SEA98LA033

NTSB accident investigation · Sherman Executive · Stayton, OR · January 31, 1998

Accident · FatalLimited investigationFinal report
Date
January 31, 1998, 14:00 local (22:00 UTC)
Place
Stayton, OR
Injuries
2 fatal
Damage
Destroyed
Phase of flight
Maneuvering
Aircraft
N50499Sherman Executive
Weather
Visual (VMC) · Day
Status
Completed · report February 15, 2001
Report
Approved by Office Director
FAA report
19980131002749A
Case key
42753

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 NTSB’s determination of the probable cause, and any contributing factors.

Main rotor strike and separation of the tail boom for undetermined reasons.

Analysis

The amateur-built helicopter collided with terrain after in-flight separation of its tail boom and tail rotor while maneuvering. Witnesses described the helicopter making about 4 passes over the field at about 500 feet above the surface. On the last pass, there was a hard yaw to the right; the helicopter then straightened out, pitched into a flare, then the tail came up and the main rotor struck the tail-boom. The tail-boom, tail rotor, and bubble canopy separated from the helicopter. The main wreckage was located about 300 feet from those components.

Factual narrative

On January 31, 1998, approximately 1400 Pacific standard time, N50499, a amateur-built Sherman Executive helicopter, collided with terrain after in-flight separation of its tail boom and tail rotor while maneuvering, near Stayton, Oregon. The two occupants, a commercial helicopter pilot and the owner (a private pilot) were fatally injured. The helicopter had departed Salem, Oregon, on a training flight for the private pilot. Visual meteorological conditions prevailed at the time of the accident. The wreckage was consumed by fire. There was no ELT onboard the aircraft.

Witnesses described the helicopter making about 4 passes over the field at about 500 feet above the surface. On the last pass, there was a hard yaw to the right; the helicopter then straightened out, pitched into a flare, then the tail came up and the main rotor struck the tail-boom. The tail-boom, tail rotor, and bubble canopy separated from the helicopter. The main wreckage was located about 300 feet from those components.

The owner-builder had brought the helicopter to Salem to acquire helicopter flight training. The commercial pilot had extensive experience in helicopters, but he did not have a flight instructor certificate.

Toxicological testing on both pilots on board the helicopter was negative. Autopsies of the two occupants were performed at Portland, Oregon by Drs. Nikolas J. Hartshorne and Steve Shapiro. The NTSB did not take possession of the aircraft.

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.

Loss of control - in flightManeuvering
Misc rotorcraft,tail boom - separationCause
Reason for occurrence undetermined
In flight collision with terrain/waterDescent - uncontrolled
Terrain condition - ground

Aircraft

Registration
N50499
Reported as
Sherman Executive
Category
Helicopter, amateur-built
Serial number
ES002
Engine
Rotorway RW152D, 150 horsepower, reciprocating
Damage
Destroyed
Fire
On-Ground
Flight
Instructional · Part 91
Registered owner
Evan J. Sherman
Airworthiness certificate
Special, Experimental (Special)
Departed
Salem, OR

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
33
Certificate
Commercial
Airplane ratings
Single-engine land, Single-engine sea
Instrument ratings
Helicopter
Medical
Class 2, Expired
Seat
Left
Toxicology
Performed
Flight hours
2,500 total

Weather

Conditions
Visual (VMC) · Day
Lowest ceiling
None
Temperature
52 °F

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.