LAX00LA055

NTSB accident investigation · Bell 206B · Apache Junction, AZ · October 7, 1999

Accident · No injuriesLimited investigationFinal report
Date
October 7, 1999, 10:15 local (17:15 UTC)
Place
Apache Junction, AZ
Injuries
3 uninjured
Damage
Substantial damage
Phase of flight
Enroute
Aircraft
N6624NBell 206B
Weather
Visual (VMC) · Day
Status
Completed · report May 16, 2001
Report
Approved by Office Director
FAA report
19991007036939A
Case key
48367

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

Oil starvation and seizure of the engines Nos. 6 and 7 bearings due to a clogged oil jet, which resulted in a total loss of engine power.

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 power(total) - mech failure/malfCruise
Lubricating system,oil port/passage,internal - blocked(partial)Cause
Fluid,oil - starvationCause
Forced landingEmergency descent/landing
Autorotation - performedPilot in command
On ground/water encounter with terrain/waterLanding - flare/touchdown
Terrain condition - high vegetation
Landing gear,skid assembly - separation

Analysis

While in cruise flight about 600 feet agl, the pilot noticed that the engine oil pressure was high and the torque gauge was exceeding the high limits. The engine chip light became illuminated. As the pilot descended to make an immediate landing, the engine quit about 75 to 100 feet agl. The pilot autorotated to the ground. The main rotor blades severed the tail cone aft of the horizontal stabilizer after the toe of the left skid became entangled in a large bush and separated. A teardown examination of the engine was conducted. The mechanic reported that the Nos. 6 and 7 bearings displayed evidence of heat distress and oil starvation. When he blew through the oil jet for the Nos. 6 and 7 bearings, he heard something pop out. He opined that it might have been a piece of carbon, which could have prevented the flow of oil into the turbine. He stated that all other components of the lubrication system were intact and functional. No other discrepancies were found.

Factual narrative

On October 7, 1999, at 1015 hours mountain standard time, a Bell 206B, N6624N, experienced a loss of engine power and collided with high vegitation during a forced landing near Apache Junction, Arizona. The helicopter, operated by Arizona HeliServices, Inc., of Chandler, Arizona, sustained substantial damage. The commercial pilot and two passengers were not injured. The local personal flight, conducted under the provisions of 14 CFR Part 91, originated from the Cochise County Airport, Willcox, Arizona, about 0905, and was en route to Falcon Field, Mesa, Arizona. Visual meteorological conditions prevailed and no flight plan was filed.

The pilot reported that while in cruise flight about 600 feet agl, he noticed that the engine oil pressure was "exceedingly high," and the torque gauge was exceeding the high limits (120+). The engine chip light became illuminated. The pilot lowered the collective with no apparent effect on the torque gauge reading. As he descended to make an immediate landing, the engine quit about 75 to 100 feet agl. The pilot autorotated to the ground with a slight aft skid touchdown and minimum forward airspeed. The left skid toe became embedded in a creosote bush and the helicopter turned left 90 degrees. The left skid separated from the crossmember and the left side of the nose dipped. The main rotor blades severed the tail cone aft of the horizontal stabilizer. The right skid separated but the helicopter remained upright.

A teardown examination of the engine was conducted. The mechanic reported that the Nos. 6 and 7 bearings displayed evidence of heat distress and oil starvation. He blew through the oil jet for the Nos. 6 and 7 bearings and thought it seemed to be partially blocked. He then blew compressed air through the oil jet and heard something pop out. He opined that it might have been a piece of carbon, which could have clogged the jet and blocked the flow of oil. He stated that all other components of the lubrication system were intact and functional. No other discrepancies were found.

Aircraft

Registration
N6624N
Reported as
Bell 206B
Category
Helicopter
Serial number
3169
Airframe hours
6,335
Engine
Allison 250-C20B, 420 horsepower, turbo shaft
Damage
Substantial damage
Flight
Personal · Part 91
Operator
Arizona Heliservices Inc.
Registered owner
Bell Ford, Inc.
Airworthiness certificate
Standard, Normal
Last inspection
100 hour · March 31, 1999 · 93 hours before
Departed
P33 · Willcox, AZ
Destination
FFZ · Mesa, AZ

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
52
Certificate
Commercial
Airplane ratings
Single-engine land
Medical
Class 2, Valid Medical--no waivers/lim.
Seat
Right
Flight hours
5,800 total · 2,300 in this make and model · 5,700 as pilot in command · 20 in the last 90 days · 20 in the last 30 days

Weather

Conditions
Visual (VMC) · Day
Wind
Variable at 4 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
75 °F, dew point 43 °F
Altimeter
29.00 inHg
Observed at
PHX, 23 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.