# NTSB CHI96LA093: Cessna 172, N758CQ, Worthington, MN, February 18, 1996 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: February 18, 1996, 13:10 local (19:10 UTC) - Place: Worthington, MN - Coordinates: 43.619873, -95.59069 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.6199&lon=-95.5907&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report May 29, 1996 - Report: Approved by Office Director - NTSB case key (mKey): 10198 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI96LA093 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/10198/pdf - Page: https://openairdocs.org/ntsb/CHI96LA093 ## Probable cause Progressive failure of the engine, beginning with failure of the left magneto, which resulted in preignition or detonation, a burned hole in the #3 piston, subsequent oil exhaustion, and failure of the #1 and #2 connecting rods. ## 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, climb - to cruise - ignition system,magneto - failure,partial (cause) - misc,engine pre-ignition and/or detonation (cause) - engine assembly,piston - burned (cause) - fluid,oil - exhaustion (cause) - engine assembly,connecting rod - failure,total (cause) - Forced landing, emergency descent/landing - On ground/water collision with object, emergency landing - object - sign ## Analysis After climbing to 3500 feet, the pilot noted that smoke was entering the cockpit and that the engine was beginning to run rough. He diverted back toward the airport, but noted that the oil pressure began dropping rapidly and that the RPM began to fluctuate. The pilot then decided to secured the engine and make an emergency landing on a gravel road. During the landing, the right wing hit a yield sign on the side of the road. There was no indication of oil on the dipstick. A two to three inch hole was discovered in the crankcase of the engine. Examination of the engine revealed that a hole had been burned through the number three piston; the #1 and #2 connecting rods were off the crankshaft; and the #1 and #2 crankshaft journals were partially melted. The fuel system was checked and no defects were discovered. An examination of the magnetos revealed that the race inside the left magneto was loose and rotating within the aluminum housing. Metal particles from the race and housing covered the surface around the magneto block. ## Factual narrative On February 18, 1996, at 1310 central standard time, a Cessna 172, N758CQ, sustained substantial damage during a forced landing due to loss of engine power near Worthington, Minnesota. The private pilot and two passengers reported no injuries. The 14 CFR Part 91 flight departed Worthington Municipal Airport, Worthington, Minnesota, at 1255 cst, en route to Buffalo Municipal Airport, Buffalo, Minnesota. Visual meteorological conditions prevailed and no flight plan was filed. The pilot reported that he departed Worthington, Minnesota, and climbed to 3,500 feet. The first indication that something was wrong was the engine began running rough and there was light smoke in the cockpit. The pilot reported that all the instruments were in the green, the power was set at 2500 RPM with 23 inches of manifold pressure, and the mixture was at full rich. He noticed the oil pressure decreasing and he turned back to land at Worthington Airport. He reported that the engine RPM's began fluctuating, the oil pressure dropped rapidly, and the cockpit began filling with smoke. The pilot decided to secure the engine and execute a forced landing to a gravel road. The airplane touched down on the road, but during landing rollout the right wing hit a yield sign on the side of the road. The airplane swerved into an adjacent field and came to a complete stop. The oil was checked and there was no indication of oil on the dipstick. A two to three inch hole was discovered in the crankcase of the engine. An examination of the engine revealed that the number three piston exhibited a hole burned in the bottom side through the crown structure to the piston interior. The number one and number two connecting rods were off the crankshaft. The connecting rod bolts were broken. The bolts were black and necked down at the fractured area. The number one and two crankshaft journals were partially melted. The number three, four, and five connecting rods were burned and discolored. The crankshaft main bearings exhibited normal operational signatures. The fuel system was checked and no defects were discovered. An examination of the magnetos revealed that the left magneto was contaminated with a blackish debris. The left magneto distributor block interior was coated with the debris. The rear bearing race was found spinning in the left magneto's aluminum housing. Metal particles from the race and housing covered the surface around the magneto distributor block. ## Aircraft - Registration: [N758CQ](https://openairdocs.org/aircraft/N758CQ), registered now, S/N R1722992, built 1978 (OpenAirDocs) - Reported make and model: CESSNA 172 - Registry model: [Cessna R172K](https://openairdocs.org/model/cessna-r172k) (registry code 2072431) (OpenAirDocs) - Registry engine: [Continental IO-360 series](https://openairdocs.org/engine/continental-io-360-series) (registry code 17025, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: R172-2992 - Airframe hours: 924 - Engines: CONTINENTAL IO-360-KB 210 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Michael C. Schmitt - Airworthiness certificate: Standard, Normal - Last inspection: Annual, April 14, 1995, 98 hours before - Departed: OTG - Destination: 8Y2, BUFFALO, MN ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 47; private; airplane ratings: single-engine land, multi-engine land; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 1,035 total, 560 in this make and model, 970 as pilot in command, 25 in the last 90 days, 22 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 180° at 15 knots, gusting 19 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 28 °F, dew point 12 °F - Altimeter: 29.00 inHg - Observed at: OTG ## 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 19960218005949A](https://openairdocs.org/incident/19960218005949A), Feb 18, 1996: Cessna R172K, Worthington, MN, Substantial damage. Lost power landed on dirt road. Struck road sign. Veered into ditch. Broke connecting rod. ELT battery out of date. (-23) emergency landing on dirt road due to… 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.