FTW03LA159

NTSB accident investigation · Ayres S2R-G6 · Palestine, AR · May 25, 2003

Accident · No injuriesLimited investigationFinal report
Date
May 25, 2003, 13:15 local (18:15 UTC)
Place
Palestine, AR
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N6136ZAyres S2R-G6
Weather
Visual (VMC) · Day
Status
Completed · report November 25, 2003
Report
Approved by Office Director
Parties
FAA FSDO
FAA report
20030525014629A
Case key
57047

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 shearing of the torsion shaft which resulted in a loss of engine power. A contributing factor was the lack of suitable terrain for the 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
Turboshaft engine,power output shaft - shearedCause
Forced landingEmergency descent/landing
In flight collision with terrain/waterEmergency descent/landing
Terrain condition - dirt bank/rising embankment
Terrain condition - none suitableFactor

Analysis

Upon completing an aerial application of a field, the pilot was returning to a private airstrip to reload the hopper and refuel. During the return flight, the airplane "felt like it tried to nosedive." The pilot stated that he checked the power settings, extended the flaps, and initiated a forced landing to a field. During the forced landing, the airplane struck a levee and came to rest upright. Examination of the engine revealed that torsion shaft was fractured at the shear point.

Factual narrative

On May 25, 2003, approximately 1315 central daylight time, an Ayres S2R-G6 single-engine agricultural airplane, N6136Z, sustained substantial during a forced landing following a loss of engine power while maneuvering near Palestine, Arkansas. The commercial pilot, who was the sole occupant of the airplane, was not injured. The airplane was registered to and operated by Chism Flying Service, Inc., near Brinkley, Arkansas. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 137 aerial application flight. The local flight departed a private airstrip near Brinkley at an unknown time and was returning to the airstrip at the time of accident.

According to the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2), after completing an aerial application of a chemical fertilizer, the pilot was returning to the private airstrip to reload the hopper and refuel the airplane. During the return flight, "the airplane felt like it tried to nosedive." The pilot checked the power settings, extended the flaps, and initiated a forced landing to a field. During the forced landing, the airplane struck a levee and came to rest upright.

Examination of the aircraft by an FAA inspector, who responded to the accident site, reported the left wing and both flaps were bent.

On June 3, 2003, at the facilities of Kelner Turbine, a FAA certified repair station, near Neosho, Missouri, the Garrett TPE-331-6 engine was disassembled and examined for subsequent repair. The examination revealed that the torsion shaft was fractured at the shear point on the shaft. According to the examination report, " the torsion shaft sheared thus uncoupling the power section from the gearbox. With nothing driving the gearbox the engine would begin to spool down because the fuel pump will not have enough pressure to keep it running. This is when [the mechanic] feel the pilot noticed no response from the throttle. The emergency stop and feather lever was not pulled therefore the prop[eller] did not go to the feather position. The result is a flat-pitched prop[eller], which causes enormous drag that made the nose of the aircraft pitch down just as the pilot reported."

Aircraft

Registration
N6136Z
Reported as
Ayres S2R-G6
Category
Airplane
Serial number
G6-138
Engine
Garrett TPE-331-6, 860 horsepower, turbo prop
Damage
Substantial damage
Flight
Aerial application · Part 137
Registered owner
Chism Flying Service, Inc
Airworthiness certificate
Special, Restricted (Special)
Departed
Brinkley, AR

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
34
Injuries
None
Certificate
Commercial
Airplane ratings
Single-engine land
Medical
Class 2, Valid Medical--w/ waivers/lim
Last flight review
February 4, 2003
Seat
Center
Flight hours
1,500 total · 70 in this make and model · 1,450 as pilot in command · 70 in the last 90 days · 50 in the last 30 days · 10 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
10° at 13 knots, gusting 19
Visibility
5 statute miles
Lowest ceiling
None
Temperature
75 °F, dew point 64 °F
Altimeter
29.85 inHg
Observed at
SGT, 41 nm away

Docket · 2

The files NTSB released with the investigation on September 4, 2003, on NTSB’s docket system: statements, records, photos and specialists’ reports. 1.9 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 N6136Z · 1

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