LAX96LA172

NTSB accident investigation · Bell 206B III · San Diego, CA · April 16, 1996

Accident · No injuriesLimited investigationFinal report
Date
April 16, 1996, 16:00 local (23:00 UTC)
Place
San Diego, CA
Injuries
2 uninjured
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N2750FBell 206B III
Weather
Visual (VMC) · Day
Status
Completed · report August 20, 1996
Report
Approved by Office Director
FAA report
19960416007549A
Case key
29422

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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Probable cause

the student's failure to maintain adequate main rotor rpm and airspeed during a practice autorotation, and the instructor's inadequate supervision of the flight.

Sequence of events

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Hard landingLanding - flare/touchdown
Autorotation - performedDual student
Terrain condition - rough/uneven
Planned approach - misjudgedDual studentCause
Distance/altitude - misjudgedDual studentCause
Rotor rpm - not maintainedDual studentCause
Supervision - inadequatePilot in command(cfi)Cause
Remedial action - delayedPilot in command(cfi)Cause

Analysis

While practicing touchdown autorotations, the helicopter landed hard on uneven terrain short of the intended touchdown point. The commercial pilot-rated student was demonstrating a autorotation with a turn to the runway. As he completed the turn and was aligning with the runway, the helicopter rotor rpm dropped to 70 percent. Halfway into the maneuver the flight instructor realized the helicopter was too low and slow to accomplish a power recovery and took control. The helicopter landed short of the runway in rough terrain. A postflight inspection of the helicopter revealed wrinkles in the tail boom. The pilot under instruction held a rotorcraft helicopter rating.

Factual narrative

On April 16, 1996, at 1600 hours Pacific daylight time, a Bell 206B III helicopter, N2750F, landed hard on uneven terrain while practicing touchdown autorotations at Montgomery Field, San Diego, California. The helicopter sustained substantial damage. The certified flight instructor (CFI) and the certificated commercial pilot student were not injured. The helicopter was being operated as an instructional flight under 14 CFR Part 91 when the accident occurred. The local flight originated from Montgomery Field. Visual Instrument meteorological conditions prevailed.

The CFI indicated that the commercial pilot was demonstrating an autorotation with a turn from 200 feet above ground level to runway 23. As the commercial pilot completed the turn and was aligning with the runway, the helicopter rotor rpm dropped to 70 percent. According to the CFI, halfway into the maneuver he realized the helicopter was too low and slow to accomplish a power recovery.

The flight instructor took control of the helicopter. The helicopter touched down short of the intended point on the runway in rough uneven terrain. Post-flight inspection of the helicopter revealed wrinkles in the tail boom.

The commercial pilot under instruction held a rotorcraft helicopter rating.

The surface winds at Montgomery Field at the time were reported from 240 degrees at 11 knots.

Aircraft

Registration
N2750F
Reported as
Bell 206B III
Category
Helicopter
Serial number
2674
Airframe hours
13,647
Engine
Allison 250-C20B, 420 horsepower, turbo shaft
Damage
Substantial damage
Flight
Instructional · Part 91
Registered owner
Corporate Helicopters
Airworthiness certificate
Standard, Normal
Last inspection
100 hour · February 7, 1996 · 67 hours before
Departed
MYF
Airport
MYF · Montgomery Field, runway 23, 3,402 × 150 ft, asphalt

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
34
Certificates
Flight instructor, Airline transport
Instrument ratings
Helicopter
Medical
Class 1, Valid Medical--no waivers/lim.
Seat
Left
Flight hours
3,300 total · 1,250 in this make and model · 3,260 as pilot in command · 120 in the last 90 days · 40 in the last 30 days · 5 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
240° at 11 knots
Visibility
30 statute miles
Lowest ceiling
None
Temperature
70 °F, dew point 59 °F
Altimeter
30.00 inHg
Observed at
MYF, 1 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.