# NTSB DEN00IA076: Beech A60, N928PT, Englewood, CO, April 8, 2000 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: April 8, 2000, 08:30 local (14:30 UTC) - Place: Englewood, CO - Coordinates: 39.640529, -104.990486 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.6405&lon=-104.9905&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report April 6, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 49021 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN00IA076 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/49021/pdf - Page: https://openairdocs.org/ntsb/DEN00IA076 ## Probable cause The failure of a number one cylinder connecting rod bolt due to under-torquing during engine major overhaul. ## 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, takeoff - initial climb - 1 engine - engine assembly,connecting rod bolt - undertorqued - maintenance,overhaul,major - improper, other maintenance personnel (cause) ## Analysis On departure, the left engine of the twin-engine airplane failed. Postincident examination of the left engine revealed a six-inch hole in the case, and that two connecting rod bolts on the number one cylinder had separated. Examination indicated that one of the rod bolt failed due to fatigue. An SEM examination of the outside surface adjacent to the fracture face revealed no indication of a manufacturing anomaly. Fretting damage was found on the arm of the connecting rod that was associated with this bolt. The physical evidence suggested that the bolt was improperly torqued. Maintenance records indicate that the left engine received a major overhaul 2.5 hours before the incident. A representative of the engine manufacturer said that the rod bolts on this engine are properly installed when the tightening of the nut stretches the bolt to a specified dimension. ## Factual narrative On April 8, 2000, approximately 0830 mountain daylight time, a Beech A60, N928PT, received minor damage following an engine failure during initial climb after takeoff from Centennial Airport, Englewood, Colorado. The flight instructor, the private pilot receiving instruction, and a passenger were not injured. The airplane was being operated by the private pilot under Title 14 CFR Part 91. Visual meteorological conditions prevailed for the cross-country instructional flight that originated approximately 15 minutes before the incident. An instrument flight plan had been filed. The flight instructor said that while on departure from Centennial Airport, the left engine failed. He said that they returned to the airport and landed without incident. Postincident examination of the left engine revealed a six-inch hole in the case, and that two rod bolts on the number one cylinder connecting rod had separated. Examination by a National Transportation Safety Board's (NTSB) Materials Laboratory engineer indicated that one of the rod bolts separated due to a fatigue failure. An SEM examination of the outside surface adjacent to the fracture face revealed no indication of a manufacturing anomaly. Fretting damage was found on the arm of the connecting rod that was associated with this bolt. Maintenance records indicate that the left engine received a major overhaul 2.5 hours before the incident. A representative of the engine manufacturer said that the rod bolts on this engine are properly installed when the tightening of the nut stretches the bolt to a specified dimension. ## Aircraft - Registration: [N928PT](https://openairdocs.org/deregistered/N928PT-2020-09-04), registration cancelled 2020-09-04, S/N P-174, built 1971 (OpenAirDocs) - Reported make and model: Beech A60 - Registry model: [Beech A60](https://openairdocs.org/model/beech-a60) (registry code 1153604) (OpenAirDocs) - Registry engine: [Lycoming TI0-541 series](https://openairdocs.org/engine/lycoming-ti0-541-series) (registry code 41536, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: P-174 - Engines: Lycoming TIO-541 385 horsepower reciprocating - Damage: Minor damage - Flight: Instructional, Part 91 - Registered owner: Raulf D. Janitell, III - Airworthiness certificate: Standard, Normal - Departed: APA - Destination: SDL, SCOTTSDALE, AZ - Flight plan: IFR - Airport: APA, Centennial Airport ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 40; flight instructor, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 3,123 total, 210 in this make and model, 2,983 as pilot in command, 125 in the last 90 days, 35 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 280° at 6 knots - Visibility: 20 statute miles - Lowest ceiling: none - Temperature: 70 °F, dew point 36 °F - Altimeter: 30.00 inHg 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.