Amateur-built ZENAIR 701 accident near Zephyrhills, Florida, October 19, 2013
On October 19, 2013 at about 3:32 pm local time, a 2012 amateur-built ZENAIR 701, registered N538HB, was substantially damaged in an accident during approach (VFR pattern downwind) near Zephyrhills, Florida (Zephyrhills Municipal Airport). It was a personal flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The failure of the propeller speed reduction unit drive belts due to inadequate belt tension being applied during installation, which resulted in a complete loss of thrust.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 19, 2013 · about 3:32 pm local time
- Place
- Zephyrhills, Florida · Zephyrhills Municipal Airport · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built ZENAIR 701, built 2012
- Registration
- N538HB · no longer on the register · serial 1001
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported that, while in the traffic pattern at his home airport practicing touch-and-go landings, the experimental, amateur-built airplane experienced a complete loss of thrust from the propeller. While turning from the crosswind leg of the traffic pattern onto the downwind leg of the traffic pattern, the engine suddenly "overreved." The pilot reduced power and chose to perform an emergency landing. He then tried adding power, but the propeller did not respond and was windmilling. He established best glide speed, but the airplane had developed a high sink rate and was losing altitude rapidly. He then slowed the airplane as it approached a set of powerlines. The airplane clipped one of the powerlines, which nearly severed the left wing. The pilot then "stalled" the airplane and touched down hard. The airplane was substantially damaged during the forced landing. Examination of the engine revealed that a belt-driven propeller speed reduction unit (PSRU) was installed. Further examination revealed that both drive belts from the PSRU were broken into several pieces, and shredded material from the belts was present throughout the engine compartment. Small pieces of rubber were also present on the forward part of the engine, the propeller hub assembly, and the PSRU pulleys' grooves. Examination of the broken belts revealed jagged belt fractures and evidence of overheating, hardening, back cracks, land area wear, and "V" rib wear, all of which is indicative of inadequate belt tension, which can cause the belts to slip as they travel around the pulleys and generate heat buildup. The heat buildup can cause the rubber compounds in the belt to break down and crack and lead to a belt failure. According to maintenance records, the drive belts for the PSRU had been replaced about 20 hours of operation before 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
What happened, in order
- Powerplant sys/comp malf/fail during approach (VFR pattern downwind) defining event
- Loss of engine power (total) during approach (VFR pattern downwind)
- Off-field or emergency landing during emergency descent
- Hard landing during landing
The NTSB's findings
- cause Aircraft › Aircraft propeller/rotor › Propeller system › (general) › Failure
- cause Aircraft › Aircraft propeller/rotor › Propeller system › (general) › Incorrect service/maintenance
- cause Personnel issues › Task performance › Maintenance › Installation › Maintenance personnel
Pilot
- Certificate: sport pilot
- Ratings: single-engine land
- Flight time: 4,800 hours in all; 50 in this make and model; 32 in the last 90 days
- Last flight review: March 1, 2013
- Medical certificate: Sport Pilot
- Seat: left
- Injury: no injuries
Pilot-Rated Passenger
- Certificate: private
- Ratings: single-engine land
- Flight time: 100 hours in all; 1 in this make and model
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 43 hours
- Last inspection: condition inspection, September 10, 2013; 20 hours since
- Maximum gross weight: 1,100 lb
- Seats: 2
- Landing gear: fixed
- Engine: Greatplains GREATPLAIN VW (piston); 43 hours total
The flight
- Departed from: ZPH Zephyrhills FL at 3:00 pm
- Destination: ZPH Zephyrhills FL
- Flight plan: none
- Runway 22, 4,999 ft by 100 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 190° at 4 knots
- Visibility: 10 statute miles
- Sky: overcast at 9,500 ft
- Temperature: 82°F (28°C), dew point 70°F (21°C)
- Altimeter: 29.97 inHg
- Observation at 3:35 pm from ZPH, 2 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 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.