ERA10LA383

NTSB accident investigation · Hiller UH-12E · Holly Hill, SC · July 29, 2010

Accident · Serious injuriesLimited investigationFinal report
Date
July 29, 2010, 09:30 local (13:30 UTC)
Place
Holly Hill, SC
Injuries
1 serious
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N104HHHiller UH-12E
Defining event
Maneuvering-low-alt flying: Loss of engine power (total)
Weather
Visual (VMC) · Day
Status
Completed · report September 19, 2011
Report
Approved by Office Director
NTSB office
Eastern Region Aviation
Parties
FAA/FSDO
FAA report
20100729042709A
Case key
76792

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

Maintenance personnel's improper inspection and cleaning of the fuel nozzle, which resulted in a total loss of engine power.

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.

Engine fuel and control: fuel injector nozzleAircraft › Aircraft power plant · Inadequate inspectionHiller UH-12E: 1 caseAll aircraft: 20 casesProbable cause
Maintenance: scheduled/routine maintenancePersonnel issues › Task performance · Maintenance personnelHiller UH-12E: 3 casesAll aircraft: 320 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 stated that as he approached a tree line for aerial application his chemical ran out. As he turned back to reload the chemical, the engine experienced a total loss of power. The pilot quickly conducted an autorotation and collided with trees before coming to rest on the ground. A postaccident examination of the engine revealed that the combustion chamber fuel spray nozzle was clogged with carbon and soot deposits, which is likely the result of the nozzle not being properly inspected and cleaned during the last 100-hour inspection. A review of the engine maintenance logbooks revealed that the last 100-hour inspection was completed 41 days prior to the accident. According to the aircraft Hobbs time, the engine accumulated 40 hours since the 100-hour inspection.

Factual narrative

On July 29, 2010, at 0930 eastern daylight time, a Hiller UH-12E, N104HH, registered to and operated by Haddock Flying Service Inc., collided with a tree during an autorotation following a total loss of engine power near Holly Hill, South Carolina. The aerial application flight was operated under the provisions of 14 Code of Federal Regulations Part 137, with no flight plan filed. Visual meteorological conditions prevailed. The certificated commercial pilot received serious injuries, and the helicopter was substantially damaged. The flight departed from a landing pad in Holly Hill, South Carolina, at 0925. The pilot stated that as he approached a tree line for aerial application, his chemical ran out. As he turned back to reload chemical the engine experienced a total loss of power. Due to the low operating altitude he quickly conducted an autorotation and collided with trees before coming to rest on the ground. Examination of the wreckage by a Federal Aviation Administration inspector revealed that the helicopter collided with a tree during the autorotation which resulted in substantial damage to the fuselage and the main rotor assembly. Flight control continuity was confirmed from the cockpit through the tail rotor system, and from the cockpit cyclic and collective controls through the main rotor head. Further examination of the helicopter revealed that fuel was present in the fuel tank. The helicopter was recovered for further examination. An examination of the engine revealed that the combustion chamber fuel spray nozzle was clogged with carbon and soot deposits. A review of the engine maintenance logbooks revealed that the most recent 100-hour inspection was completed 41 days prior to the accident. According to the aircraft Hobbs time, the engine accumulated 40 hours since the 100-hour inspection. A review of the engine logbooks did not reveal documentation of the inspection or the cleaning of the fuel spray nozzle. A review of the Rolls Royce 250-C20 series operation and maintenance schedule inspection pages revealed that at the 100-hour inspection, item 21.A states: "remove, inspect and clean the fuel nozzle. If no airframe mounted fuel filter is installed, inspect the fuel nozzle filter." It also noted that operators may find it necessary to inspect and clean the fuel nozzle more often depending on past experience or operating conditions.

Aircraft

Registration
N104HH
Reported as
Hiller UH-12E
Category
Helicopter
Serial number
2062
Airframe hours
10,099
Engine
Allison 250 SERIES, 300 horsepower, reciprocating
Damage
Substantial damage
Flight
Aerial application · Part 137
Operator
Haddock Flying Service Inc
Registered owner
Haddock Flying Service Inc
Airworthiness certificate
Standard, Utility
Last inspection
100 hour · May 19, 2010 · 40 hours before
Departed
Holly Hill, SC
Destination
Holly Hill, SC

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
Serious
Certificate
Commercial
Airplane ratings
Multi-engine land, Single-engine land
Instrument ratings
Airplane
Medical
Class 2, With waivers/limitations
Last flight review
March 10, 2010
Seat
Right
Flight hours
19,890 total · 5,700 in this make and model · 19,790 as pilot in command · 150 in the last 90 days · 12 in the last 30 days

Weather

Conditions
Visual (VMC) · Day
Wind
260° at 3 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
82 °F, dew point 77 °F
Altimeter
30.01 inHg
Observed at
DYB

Docket · 8

The files NTSB released with the investigation on June 29, 2011, on NTSB’s docket system: statements, records, photos and specialists’ reports. 3.4 MB 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.