# NTSB CHI97IA127: Cessna T210, N7398M, Winona, MN, May 8, 1997 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: May 8, 1997, 07:14 local (12:14 UTC) - Place: Winona, MN - Coordinates: 44.040523, -91.650077 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=44.0405&lon=-91.6501&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report September 28, 1999 - Report: Approved by Office Director - NTSB case key (mKey): 10464 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI97IA127 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/10464/pdf - Page: https://openairdocs.org/ntsb/CHI97IA127 ## Probable cause Loss of engine power due to improper maintenance installation. ## 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,piston - improper (cause) - maintenance,installation - improper, other maintenance personnel (cause) - Forced landing, emergency landing - terrain condition - runway ## Analysis The pilot reported that while flying at 8,000 feet msl, about a half hour into the flight, the engine missed then ran normal again. The engine power then decreased to 20 inches of manifold pressure. He stated he informed Air Traffic Control of the situation and requested the nearest airport which was 8 miles away. The pilot attempted to re-establish engine power to no avail. The pilot was able to reach the airport and the engine lost all power while on final approach. The pilot made an uneventful forced landing on the runway. Inspection of the engine revealed that the wrong pistons were installed in the engine. The pistons should have been part number 648044 (compression ratio of 7 to 1). The pistons found installed in the engine were part number 648045 (compression ratio of 8.5 to 1). The engine was overhauled on July 30, 1996. ## Factual narrative On May 8, 1997, at 0714 central daylight time, a Cessna 210, N7398M, operated as Prompt Air Flight 752, sustained a total loss of engine power during cruise flight near Winona, Minnesota. The commercial rated pilot conducted a forced landing at the Max Conrad Airport, Winona, Minnesota, without further incident. The pilot was not injured. The airplane was not damaged. The 14 CFR part 135, unscheduled air taxi flight departed Milwaukee, Wisconsin, at 0550 with a planned destination of Minneapolis, Minnesota. Visual meteorological conditions prevailed and an IFR flight plan was filed. The pilot reported that while flying at 8,000 feet mean sea level, about a half hour into the flight, the engine missed then ran normal again. He reported the oil pressure was at the bottom of the green arc, the oil temperature was running high, but still in the green arc, and the cylinder head temperature was high, but also still in the green arc. He stated the engine then lost partial power with the manifold pressure dropping to around 20 inches. He stated he informed air traffic control of the situation and requested the nearest airport which was the Winona Max Conrad Airport, 8 miles away. The pilot stated he turned toward the airport and established the best glide speed. He stated he applied full mixture, put on the fuel pump, switched fuel tanks, and tried switching magnetos to no avail. The pilot stated he pulled out the emergency checklist and used the restart and engine securing procedures. Air traffic control then instructed him to contact the unicom frequency at which time he stated he had the airport in sight. He stated he lowered the gear and flaps, and on short final the engine lost all power. The pilot landed the airplane on runway 29 without incident. The airplane was equipped with a Continental TSIO-520-R engine, s/n 517445. The engine was removed from the airplane and shipped to Teledyne Continental Motors, Mobile, Alabama, for a teardown inspection. The teardown inspection revealed that the wrong pistons were installed in the engine. The pistons should have been part number 648044 (compression ratio of 7 to 1). The pistons found installed in the engine were part number 648045 (compression ratio of 8.5 to 1). See teardown inspection reports for further details. The engine was overhauled on July 30, 1996, by G & N Aircraft, Griffith, Indiana. The last inspection on the engine was a 100 hour inspection on May 2, 1997 (6 days prior to the accident) at which time the engine had 736.6 hours since the overhaul. ## Aircraft - Registration: [N7398M](https://openairdocs.org/deregistered/N7398M-2015-05-08), registration cancelled 2015-05-08, S/N 21062018, built 1977 (OpenAirDocs) - Reported make and model: Cessna T210 - Registry model: [Cessna T210M](https://openairdocs.org/model/cessna-t210m) (registry code 2073451) (OpenAirDocs) - Registry engine: [Continental TSIO-520 series](https://openairdocs.org/engine/continental-tsio-520-series) (registry code 17040, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 21062018 - Engines: Continental TSIO-502-R 310 horsepower reciprocating - Damage: No damage - Flight: Part 135 - Registered owner: Prompt Air, Inc - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, May 2, 1997 - Departed: MKE, MILWAUKEE, WI - Destination: MSP, MINNEAPOLIS, MN - Flight plan: IFR - Airport: ONA, Max Conrad Field, runway 29, 5,199 × 100 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 28; flight instructor, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left; flight hours: 1,333 total, 93 in this make and model, 1,275 as pilot in command, 246 in the last 90 days, 96 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Dawn - Wind: 290° at 7 knots - Visibility: 6 statute miles - Lowest ceiling: 1,500 ft broken ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Incident 19970508017279I](https://openairdocs.org/incident/19970508017279I), May 8, 1997: Cessna 210N, Winona, MN. Narrative: engine lost power due to number six piston and/or valve failure. NTSB participated in investigation. Engine was shipped to Continental engines for… 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.