# NTSB CHI95LA048: Piper PA-28R-201T, N1194H, La Porte City, IA, November 29, 1994 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: November 29, 1994, 11:30 local (17:30 UTC) - Place: La Porte City, IA - Coordinates: 42.310749, -92.189422 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=42.3107&lon=-92.1894&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor, 2 uninjured - Status: Completed, report October 27, 1995 - Report: Approved by Office Director - NTSB case key (mKey): 9805 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI95LA048 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/9805/pdf - Page: https://openairdocs.org/ntsb/CHI95LA048 ## Probable cause a material defect which resulted in the fatigue failure of the crankshaft and the aircraft owner's failure to comply with a Mandatory Service Bulletin addressing the defect. A factor related to the accident was the rough terrain on which the forced landing was made. ## 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, cruise - engine assembly,crankshaft - fatigue (cause) - material defect, manufacturer (cause) - maintenance,service bulletin/letter - issued, manufacturer - maintenance,service bulletin/letter - not complied with, company/operator management (cause) - Forced landing, emergency descent/landing - In flight collision with terrain/water, landing - terrain condition - rough/uneven (contributing factor) ## Analysis WHILE EN ROUTE THE PILOT HEARD A LOUD POP FOLLOWED BY ENGINE VIBRATIONS AND A PARTIAL LOSS OF ENGINE POWER. THE PILOT DECLARED AN EMERGENCY AND WAS VECTORED TOWARD A GRASS AIRSTRIP WHICH HE COULD NOT LOCATE. EN ROUTE TO THE GRASS STRIP A TOTAL LOSS OF ENGINE POWER WAS EXPERIENCED. THE AIRPLANE WAS LANDED IN A PLOWED CORN FIELD. POST ACCIDENT INSPECTION REVEALED THE CRANKSHAFT HAD SEPARATED BETWEEN THE NO. 3 MAIN BEARING JOURNAL AND THE NO. 5 CYLINDER CRANKPIN DUE TO FATIGUE CRACKING. TCM SERVICE BULLETIN 92-16 ADDRESSING CRANKSHAFTS MADE FROM NON-VACUUM ARC REMELTED STEEL HAD NOT BEEN COMPLIED WITH. ## Factual narrative On November 29, 1994, about 1130 central standard time, a Piper PA-28R-201T, N1194H, sustained substantial damage in a forced landing near La Porte City, Iowa, following a total loss of engine power. The private pilot and one passenger aboard the airplane were not injured. A second passenger received minor injuries. The personal flight originated at the St. Paul Downtown Airport, St. Paul, Missouri, at 1000, with an intended destination of Walnut Ridge, Arkansas. A VFR flight plan was filed, and visual meteorological conditions prevailed at the time. While at 7,500 feet above mean sea level, 18.7 miles south of Waterloo, Iowa, the pilot reported he heard a "pop" from the engine and it started vibrating violently. He stated that at this time he still had partial engine power. The pilot was given vectors to a grass strip near LaPorte City. En route to the airport a complete loss of engine power was experienced. The airplane was landed one mile short of the airport in a field. The wreckage was inspected by a Federal Aviation Administration Inspector from the Des Moines, Iowa, Flight Standards District Office. This inspector determined that there was no engine continuity between the front of the engine and the accessory drive. There was no movement of the #5 and #6 cylinder pistons when the crankshaft was rotated. No other anomalies were found which would have resulted in the loss of engine power. The crankshaft, s/n F940, was removed from the engine and was shipped to the NTSB Materials Laboratory, in Washington D.C. for further examination. Inspection of the crankshaft showed a separation between the No. 3 main bearing journal and the No. 5 cylinder crankpin. The fracture contained, "crack arrest features and a smooth fracture surface, typical of high cycle fatigue cracking." See attached Metallurgists Factual Report for more details. On September 29, 1992, Teledyne Continental Motors issued Mandatory Service Bulletin 92-16 addressing the replacement of Non-VAR crankshafts. This crankshaft was not manufactured from vacuum arc remelted steel. The service bulletin states, "Sufficient field service data has now been accumulated to lead us to believe that it is prudent to require replacement of all non-VAR crankshafts in service with VAR crankshafts." This service bulletin had not been complied with on the accident engine. ## Aircraft - Registration: [N1194H](https://openairdocs.org/aircraft/N1194H), registered now, S/N 28R-7703016 (OpenAirDocs) - Reported make and model: PIPER PA-28R-201T (PA-28R-201) - Registry model: [Piper PA-28R-201T](https://openairdocs.org/model/piper-pa-28r-201t) (registry code 7102813) (OpenAirDocs) - Category: Airplane - Serial number: 28R-7703016 - Airframe hours: 1670 - Engines: CONTINENTAL TSIO-360-F 200 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Eric S. Burka - Airworthiness certificate: Standard, Normal - Last inspection: Annual, August 4, 1994, 40 hours before - Departed: STP, ST. PAUL, MN - Destination: ARG, WALNUT RIDGE, AR - Flight plan: VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 44; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 208 total, 64 in this make and model, 97 as pilot in command, 40 in the last 90 days, 33 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 310° at 7 knots - Visibility: 7 statute miles - Lowest ceiling: 2,000 ft overcast - Temperature: 28 °F, dew point 19 °F - Altimeter: 30.00 inHg - Observed at: ALO, 17 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 19941129039839A](https://openairdocs.org/incident/19941129039839A), Nov 29, 1994: Piper PA28R201T, La Porte City, IA, Substantial damage. Loud pop vibration power loss. Landed plowed cornfield. Crankshaft broke due fatique cracking. Sb not complied. 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.