Mid-air collision between ultralight and glider at Saarmund aerodrome results in three fatalities

Casualties unknown • Sonderlandeplatz Saarmund, DE

A mid-air collision between an ultralight aircraft and a glider during a winch launch at Saarmund aerodrome led to the deaths of three people.

What happened

On May 21, 2011, an ultralight aircraft, a REMOS GX, departed Schönhagen for a flight to Saarmund. While flying north, the pilot began a descent, reaching an altitude of 1,126 ft GND shortly before crossing the Saarmund aerodrome. Simultaneously, a student pilot was performing a winch launch in a Grob Astir CS Jeans glider at the same airfield.

As the glider was approaching release from the winch cable, it collided with the approaching ultralight. The impact was severe: the glider's wings were severed from the fuselage, and the ultralight's left wing was destroyed, with its wings also separating from the fuselage. Both aircraft fuselages struck the ground north of runway 09. The collision resulted in three fatalities.

The investigation

The BFU investigation examined the flight paths, aircraft condition, and visibility. GPS data revealed the REMOS GX had been flying at an altitude below the required safety minimum for overland flights. The investigation also reviewed the visibility from the winch station, noting that a forest edge partially obstructed the view of the winch operator, and a sunshade at the winch station may have obscured the visibility of the airfield's warning light.

Investigators found that the ultralight pilot had not established radio contact with Saarmund ground services and was flying with an incorrect frequency set on standby. The glider pilot, focused on the launch and release process, had significantly restricted visibility due to the aircraft's flight attitude during the climb.

Findings

  • The primary cause of the accident was the unannounced approach of the ultralight aircraft at a low altitude while a glider was undergoing a winch launch.
  • The ultralight pilot was flying below the legal safety altitude for overland flights.
  • The ultrallight pilot failed to monitor the activities at the Saarmund aerodrome and did not establish radio contact with the airfield.
  • The glider pilot's view of the approaching ultralight was severely limited by the aircraft's pitch during the climb.
  • The winch operator's ability to observe the airspace was hindered by the position of the forest edge and the focus on the glider.
  • The ultralight's takeoff mass exceeded its maximum allowable weight by at least 32.1 kg.

Probable cause

The collision occurred because the ultralight aircraft approached the airfield at an altitude below the required safety minimums without establishing radio contact, while the glider pilot's visibility was restricted by the flight attitude during a winch launch.

Frequently asked questions

What happened in the 2011-05-21 1. Grob –Werke Astir CS Jeans accident near Sonderlandeplatz Saarmund, DE?

A mid-air collision between an ultralight aircraft and a glider during a winch launch at Saarmund aerodrome led to the deaths of three people.

What aircraft was involved and where did it happen?

The accident on 2011-05-21 involved a 1. Grob –Werke Astir CS Jeans, at Sonderlandeplatz Saarmund, DE.

What was the probable cause of the accident?

The collision occurred because the ultralight aircraft approached the airfield at an altitude below the required safety minimums without establishing radio contact, while the glider pilot's visibility was restricted by the flight attitude during a winch launch.

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