# NTSB BFO96LA038: Ercoupe 415-C, N87424, Hurlock, MD, January 14, 1996 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: January 14, 1996, 16:00 local (21:00 UTC) - Place: Hurlock, MD - Coordinates: 38.619297, -75.870681 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.6193&lon=-75.8707&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report March 31, 1998 - Report: Approved by Office Director - NTSB case key (mKey): 9127 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=BFO96LA038 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/9127/pdf - Page: https://openairdocs.org/ntsb/BFO96LA038 ## Probable cause inadequate inspection by maintenance personnel which failed to detect a fatigue crack, and resulted in an in-flight crankshaft fracture and propeller assembly separation. A related factor was the deep snow encountered during the subsequent forced landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Propeller failure/malfunction, cruise - engine assembly,crankshaft - fractured (cause) - maintenance - inadequate, other maintenance personnel (cause) - engine assembly,crankshaft - failure,total - Forced landing, emergency descent/landing - On ground/water encounter with terrain/water, landing - roll - terrain condition - snow covered (contributing factor) - Nose gear collapsed, landing - roll - landing gear,nose gear - overload ## Analysis The pilot stated that the airplane was in cruise flight at 1,500 feet MSL when the propeller separated from the airplane. The pilot made an emergency landing in a snow covered field. Upon touchdown in 18-inch deep snow, the nose wheel collapsed. The separated propeller assembly and the attached forward portion of the crankshaft flange were located, and examined in the NTSB laboratory. Postaccident inspection of the crankshaft revealed a spiral crack that intersected the fracture at the bottom corner of a keyway. Further examination showed that the cracks were filled with a iron nitride white layer. Maintenance records indicated that the main journals and pins of the crankshaft were ground, nitrided, inspected, and returned for service, in October, 1994. ## Factual narrative On January 14, 1996, at about 1600 eastern standard time, an Ercoupe 415-C, N87424, made an emergency landing in a snow covered field after the propeller separated from the airplane near Hurlock, Maryland. The flight originated at 1545 eastern standard time from Easton/Newnan Field, in Easton, Maryland, with an intended destination of Salisbury-Wicomico County Regional Airport, in Salisbury, Maryland. The pilot and the one passenger reported no injuries. The airplane sustained substantial damage. No flight plan had been filed and visual meteorological conditions prevailed at the time of the accident. The flight was conducted under 14 CFR Part 91. The pilot stated that the airplane was in cruise flight at 1,500 feet mean sea level (MSL), when the propeller assembly separated. He reported that the propeller assembly impacted the airplanes left wing as it departed the aircraft. The separated propeller assembly and the attached forward portion of the crankshaft flange were found in a field near the where the airplane impacted the snow. The crankshaft and the recovered forward fragment of the crankshaft flange were sent to the Office of Research and Engineering of the National Transportation Safety Board. An examination of the separated crankshaft P/N A5334, S/N 15C6 from the Continental C85-12 engine was conducted. The examination revealed that the crankshaft had separated at the propeller flange. The forward portion of the crankshaft contained a spiral crack that intersected the fracture at the bottom corner of the keyway. The scanning electron microscope examination of both halves of the mating fractures showed that original microscopic fracture features were mechanically damaged by relative movement between the mating fractures. The metallurgist's factual report stated: "No anomalies, such as corrosion pits or gouge marks were noted at the surface of the keyway." Maintenance records indicate that in October, 1994, the main journals and pins of the crankshaft were ground 0.02 inch undersize, nitrided, inspected by visual and magnetic particle method, and installed with replacement main bearing and rod bearing set. According to the metallurgist's report, a light colored layer extended approximately 0.06 inches deep from the bottom corner of the keyway. The metallurgist reported that further examination of this layer revealed a spectrum consistent with an iron nitride white layer. ## Aircraft - Registration: [N87424](https://openairdocs.org/aircraft/N87424), registered now, S/N 597, built 1946 (OpenAirDocs) - Reported make and model: Ercoupe (Eng & Research Corp.) 415-C - Registry model: [Ercoupe 415-C](https://openairdocs.org/model/ercoupe-415-c) (registry code 0420322) (OpenAirDocs) - Registry engine: [Continental A&C75 series](https://openairdocs.org/engine/continental-a-c75-series) (registry code 17005, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 597 - Airframe hours: 1677 - Engines: Continental C85-12 85 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Eastern Shore Aero - Airworthiness certificate: Standard, Normal - Last inspection: Annual, April 7, 1995, 1,556 hours before - Departed: ESN, EASTON, MD - Destination: SBY, SALISBURY, MD ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 63; commercial; airplane ratings: single-engine land; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 1,960 total, 96 in this make and model, 1,775 as pilot in command, 56 in the last 90 days, 18 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 220° at 10 knots - Visibility: 10 statute miles - Temperature: 46 °F, dew point 28 °F - Altimeter: 29.00 inHg - Observed at: SBY, 24 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 19960114000649A](https://openairdocs.org/incident/19960114000649A), Jan 14, 1996: Univar 415C, Hurlock, MD, Substantial damage. Aircraft lost prop and made an emergency landing in a field. 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.