Mid-air collision Accident Glaser-Dirks DG-400 N400WJ, Thursday 1 April 2004
ASN logo
This information is added by users of ASN. Neither ASN nor the Flight Safety Foundation are responsible for the completeness or correctness of this information. If you feel this information is incomplete or incorrect, you can submit corrected information.

Date:Thursday 1 April 2004
Type:Silhouette image of generic DG40 model; specific model in this crash may look slightly different    
Glaser-Dirks DG-400
Registration: N400WJ
MSN: 4-91
Fatalities:Fatalities: 1 / Occupants: 1
Other fatalities:0
Aircraft damage: Substantial
Location:Oso, WA -   United States of America
Phase: Manoeuvring (airshow, firefighting, ag.ops.)
Departure airport:Arlington Municipal Airport, WA (AWO/KAWO)
Destination airport:
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
On April 1, 2004, about 1700 Pacific standard time, a Glasflugel STD Libelle 201B, N161D, and a Glaser-Dirks DG-400, N400WJ, experienced a mid-air collision while maneuvering over mountainous terrain located about three nautical miles south of Oso, Washington. Visual meteorological conditions prevailed at the time and no flight plan was filed by the pilot of either glider. The pilot of the Glasflugel received minor injuries while the pilot of the Glaser-Dirks was fatally injured. The pilot of the Glasflugel reported that he departed from Arlington Municipal Airport, Arlington, Washington, about 1130, while the pilot of the Glaser-Dirks departed from the same airport about 1600.

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.

Probable Cause: 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.

Accident investigation:
Investigating agency: NTSB
Report number: SEA04LA063
Status: Investigation completed
Duration: 6 months
Download report: Final report


NTSB: https://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20040414X00461&key=1


Photo: NTSB

Revision history:

28-Oct-2008 00:45 ASN archive Added
02-Jul-2009 09:47 DColclasure Updated
21-Dec-2010 12:49 Alpine Flight Updated [Damage]
26-Jun-2013 14:07 Alpine Flight Updated [Time, Operator, Departure airport, Destination airport]
21-Dec-2016 19:24 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
07-Dec-2017 17:55 ASN Update Bot Updated [Other fatalities, Departure airport, Destination airport, Source, Narrative]

Corrections or additions? ... Edit this accident description

The Aviation Safety Network is an exclusive service provided by:
Quick Links:

CONNECT WITH US: FSF on social media FSF Facebook FSF Twitter FSF Youtube FSF LinkedIn FSF Instagram

©2024 Flight Safety Foundation

1920 Ballenger Av, 4th Fl.
Alexandria, Virginia 22314