# Accident 19910317006699A: Mooney M20D, Herlong, CA, March 17, 1991

- Type: FAA accident report (Accident/Incident Data System), as reported
- Date: March 17, 1991, 16:30 local time
- Place: Herlong, CA
- Damage: Substantial damage
- Phase of flight: Normal Cruise
- Operating rules: General operating rules (Part 91)
- Location: 40.1397° N, 120.1605° W: From the FAA, an estimate near the named town, within about 3 miles
- Nearby events: https://openairdocs.org/map.md?lat=40.1397&lon=-120.1605&mi=10
- Aircraft: N1921Y, a cancelled registration (https://openairdocs.org/deregistered/N1921Y-2013-02-01) (OpenAirDocs)
- Registry model: Mooney M20D (registry code 5870210, https://openairdocs.org/model/mooney-m20d) (OpenAirDocs)
- Registry engine: Lycoming O&VO-360 series (registry code 41514, https://openairdocs.org/engine/lycoming-o-vo-360-series) (OpenAirDocs)
- Reported make and model: MOONEY M20D
- Reported engine: LYC O360A1D
- People aboard: 3
- Fatal injuries: 0
- Pilot flight hours: 1,940 total, 1,000 in this make and model, 39 in the last 90 days
- NTSB investigation: [NTSB LAX91LA135](https://openairdocs.org/ntsb/LAX91LA135) (OpenAirDocs)
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/19910317006699A

## Narrative

As the FAA filed it, in capitals; the FAA replaces private details with ^PRIVACY DATA OMITTED^.

LOST A PROP BLADE AT CRUISE. SEVERE VIBRATION. LANDED SAFELY. FIXED PITCH PROP WAS WRONG PITCH. VIBRATION DAMAGE.

## The NTSB's investigation of this event (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 LAX91LA135](https://openairdocs.org/ntsb/LAX91LA135), Mar 18, 1991: Mooney M20D (N1921Y), Herlong, CA, substantial damage. Probable cause: THE INADEQUATE PREPARATION OF THE PROPELLER DURING OVERHAUL. THE INSTALLATION OF AN IMPROPER PITCHED PROPELLER AND THE FATIGUE FAILURE OF THE PROPELLER BLADE EMANATING FROM CORROSION WERE FACTORS IN…

## Other reports on N1921Y (2)

Matched to the same aircraft by N-number and date.

- [Incident 19800913070589I](https://openairdocs.org/incident/19800913070589I), Sep 13, 1980: Mooney M20D (N1921Y), Eugene, OR, Minor damage. Pilot landed gear up. Warning horn inoperative.
- [Incident 19800710060369I](https://openairdocs.org/incident/19800710060369I), Jul 10, 1980: Mooney M20D (N1921Y), Crescent Lake, OR. Crankshaft idler gear came loose, allowing crankshaft to go out of time.

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. For accidents, the NTSB's own investigation is the fuller record.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.