SEA98LA017

NTSB accident investigation · Bell TH-1L · Canby, OR · November 25, 1997

Accident · Minor injuriesLimited investigationFinal report
Date
November 25, 1997, 10:30 local (18:30 UTC)
Place
Canby, OR
Injuries
7 minor
Damage
Substantial damage
Phase of flight
Enroute
Aircraft
N8160GBell TH-1L
Weather
Visual (VMC) · Day
Status
Completed · report December 1, 1999
Report
Approved by Office Director
FAA report
19971125034969A
Case key
42739

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's allowance of excessive airspeed resulting in the long-line hook impacting the tail rotor, and his allowance of an airspeed bleed-off preventing a successful run-on landing due to a loss of yaw control.

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.

Airframe/component/system failure/malfunctionCruise
External load cable/hook - blade strikeCause
Airspeed - excessivePilot in commandCause
Forced landingDescent - emergency
Hard landingEmergency landing
Run on landing - attempted
Airspeed - inadequatePilot in commandCause

Analysis

The pilot was repositioning the helicopter to a new work location with the 30 foot long-line in trail. While en route at 80 knots and 500 feet AGL, the pilot lost view of the line and hook in the aircraft's chin mirror when, in his words it 'became unstable.' Shortly thereafter, the hook impacted the tail-rotor blade assembly. The pilot then attempted to execute a run-on landing, but allowed his airspeed to bleed off beyond the point where he could maintain any directional control. The aircraft then began a right yaw and, after approximately 720 degrees of revolution, impacted the ground in a near level attitude with a near vertical flight path.

Factual narrative

On November 25, 1997, approximately 1030 Pacific standard time, a Bell TH-1L rotorcraft, N8160G, registered to Kenneth G. Guthrie, d/b/a Blue Bird Helicopters, and being flown by a commercial pilot, was substantially damaged during an emergency landing in a field following a loss of control while in cruise approximately five nautical miles south of Canby, Oregon. The pilot and six passengers sustained minor injuries. Visual meteorological conditions existed and no flight plan had been filed. The flight, which had been engaged in external long-line operations (slinging Christmas trees), was repositioning with the six member ground crew team. The flight was to have been operated under 14CFR133, and originated from a site near Molalla, Oregon, approximately 1025.

The pilot reported that he was repositioning the helicopter to another work site with the 30 foot long-line trailing from the aircraft, and that "the hook (was) trailing smoothly beneath the aircraft as observed by myself in the chin mirror" and that "the hook suddenly became unstable and could no longer be seen in the chin mirror." Shortly thereafter the pilot heard a loud "bang" and felt the aircraft "lurch."

The pilot, having been operating the helicopter at 80 knots and approximately 500 feet above ground at the time of the event, attempted to execute a run-on landing to a nearby field. He reported that "as I attempted to roll out on final I realized that I had allowed my airspeed to bleed off beyond the point where I could maintain any directional control with cyclic." The aircraft then began to yaw right, and after approximately 720 degrees of revolution impacted the ground in a near level attitude with a near vertical flight path.

An FAA inspector responding to the accident site reported finding fragments of aluminum rotor blade imbedded in the hook at the end of the long-line.

Aircraft

Registration
N8160G
Reported as
Bell TH-1L
Category
Helicopter
Serial number
157839
Engine
Lycoming T53-L-13B, 1,400 horsepower, turbo shaft
Damage
Substantial damage
Flight
Other work use · Part 133
Registered owner
Guthrie, Kenneth, G.
Airworthiness certificate
Special, Restricted (Special)
Departed
Molalla, OR
Destination
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
53
Certificate
Commercial
Instrument ratings
Helicopter
Medical
Class 2, Valid Medical--w/ waivers/lim
Seat
Left
Flight hours
11,329 total · 52 in this make and model · 7,439 as pilot in command · 86 in the last 90 days · 53 in the last 30 days · 7 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
30° at 5 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
52 °F, dew point 45 °F
Altimeter
30.00 inHg
Observed at
AUO, 5 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.