# NTSB MIA92LA031: Robinson R22 Mariner, N4072U, Ocala, FL, November 17, 1991

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: November 17, 1991, 16:00 local (21:00 UTC)
- Place: Ocala, FL
- Location: 29.1872° N, 82.1401° W: Placed by OpenAirDocs: center of Ocala, FL, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=29.1872&lon=-82.1401&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 2 minor
- Status: Completed, report April 27, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 33032
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MIA92LA031
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/33032/pdf
- Page: https://openairdocs.org/ntsb/MIA92LA031

## Probable cause

THE PILOT-IN-COMMAND'S IMPROPER USE OF COLLECTIVE CONTROL AND THROTTLE DURING RECOVERY FROM AN AUTOROTATION WHICH RESULTED IN LOSS OF ROTOR RPM AND A SUBSEQUENT HARD LANDING.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Miscellaneous/other, maneuvering
  - procedures/directives - not followed, pilot in command (cause)
  - collective - improper use of, pilot in command (cause)
  - throttle/power control - improper use of, pilot in command (cause)
  - rotor rpm - not maintained, pilot in command (cause)
- Forced landing, descent - emergency
- Hard landing, landing - flare/touchdown

## Analysis

PILOT INITIATED PRACTICE AUTOROTATION. AT 500 FEET ALTITUDE RECOVERY WAS ATTEMPTED BY INCREASING COLLECTIVE AND INCREASING THROTTLE. LOW ROTOR SPEED WARNING WAS HEARD AND ENGINE DID NOT ACCELERATE. PILOT LOWERED COLLECTIVE AND CONTINUED AUTOROTATION TO THE GROUND AT WHICH TIME A HARD LANDING WAS MADE. POSTCRASH EXAMINATION OF THE AIRCRAFT BY FAA INSPECTORS REVEALED NO EVIDENCE OF FAILURE OR MALFUNCTION OF THE AIRCRAFT ENGINE. THE ENGINE WAS OPERATED AFTER THE ACCIDENT WITH NO EVIDENCE OF FAILURE.

## Aircraft

- Registration: [N4072U](https://openairdocs.org/deregistered/N4072U-2013-09-24), registration cancelled 2013-09-24, S/N 1788M, built 1991 (OpenAirDocs)
- Reported make and model: ROBINSON R22 MARINER (R22 MARINE)
- Registry model: [Robinson Helicopter R22 MARINER](https://openairdocs.org/model/robinson-helicopter-r22-mariner) (registry code 7640115) (OpenAirDocs)
- Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 1788M
- Airframe hours: 127
- Engines: LYCOMING O-320-B2C 131 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Drax Corp.
- Registered owner: Drax Corp.
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, September 1, 1991, 27 hours before
- Departed: OCF, OCALA, FL

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 38; private; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 276 total, 127 in this make and model, 276 as pilot in command, 40 in the last 90 days, 20 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 80° at 6 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 81 °F, dew point 57 °F
- Altimeter: 30.00 inHg
- Observed at: OCF, 6 nm away

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19911117052029A](https://openairdocs.org/incident/19911117052029A), Nov 17, 1991: Robsin R22MARINER, Ocala, FL, Substantial damage. Engine did not respond on recovery from practice autorotation. RPM decayed hard landing chopped off tailboom.

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.

---
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.