Byron J. Moore Zealot accident near Clermont, Florida, April 9, 2009
On April 9, 2009 at about 3:45 pm local time, a Byron J. Moore Zealot (glider), registered N61ZT, was substantially damaged in an accident during enroute (cruise) near Clermont, Florida. It was a personal 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 loss of engine power due to oil starvation as a result of the previous owner's improper servicing of the engine oil.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 9, 2009 · about 3:45 pm local time
- Place
- Clermont, Florida · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Byron J. Moore Zealot
- Registration
- N61ZT · no longer on the register · serial 061
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot stated that he was in cruise flight at 1,800 feet when the motorized glider experienced a total loss of engine power. He attempted an engine restart with negative results and made a forced landing. The current owner stated that he purchased the motor glider about 4 months before the accident. The engine had been removed by the previous owner, rebuilt, serviced, installed on the glider, and placed in storage. A Federal Aviation Administration inspector disassembled the engine after the accident. Prior to disassembly, the oil tank indicated that it was full of oil. Disassembly of the engine revealed the rotary valve disc drive gear had failed due to insufficient lubrication. There were about 2 ounces of oil drained from the oil bath reservoir. The engine manufacturer's installation manual indicated that if the vent plug in the engine case is not removed when servicing the engine with oil. The oil reservoir can indicate it is full of oil, and an air bubble can form which will prevent oil from filling the chamber. This will result in significant heat, and cause catastrophic failure of the drive gear due to insufficient lubrication. The previous owner stated that he did not remove the vent plug when he serviced the oil after the engine was rebuilt and installed on the motor glider.
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
What happened, in order
- Aircraft servicing event during prior to flight
- Loss of engine power (total) during enroute (cruise) defining event
- Off-field or emergency landing during emergency descent
- Collision with terrain or object (not controlled flight into terrain) during landing (flare/touchdown)
The NTSB's findings
- cause Aircraft › Aircraft handling/service › Maintenance/inspections › (general) › Incorrect service/maintenance
- cause Aircraft › Fluids/misc hardware › Fluids › Oil › Incorrect service/maintenance
- Aircraft › Aircraft power plant › Engine (reciprocating) › Recip engine power section › Failure
- cause Personnel issues › Task performance › (general) › (general) › Owner/builder
- Environmental issues › Physical environment › Terrain › Rough terrain › Contributed to outcome
Pilot
- Certificate: private
- Ratings: rotorcraft: glider
- Flight time: 1,100 hours in all; 3 in this make and model; 3 in the last 90 days; 3 in the last 30 days; 1,100 as pilot in command
- Last flight review: November 30, 2008
- Medical certificate: None
- Seat: sngl
- Injury: no injuries
The aircraft
- Airframe total time: 200 hours
- Last inspection: condition inspection, March 25, 2009; 3 hours since
- Maximum gross weight: 925 lb
- Seats: 1
- Landing gear: fixed
- Engine: Rotax 582 (piston); 0 hours total
The flight
- Departed from: 06FD Mascotte FL at 3:20 pm
- Destination: 06FD Mascotte FL
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 260° at 4 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 72°F (22°C), dew point 54°F (12°C)
- Altimeter: 30.00 inHg
- Observation at 3:53 pm from LEE, 25 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight 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.
Other NTSB records under N61ZT the same tail number, which may have belonged to a different aircraft at the time
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.