WPR17LA121 · Bob Frederick Titan T-51
Bob Frederick Titan T-51 · Accident: powerplant system/component malfunction/failure during initial climb
From Phoenix Goodyear Airport (GYR) to Phoenix Goodyear Airport (GYR)
Event
- NTSB case
- WPR17LA121
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Bob Frederick Titan T-51
- Aircraft type
- Bob Frederick TITAN T-51
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N51FB
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Phoenix Goodyear Airport (GYR), Goodyear, AZTo Phoenix Goodyear Airport (GYR), Goodyear, AZ
- Aircraft age
- About 2 years (built 2015)
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Initial climb
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Powerplant system/component malfunction/failure
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
No findings designated as a cause are recorded in the NTSB data yet.
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The airline transport pilot indicated that, immediately after takeoff for the local flight, the experimental, amateur-built airplane began to vibrate. As he transitioned the airplane to the downwind leg, the vibration increased, and the engine then experienced an overspeed and lost all power. The cockpit filled with smoke and the pilot subsequently performed a forced off-airport landing, which resulted in substantial damage to the left wing and aft fuselage.
The airplane had accrued about 43 flight hours since its construction, which was completed about 2 years before the accident.
Examination of the propeller speed reduction gearbox revealed that the teeth of the input drive gear had separated, which caused a loss of drive continuity to the propeller. The drive and idler gears did not appear to meet the manufacturer's case hardness requirements; however, evidence suggests that the gearbox had undergone severe heat buildup during the failure sequence, which may have subsequently altered the hardness. Oil starvation or exhaustion likely did not occur, as the gearbox bearings were intact and largely undamaged. Due to damage sustained to the gears, an accurate assessment of the initial failure mode could not be determined. Thus, the investigation could not determine the reason for the failure of the propeller speed reduction gearbox input drive gear.
Probable cause
Failure of the propeller speed reduction gearbox input drive gear during the airplane’s initial climb for reasons that could not be determined due to extensive damage.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR17LA121
- Event ID
- 20170604X43305
- Case number
- WPR17LA121
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 2dd77e9273e03f97246415651ee46cbdd9b55eddd806d6f79e2b1db7613bf78d; retrieved 2026-09-16T05:22:00.570Z.