airport |
| Highest Injury | NONE |
Aircraft
| Make | Schleicher |
| Model | ASK-21 |
| Category | GLI |
| FAR Part | 091 |
| Aircraft Damage | SUBS |
Conditions
| Light Condition | DAYL |
| Weather | VMC |
Injuries
| Fatal | 0 |
| Serious | 0 |
| Minor | 0 |
| None | 2 |
| Total Injured | 0 |
Event Location
Probable Cause
The pilot's inadequate preflight procedures and failure to check the spoiler control position, which resulted in the inadvertent deployment of the spoilers during takeoff. A contributing factor was the pilot's misinterpretation of the tow pilot's instructions.
Full Narrative
The glider was being towed to altitude by a tow airplane. During the takeoff initial climb, the spoiler handle was not locked and the spoilers momentarily extended twice and although the pilot felt that he had to input forward control forces, he did not visually check the position of the spoiler control handle. The tow pilot then gave a rudder wave signal to the pilot telling him to check the spoilers; however, because the spoilers appeared retracted when the pilot verified their position, the glider pilot misinterpreted the tow pilot and released the glider from the tow airplane at approximately 100 feet above ground level. The glider pilot force-landed the glider in a field. During the landing, the empennage broke from the remainder of the glider. The glider pilot did not report any mechanical malfunctions with the glider.
About This NTSB Record
This aviation event was investigated by the National Transportation Safety Board (NTSB). NTSB investigates all U.S. civil aviation accidents to determine probable cause and issue safety recommendations to prevent future accidents.