CEN10LA353

NTSB accident investigation · Air Tractor AT-602 · Penrose, AR · June 14, 2010

Accident · Minor injuriesLimited investigationFinal report
Date
June 14, 2010, 09:15 local (14:15 UTC)
Place
Penrose, AR
Injuries
1 minor
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N4257RAir Tractor AT-602
Defining event
Maneuvering-low-alt flying: Loss of engine power (partial)
Weather
Visual (VMC) · Day
Status
Completed · report November 17, 2011
Report
Approved by Office Director
NTSB office
Central Region
Parties
Federal Aviation Administration, Pratt & Whitney Canada Inc.
FAA report
20100614050329A
Case key
76466

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 partial engine power due to a fatigue crack in the engine's fuel control bellows.

Findings · 1

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 controlling systemAircraft › Aircraft power plant · Fatigue/wear/corrosionAir Tractor AT-602: 1 caseAll aircraft: 59 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

While approximately 75 feet above the ground, the airplane experienced a partial loss of engine power. Unable to maintain altitude, the pilot performed a forced landing to a wet rice field. During the landing, the airplane impacted a dirt mound, nosed over, and came to rest inverted. During the postaccident engine examination, the fuel control unit was removed and a functional test of the unit performed. The test revealed that the fuel unit's evacuated bellows had developed a fatigue crack in the outer ply surface. This crack would have resulted in a reduced fuel flow to the engine and a subsequent loss of engine power. Laboratory analysis concluded that the crack had originated in an area of several corrosion pits. The cause of the corrosion could not be determined.

Factual narrative

On June 14, 2010, about 0915 central daylight time, an Air Tractor Inc., AT-602, N4257R, was substantially damaged during a forced landing following a partial loss of engine power near Penrose, Arkansas. The commercial pilot, the sole occupant, sustained minor injuries. The airplane was registered to and operated by Reynolds Flying Service Inc., of McCrory, Arkansas. Visual meteorological conditions prevailed and a company flight plan was filed for the 14 Code of Federal Regulations Part 137 agricultural application flight. The local flight departed at an unknown time. According to the pilot, while approximately 75 feet above the ground, the turbine powered airplane experienced a partial loss of engine power. Unable to maintain altitude, the pilot performed a forced landing to a wet rice field. During landing, the airplane impacted a dirt mound, nosed over, and came to rest inverted. A Federal Aviation Administration (FAA) inspector responded to the accident site and reported that the airplane's empennage, left wing and fuselage, sustained structural damage during the accident. The FAA inspector, along with a representative from Pratt and Whitney Canada Inc., examined the engine. The compressor turbine and the first stage power turbine vane ring displayed contact signatures consistent with the engine being powered near idle at the time of impact. Functional testing of the fuel control unit revealed that the unit's evacuated bellows had developed a fatigue crack in the outer ply surface. This crack would have resulted in a reduced fuel flow to the engine, and a subsequent loss of engine power. Laboratory analysis concluded that the crack had originated in an area of several corrosion pits. The cause of the corrosion could not be conclusively determined.

Aircraft

Registration
N4257R
Reported as
Air Tractor AT-602
Category
Airplane
Serial number
602-1146
Airframe hours
1,940
Engine
P&W Canada PT6A-60AG, 1,050 horsepower, turbo prop
Damage
Substantial damage
Flight
Aerial application · Part 137
Operator
Reynolds Flying Service Inc
Registered owner
Reynolds Flying Service Inc
Airworthiness certificate
Special, Restricted (Special)
Last inspection
100 hour · January 20, 2010
Departed
Penrose, AR
Destination
Penrose, AR
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
50
Injuries
Minor
Certificate
Commercial
Airplane ratings
Single-engine land
Medical
Class 2, With waivers/limitations
Last flight review
January 27, 2009
Seat
Single
Flight hours
16,000 total · 6,000 in this make and model · 16,000 as pilot in command · 300 in the last 90 days · 100 in the last 30 days · 10 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
210° at 8 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
88 °F, dew point 75 °F
Altimeter
29.97 inHg
Observed at
M19, 28 nm away

Docket · 1

The files NTSB released with the investigation on July 11, 2011, on NTSB’s docket system: statements, records, photos and specialists’ reports. 4.9 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.

Other investigations on N4257R · 1

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