Skip Ribbon Commands
Skip to main content
Aviation Accident

Quick Launch

NTSB Identification: SEA04LA063A
Accident occurred Thursday, April 01, 2004 in Oso, WA
Probable Cause Approval Date: 09/29/2004
Aircraft: Glasflugel STD Libelle 201B, registration: N161D
Injuries: 1 Fatal, 1 Minor.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

While flying in trail along a ridgeline at the same altitude, the pilot of the Glaser-Dirks (lead glider) made a left turn, while the pilot of the Glasflugel (trailing glider) remained on course over the ridgeline. The Glasflugel pilot reported that he recalled that the Glaser-Dirks was at his 10:00 position when he encountered turbulence and he looked down to check his airspeed. When he looked back up, he lost sight of the Glaser-Dirks and assumed that he had rolled out to run the ridgeline to the south. The Glasflugel pilot continued along the ridgeline to the north when the Glaser-Dirks pilot transmitted to the Glasflugel pilot to "watch out/it." The Glasflugel pilot looked around to his left and spotted the other glider about 80 feet away at his 8:00 position and converging at the same altitude. The Glasflugel pilot reacted by making a right banking turn. During this maneuver, the left wing tip of the Glasflugel glider came up under the right wing of the Glaser-Dirks glider. The left wing tip of the Glasflugel contacted the underside of the right wing of the Glaser-Dirks about 13 feet 5 inches outboard of the wing root resulting in the outboard section of the right wing separating in flight. The pilot of the Glaser-Dirks was fatally injured, while the pilot of the Glasflugel was able to bail-out and deploy his parachute.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
  • The pilot of the Glaser-Dirks (lead glider) failure to maintain clearance form the Glasflugel (trailing glider) resulting in a mid-air collision while maneuvering.