CHI07LA193

NTSB accident investigation · Hughes 369D · Comfrey, MN · July 5, 2007

Accident · No injuriesLimited investigationFinal report
Date
July 5, 2007, 08:00 local (13:00 UTC)
Place
Comfrey, MN
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N500NCHughes 369D
Weather
Visual (VMC) · Day
Status
Completed · report March 31, 2008
Report
Approved by Office Director
Parties
Federal Aviation Administration
FAA report
20070705019599A
Case key
66167

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 loss of engine power due to the loose pressure line during aerial application maneuvers which resulted in a hard forced 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.

Loss of engine powerManeuvering - aerial application
Fuel system,line fitting - looseCause
Forced landingDescent - emergency
Hard landingEmergency descent/landing
Terrain condition - ground

Analysis

A helicopter sustained substantial damage on impact with terrain during a forced landing following a loss of engine power during an aerial application spray run. The pilot reported that he "was able to land square on the skids, but the helicopter still bounced. The landing gear spread hitting the tanks, and snapping the uprights above the tanks. At that point, forward leg stuck in the ground, making the helicopter pitch forward. The blade in front made contact with the ground. The rotor system came around cutting the boom faring and tail off." The pressure line which connects to the Pg boss on the fuel control was found to be finger tight during an examination of the wreckage.

Factual narrative

On July 5, 2007, about 0800 central daylight time, N500NC, registered as Hughes 369D helicopter, piloted by a commercial pilot, sustained substantial damage on impact with terrain during a forced landing following a loss of engine power during an aerial application spray run near Comfrey, Minnesota. The local aerial application flight was operating under 14 CFR Part 137. No flight plan was on file. Visual meteorological conditions prevailed at the time of the accident. The pilot, the sole occupant, reported no injuries. The origin and destination of the flight are unknown.

The pilot's accident report, in part, stated:

On the second pass of the second load, and in the middle of

the field headed west, the engine began to spool down in RPM.

I heard the engine sound of lost RPM, at that time my eyes were

on the wires that the aircraft was approaching, N2 Rotor was at

or about the bottom Red Line. My choices were to attempt to

auto rotate across the wires, the road, and the people to the field

beyond. At that split second I decided to attempt the grass area

south of the field. Low N2 and air speed (about 75 mph), lowered

collective attempted a 180 [degree] auto rotation, the engine and

rotor seemed to speed up or surge. I attempted to do the auto as best

as I could. Was able to land square on the skids, but the helicopter

still bounced. The landing gear spread hitting the tanks, and

snapping the uprights above the tanks. At that point, forward leg

stuck in the ground, making the helicopter pitch forward. The blade

in front made contact with the ground. The rotor system came around

cutting the boom faring and tail off.

Federal Aviation Administration Inspectors examined the wreckage. The pressure line which connected to the Pg boss on the fuel control was found finger tight.

Aircraft

Registration
N500NC
Reported as
Hughes 369D
Category
Helicopter
Serial number
1260052D
Airframe hours
3,284.7
Engine
Allison 250-C20B, 420 horsepower, turbo shaft
Damage
Substantial damage
Flight
Aerial application · Part 137
Operator
Teryjon Aviation Inc.
Registered owner
Big Bird Leasing Inc.
Airworthiness certificate
Special, Restricted (Special)
Last inspection
Annual · March 1, 2007
Departed
MN

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
59
Injuries
None
Certificate
Commercial
Airplane ratings
Single-engine land
Medical
Class 2, With waivers/limitations
Last flight review
November 1, 2006
Seat
Left
Flight hours
4,000 as pilot in command

Weather

Conditions
Visual (VMC) · Day
Wind
310° at 4 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
72 °F, dew point 63 °F
Altimeter
30.05 inHg
Observed at
KMKT, 45 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.

Other investigations on N500NC · 1

Matched to the same aircraft by N-number and date.