DEN00LA001

NTSB accident investigation · Gray Rotorway Exec · Gallup, NM · October 1, 1999

Accident · Serious injuriesLimited investigationFinal report
Date
October 1, 1999, 06:45 local (12:45 UTC)
Place
Gallup, NM
Injuries
1 serious
Damage
Substantial damage
Phase of flight
Approach
Aircraft
N716JBGray Rotorway Exec
Weather
Visual (VMC) · Dawn
Status
Completed · report June 21, 2000
Report
Approved by Office Director
FAA report
19991001040219A
Case key
47524

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 pilot inadvertently allowing main rotor rpm to decay while avoiding obstacles during an emergency autorotation following a loss of power for reasons undetermined. Factors were houses and powerlines.

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 engine powerApproach - vfr pattern - base turn
Autorotation - performedPilot in command
Reason for occurrence undetermined
Forced landingDescent - emergency
Object - residence
Rotor rpm - not maintainedPilot in command
Object - wire,transmission
In flight collision with terrain/waterDescent - emergency

Analysis

The pilot remained in the traffic pattern to practice touch and go landings. At approximately the point where the helicopter would turn onto the base leg, rotor rpm began to decay (95%). The pilot turned towards the runway and began autorotation. During the descent, the pilot managed to avoid houses and powerlines. The helicopter struck the ground tail first, then rolled over on its left side. The engine was later functionally tested and, despite impact damage to the crankshaft, operated normally.

Factual narrative

On October 1, 1999, approximately 0645 mountain daylight time, a Gray Rotorway Executive homebuilt helicopter, N716JB, registered to and operated by the pilot, was destroyed when it collided with terrain during descent at Gallup, New Mexico. The solo student pilot was seriously injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the instructional flight being conducted under Title 14 CFR Part 91. The flight originated at Gallup, New Mexico, approximately 0630.

In his accident report, the pilot said he intended on remaining in the traffic pattern to practice touch and go landings. He had purposely planned the early morning flight because the "wind is usually calm and density altitude is lowest, giving the helicopter best performance capabilities." The flight was uneventful until the helicopter reached the point where the pilot would turn from downwind to base leg, and he noticed the "rotor rpm was low (95%)." He turned the helicopter towards the runway and "lowered collective [to] stabilize rotor rpm." At this point, "the engine failed." He "lowered collective [control] all the way down, [pushed] the cyclic [control] forward, and began autorotation." The helicopter descended toward houses, so he "extended [the descent path] by pulling collective." Rotor rpm fell to 80%. The pilot headed towards a small open field but as he descended to 100 feet agl (above ground level), he noticed powerlines ahead. He did a "second extension," and power dropped to 60%. Approximately 30 feet agl, he pulled the nose up and added full up collective to arrest the descent. The helicopter struck the ground tail first, then rolled over on its left side.

In December 1999, the engine was functionally tested at the facilities of Rotorway in Chandler, Arizona. Despite impact damage to the crankshaft, the engine operated normally.

Aircraft

Registration
N716JB
Reported as
Gray Rotorway Exec (ROTORWAY E)
Category
Helicopter, amateur-built
Serial number
EXEC-3000
Airframe hours
140
Engine
Rotorway RW-152, 152 horsepower, reciprocating
Damage
Substantial damage
Flight
Instructional · Part 91
Registered owner
Jim R. Gray
Airworthiness certificate
Special, Experimental (Special)
Last inspection
Annual · September 18, 1999 · 10 hours before
Departed
GUP · NM
Airport
GUP · Gallup Municipal, runway 24, 7,312 × 100 ft, asphalt

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
51
Certificate
Student
Medical
Class 3, Valid Medical--w/ waivers/lim
Seat
Left
Flight hours
158 total · 155 in this make and model · 127 as pilot in command · 14 in the last 90 days · 5 in the last 30 days · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Dawn
Wind
Calm
Visibility
15 statute miles
Lowest ceiling
None
Temperature
30 °F, dew point 28 °F
Altimeter
30.00 inHg
Observed at
GUP

FAA reports on this event · 1

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

Other investigations on N716JB · 3

Matched to the same aircraft by N-number and date.