# NTSB CHI06LA240: Cessna A188B, N9224R, Rolla, ND, August 18, 2006 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 18, 2006, 16:45 local (21:45 UTC) - Place: Rolla, ND - Coordinates: 48.884445, -99.620834 - Nearby events: https://openairdocs.org/map.md?lat=48.8844&lon=-99.6208&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report November 29, 2007 - Report: Approved by Office Director - Parties: Federal Aviation Administration - Fargo FSDO - NTSB case key (mKey): 64391 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI06LA240 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/64391/pdf - Page: https://openairdocs.org/ntsb/CHI06LA240 ## Probable cause The pilot's failure to maintain clearance from terrain during the aerial-application flight, and the loss of engine power due to the overstress failure of the engine crankshaft sustained during ground impact. Contributing to the accident was the low-altitude at which the flight was being operated and the wheat crop the airplane encountered during the forced landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with terrain/water, maneuvering - aerial application - altitude/clearance - not maintained, pilot in command (cause) - terrain condition - ground - Loss of engine power(total) - mech failure/malf, maneuvering - aerial application - engine assembly,crankshaft - overload (cause) - Forced landing, emergency descent/landing - In flight collision with terrain/water, emergency descent/landing - unsuitable terrain or takeoff/landing/taxi area - encountered, pilot in command (contributing factor) - terrain condition - crop (contributing factor) ## Analysis The aerial-application flight experienced a loss of engine power during a low-altitude turn while spraying a field. The pilot performed an immediate forced landing into a nearby wheat field. The airplane was damaged when it encountered the wheat crop, spun around, and impacted terrain. The on-site investigation revealed that the engine crankshaft had fractured and the propeller had separated from the engine. The propeller was never located and is believed to be in a nearby slough or a densely wooded area. The fracture of the crankshaft and the cracking of the oil slinger flange were the result of an extreme load on the front of the engine pushing aft and offset from the crankshaft centerline. Ground impact is the most likely source of the load. The offset load created bending loads on the crankshaft that led to an overstress fracture of the crankshaft. The aft loads pushed the crankshaft aft into the case, causing one side of the oil slinger flange to crack because it was restrained by the case. The location of the crankshaft fracture initiation was not diametrically opposite from the final fracture region, consistent with some amount of clockwise (as viewed from the aft) rotation during the fracture. ## Factual narrative On August 18, 2006, about 1645 central daylight time, a Cessna A188B, N9224R, piloted by a commercial pilot, was substantially damaged during a forced landing in a wheat field following a loss of engine power while performing an aerial-application flight near Rolla, North Dakota. Visual meteorological conditions prevailed at the time of the accident. The flight was operating under the provisions of 14 Code of Federal Regulations (CFR) Part 137 without a flight plan. The pilot reported no injuries. The local area flight departed the Rolla Municipal Airport, Rolla, North Dakota, about 1600. The pilot reported that during an aerial-application turn, the engine lost power and the windshield was sprayed with oil. The pilot performed an immediate forced landing into a nearby wheat field. The airplane was damaged when it encountered the wheat crop, spun around, and impacted terrain. The on-site investigation revealed that the engine crankshaft had fractured and the propeller had separated from the engine. The propeller was never located and is believed to be in a nearby slough or a densely wooded area. The engine was disassembled and the fractured crankshaft was examined by the National Transportation Safety Board Materials Laboratory in Washington, D.C. The crankshaft fracture was just forward of the oil slinger flange. Fracture features and deformation associated with the fracture were typical of an overstress bending failure. The final area of fracture was at the region with the greatest bending deformation. The location of the fracture initiation was not diametrically opposite from the final fracture region, consistent with some amount of clockwise (as viewed from the aft) rotation during the fracture. The oil slinger flange had a circumferential crack at the base of the flange, around approximately 1/3 of the circumference of the flange. The cracked portion was deformed forward relative to the remainder of the piece. The crack in the oil slinger flange was approximately opposite the fracture origin area. One of the thrust washer halves contained impact and smearing damage on one face, consistent with hard contact from the oil slinger flange. The overstress bending fracture of the crankshaft and the crack and the deformation in the oil slinger were consistent with ground impact. During impact, the large aft load on the propeller generated bending stresses in the crankshaft and forced the crankshaft aft, cracking the oil slinger flange. ## Aircraft - Registration: [N9224R](https://openairdocs.org/deregistered/N9224R-2008-09-16), registration cancelled 2008-09-16, S/N 18802167T, built 1975 (OpenAirDocs) - Reported make and model: Cessna A188B - Registry model: [Cessna A188B](https://openairdocs.org/model/cessna-a188b) (registry code 2073005) (OpenAirDocs) - Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18802167T - Airframe hours: 8167.3 - Engines: Teledyne Continental IO-550-D 300 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: Rolla Flying Service, Inc. - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, May 1, 2006 - Departed: 06D, Rolla, ND - Destination: 06D ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 31; injuries: none; commercial; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; last flight review October 1, 2005; seat: center; flight hours: 3,015 total, 2,232 in this make and model, 2,968 as pilot in command, 167 in the last 90 days, 113 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Lowest ceiling: 2,000 ft broken - Temperature: 70 °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 20060818027909A](https://openairdocs.org/incident/20060818027909A), Aug 18, 2006: Cessna A188B, Rolla, ND, Substantial damage. (-23) Pilot reported engine failure on return trip to base. Attempted landing in field, substantial damage to aircraft. Weather not a factor. 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.