Loss of control following premature flap and gear retraction at Mauterndorf

Casualties unknown • am Flugplatz Mauterndorf, Salzburg, AT

A GY 80-160 aircraft crashed into trees during the initial climb phase at Mauterndorf airfield after the pilot retracted the landing gear and flaps too early.

What happened

On August 21, 2011, at approximately 12:26 UTC, a GY 80-160 aircraft departed from Mauterndorf airfield on runway 25. The flight was a VFR operation with a pilot and one passenger on board. After taking off approximately 460 meters into the takeoff roll, the aircraft reached an altitude of about 15 meters above the ground. During this early climb phase, the pilot began retracting the landing gear and the flaps.

As the aircraft continued its climb, the left wing collided with the treetops of a group of trees approximately 1,124 meters from the start of the runway. Following this impact, the aircraft entered a steep left turn and struck a rising meadow about 100 meters beyond the collision point. The impact triggered a post-crash fire that caused extensive damage to the airframe.

The investigation

The Austrian Federal Safety Investigation Board (SUB) examined the aircraft, the flight conditions, and video footage of the event. The investigation confirmed that the aircraft's maintenance was up to date and all required documentation was valid. The aircraft's weight and center of gravity were within permissible limits.

Investigators analyzed the engine and fuel system, finding that the fuel was a 1:1 mixture of AVGAS and regular gasoline, though this was not considered a cause of the accident. While the spark plugs showed signs of wear and a lean burn pattern, no mechanical failures or engine malfunctions were identified as contributing to the crash. The investigation also reviewed the takeoff performance calculations, noting that while the calculated distance to clear a 15-meter obstacle was sufficient under the prevailing weather, the actual flight path deviated due to aerodynamic changes.

Findings

  • The pilot retracted the flaps and landing gear prematurely before clearing obstacles.
  • The retraction of the gear and flaps increased the aircraft's angle of attack to maintain altitude, which subsequently increased drag.
  • This increased drag led to a significant loss of airspeed, causing the aircraft to enter a sink condition (stall/sink rate increase).
  • The pilot was unable to recover the lost airspeed due to the low altitude and proximity to obstacles.

Probable cause

The accident was caused by the premature retraction of the landing gear and flaps during the initial climb, which increased drag and induced a loss of airspeed, resulting in a sink condition and subsequent collision with trees.

Frequently asked questions

What happened in the 2011-08-21 GY80-160 accident near am Flugplatz Mauterndorf, Salzburg, AT?

A GY 80-160 aircraft crashed into trees during the initial climb phase at Mauterndorf airfield after the pilot retracted the landing gear and flaps too early.

What aircraft was involved and where did it happen?

The accident on 2011-08-21 involved a GY80-160, at am Flugplatz Mauterndorf, Salzburg, AT.

What was the probable cause of the accident?

The accident was caused by the premature retraction of the landing gear and flaps during the initial climb, which increased drag and induced a loss of airspeed, resulting in a sink condition and subsequent collision with trees.

Loading the flight search…