Grumman-Schweizer G-164B accident near Frederick, Maryland, July 11, 2006
On July 11, 2006 at about 7:00 pm local time, a Grumman-Schweizer G-164B, registered N6645Q, was substantially damaged in an accident near Frederick, Maryland (Frederick Municipal Airport). It was an aerial application (crop spraying) flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A failure of the masterod, due to a hydraulic lock on a previous flight, which resulted in a total loss of engine power.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 11, 2006 · about 7:00 pm local time
- Place
- Frederick, Maryland · Frederick Municipal Airport · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Grumman-Schweizer G-164B
- Registration
- N6645Q · registry record · serial 172B
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
During cruise flight, the pilot of a Grumman-Schweizer G-164B airplane noted that the engine began to run rough, and shake violently. He also noted smoke coming from the exhaust. The engine subsequently lost power, and the pilot performed an emergency landing to a cornfield. During the landing, the airplane came to rest inverted, resulting in substantial damage. A post-accident examination of the engine revealed a fractured masterod. Deformation and damage to the masterod was consistent with being exposed to a hydraulic lock prior to the accident flight.
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
- Flight time: 1,145 hours in all; 619 in this make and model; 31 in the last 90 days; 23 in the last 30 days; 1,106 as pilot in command
- Last flight review: October 1, 2005
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: sngl
- Injury: no injuries
The aircraft
- Airframe total time: 7,306 hours
- Last inspection: annual inspection, November 1, 2005; 41 hours since
- Maximum gross weight: 4,500 lb
- Seats: 1
- Landing gear: fixed
- Engine: Pratt & Whitney R-985-AN-14B (piston); 0 hours total
- Operator: Tri State Aero
The flight
- Departed from: W42 Fallston MD at 5:30 pm
- Destination: NONE Martinsburg WV
- Flight plan: none
- Runway 230, 5,220 ft by 100 ft
Weather at the time
- Light: daylight
- Wind: from 170° at 3 knots
- Visibility: 10 statute miles
- Sky: scat at 5,000 ft
- Temperature: 91°F (33°C), dew point 66°F (19°C)
- Altimeter: 30.12 inHg
- Observation at 6:20 pm from KFDK, 1 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.