# NTSB CHI96LA006: Cessna 172F, N8740U, Danbury, WI, October 11, 1995 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: October 11, 1995, 13:45 local (18:45 UTC) - Place: Danbury, WI - Coordinates: 46.000251, -92.369155 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=46.0003&lon=-92.3692&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 4, 1995 - Report: Approved by Office Director - NTSB case key (mKey): 10129 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI96LA006 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/10129/pdf - Page: https://openairdocs.org/ntsb/CHI96LA006 ## Probable cause the partial failure of the left magneto, the road sign, and the road embankment. A factor relating to this accident is the brush which obscured the road sign. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(partial) - mech failure/malf, cruise - ignition system,magneto - failure,partial (cause) - precautionary landing - performed, pilot in command - On ground/water collision with object, landing - roll - object - sign (cause) - terrain condition - high vegetation (contributing factor) - Nose over, landing - roll - terrain condition - drop-off/descending embankment (contributing factor) ## Analysis THE PILOT REPORTED THAT HE WAS CRUISING AT 500 FEET ABOVE GROUND LEVEL WHEN THE 'ENGINE STARTED TO RUN ROUGHLY.' HE DECIDED TO LAND THE AIRPLANE AND 'INVESTIGATE THE PROBLEM.' ON LANDING ROLL THE AIRPLANE'S RIGHT WING TIP STRUCK A ROAD SIGN, THAT WAS OBSCURED BY BRUSH, WHICH 'SPUN THE AIRPLANE AROUND TO THE RIGHT.' THE AIRPLANE'S NOSE GEAR STRUCK A SAND EMBANKMENT ON THE ROAD'S EDGE AND NOSED OVER. EXAMINATION OF THE WRECKAGE FOUND THE LEFT MAGNETO REAR COVER HAD SEPARATED FROM THE MAGNETO'S MAIN CASE EXPOSING THE GEARS AND POINTS. THREE OF THE FOUR SCREWS WHICH HELD THE MAGNETO COVER IN PLACE WERE MISSING. THE FOURTH SCREW HAD SHEARED OFF IN THE CASE. BOTH MAGNETOS WERE TESTED FOR SPARK. NO ABNORMALITIES WERE FOUND. EXAMINATION OF FUEL IN THE TANKS SHOWED EVIDENCE OF WATER AND SEDIMENT. ## Factual narrative On October 11, 1995, at 1345 central daylight time, a Cessna 172F, N8740U, piloted by a private pilot, sustained substantial damage when during a precautionary landing to a dirt road the airplane's right wing struck a sign and the airplane overturned. Visual meteorological conditions prevailed at the time of the accident. The flight was operated under 14 CFR Part 91. A flight plan was not on file. The pilot sustained no injuries. The airplane was on a local flight originating at Cumberland, Wisconsin at 1100 central daylight time. The pilot reported that he was cruising at 500 feet above ground level when the "engine started to run roughly." He decided to land the airplane on "what appeared to be a level road" and "investigate the problem." The pilot said, "it was the only place to land for many miles." On landing roll "at a ground speed of approximately 20 to 30 miles per hour," the pilot saw a sign which had been "obscured by brush." "The right wing tip struck the sign and spun the airplane around to the right." The airplane's nose gear struck a sand embankment on the road's edge and the airplane nosed over. The Federal Aviation Administration (FAA) inspector who examined the wreckage found the left magneto rear cover had separated from the magneto's main case exposing the gears and points. Three of the four screws which held the magneto cover in place were missing. The fourth screw had sheared off in the case. Both magnetos were tested for spark. No abnormalities were found. Examination of fuel in the tanks showed evidence of water and sediment. ## Aircraft - Registration: [N8740U](https://openairdocs.org/deregistered/N8740U-1996-04-17), registration cancelled 1996-04-17, S/N 17252644 (OpenAirDocs) - Reported make and model: CESSNA 172F - Registry model: [Cessna 172F](https://openairdocs.org/model/cessna-172f) (registry code 2072414) (OpenAirDocs) - Category: Airplane - Serial number: 17252644 - Airframe hours: 4748 - Engines: CONTINENTAL O-300-D 145 horsepower reciprocating - Damage: Substantial damage - Flight: Business, Part 91 - Operator: John Watts - Registered owner: Loren A. Wiesner - Airworthiness certificate: Standard, Normal - Last inspection: Annual, September 25, 1995, 40 hours before - Departed: UBE, CUMBERLAND, WI ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 36; flight instructor, commercial; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 2,250 total, 290 in this make and model, 2,250 as pilot in command, 200 in the last 90 days, 50 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 230° at 8 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 70 °F, dew point 50 °F - Altimeter: 29.00 inHg - Observed at: SUW, 55 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 19951011032059A](https://openairdocs.org/incident/19951011032059A), Oct 11, 1995: Cessna 172F, Blaine Township, WI, Substantial damage. Lost power. Forced landing. Magneto cover came loose. Crossfired. Using unaproved dirty fuel. No fuel STC. (-23) the accident investigation revealed an… ## Other investigations on N8740U (2) 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 MKC81DCJ13](https://openairdocs.org/ntsb/MKC81DCJ13), May 25, 1981: Cessna 172 (N8740U), Boelus, NE, destroyed - [NTSB CHI69D0393](https://openairdocs.org/ntsb/CHI69D0393), Jul 23, 1968: Cessna 172 (N8740U), Bellville, WI, substantial damage 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.