# NTSB LAX07CA229: Robinson R22 Beta II, N147SH, Boise, ID, July 24, 2007

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Data collection · Final report
- Date: July 24, 2007, 08:45 local (14:45 UTC)
- Place: Boise, ID
- Coordinates: 43.573612, -116.226943
- Nearby events: https://openairdocs.org/map.md?lat=43.5736&lon=-116.2269&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 2 minor
- Status: Completed, report November 29, 2007
- Report: Approved by Office Director
- Parties: Federal Aviation Administration
- NTSB case key (mKey): 66315
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX07CA229
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/66315/pdf
- Page: https://openairdocs.org/ntsb/LAX07CA229

## Probable cause

The student pilot's failure to maintain rotor rpm resulting in an excessive descent rate and a hard landing.  Factors in the accident were the student's failure to relinquish the controls, and the CFI's inadequate supervision.

## Sequence of events

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

- Hard landing, landing - flare/touchdown
  - rotor rpm - not maintained, dual student (cause)
  - descent - excessive, dual student (cause)
  - relinquishing of control - not performed, dual student (contributing factor)
  - supervision - inadequate, pilot in command(cfi) (contributing factor)

## Analysis

The flight instructor reported that during their fifth practice autorotation, the student let the rotor rpm decay to the point that the certified flight instructor (CFI) attempted to intercede and perform a run on landing.  The student and CFI both struggled with each other on the controls until the helicopter hit the ground hard.  During the impact sequence, the helicopter spun around, and ultimately came to rest on the left side.

## Factual narrative

The flight instructor reported that during their fifth practice autorotation, the student let the rotor rpm decay to the point that the CFI attempted to intercede and perform a run on landing.  The student and CFI both struggled with each other on the controls until the helicopter hit the ground hard.  During the impact sequence, the helicopter spun around, and ultimately came to rest on the left side.

## Aircraft

- Registration: N147SH (not matched to a registry record)
- Reported make and model: Robinson R22 Beta II
- Category: Helicopter
- Serial number: 4137
- Airframe hours: 298.7
- Engines: Lycoming O-360-J2A 145 horsepower reciprocating
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Registered owner: Silver State Helicopters LLC
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, June 1, 2007
- Departed: Boise, ID
- Airport: BOI, Boise Air Terminal /Gowen Fld/

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Flight instructor; age 30; injuries: minor; commercial, flight instructor; instrument ratings: helicopter; medical: class 2, without waivers/limitations; last flight review April 1, 2007; seat: left; flight hours: 648 total, 477 in this make and model, 578 as pilot in command
- Student pilot; age 46; injuries: minor; student; medical: class 2, without waivers/limitations; last flight review April 1, 2007; seat: right; flight hours: 69 total, 69 in this make and model, 6 as pilot in command, 19 in the last 90 days, 8 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 290° at 8 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 72 °F, dew point 52 °F
- Altimeter: 29.92 inHg
- Observed at: BOI

## 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 20070724014509A](https://openairdocs.org/incident/20070724014509A), Jul 24, 2007: Robsin R22, Boise, ID, Substantial damage. (-23) Instructor pilot stated that during practice autorotative descent, student allowed airspeed and rotor RPM to deteriorate in last 200 feet of glide.…

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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