# N9991F: not currently registered

- Registered now: No (not in the FAA registry file). The mark may be reserved or free to assign
- Earlier aircraft: 1
- Last cancelled: August 26, 1988
- FAA registry: https://registry.faa.gov/AircraftInquiry/Search/NNumberResult?nNumberTxt=9991F
- Page: https://openairdocs.org/aircraft/N9991F

## Aircraft that carried N9991F

- [Cancelled 1988-08-26](https://openairdocs.org/deregistered/N9991F-1988-08-26): Helio HST-550A, S/N 004. N-number assigned, not yet registered

## NTSB investigations on N9991F (1)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB LAX88FA241](https://openairdocs.org/ntsb/LAX88FA241), Jun 30, 1988: Helio HST-550A (N9991F), Perris, CA, destroyed, 1 fatal. Probable cause: FAILURE OF THE ELECTRICAL STABILIZER TRIM CONTROL THAT RESULTED IN AN UNCOMMANDED FULL NOSE DOWN ELEVATOR TRIM COMMAND.

## FAA accident and incident reports on N9991F (2)

From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [Accident 19880630027299A](https://openairdocs.org/incident/19880630027299A), Jun 30, 1988: Helio HST550A (N9991F), Perris, CA, Destroyed, 1 fatal. Pitch trim in full down position after dropping skydivers. No time to parachute.
- [Incident 19870821062539I](https://openairdocs.org/incident/19870821062539I), Aug 21, 1987: Helio HST550A (N9991F), Davis, CA, 1 fatal. Main chute failed to open after free fall. Reserve deployed too late. Chutist impacted the ground.

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