# NTSB SEA94LA138: Siai-Marchetti SF.260B, N943TA, Prospect, OR, June 6, 1994 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 5, 1994, 19:15 local (Jun 6, 1994, 02:15 UTC) - Place: Prospect, OR - Coordinates: 42.780414, -122.49073 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=42.7804&lon=-122.4907&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report January 12, 1995 - Report: Approved by Office Director - NTSB case key (mKey): 41941 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA94LA138 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41941/pdf - Page: https://openairdocs.org/ntsb/SEA94LA138 ## Probable cause THE FRACTURE OF A CONNECTING ROD. FACTORS INCLUDE NO SUITABLE FORCED LANDING SITE, AND A FENCE AND IRRIGATION SYSTEM IN THE FIELD WHERE THE FORCED LANDING TOOK PLACE. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(partial) - mech failure/malf, maneuvering - engine assembly,connecting rod - fractured (cause) - Forced landing, descent - emergency - On ground/water collision with object, landing - roll - terrain condition - none suitable (contributing factor) - object - fence (contributing factor) - object - other (contributing factor) ## Analysis ABOUT 45 MINUTES INTO THE FLIGHT, THE NUMBER SIX CONNECTING ROD EXPERIENCED A FATIGUE FAILURE, AND CAUSED CATASTROPHIC DAMAGE TO THE ENGINE CRANKCASE. THE FRACTURING OF THE CASE RESULTED IN A LOSS OF OIL, AND THE LOSS OF OIL PRESSURE RESULTED IN A RUNAWAY PROPELLER. THE PILOT THEN EXECUTED A SUCCESSFUL FORCED LANDING, BUT THE AIRCRAFT WAS DAMAGED WHEN IT COLLIDED WITH AN IRRIGATION PIPE AND A FENCE DURING THE LANDING ROLL. THE AIRCRAFT, WHICH IS USED EXTENSIVELY FOR PROFESSIONAL AIR SHOW AEROBATICS, IS POWERED BY AN ENGINE THAT IS CLASSED AS EXPERIMENTAL BECAUSE IT CONTAINS HIGH COMPRESSION PISTONS. ## Factual narrative On June 5, 1994, approximately 1915 Pacific daylight time (PDT), a Siai-Marchetti SF.260B, N943TA, collided with irrigation equipment and a fence during a forced landing near Prospect, Oregon. Neither the commercial pilot, nor his passenger were injured, but the airplane sustained substantial damage. The personal pleasure flight, which departed Medford, Oregon, about 1830 PDT, was in visual meteorological conditions at the time of the accident. There was no flight plan filed, and no report of an ELT activation. According to the pilot, about 45 minutes into the flight, there was sudden and violent vibration from the engine. Immediately thereafter, the oil pressure dropped to zero, and the propeller went to maximum rpm, and could not be controlled with the propeller control lever. There were no unobstructed fields available for a forced landing, so he elected to land in a nearby field that was crossed by a fence and an irrigation pipe line. The touchdown was successful, but the aircraft sustained substantial damage when it rolled through the pipe and fence. This aircraft, which is used extensively for professional air show aerobatics, was powered by a Lycoming IO-540-G engine. The engine was classed as experimental because it contained 10.1 to 1 compression ratio pistons, instead of the standard 8.71 to 1 pistons. The engine was sent to Fort Collins, Colorado, where the FAA supervised an inspection teardown by Demars Aero Limited. The FAA report stated that it appeared the number six connecting rod experienced a fatigue failure, which caused catastrophic damage to the engine crankcase. The fracturing of the case released the engine oil, and the loss of oil pressure resulted in a runaway propeller. ## Aircraft - Registration: [N943TA](https://openairdocs.org/aircraft/N943TA), registered now, S/N 11-01, built 1970 (OpenAirDocs) - Reported make and model: SIAI-MARCHETTI SF.260B - Registry model: [Siai-Marchetti F.260B](https://openairdocs.org/model/siai-marchetti-f-260b) (registry code 8121209) (OpenAirDocs) - Registry engine: [Lycoming IO-540-G1C5](https://openairdocs.org/engine/lycoming-io-540-g1c5) (registry code 41643, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 11-01 - Airframe hours: 3307 - Engines: LYCOMING IO-540-G 290 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Register, Barney E. - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, April 1, 1994, 100 hours before - Departed: MFD, MEDFORD, OR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 46; commercial, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 17,500 total, 2,300 in this make and model, 17,150 as pilot in command, 100 in the last 90 days, 60 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 180° at 3 knots - Visibility: 20 statute miles - Lowest ceiling: none - Temperature: 64 °F - Altimeter: 29.00 inHg ## 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 19940605017689A](https://openairdocs.org/incident/19940605017689A), Jun 5, 1994: Mrchti F260B, Prospect, OR, Substantial damage. Collided with pipeline and fence on forced landing. Special beefed up air show engine had thrown a connecting rod. 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.