Glaser-Dirks DIRK-DG-400 and Schweizer SGS-1-26B mid-air collision near Julian, Pennsylvania, April 28, 1986
On April 28, 1986 at about 5:30 pm local time, 2 aircraft, Glaser-Dirks DIRK-DG-400 (N40MS) and Schweizer SGS-1-26B (N686U), were involved in a mid-air collision near Julian, Pennsylvania. 1 person was killed and 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The NTSB has not yet published a probable cause for this accident. Investigations usually take one to two years; this page updates when the final report is released.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 28, 1986 · about 5:30 pm local time
- Place
- Julian, Pennsylvania · map
- Type
- Accident · mid-air collision
- Injuries
- 1 person was killed and 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft 1
- Glaser-Dirks DIRK-DG-400 DIRK-DG-40
- Registration
- N40MS · no longer on the register · serial 4-50
- Damage
- Destroyed
- Flight
- Personal flight · general aviation rules (Part 91)
- Aircraft 2
- Schweizer SGS-1-26B · all SGS-1-26Bs on the register
- Registration
- N686U · registry record · serial 305
- Damage
- Destroyed
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative for the Glaser-Dirks DIRK-DG-400 final · quoted from the NTSB record
THE PLT OF N686U REPORTED HE WAS ESTABLISHED IN A WEAK THERMAL AT AN ALT OF APRX 2500 AGL WHEN TWO OTHER GLIDERS WERE SEEN. ONE AT APRX THE SAME ALT AND ONE BELOW HIS ALT. HE CONTINUED TO STATE THAT THE GLIDER WHICH WAS AT HIS ALT PASSED VERY CLOSE TO BUT UNDERNEATH HIS GLIDER. HE STATED HE MOMENTARILY LOST SIGHT OF THE GLIDER BEFORE SEEING IT TURN AND AND CONTINUE IN THE THERMAL, HOWEVER, BECAUSE OF HIS GLIDERS ATTITUDE HE WAS UNABLE TO MAINTAIN VISUAL CONTACT WITH THE OTHER GLIDER. N686U WAS THEN STRUCK FROM THE RIGHT REAR BY N40MS. BOTH PLTS THEN LOST CONTROL OF THEIR GLIDERS WHICH DESCENDED TO GROUND IMPACT.
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 NTSB's narrative for the Schweizer SGS-1-26B final · quoted from the NTSB record
THE PLT OF N686U REPORTED HE WAS ESTABLISHED IN WEAK THERMAL AT AN ALT OF APRX 2500 AGL WHEN TWO OTHER GLIDERS WERE SEEN. ONE AT APRX THE SAME ALT AND ONE BELOW HIS ALT. HE CONTINUED TO STATE THAT THE GLIDER WHICH WAS AT HIS ALT PASSED VERY CLOSE TO BUT UNDERNEATH HIS GLIDER. HE STATED HE MOMENTARILY LOST SIGHT OF THE GLIDER BEFORE SEEING IT TURN AND AND CONTINUE IN THE THERMAL, HOWEVER, BECAUSE OF HIS GLIDERS ATTITUDE HE WAS UNABLE TO MAINTAIN VISUAL CONTACT WITH THE OTHER GLIDER. N686U WAS THEN STRUCK FROM THE RIGHT REAR BY N40MS. BOTH PLTS THEN LOST CONTROL OF THEIR GLIDERS WHICH DESCENDED TO GROUND IMPACT.
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 for the Glaser-Dirks DIRK-DG-400 from the NTSB's investigation tables, in plain English
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 11,475 hours in all; 373 in this make and model; 68 in the last 90 days; 27 in the last 30 days; 11,390 as pilot in command
- Medical certificate: None (expired)
- Seat: ctr
The aircraft
- Last inspection: inspection type not recorded
- Maximum gross weight: 1,014 lb
- Seats: 1
- Landing gear: retractable
- Engine: Rotax BOMBARDIER (piston); 0 hours total
The flight
- Departed from: Julian PA at 6:15 pm
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 140° at 14 knots
- Visibility: 20 statute miles
- Sky: clear
- Temperature: 73°F (23°C), dew point 48°F (9°C)
- Altimeter: 29.00 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
The factual record for the Schweizer SGS-1-26B from the NTSB's investigation tables, in plain English
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; multi-engine sea; single-engine land; instrument: airplane; rotorcraft: glider
- Flight time: 5,250 hours in all; 500 in this make and model; 17 in the last 90 days; 3,025 as pilot in command
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: ctr
The aircraft
- Last inspection: annual inspection
- Maximum gross weight: 1,021 lb
- Seats: 1
- Landing gear: fixed
- Engine: (type not recorded); 0 hours total
The flight
- Departed from: Julian PA at 6:15 pm
- Flight plan: none
- Runway 0
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.