# NTSB LAX93LA308: Robinson R-22, N549SM, Verdi, NV, July 30, 1993

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: July 30, 1993, 12:29 local (19:29 UTC)
- Place: Verdi, NV
- Coordinates: 39.510414, -119.989784 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.5104&lon=-119.9898&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report November 15, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 27988
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX93LA308
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/27988/pdf
- Page: https://openairdocs.org/ntsb/LAX93LA308

## Probable cause

THE INSTRUCTOR'S IMPROPER SUPERVISION OF THE FLIGHT; THE DUAL STUDENT'S IMPROPER IN-FLIGHT DECISION TO FOLLOW ANOTHER HELICOPTER ON DEPARTURE AND THE DUAL STUDENTS DELAY IN CORRECTING THE INADVERTENT YAW.  FACTORS RELATED TO THIS ACCIDENT WAS THE INADVERTENT ENCOUNTER WITH THE WAKE TURBULENCE FROM THE PRECEDING DEPARTING HELICOPTER; THE DUAL STUDENT'S IMPROPER USE OF THE THROTTLE AND THE DUAL STUDENTS FAILURE TO MAINTAIN ADEQUATE ROTOR RPM.

## Sequence of events

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

- Loss of control - in flight, takeoff - initial climb
  - supervision - improper, pilot in command(cfi) (cause)
  - in-flight planning/decision - improper, dual student (cause)
  - remedial action - delayed, dual student (cause)
  - wake turbulence - encountered, dual student (contributing factor)
  - throttle/power control - improper use of, dual student (contributing factor)
  - rotor rpm - not maintained, dual student (contributing factor)
- In flight collision with object, takeoff - initial climb
  - object - other
- Roll over, descent - uncontrolled

## Analysis

THE HELICOPTER WAS ONE OF A FLIGHT OF FOUR HELICOPTERS CONDUCTING A MOUNTAIN FLYING COURSE WHICH CONSISTED OF EXECUTING PINNACLE LANDINGS AND TAKEOFFS.  THE CFI ALLOWED THE DUAL STUDENT TO FOLLOW ANOTHER HELICOPTER ON ITS DEPARTURE FROM THE PINNACLE. THE HELICOPTER ENCOUNTERED THE PRECEDING HELICOPTER'S ROTOR WASH AND IMMEDIATELY TURNED RIGHT. THE STUDENT APPLIED LEFT PEDAL CORRECTIVE ACTION, BUT THE MAIN ROTOR RPM'S BEGAN TO DECAY. THE CFI ASSUMED THE CONTROLS AND IMMEDIATELY LOWERED THE COLLECTIVE AND APPLIED FULL THROTTLE, BUT THE REAR SKIDS STRUCK THE GROUND. THE CFI WAS ABLE TO REGAIN A LEVEL ATTITUDE, BUT THE HELICOPTER STRUCK SOME ROCKS AND CRASHED.

## Aircraft

- Registration: N549SM (not matched to a registry record)
- Reported make and model: ROBINSON R-22
- Category: Helicopter
- Serial number: 1549
- Airframe hours: 1795
- Engines: LYCOMING O-320-B2C 160 horsepower reciprocating
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Operator: Helicopter Adventures, Inc.
- Registered owner: Charles L. Marlow
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, June 30, 1993, 85 hours before
- Departed: RNO, RENO, NV
- Destination: TRK, TRUCKEE, CA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 24; commercial, flight instructor; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 340 total, 340 in this make and model, 304 as pilot in command, 100 in the last 90 days, 34 in the last 30 days, 4 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Visibility: 30 statute miles
- Lowest ceiling: none
- Temperature: 75 °F, dew point 39 °F
- Altimeter: 30.00 inHg

## 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 19930730056849A](https://openairdocs.org/incident/19930730056849A), Jul 30, 1993: Robsin R22BETA, Verdi, NV, Substantial damage. Yaw developed as forward speed increased after takeoff. Lost rotor RPM. CFI took over. Skids hit rocks. Rolled.

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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