Glaser-Dirks DG-400 accident near New Milford, Connecticut, May 1, 1999
On May 1, 1999 at about 7:03 pm local time, a Glaser-Dirks DG-400 (glider), registered N400FJ, was destroyed in an accident near New Milford, Connecticut. It was a personal flight under general aviation rules (Part 91). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The manufacturer's use of inadequate adhesive material which resulted in the de-bonding and subsequent failure of the wing spar pin-lock assembly.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 1, 1999 · about 7:03 pm local time
- Place
- New Milford, Connecticut
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Glaser-Dirks DG-400 · all DG-400s on the register
- Registration
- N400FJ · registry record · serial 4-78
- Damage
- Destroyed
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
While in flight, at an indicated airspeed of 60 knots, a 'loud bang' was heard and the gear warning alarm began to sound. The pilot looked to the left and observed the left wing displaced 20 degrees up from its normal position. The glider began to descend and control inputs by the pilot were unresponsive. In the decent, as the glider's speed began to increase, the pilot elected to egress from the glider. The glider broke apart in flight and descended to the ground. A piece of the glider's fiberglass skin that contained a residue of an adhesive on the inside surface was removed and examined. The adhesive area would have attached spar pin-lock assembly, which secured the wing spar pins. The surface of this epoxy layer contained impression marks similar to a cross-weave pattern found on the surface of fiberglass. The cross-weave pattern on the surface of the epoxy was consistent with a fracture that traveled between the UD-glass fabric tape and the epoxy layer. This separation was characterized as an adhesive separation. The surface of the epoxy layer also contained exposed voids. No bonding between the epoxy and UD-glass fabric tape was observed in the void areas.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; instrument: airplane; rotorcraft: glider
- Flight time: 4,750 hours in all; 1,840 in this make and model; 21 in the last 90 days; 21 in the last 30 days
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: ctr
The aircraft
- Airframe total time: 1,840 hours
- Last inspection: annual inspection, June 18, 1998; 62 hours since
- Maximum gross weight: 1,015 lb
- Seats: 1
- Landing gear: retractable
- Engine: Bombardier 505 (piston); 0 hours total
The flight
- Departed from: 22B Burlington CT at 5:30 pm
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 120° at 8 knots, gusting 16
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 66°F (19°C), dew point 36°F (2°C)
- Altimeter: 30.00 inHg
- Observation at 6:53 pm from DXR, 14 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.