WPR11LA056

NTSB accident investigation · Bell 407 · Riverdale, UT · November 22, 2010

Accident · No injuriesLimited investigationFinal report
Date
November 22, 2010, 13:15 local (20:15 UTC)
Place
Riverdale, UT
Injuries
3 uninjured
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N408UHBell 407
Defining event
Maneuvering-hover: Collision with terr/obj (non-CFIT)
Weather
Visual (VMC) · Day
Status
Completed · report May 16, 2011
Report
Approved by Office Director
NTSB office
Western Pacific Region
Parties
Federal Aviation Administration
FAA report
20101122052099A
Case key
77859

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 failure to maintain clearance from a highway marker sign while maneuvering.

Findings · 2

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Use of equip/infoPersonnel issues › Task performance · PilotBell 407: 2 casesAll aircraft: 111 casesProbable cause
Object/animal/substance: sign/markerEnvironmental issues › Physical environment · Response/compensationBell 407: 1 caseAll aircraft: 214 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

Analysis

The pilot reported that the intent of the air medical flight was to respond to an automobile accident to pick up a patient for medical transport. Prior to landing at the accident scene, he performed an aerial reconnaissance of the intended landing area on a highway and noted the wind conditions and all pertinent obstacles. The pilot initiated a high-angle approach perpendicular to the highway, and prior to touchdown he noted the landing area was sloped downward. As the pilot performed a pedal turn to reposition the helicopter, the tail rotor contacted a highway reflector pole. He reduced the throttle and initiated a hovering auto rotation, during which the helicopter landed hard on the highway. Examination of the helicopter revealed that the tail rotor and tail rotor gearbox were substantially damaged. The pilot reported there were no preaccident mechanical malfunctions with the helicopter.

Factual narrative

On November 22, 2010, about 1315 mountain standard time, a Bell 407 helicopter, N408UH, sustained substantial damage when it struck a highway reflector pole near Riverdale, Utah. The helicopter was registered to the University of Utah, Salt Lake City, Utah, and operated by Air Methods, Englewood, Colorado, under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91. The commercial pilot and his two passengers were not injured. Visual meteorological conditions prevailed and a company flight plan was filed for the local flight. The flight originated from the Ogden Regional Medical Center, Ogden, Utah, about 3 minutes prior to the accident. During a telephone conversation with the Safety Board investigator-in-charge, the pilot reported that the intent of the flight was to respond to an automobile accident and transport a patient to the Ogden Regional Medical Center. The pilot stated he performed an aerial observation of the intended landing area on interstate 84, noting the wind from 230 to 240 degrees at 15 to 20 knots and all pertinent obstacles. The pilot initiated a high-angle approach perpendicular to the highway; upon landing the pilot noted a forward nose down slope and decided to reposition the helicopter. As the pilot performed a pedal turn to reposition the helicopter, the tail rotor struck a highway reflector pole. The pilot said that after colliding with the highway reflector pole, he rolled the throttle off and initiated a hovering auto rotation. The helicopter subsequently landed hard on the highway. The pilot reported there were no preaccident mechanical problems with the helicopter. Examination of the helicopter by a Federal Aviation Administration (FAA) inspector revealed that the tail rotor and tail rotor gearbox were damaged. The tail rotor drive shaft was separated at the forward Thomas coupling near the tail boom attachment point and at the tail rotor gearbox attachment point.

Aircraft

Registration
N408UH
Reported as
Bell 407
Category
Helicopter
Serial number
53663
Airframe hours
2,423
Engine
Allison 250 SER 250HP, 250 horsepower, turbo shaft
Damage
Substantial damage
Flight
Positioning · Part 91
Operator
Air Methods
Registered owner
University Of Utah
Airworthiness certificate
Standard, Normal
Last inspection
AAIP · November 18, 2010 · 29 hours before
Departed
54UT · Ogden, UT
Destination
Riverdale, UT
Flight plan
Company VFR

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
48
Injuries
None
Certificate
Commercial
Airplane ratings
Single-engine land
Instrument ratings
Helicopter, Airplane
Medical
Class 1, With waivers/limitations
Last flight review
October 10, 2010
Seat
Right
Flight hours
5,532 total · 307 in this make and model · 2,810 as pilot in command · 22 in the last 90 days · 3 in the last 30 days · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
240° at 14 knots, gusting 27
Visibility
10 statute miles
Lowest ceiling
5,000 ft broken
Temperature
36 °F, dew point 21 °F
Altimeter
29.85 inHg
Observed at
OGD, 4 nm away

Docket · 2

The files NTSB released with the investigation on January 5, 2011, on NTSB’s docket system: statements, records, photos and specialists’ reports. 595 KB in all.

FAA reports on this event · 1

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