# NTSB BFO93LA164: Cessna 402B, N4504B, Eau Claire, PA, September 8, 1993 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: September 8, 1993, 12:15 local (16:15 UTC) - Place: Eau Claire, PA - Coordinates: 41.130722, -79.78984 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=41.1307&lon=-79.7898&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report December 2, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 8812 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=BFO93LA164 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/8812/pdf - Page: https://openairdocs.org/ntsb/BFO93LA164 ## Probable cause The separation of the number four cylinder on the airplane's left engine for undetermined reasons. A factor in the accident was the rough/uneven terrain. ## 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 - normal - engine assembly,cylinder - separation (cause) - engine assembly,crankcase - fatigue - engine assembly,connecting rod bolt - fatigue - Forced landing, descent - emergency - Main gear collapsed, landing - roll - terrain condition - rough/uneven (contributing factor) ## Analysis While in cruise flight, the airplane's left engine lost total power. Due to the damage incurred by the engine during its failure, the propeller could not be feathered and the airplane could not sustain flight. The pilot made an emergency landing in a field and during the roll out the left main gear and nose gear collapsed. Post accident examination of the failed engine revealed the number four cylinder and piston were gone from the case. The left case and fasteners were examined at the Safety Board's Materials Laboratory. The examination revealed fatigue cracking in the engine case, through bolts and studs. Three of the six studs around the number four cylinder were not recovered. The initial failure was not determined. ## Factual narrative HISTORY OF FLIGHT On Wednesday, September 8, 1993, at about 1215 eastern daylight time, a Cessna 402B, N4504B, operated by Freight Runners Express Inc., of Milwaukee, Wisconsin, lost total power from the left engine during cruise flight and sustained substantial damage during the subsequent forced landing in a field in Eau Claire, Pennsylvania. The pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed at the time of the accident. The cross country positioning flight originated from Harrisburg, Pennsylvania, and was destined for Milwaukee, Wisconsin. An instrument flight rules flight plan was filed for the flight. The flight was conducted under 14 CFR Part 91. The pilot reported that while in cruise "...the left engine started to develop engine vibrations." He stated he started to look for an airport to land when he heard a "bang" from the let side of the airplane. He said he looked over to the left wing and saw an engine cylinder depart the engine from the "out board side of the engine cowling..." and go over the wing. He stated he turned the airplane around and headed towards the Clarion Airport which he had passed a few minutes earlier. The pilot stated that due to the damage incurred by the engine, the propellers would not feather and that the drag of the left engine would not allow sustained flight. He stated that he put the flaps and gear down and made a forced landing in a field. The pilot reported that during the landing roll the left main gear sheared and the nose gear collapsed. He stated that the field was hilly and the terrain was soft and uneven. The left engine was removed from the airplane and sent to G & N Aircraft, Inc., located in Griffith, Indiana, for examination. (See TESTS AND RESEARCH section of this report for engine examination results.) ENGINE INFORMATION The left engine was remanufactured and had been overhauled by AeroSmith Engines of Springdale, Arkansas, in December, 1991. At the time of the accident, the engine had accrued about 302 flight hours since the overhaul. The engine had a 100 hour inspection on July 20, 1993, at a tach time of 1904, 14 hours prior to the accident. TESTS AND RESEARCH The examination revealed that the number four cylinder and piston were gone from the engine case. A hole larger than the cylinder base was noted in the case half. Pieces of piston were throughout the casing. The number four connecting rod was attached to the crankshaft. The piston pin end of the connecting rod was intact but caved inward. Material from the piston, a counterweight bushing, and piston rings were found in the oil sump. The oil pump housing and gears were not contaminated. The cam shaft was not damaged except for some marring near the number four cylinder. The crankshaft was not damaged. The 4th order counterweight was damaged and a section of it was missing near the dampener counterweight pin hole. The left half of the engine case with three studs and two through bolts were sent to the Safety Board's Materials Laboratory Division for further examination. The examination revealed extensive fatigue cracking in the engine case, through bolts and studs. Three of the six studs were not recovered. The initial failure was not determined. (See attached Metallurgist's Factual Report for details.) ## Aircraft - Registration: [N4504B](https://openairdocs.org/deregistered/N4504B-2017-06-30), registration cancelled 2017-06-30, S/N 402B1370, built 1978 (OpenAirDocs) - Reported make and model: CESSNA 402B - Registry model: [Cessna 402B](https://openairdocs.org/model/cessna-402b) (registry code 207590P) (OpenAirDocs) - Registry engine: [Continental TSIO-520 series](https://openairdocs.org/engine/continental-tsio-520-series) (registry code 17040, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 402B1370 - Airframe hours: 7584 - Engines: CONTINENTAL TSIO-520E 300 horsepower reciprocating - Damage: Substantial damage - Flight: Positioning, Part 91 - Operator: Freight Runners Express Inc. - Registered owner: Freight Runners Express Inc. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, July 20, 1993, 14 hours before - Departed: MDT, HARRISBURG, PA - Destination: MKL, MILWAUKEE, WI - Flight plan: IFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 33; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 4,132 total, 1,765 in this make and model, 4,080 as pilot in command, 126 in the last 90 days, 45 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 120° at 4 knots - Visibility: 4 statute miles - Lowest ceiling: 1,300 ft overcast - Temperature: 66 °F, dew point 61 °F - Altimeter: 30.00 inHg - Observed at: AOO, 60 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 19930908033599A](https://openairdocs.org/incident/19930908033599A), Sep 8, 1993: Cessna 402B, Eauclaire, PA, Substantial damage. Left engine lost power. Loud bang. Cylinder departed through cowling. Prop drag forced landing. Engine case cracked ## Other investigations on N4504B (1) 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. - [NTSB CEN09LA095](https://openairdocs.org/ntsb/CEN09LA095), Dec 17, 2008: Cessna 402 (N4504B), Madison, WI, substantial damage. Probable cause: The pilot’s improper fuel management, which resulted in a loss of engine power during an instrument landing due to fuel exhaustion. 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.