Glider collision with tree following spoiler deployment during tow

Casualties unknown • Mulberry, FL, US

A glider pilot experienced an uncontrolled descent and struck a tree after failing to verify that the spoiler handle was locked prior to takeoff.

What happened

During a flight involving a glider and a tow aircraft, the pilot failed to confirm that the spoiler handle was secured in the retracted position before beginning the takeoff sequence. Shortly after the aircraft departed the ground, the spoilers deployed.

While in flight, the pilot did not monitor radio transmissions from the tow pilot or ground personnel, which contained warnings that the spoilers were extended. Because of this lack of communication, the pilot only noticed a decrease in airspeed and incorrectly assumed the tow aircraft was experiencing mechanical issues.

To alert the glider pilot to the configuration error, the tow pilot used rudder movements as a signal. This maneuver resulted in the glider releasing from the tow plane. Following the release, the glider entered a rapid descent. Upon realizing the spoilers were extended, the pilot attempted to retract them; however, the aircraft lacked sufficient altitude to return to the airport. The glider subsequently collided with a tree and came to rest within the foliage.

Probable cause

The pilot's failure to verify that the spoiler handle was locked in the retracted position prior to takeoff, combined with a failure to monitor radio communications regarding the extended spoiler configuration.

Frequently asked questions

What happened in the 1996-12-22 Let BLANIK L-13 accident near Mulberry, FL?

A glider pilot experienced an uncontrolled descent and struck a tree after failing to verify that the spoiler handle was locked prior to takeoff.

What aircraft was involved and where did it happen?

The accident on 1996-12-22 involved a Let BLANIK L-13, registration N48052, at Mulberry, FL.

What was the probable cause of the accident?

The pilot's failure to verify that the spoiler handle was locked in the retracted position prior to takeoff, combined with a failure to monitor radio communications regarding the extended spoiler configuration.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001208X07217. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.

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