# NTSB SEA95LA056: Pitts S-2B, N49335, Spokane, WA, February 25, 1995 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: February 24, 1995, 17:15 local (Feb 25, 1995, 01:15 UTC) - Place: Spokane, WA - Location: 47.6588° N, 117.4260° W: Placed by OpenAirDocs: center of Spokane, WA, within about 6 miles (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=47.6588&lon=-117.4260&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report September 24, 1995 - Report: Approved by Office Director - NTSB case key (mKey): 42114 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA95LA056 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/42114/pdf - Page: https://openairdocs.org/ntsb/SEA95LA056 ## Probable cause FATIGUE FAILURE OF THE CRANKSHAFT. FACTORS WERE THE SOFT TERRAIN AND THE PILOT/OWNER'S FAILURE TO CONDUCT RECURRING CRANKSHAFT INSPECTIONS RECOMMENDED BY THE MANUFACTURER. ## 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 - engine assembly,crankshaft - fatigue (cause) - maintenance,inspection - not performed, pilot in command (contributing factor) - propeller system/accessories - separation - Forced landing, emergency descent/landing - Nose over, emergency descent/landing - terrain condition - soft (contributing factor) ## Analysis THE PILOT OF THE AEROBATIC AIRPLANE WAS PRACTICING AN INVERTED FLAT SPIN WHEN THE PROPELLER AND CRANKSHAFT FLANGE SEPARATED FROM THE ENGINE. THE PILOT RECOVERED FROM THE MANEUVER, THEN MADE A FORCED LANDING ONTO A 780 FOOT MODEL AIRPLANE RUNWAY. THE AIRCRAFT OVERRAN THE END OF THE RUNWAY, THEN THE MAIN LANDING GEAR SETTLED INTO SOFT SOIL AND THE AIRCRAFT NOSED OVER. THE PILOT STATED THAT HE HAD NOT BEEN CONDUCTING RECURRENT CRANKSHAFT FLANGE INSPECTIONS, AS RECOMMENDED BY A MANUFACTURER'S SERVICE BULLETIN. ## Factual narrative On February 24, 1995, approximately 1715 Pacific standard time (PST), a Pitts S-2B, N49335, nosed over after making a forced landing about 10 miles northwest of Spokane, Washington. The commercial pilot, who was the sole occupant of the aircraft, was not injured, but the aircraft sustained substantial damage. The practice aerobatic flight, which departed Felts Field, Spokane, Washington at about 1630, was being operated in visual meteorological conditions. No flight plan had been filed, and there was no report of an ELT activation. According to the pilot, while practicing an inverted flat spin, the propeller and crankshaft flange separated from the engine. He then recovered from the maneuver, and made a forced landing at a 780 foot model airplane runway. During the landing roll, the aircraft rolled beyond the end of the runway and the main gear settled into soft soil and the aircraft nosed over. The pilot stated that he had not been conducting the recurring (each ten hours of operation) crankshaft inspections recommended by the manufacturer in Lycoming service bulletin number 482, which relates to crankshaft flange area cracking on this model engine when it is used for unlimited-style aerobatics, including inverted spins. ## Aircraft - Registration: [N49335](https://openairdocs.org/aircraft/N49335), registered now, S/N 5102, built 1986 (OpenAirDocs) - Reported make and model: PITTS S-2B - Registry model: [Pitts Aerobatics S-2B](https://openairdocs.org/model/pitts-aerobatics-s-2b) (registry code 7220450) (OpenAirDocs) - Registry engine: [Lycoming AEIO-540 series](https://openairdocs.org/engine/lycoming-aeio-540-series) (registry code 41568, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 5102 - Airframe hours: 708 - Engines: LYCOMING AEIO-540-D4A5 260 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Coombes, James A. - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, October 22, 1994, 15 hours before - Departed: SFF, WA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 55; commercial; airplane ratings: multi-engine land, single-engine land, single-engine sea; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: front; flight hours: 2,723 total, 652 in this make and model, 2,608 as pilot in command, 13 in the last 90 days, 6 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 210° at 5 knots - Visibility: 2,530 statute miles - Lowest ceiling: none - Temperature: 50 °F ## 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 19950224002639A](https://openairdocs.org/incident/19950224002639A), Feb 24, 1995: Child S2BPITTS, Spokane, WA, Substantial damage. Prop and crankshaft separated during a practice inverted spin. Recovered. Landed short strip. Nosed over. 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.