SEA06LA121

NTSB accident investigation · Bell 206L · Vernal, UT · June 15, 2006

Accident · Minor injuriesLimited investigationFinal report
Date
June 15, 2006, 17:15 local (23:15 UTC)
Place
Vernal, UT
Injuries
6 minor
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N265SHBell 206L
Weather
Visual (VMC) · Day
Status
Completed · report November 29, 2006
Report
Approved by Office Director
Parties
Salt Lake City FSDO
FAA report
20060615010819A
Case key
63982

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

On this page

Probable cause

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

The loss of tail rotor effectiveness during an attempted precationary landing after a takeoff over uneven, sloping, brush-covered terrain. Factors include the pilot using the wrong performance chart while completing his preflight performance calculations, the uneven, sloping, brush-covered terrain, and a high density altitude.

Analysis

Prior to takeoff in conditions that resulted in a density altitude of over 10,000 feet, the pilot figured his takeoff/hover performance using the Hover Ceiling In Ground Effect chart, which indicated the helicopter could safely depart the landing zone (LZ). Because he was taking off over uneven, sloping, brush-covered terrain, he should have used the Hover Ceiling Out of Ground Effect chart, which indicated the helicopter did not have the performance to safely depart the LZ. After liftoff, the pilot started moving the aircraft forward, but it could not out-climb the up-sloping terrain, so he elected to make a precautionary landing on a nearby road. During the landing attempt, the helicopter's tail rotor lost its effectiveness, and the aircraft spun around once and descended into the terrain.

Factual narrative

The factual narrative553 words

On June 15, 2006, approximately 1715, mountain daylight time, a Bell 206L, N265SH, impacted the terrain during a precautionary landing almost immediately after taking off from a remote landing zone (LZ) about 60 miles southeast of Vernal, Utah. The commercial pilot and his five passengers received minor injuries, and the helicopter, which is owned and operated by Silver State Helicopters, of North Las Vegas, Nevada, sustained substantial damage. No flight plan had been filed for the 14 CFR Part 135 passenger repositioning flight. The flight was being operated in visual meteorological conditions.

According to the pilot, he had been using the same LZ for four or five days, and had been taking off into an upslope, because that allowed him to depart into a headwind. On the day of the accident, the wind was calm, but the pilot chose to takeoff in the same direction as he had on the previous days (into the upslope). The pilot lifted off into a hover, and then started moving forward toward the up-sloping terrain. In order to clear the brush growing on the up-sloping terrain, soon after starting to move forward, he increased power and applied a small amount of right anti-torque pedal in order to direct more lift to the main rotor blades. When he applied the right anti-torque pedal, the helicopter's heading rotated about 45 degrees to the right, but it did not climb any higher. Because he could see that he might not have the power to out-climb the up-sloping terrain, the pilot elected to try to put the helicopter down on a nearby road about 100 feet away. Just about the time he got to the road, the pilot heard a noise, and the helicopter spun rapidly to the right. Then the nose of the helicopter dropped, and the airframe impacted the terrain in a nose-down attitude, and then rolled onto its side.

At the time of the accident, the helicopter was being operated at an altitude of 7,500 feet mean sea level (MSL) and an ambient temperature of 75 degrees Fahrenheit (approximate density altitude of 10,200 feet). According to the pilot's calculations, the weight of the aircraft at the time of the accident was 4,100 pounds, which is 50 pounds below its certified maximum gross internal operating weight. During the post-accident investigation, the FAA Inspector who interviewed the pilot and the operator, determined that for his pre-takeoff calculations, the pilot had used the "Hover Ceiling In Ground Effect" chart instead of the "Hover Ceiling Out of Ground Effect" chart, that he should have used. According to the FAA inspector, the "Hover Ceiling In Ground Effect" chart, which should only be used for calculating hover over level, flat terrain, without any significant growth of brush on it, indicated that the helicopter would have the performance to safely takeoff and depart the area. But his review of the "Hover Out of Ground Effect" chart, which should have been used for the takeoff over the uneven, brush-covered, sloping terrain, indicated that the the helicopter could not safely takeoff and depart the area.

An inspection of the helicopter's engine, rotor drive, and flight control system by the FAA and the engine manufacturer (Rolls-Royce/Allison) did not find any anomaly that would have lead to the sequence of events that resulted in the aircraft impacting the terrain.

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 flightLanding
Loss of tail rotor effectiveness - inadvertentPilot in commandCause
Preflight planning/preparation - inadequatePilot in commandFactor
Terrain condition - mountainous/hillyFactor
Terrain condition - high vegetationFactor
Weather condition - high density altitudeFactor

Aircraft

Registration
N265SH
Reported as
Bell 206L
Category
Helicopter
Serial number
51447
Airframe hours
5,227
Engine
Lycoming 250-C30P, 650 horsepower, turbo shaft
Damage
Substantial damage
Flight
Part 135
Registered owner
Silver State Helicopters
Airworthiness certificate
Standard, Normal
Last inspection
100 hour · May 1, 2006
Departed
Vernal, UT

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
36
Injuries
Minor
Certificates
Flight instructor, Commercial
Medical
Class 2, Without waivers/limitations
Last flight review
December 1, 2005
Seat
Front
Flight hours
1,607 total · 557 in this make and model · 1,537 as pilot in command · 134 in the last 90 days · 53 in the last 30 days · 2 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
Calm
Visibility
10 statute miles
Lowest ceiling
10,000 ft overcast
Temperature
75 °F

FAA reports on this event · 1

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