ASN Wikibase Occurrence # 232125
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| Date: | Tuesday 14 January 2020 |
| Time: | 16:00 LT |
| Type: |  Velocity Elite RG |
| Owner/operator: | Barraza Marin |
| Registration: | N78BM |
| MSN: | DMO339 |
| Year of manufacture: | 1997 |
| Total airframe hrs: | 443 hours |
| Engine model: | Franklin 6A-350-C1R |
| Fatalities: | Fatalities: 0 / Occupants: 3 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Albert Whitted Airport (SPG/KSPG), St Petersburg, FL -
 United States of America
|
| Phase: | Take off |
| Nature: | Private |
| Departure airport: | St. Petersburg-Albert Whitted Airport, FL (SPG/KSPG) |
| Orlando Executive Airport, FL (ORL/KORL) | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
The pilot of the experimental amateur-built airplane stated that the first part of the takeoff roll was normal, but he noticed a sudden lack of acceleration and that the indicated airspeed was not increasing past 60 knots. He aborted the takeoff, reduced engine power to idle, and applied maximum braking. The airplane departed the end of the runway and came to rest on top of a rock embankment, resulting in substantial damage.
Examination of the engine revealed no preimpact anomalies that would have precluded normal operation. Examination of the electrically-controlled variable pitch propeller system revealed that the propeller exhibited signs of inadequate maintenance as the gaps between the three propeller blades were not sealed in accordance with manufacturer guidance. Also, corrosion was present on the propeller slip rings (which would have increased electrical resistance), supercams, and spool. Additional examination revealed that the propeller would not change pitch when the switch lever was operated, though electrical continuity was confirmed from the battery to the carbon brushes that were in contact with the slip rings. Examination of the spool that controlled propeller blade pitch angle indicated that the propeller was not in the fine-pitch, high-rpm takeoff position. The planetary gearbox contained very little lubricant and there were areas that were visibly dry. Examination of the electric motor (gear motor), which powered the propeller pitch mechanism, revealed intermittent operation due to worn carbon brushes. Internal examination of the electric motor revealed a broken end on one of the armature coil windings that surrounded one of the three electromagnetic coils in the electric motor, indicating that the motor needed replacement.
Review of propeller system maintenance records revealed no entries regarding preventive maintenance of the system in the approximate 2 years before the accident.
The propeller manufacturer's written guidance regarding operation of the propeller revealed that, before takeoff, the engine should be run at wide open throttle and the propeller blade pitch adjusted to the maximum horsepower rpm. Had the pilot performed this check, it would have been apparent that the propeller was not in the correct takeoff setting.
Wind conditions at the time of the accident were consistent with a 9-knot tailwind, which would have increased the distance necessary for takeoff and placed the airplane farther down the runway when the pilot aborted takeoff.
Probable Cause: A failure of the propeller pitch change electric motor, which resulted in an improper setting for takeoff and a subsequent runway overrun. Also causal was the inadequate maintenance and inspection of the propeller system and the pilot's failure to follow the propeller manufacturer's pretakeoff guidance, which would have indicated that the propeller was not in the takeoff position. Contributing to the accident was the pilot's decision to depart with a tailwind.
Accident investigation:
 |
|
Sources:
NTSB ERA20LA077
https://flightaware.com/live/flight/N78BM/history/20200114/1715Z/KORL/KSPG
FAA register: https://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?NNumbertxt=N78BM
History of this aircraft
Other occurrences involving this aircraft
| 6 October 2020 | N78BM | Barraza Marin | 0 | The Villages, Sumter County, FL | |
sub |
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 14-Jan-2020 22:10 | Geno | Added |
| 14-Jan-2020 22:29 | Geno | Updated [Time, Location, Phase, Departure airport, Destination airport, Source, Narrative] |
| 01-Jul-2022 14:46 | ASN Update Bot | Updated [Time, Operator, Other fatalities, Nature, Departure airport, Source, Narrative, Category, Accident report] |
Corrections or additions? ... Edit this accident description
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