# NTSB DEN04LA083: Ayres S-2R, N5686X, Beaver, UT, May 31, 2004 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 31, 2004, 12:15 local (18:15 UTC) - Place: Beaver, UT - Coordinates: 38.380538, -112.660827 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.3805&lon=-112.6608&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report October 28, 2004 - Report: Approved by Office Director - Parties: Federal Aviation Administration - NTSB case key (mKey): 59388 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN04LA083 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/59388/pdf - Page: https://openairdocs.org/ntsb/DEN04LA083 ## Probable cause the in-flight failure of the engine's P3 tube which resulted in the loss of engine power and the subsequent impact with terrain during a forced landing. Contributing factors include the lack of suitable terrain for a forced landing and the fence. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(total) - mech failure/malf, maneuvering - fuel system,line - cracked (cause) - Forced landing, emergency descent/landing - In flight collision with terrain/water, emergency descent/landing - unsuitable terrain or takeoff/landing/taxi area (contributing factor) - terrain condition - rough/uneven (contributing factor) - object - fence (contributing factor) ## Analysis According to the pilot, he had finished spraying a field and was returning to the airport for another load. He said that he had half a tank of fuel remaining and the engine was producing "excellent power." A few moments later, the engine ran rough for about a second and then stopped. He did not notice anything coming out of the exhaust. The pilot tried twice to restart the engine but was unsuccessful and he attempted a forced landing to an open field. During the landing, the airplane impacted terrain and struck a fence. Both wings were displaced aft and the right main landing gear was collapsed. A visual examination of the engine revealed a 360 degree crack around the P3 air pressure tube, causing a separation of the tube between the engine plenum and fuel control unit. The crack was approximately one-quarter inch aft of the "B" nut, which connects the P3 air pressure tube to the fuel control unit. There was a "notable" amount of carbon build-up in the area around the crack. According to a maintenance representative, failure of the tube in flight would have resulted in a "significant reduction in fuel scheduling which could result in an engine flameout." An attempt to restart the engine in flight would "likely have failed," however; an attempt would have accounted for the "notable" amount of carbon build-up around the break in the tube. No other aircraft anomalies were noted. ## Factual narrative On May 31, 2004, at approximately 1215 mountain daylight time, an Ayres Corporation S-2R, N5686X, was substantially damaged when it impacted terrain during a forced landing to a field approximately 1 nautical mile north of Beaver, Utah. The commercial certificated pilot, the sole occupant on board, was not injured. Visual meteorological conditions prevailed at the time of the accident. The local aerial application flight was being conducted under the provisions of Title 14 CFR Part 137 without a flight plan. The flight originated at approximately 1120. According to the pilot, he had finished spraying a field and was returning to Beaver Municipal Airport (U52), for another load. He said that he had half a tank of fuel remaining and the engine was producing "excellent power." A few moments later, the engine ran rough for about a second and then stopped. He did not notice anything coming out of the exhaust. The pilot tried twice to restart the engine but was unsuccessful and he attempted a forced landing to an open field. During the landing, the airplane impacted terrain and struck a fence. Both wings were displaced aft and the right main landing gear was collapsed. A visual examination of the engine revealed a 360 degree crack around the P3 air pressure tube, causing a separation of the tube between the engine plenum and fuel control unit. The crack was approximately one-quarter inch aft of the "B" nut, which connects the P3 air pressure tube to the fuel control unit. There was a "notable" amount of carbon build-up in the area around the crack. According to a maintenance representative, failure of the tube in flight would have resulted in a "significant reduction in fuel scheduling which could result in an engine flameout." An attempt to restart the engine in flight would "likely have failed," however; an attempt would have accounted for the "notable" amount of carbon build-up around the break in the tube. No other aircraft anomalies were noted. ## Aircraft - Registration: [N5686X](https://openairdocs.org/aircraft/N5686X), registered now, S/N 2395R, built 1977 (OpenAirDocs) - Reported make and model: Ayres Corporation S-2R - Registry model: [Ayres S-2R](https://openairdocs.org/model/ayres-s-2r) (registry code 0970101) (OpenAirDocs) - Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 2359R - Engines: Garrett 331-1 675 horsepower turbo prop - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: David S. Sheppard - Airworthiness certificate: Special, Restricted (Special) - Departed: U52, Beaver, UT - Destination: U52, Beaver, UT ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 48; injuries: none; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; last flight review May 18, 2004; seat: center; flight hours: 7,150 total, 2,625 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 210° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 75 °F, dew point 27 °F - Altimeter: 30.07 inHg - Observed at: KMLF, 19 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 (OpenAirDocs). - [Accident 20040531010199A](https://openairdocs.org/incident/20040531010199A), May 31, 2004: Ayres S2RRESTD, Beaver, UT, Substantial damage. (-23) Power failure during cruise flight. Emergency landing resulted in substantial damage to the aircraft. There were no injuries to the pilot. ## Other investigations on N5686X (2) 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. - [NTSB SEA96LA113](https://openairdocs.org/ntsb/SEA96LA113), Jun 6, 1996: Ayres S2R (N5686X), Aberdeen, ID, substantial damage. Probable cause: pilot's improper planning/decision, and subsequent incapacitation, which resulted in a loss of aircraft control and collision with the terrain. Factors relating to the accident were: pilot fatigued… - [NTSB DEN82FTA04](https://openairdocs.org/ntsb/DEN82FTA04), Nov 23, 1981: Ayres S2R (N5686X), Richey, MT, substantial damage 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.