# NTSB CEN13LA216: Cessna 172, N8033B, Wonewoc, WI, April 1, 2013 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: April 1, 2013, 12:20 local (17:20 UTC) - Place: Wonewoc, WI - Coordinates: 43.669998, -90.232498 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.6700&lon=-90.2325&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report January 30, 2014 - Report: Approved by Office Director - NTSB office: Central Region - Parties: Federal Aviation Administration - Milwaukee FSDO - NTSB case key (mKey): 86558 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN13LA216 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/86558/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=86558 - Page: https://openairdocs.org/ntsb/CEN13LA216 ## Probable cause The restricted vented fuel cap and obstructed fuel vent lines, which resulted in a total loss of engine power due to fuel starvation. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Fuel system](https://openairdocs.org/ntsb-findings/01022800): Aircraft › Aircraft systems · Inoperative (probable cause); cases with it: [Cessna 172, 2 cases](https://openairdocs.org/ntsb-findings/01022800/cases.md?model=2072402), [All aircraft, 181 cases](https://openairdocs.org/ntsb-findings/01022800/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Fuel related](https://openairdocs.org/ntsb-events/190); cases with it: [Cessna 172, 3 cases](https://openairdocs.org/ntsb-events/190/sequence.md?model=2072402), [All aircraft, 361 cases](https://openairdocs.org/ntsb-events/190/sequence.md) - [Initial climb: Fuel starvation](https://openairdocs.org/ntsb-events/191); cases with it: [Cessna 172, 5 cases](https://openairdocs.org/ntsb-events/191/sequence.md?model=2072402), [All aircraft, 733 cases](https://openairdocs.org/ntsb-events/191/sequence.md) - [Initial climb: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Cessna 172, 7 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=2072402), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Cessna 172, 10 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2072402), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Cessna 172, 36 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2072402), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot reported that, during the flight before the accident flight, the engine began running roughly during cruise flight with the right wing fuel tank selected. After attempting to resolve the issue by applying carburetor heat, he made a precautionary landing at a nearby grass airstrip. After landing, the pilot loosened the right fuel tank cap and heard a "whoosh" sound and the metal fuel tank "crinkle." The pilot stated that he thought he had resolved the fuel tank venting issue when he removed the right fuel tank cap. After spending 30 minutes on the ground, the pilot restarted the engine with both fuel tanks selected and performed an uneventful engine run-up before departing. Shortly after takeoff, the engine experienced a total loss of power, and the pilot executed a forced landing into a marsh. A postaccident examination revealed that the external and cross-tank vent lines were obstructed by foreign material likely deposited by insects. In this condition, the engine responded to cockpit controls during an operational test run. Following the engine test run, the right fuel tank cap was loosened, and a "whoosh" sound was heard. Testing of the right fuel cap revealed a restriction to the flapper-valve assembly, which prevented air from passing freely through the vented cap as designed. The combination of a restricted vented fuel cap and the obstructed vent lines likely prevented the fuel from flowing to the engine and resulted in fuel starvation and the total loss of engine power. ## Factual narrative On April 1, 2013, at 1220 central daylight time, a Cessna model 172 airplane, N8033B, was substantially damaged during a forced landing following a loss of engine power shortly after takeoff from Three Castles Airpark (4D1), Wonewoc, Wisconsin. The commercial pilot was not injured. The airplane was registered to and operated by the pilot, under the provisions of 14 Code of Federal Regulations Part 91, without a flight plan. Day visual meteorological conditions prevailed for the personal flight. The flight originally departed Park Falls Municipal Airport (KPKF), Park River, Wisconsin, at 1030, and was destined for St Louis Metro-East Airport (3K6), St. Jacob, Illinois.The pilot reported that he planned on making one fuel stop during the cross-country trip, although he had not selected the actual airport because the airplane still had ample fuel. The engine began running rough during cruise flight while operating on the right wing fuel tank. After attempting to resolve the issue with an application of carburetor heat, he made an uneventful precautionary landing at a nearby grass airstrip (4D1). After landing, the pilot reported that he couldn't find anything wrong with engine during a visual check of the engine. However, he heard a "whoosh" sound and heard the metal fuel tank "crinkle" as he loosened the right fuel tank cap. The pilot reported that he attributed these sounds to an accumulated pressure differential that occurred during his rapid descent while operating on a single fuel tank. The left wing fuel tank contained about 2 gallons of fuel. The right tank contained about 10 gallons of fuel. The pilot stated that he thought he had resolved the fuel tank venting issue when he removed the right fuel tank cap. The pilot subsequently restarted the engine, with the fuel selector drawing fuel from both fuel tanks, and performed an uneventful engine run-up before departing again. Shortly after takeoff, at an altitude of about 300 feet, the engine began running rough. The pilot reported that the engine lost power completely at an altitude of about 200 feet as he attempted to return to the airport. The airplane's left wing collided with a tree during the forced landing into a seasonal marsh. A postaccident examination was performed by a Federal Aviation Administration Airworthiness Inspector. The inspector reported that the external fuel tank vent line, located on the left wing strut, was obstructed by foreign material likely deposited by insects. Additionally, he noted that the cross-tank vent line was also obstructed. The engine responded to cockpit controls during a postaccident operational test run. Following the engine test run, the inspector heard a "whoosh" sound as he loosened the right fuel tank cap. Testing of the right fuel cap revealed a restriction to the flapper-valve assembly, which prevented air to pass freely through the vented cap as designed. Although there was no foreign object debris or material noted around the valve seat, therubber-flap material would remain engaged to its corresponding metal seat when pressure was applied via plastic tubing. The air restriction became progressively less apparent after several applications of pressure and suction by the FAA Inspector. ## Aircraft - Registration: [N8033B](https://openairdocs.org/deregistered/N8033B-2018-01-09), registration cancelled 2018-01-09, S/N 29833, built 1957 (OpenAirDocs) - Reported make and model: CESSNA 172 - Registry model: [Cessna 172](https://openairdocs.org/model/cessna-172) (registry code 2072402) (OpenAirDocs) - Registry engine: [Continental 0-300 series](https://openairdocs.org/engine/continental-0-300-series) (registry code 17022, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 29833 - Airframe hours: 4488 - Engines: Continental O-300-A 145 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, September 21, 2012 - Departed: PKF, Park Falls, WI - Destination: 3K6, St Jacob, IL - Airport: 4D1, Three Castles Airpark, runway 28, 2,740 × 90 ft, grass/turf ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 29; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review September 7, 2011; seat: left; flight hours: 325 total, 194 in this make and model, 197 as pilot in command, 15 in the last 90 days, 9 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 270° at 18 knots, gusting 23 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 30 °F, dew point 12 °F - Altimeter: 30.13 inHg - Observed at: VOK, 16 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 20130401005329A](https://openairdocs.org/incident/20130401005329A), Apr 1, 2013: Cessna 172, Union Center, WI, Substantial damage. On April 1, 2013, at 1235 CDT, Cessna 172, N8033B, registered to [privacy data omitted] lost power on climb 0UT, collieded with trees and ended up in a flooded… ## Docket (4 files) The files NTSB released with the investigation on November 14, 2013, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=86558. 1.2 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 916 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40400811&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Memorandum of Conversation, Seth Pripps (Pilot) (item 2, .PDF, 127 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40401911&FileExtension=.PDF&FileName=Memorandum%20of%20Conversation,%20Seth%20Pripps%20(Pilot)-Master.PDF - Memorandum of Conversation, FAA Inspector Timothy Anderson (item 3, .PDF, 60 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40400813&FileExtension=.PDF&FileName=Memorandum%20of%20Conversation,%20FAA%20Inspector%20Timothy%20Anderson-Master.PDF - FAA Inspector Statement, Timothy Anderson (item 4, .PDF, 81 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40400812&FileExtension=.PDF&FileName=FAA%20Inspector%20Statement,%20Timothy%20Anderson-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.