# NTSB DEN08LA107: Ayres S2R-G6, N61374, Pine Bluff, AR, June 20, 2008

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: June 20, 2008, 14:00 local (19:00 UTC)
- Place: Pine Bluff, AR
- Coordinates: 34.209999, -92.023056
- Nearby events: https://openairdocs.org/map.md?lat=34.2100&lon=-92.0231&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Defining event: [Maneuvering-low-alt flying: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report July 28, 2009
- Report: Approved by Office Director
- Parties: FAA Flight Standards District Office
- NTSB case key (mKey): 68270
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN08LA107
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/68270/pdf
- Page: https://openairdocs.org/ntsb/DEN08LA107

## Probable cause

A total loss of engine power due to fuel starvation as a result of an electrical short in the wiring to the manual fuel switch that closed the fuel valves.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Fuel system: fuel sys wiring](https://openairdocs.org/ntsb-findings/01022897): Aircraft › Aircraft systems · Damaged/degraded (probable cause); cases with it: [Ayres S2R-G6, 1 case](https://openairdocs.org/ntsb-findings/01022897/cases.md?model=0970216), [All aircraft, 5 cases](https://openairdocs.org/ntsb-findings/01022897/cases.md)
- [Fuel system: fuel selector/shutoff valve](https://openairdocs.org/ntsb-findings/01022823): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Ayres S2R-G6, 1 case](https://openairdocs.org/ntsb-findings/01022823/cases.md?model=0970216), [All aircraft, 176 cases](https://openairdocs.org/ntsb-findings/01022823/cases.md)
- [Object/animal/substance: tree(s)](https://openairdocs.org/ntsb-findings/03022020): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Ayres S2R-G6, 2 cases](https://openairdocs.org/ntsb-findings/03022020/cases.md?model=0970216), [All aircraft, 933 cases](https://openairdocs.org/ntsb-findings/03022020/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Maneuvering-low-alt flying: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Ayres S2R-G6, 1 case](https://openairdocs.org/ntsb-events/330/sequence.md?model=0970216), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md)
- [Maneuvering-low-alt flying: Fuel starvation](https://openairdocs.org/ntsb-events/191); cases with it: [Ayres S2R-G6, 1 case](https://openairdocs.org/ntsb-events/191/sequence.md?model=0970216), [All aircraft, 733 cases](https://openairdocs.org/ntsb-events/191/sequence.md)
- [Maneuvering-low-alt flying: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341); cases with it: [Ayres S2R-G6, 2 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=0970216), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md)
- [Emergency descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Ayres S2R-G6, 8 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=0970216), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md)

## Analysis

The pilot was spraying a rice field with fertilizer when the "airplane began to lose altitude." The pilot attempted a forced landing in an open bean field. During the forced landing the airplane's right wing struck a tree, spinning the airplane around to the right. The airplane then impacted the terrain sideways, shearing off the landing gear, bending both wings, and buckling the fuselage. An examination of the engine showed evidence indicating the engine was not operating prior to impact. Additionally, the examination showed nothing that would have caused a loss of power or an in-flight engine shutdown. Further investigation determined that the airplane had previously experienced an uncommanded engine shut down. According to the wiring system schematic, the manufacturer did not install engine speed switches to automatically and electronically control the fuel system, but instead, installed pilot-activated switches for manual control of the fuel system. Examination of the system showed evidence of a short in the wires to the switch. The manufacturer stated that if a short in the wires occurred or if a switch failed due to contamination or corrosion, voltage could be sent to pin "B" on the Fuel Shutoff (Solenoid) Valve, causing the fuel shutoff valve to close.

## Factual narrative

On June 20, 2008, approximately 1400 central daylight time, an Ayres S2R-G6, N61374, registered to and operated by Swan Lake Flying Service, Inc., and piloted by a commercial pilot, was substantially damaged when it struck trees and impacted terrain during a forced landing following a loss of engine power near Pine Bluff, Arkansas. Visual meteorological conditions prevailed at the time of the accident. The aerial application flight was being conducted under the provisions of Title 14 Code of Federal Regulations (CFR) Part 137 without a flight plan. The pilot, the sole occupant on board, was not injured. The local flight originated approximately 1330 at Altheimer, Arkansas. The pilot said he was spraying a rice field with fertilizer when the "airplane began to lose altitude." He attempted to make a forced landing in an open bean field, but the airplane's right wing clipped a tree, spinning the airplane around to the right. The airplane impacted terrain sideways, shearing off the landing gear. The wings were bent, and the fuselage was buckled. FAA inspectors from the Little Rock Flight Standards District Office (FSDO) examined the airplane and found the fuel remaining in the engine fuel filter housing, which is integral to the engine fuel pump and is located in-line between the centrifugal boost pump and the positive displacement high pressure pump, was clean and clear. The threads on the fuel pressure line fitting on the fuel filter housing were found to be stripped, allowing the fitting to wobble about 5 to 10 degrees. When the fitting was moved, the O-ring would not seat. Examination of the adjacent aircraft cowling structure did not reveal fuel residue, indicative that the fuel pressure fitting damage was not pre-existing but rather as the result of impact with terrain. The engine was removed from the airframe and shipped to Honeywell in Phoenix, Arizona. Under Federal Aviation Administration (FAA) auspices, the engine was disassembled and examined on October 8 and 9, 2008. According to its report, Honeywell said that "the type and degree of damage to the engine was indicative of an engine not operating at the time of impact with the terrain. No pre-existing condition was found with the engine that would have caused a loss of power or an in-flight shutdown." FAA inspectors later learned that about six flights before the accident flight, the airplane sustained an uncommanded engine shutdown while being refueled and reloaded. Ayres, in their design process, did not install engine speed switches to automatically and electronically control the fuel system. Instead, they installed pilot-activated switches for manual control of the fuel system. Examination of the wiring system schematic revealed that if there was a short in the wires or if the switch failed due to contamination or corrosion, voltage could be sent to pin "B" on the Fuel Shutoff (Solenoid) Valve, causing the fuel shutoff valve to close. In the case of N51374, there was evidence ofwiring and fuel shutoff switch contamination. As a result of this investigation, a safety recommendation proposal was submitted.

## Aircraft

- Registration: [N61374](https://openairdocs.org/aircraft/N61374), registered now, S/N G6-119, built 1994 (OpenAirDocs)
- Reported make and model: Ayres S2R-G6
- Registry model: [Ayres S2R-G6](https://openairdocs.org/model/ayres-s2r-g6) (registry code 0970216) (OpenAirDocs)
- Registry engine: [AiResearch TPE331 series](https://openairdocs.org/engine/airesearch-tpe331-series) (registry code 01514, turbo-prop) (OpenAirDocs)
- Category: Airplane
- Serial number: G6-119
- Airframe hours: 7040
- Engines: Garrett TPE-331-G6 750 horsepower turbo prop
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Registered owner: Swan Lake Flying Service, Inc.
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, February 1, 2008
- Departed: NONE, Altheimer, AR
- Destination: NONE

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 49; injuries: none; commercial; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; last flight review December 1, 2006; seat: single; flight hours: 20,000 total, 5,300 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Wind: 240° at 6 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 77 °F, dew point 63 °F
- Altimeter: 30.01 inHg
- Observed at: PBF

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 20080620839029A](https://openairdocs.org/incident/20080620839029A), Jun 20, 2008: Swrngn S2RG6, Substantial damage. (-23) On 6/20/2008 at approximately 12:50 pm, airplane N61374, an ayres model S2R-G6, serial number G6-119, while performing aerial application for 14 CFR 137…

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.