# NTSB ERA12LA422: Mooney M20J, N174JB, Mc Kinnon, TN, June 28, 2012 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: June 28, 2012, 11:47 local (16:47 UTC) - Place: Mc Kinnon, TN - Coordinates: 36.316665, -87.916664 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=36.3167&lon=-87.9167&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach-VFR pattern downwind: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: Serious injuries - Injuries: 1 serious, 1 minor - Status: Completed, report September 30, 2013 - Report: Approved by Office Director - NTSB office: Eastern Region Aviation - Parties: FAA - NTSB case key (mKey): 84125 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA12LA422 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/84125/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=84125 - Page: https://openairdocs.org/ntsb/ERA12LA422 ## Probable cause The separation of the piston connecting rod from the crankshaft due to inadequate installation from a mechanic, resulting in a total loss of engine power. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating): recip engine power section](https://openairdocs.org/ntsb-findings/01058520): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Mooney M20J, 3 cases](https://openairdocs.org/ntsb-findings/01058520/cases.md?model=5870219), [All aircraft, 233 cases](https://openairdocs.org/ntsb-findings/01058520/cases.md) - [Maintenance: installation](https://openairdocs.org/ntsb-findings/02062035): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Mooney M20J, 2 cases](https://openairdocs.org/ntsb-findings/02062035/cases.md?model=5870219), [All aircraft, 371 cases](https://openairdocs.org/ntsb-findings/02062035/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Prior to flight: Aircraft maintenance event](https://openairdocs.org/ntsb-events/040); cases with it: [Mooney M20J, 2 cases](https://openairdocs.org/ntsb-events/040/sequence.md?model=5870219), [All aircraft, 484 cases](https://openairdocs.org/ntsb-events/040/sequence.md) - [Approach-VFR pattern downwind: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Mooney M20J, 13 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=5870219), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing: Landing area overshoot](https://openairdocs.org/ntsb-events/380); cases with it: [Mooney M20J, 3 cases](https://openairdocs.org/ntsb-events/380/sequence.md?model=5870219), [All aircraft, 400 cases](https://openairdocs.org/ntsb-events/380/sequence.md) - [Landing-landing roll: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Mooney M20J, 21 cases](https://openairdocs.org/ntsb-events/300/sequence.md?model=5870219), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) - [Landing-landing roll: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Mooney M20J, 41 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=5870219), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot was conducting a formation flight when the airplane’s engine experienced a loss of power. The pilot and his instructor then conducted a forced landing to a runway and landed long, with the airplane departing the surface and coming to rest in a field. Post accident examination revealed that the number three piston connecting rod cap separated from the piston connecting rod when the hardware came loose and the connecting rod disconnected during flight. Maintenance records showed that the engine had been overhauled several years prior to the accident. It is likely that the mechanic did not properly install the connecting rod bolts and nuts, which resulted in the number three piston connecting rod disconnecting during flight, and subsequent loss of engine power. ## Factual narrative According to the Lycoming Service Instruction No. 1458F, the stretch length for the connecting rod bolts must be 2.255/2.256 inches. Review of the maintenance records for the airplane showed that the last engine overhaul was completed on August 5, 2005, at a tachometer time of 3,266.0. The tachometer time at the accident was 3,938.0. The engine had accrued 672 hours since the overhaul. No additional maintenance requiring installation of the connecting rods was noted. On June 28, 2012, about 1147 central daylight time, a Mooney, M20J, N174JB, registered to and operated by an individual, collided with terrain during a forced landing at Houston County Airport (M93), McKinnon, Tennessee. The certified flight instructor (CFI) and private pilot received minor injuries, and the airplane sustained substantial damage. Visual meteorological conditions prevailed and no flight plan was filed for the 14 Code of Federal Regulations Part 91, instructional flight. The flight originated from M93 at 1100. The CFI submitted a written statement. The purpose of the flight was to practice formation flying and the CFI was instructing the pilot in formation flying procedures. The two-airplane formation made an approach to runway 26 for a formation landing. The CFI noted they were not in a safe position to land, and elected to make a go around. The lead airplane landed and rolled to the end. As they completed the crosswind to downwind maneuver, the engine continued to run, “…at perhaps 10 percent power.” The private pilot radioed that the engine was smoking and the CFI took control of the airplane. He attempted to land midfield on runway 08. Visibility became limited due to oil on the windscreen, and vibration made airspeed reading difficult. The landing was long and with excessive speed, resulting in the overrun of the runway. While traveling on the grass, the CFI noted trees ahead and to the right. He made a slight left turn, contacting the perimeter road’s berm. The airplane bounced, became airborne, and came to rest in a grassy area across the road. An examination of the airplane revealed that the nose gear separated, and the firewall and the empennage sustained substantial damage. The engine crankcase top halves were cracked. The Lycoming IO-360-A3B6D engine was examined. External inspection of the crankcase showed a crack radiating vertically from the bottom of the case mating surface to the top mating surface. Removal of the oil pan identified the bottom half of the number three piston rod, rod bearing cap, bearings, parts of the crankcase, two piston rod bearing cap bolts, and three rod bearing cap nuts. Due to damage, the piston and upper part of the broken rod could not be removed from the cylinder. The number four cylinder was removed from the crankcase with difficulty due to extensive damage to the cylinder skirt and crankcase. The number one cylinder was removed from the crankcase. The piston sustained impact damage to the bottom of the skirt and one pistonrod bearing cap nut was missing. The bolt was still in place. The number two cylinder was removed from the crankcase, and both rod bearing cap bolts were in place with nuts attached. ## Aircraft - Registration: [N174JB](https://openairdocs.org/deregistered/N174JB-2015-05-13), registration cancelled 2015-05-13, S/N 24-0954, built 1980 (OpenAirDocs) - Reported make and model: MOONEY M20J - Registry model: [Mooney M20J](https://openairdocs.org/model/mooney-m20j) (registry code 5870219) (OpenAirDocs) - Registry engine: [Lycoming I0360 SER A&C](https://openairdocs.org/engine/lycoming-i0360-ser-a-c) (registry code 41511, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 24-0954 - Airframe hours: 3930 - Engines: LYCOMING I0-360A3B6D 200 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, December 21, 2011, 8 hours before - Departed: M33, Gallatin, TN - Destination: M93, Mc Kinnon, TN - Airport: M93, Houston County Airport, runway 08, 3,000 × 914 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 65; injuries: minor; military, flight engineer, airline transport, flight instructor, private, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review May 19, 2012; seat: right; flight hours: 10,000 total, 10,000 as pilot in command, 32 in the last 90 days, 21 in the last 30 days, 1 in the last 24 hours - Pilot; age 80; injuries: serious; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review June 14, 2012; seat: left; flight hours: 2,857 total, 2,386 in this make and model, 2,824 as pilot in command, 8 in the last 90 days, 8 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 260° at 12 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 104 °F, dew point 52 °F - Altimeter: 29.95 inHg - Observed at: HOP, 29 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 20120628015599A](https://openairdocs.org/incident/20120628015599A), Jun 28, 2012: Mooney M20J, Stewart, TN, Substantial damage. Pilot initiated go around while turning crosswind to downwind the # 3 connecting rod seperated form the crankshaft. The crankshaft broke the rod in half and… ## Docket (9 files) The files NTSB released with the investigation on August 28, 2013, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=84125. 3.9 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 967 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40373693&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - CFI Statement (item 2, .PDF, 142 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40399018&FileExtension=.PDF&FileName=CFI%20Statement-Redacted.PDF - Engine Examination Notes (item 3, .PDF, 258 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40399019&FileExtension=.PDF&FileName=Engine%20Examination%20Notes-Redacted.PDF - FAA Inspector Statement (item 4, .PDF, 30 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40399021&FileExtension=.PDF&FileName=FAA%20Inspector%20Statement-Master.PDF - Lycoming Service Table of Limits (item 5, .PDF, 316 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40399022&FileExtension=.PDF&FileName=Lycoming%20Service%20Table%20of%20Limits-Master.PDF - Lycoming Service Instruction 1458F (item 6, .PDF, 238 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40400791&FileExtension=.PDF&FileName=Lycoming%20Service%20Instruction%201458F-Master.PDF - Maintenance Records Excerpts (item 7, .PDF, 528 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40399023&FileExtension=.PDF&FileName=Maintenance%20Records%20Excerpts-Redacted.PDF - Photo 1. Airplane at accident site (Provided by FAA) (item 8, .PDF, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40399026&FileExtension=.PDF&FileName=Photo%201.%20Airplane%20at%20accident%20site%20(Provided%20by%20FAA)-Master.PDF - Photo 2. Engine (Provided by FAA) (item 9, .PDF, 70 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40399027&FileExtension=.PDF&FileName=Photo%202.%20Engine%20(Provided%20by%20FAA)-Master.PDF 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.