Glaser Dirks DG500 N600TT

Summary

On 6 October 2019 at about 20:00 local time, a Glaser Dirks DG500 registered N600TT, operated by Tucson Soaring Club Inc., was involved in an accident near Marana, Arizona, United States. 2 people were on board and one had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

6 October 2019 at 20:00

Classification

Accident

Location

Marana, Arizona, United States

Nearest airport

El Tiro (AZ67)

Coordinates

32.4300, -111.3900

Aircraft

Glaser Dirks DG500

Registration

N600TT

Category

Glider

Year built

1994

Operator

Tucson Soaring Club Inc.

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Tucson → Tucson

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR20LA004

1 person had minor injuries.

The pilots’ exceedance of the glider’s never-exceed speed (VNE) during recovery from an intentional aerobatic maneuver, which resulted in a failure of the right-wing air brake control drive, asymmetrical air brake deployment, and a subsequent hard landing.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The pilots were performing aerobatic maneuvers in the glider. While recovering from a maneuver, the glider’s airspeed increased past the never-exceed speed (Vne) and the elevator began to flutter. The right air brake (spoiler) deployed fully, though the spoiler control was in the locked position. After assessing the controllability of the glider, the pilots chose to land at the gliderport rather than perform an emergency egress. The glider landed hard and impacted brush, resulting in the separation of the empennage at the tailboom. Postaccident examination revealed a separation of the right-wing air brake control drive system at the rod end, which resulted in the asymmetrical spoiler extension. The manufacturer stated that it should have been possible to deploy the left-wing air brake normally to compensate for the asymmetric behavior and have some (reduced) control over the approach glidepath. The manufacturer also stated there is no emergency procedure described in the flight manual for air brake malfunctions. It is likely that the air brake control separation was the result of the pilots’ exceedance of Vne during recovery from the aerobatic maneuver.

Quoted verbatim from the NTSB record.