DEN05TA072

NTSB accident investigation · Bell OH-58C · Colorado Sprngs, CO · April 8, 2005

Accident · No injuriesFinal report
Date
April 7, 2005, 18:15 local (Apr 8, 2005, 00:15 UTC)
Place
Colorado Sprngs, CO
Injuries
3 uninjured
Damage
Substantial damage
Phase of flight
Enroute
Aircraft
N198PDBell OH-58C
Weather
Visual (VMC) · Day
Status
Completed · report October 27, 2005
Report
Approved by Office Director
Parties
FAA Flight Standards Field Office
Case key
61457

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 failure of the N1 tachometer generator which resulted in a precautionary landing. Contributing factors include the frayed wire and the unsuitable terrain for a precautionary landing.

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 - normal
Electrical system,electric wiring - frayedFactor
Engine instruments,tachometer - failureCause
Hard landingDescent - emergency
Precautionary landing - performedPilot in command
Unsuitable terrain or takeoff/landing/taxi area - encounteredFactor
Terrain condition - uphill

Analysis

According to the pilot, he was orbiting over a campus when the "engine out light illuminated in the cockpit," followed by an "audible engine out alarm" and the "N1 gauge dropped." The pilot elected to perform a precautionary landing to a field. The pilot stated that the terrain sloped uphill and the helicopter stopped "abruptly" and rock back and forth. A postaccident examination revealed that the N1 Tachometer Generator had failed. Further examination revealed that the N1 tachometer generator wire was not connected to the cannon plug and frayed. Examination of the helicopter's remaining systems revealed no anomalies.

Factual narrative

On April 7, 2005, approximately 1815 mountain daylight time, a Bell OH-58C, N198PD, operated by the City of Colorado Springs Police Department, was substantially damaged during a forced landing 10 miles north of Colorado Springs, Colorado. Visual meteorological conditions prevailed at the time of the accident. The local public use flight was being operated under the provisions of Title 14 CFR Part 91 without a flight plan. The commercial certificated pilot and two passengers reported no injuries. The local flight originated approximately 1800.

According to the accident report submitted by the pilot, he was orbiting over a college campus when the "engine out light illuminated" in the cockpit. This light was followed by an "audible engine out alarm" and the "N1 gauge dropped." The pilot elected to perform a precautionary landing west of Interstate 25 on Air Force Academy property. The pilot stated that the terrain sloped uphill and the helicopter stopped "abruptly" and rock back and forth. Approximately 30 inches aft from the boom attach point, the boom buckled, leaving a wrinkle approximately 9 inches in length and approximately 2 inches at its deepest point.

A postaccident examination revealed that the N1 tachometer generator had failed. Further examination revealed that the N1 tachometer generator wire was not connected to the cannon plug and frayed. Examination of the helicopter's remaining systems revealed no anomalies.

Aircraft

Registration
N198PD
Reported as
Bell OH-58C
Category
Helicopter
Serial number
68-16947
Airframe hours
9,433.3
Engine
Rolls-Royce Allison 250, 420 horsepower, turbo shaft
Damage
Substantial damage
Flight
Public aircraft - local · Part 91
Registered owner
City of Colorado Springs Police Department
Airworthiness certificate
Standard, Normal
Last inspection
Continuous airworthiness · April 1, 2005
Departed
COS · Colorado Sprngs, CO

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
41
Injuries
None
Certificate
Commercial
Airplane ratings
Single-engine land
Medical
Class 2, With waivers/limitations
Last flight review
May 1, 2004
Seat
Right
Flight hours
437 total · 350 in this make and model · 288 as pilot in command · 51 in the last 90 days · 14 in the last 30 days · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
30° at 18 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
54 °F, dew point 21 °F
Altimeter
30.29 inHg
Observed at
KCOS, 10 nm away