# NTSB LAX91LA264: Robinson R-22B, N4034K, Phoenix, AZ, June 17, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: June 17, 1991, 08:00 local (15:00 UTC)
- Place: Phoenix, AZ
- Coordinates: 33.609668, -111.889442 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=33.6097&lon=-111.8894&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report May 7, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 27251
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX91LA264
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/27251/pdf
- Page: https://openairdocs.org/ntsb/LAX91LA264

## Probable cause

THE FAILURE OF THE STUDENT TO MAINTAIN THE PROPER ROTOR RPM WHILE PERFORMING A PRACTICE AUTOROTATION, AND, THE FAILURE OF THE FLIGHT INSTRUCTOR TO PROPERLY SUPERVISE THE CONDUCT OF THE FLIGHT AND TO TAKE TIMELY CORRECTIVE ACTION.

## Sequence of events

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

- Hard landing, landing - flare/touchdown
  - autorotation - initiated
  - emergency procedure - simulated
  - rotorcraft flight controls - improper use of, dual student (cause)
  - supervision - inadequate, pilot in command(cfi) (cause)
  - remedial action - delayed, pilot in command(cfi) (cause)

## Analysis

THE INSTRUCTOR SAID THAT THE STUDENT WAS PERFORMING AUTOROTATIONS WITH POWER RECOVERIES. THE INSTRUCTOR STATED THAT DURING THE LAST AUTOROTATION SHE HEARD THE LOW ROTOR SPEED WARNING HORN AND INITIATED A THROTTLE INCREASE TO RECOVER. ACCORDING TO THE INSTRUCTOR, THE ENGINE AND ROTOR FAILED TO RESPOND TO THE THROTTLE INCREASE AND THE HELICOPTER LANDED HARD. A POST CRASH FIRE IGNITED AND CONSUMED THE AIRCRAFT. FAA INSPECTORS EXAMINED THE WRECKAGE AND FOUND NO EVIDENCE OF A PRE IMPACT MECHANICAL MALFUNCTION OR FAILURE IN THE SURVIVING COMPONENTS.

## Aircraft

- Registration: [N4034K](https://openairdocs.org/deregistered/N4034K-1991-10-31), registration cancelled 1991-10-31, S/N 1515 (OpenAirDocs)
- Reported make and model: ROBINSON R-22B
- Registry model: [Robinson Helicopter R22 BETA](https://openairdocs.org/model/robinson-helicopter-r22-beta) (registry code 7640110) (OpenAirDocs)
- Category: Helicopter
- Serial number: 1515
- Engines: LYCOMING O-320-A2B 150 horsepower reciprocating
- Damage: Destroyed
- Fire: On-Ground
- Flight: Instructional, Part 91
- Operator: Arizona Wing And Rotor, Inc
- Last inspection: Unknown, January 2, 2000
- Departed: SDL, SCOTTSDALE, AZ

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 25; flight instructor, commercial; medical: class 2, valid medical--no waivers/lim.; flight hours: 222 total, 222 in this make and model, 186 as pilot in command, 66 in the last 90 days, 31 in the last 30 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 50 statute miles
- Lowest ceiling: none

## 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 19910617022389A](https://openairdocs.org/incident/19910617022389A), Jun 17, 1991: Robsin R22BETA, Phoenix, AZ, Destroyed. Lost rotor RPM on practice autorotations with power recovery. Impacted and rolled. Destroyed by fire.

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.

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