Tl Ultralight Sro STINGSPORT accident near Longmont, Colorado, September 1, 2012
On September 1, 2012 at about 5:30 pm local time, a 2006 Tl Ultralight Sro STINGSPORT, registered N898N, was substantially damaged in an accident during maneuvering near Longmont, Colorado. 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 wood propeller blades in flight. Contributing to the accident was the owner/operator’s failure to complete required inspections on the propeller within the specified interval, which reduced the likelihood of detecting the cracks and may have contributed to the crack growth.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 1, 2012 · about 5:30 pm local time
- Place
- Longmont, Colorado · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Tl Ultralight Sro STINGSPORT, built 2006 · all STINGSPORTs on the register
- Registration
- N898N · registry record · serial TLUSA129
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
While conducting maneuvers at 2,500 feet, the airplane began to vibrate violently. The pilot aborted the maneuver and retarded the throttle to idle; the engine experienced a total loss of power. The pilot executed a forced landing into a field. After the landing, the pilot and the designated pilot examiner noticed that two of the propeller blades had separated from the propeller hub. An examination of the fractured blades and blade sleeves revealed that blade A likely fractured due to progressive cracking at laminate bonds at the interface between the wood blade and the metal sleeve. The powdery wood observed in the slots and at the root end of the blade shank were indicative of rubbing wood as the cracks progressed. The blade B fracture was likely secondary and occurred due to the vibrations associated with the imbalance created by the blade A fracture and subsequent separation. The propeller log indicated that manufacturer-specified visual inspections and torque checks were not conducted at the specified interval of 150 hours but at intervals of about 203, 320, and 250 hours. The delayed visual inspections reduced the likelihood of detecting the cracks and the delayed torque checks might have contributed to crack growth in the blade.
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 maneuvering defining event
The NTSB's findings
- cause Aircraft › Aircraft propeller/rotor › Propeller system › Propeller blade section › Failure
- factor Aircraft › Aircraft propeller/rotor › Propeller system › Propeller blade section › Fatigue/wear/corrosion
- factor Aircraft › Aircraft propeller/rotor › Propeller system › Propeller blade section › Inadequate inspection
- factor Personnel issues › Task performance › Inspection › Scheduled/routine inspection › Pilot
Pilot
- Certificate: private
- Ratings: single-engine land
- Medical certificate: Class 3 (without waivers/limitations)
- Seat: left
- Injury: no injuries
Pilot (unmanned)
- Certificate: airline transport pilot, flight instructor
- Ratings: single-engine land; single-engine sea; instructor: airplane single-engine
- Seat: rgt
- Injury: no injuries
The aircraft
- Seats: 2
- Landing gear: fixed
- Engine: Rotax (piston); 0 hours total
- Operator: Sting4Fun LLC
The flight
- Departed from: EIK Erie CO
- Destination: EIK Erie CO
- Flight plan: none
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 020° at 3 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 84°F (29°C), dew point 37°F (3°C)
- Altimeter: 30.12 inHg
- Observation at 5:34 pm from KEIK, 14 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 2 |
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.