# NTSB DFW07LA108: Cessna A188A, N4413Q, Clinton, OK, May 11, 2007 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: May 11, 2007, 12:50 local (17:50 UTC) - Place: Clinton, OK - Coordinates: 35.536666, -98.913887 - Nearby events: https://openairdocs.org/map.md?lat=35.5367&lon=-98.9139&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report April 30, 2008 - Report: Approved by Office Director - Parties: Federal Aviation Administration, Teledyne Continental Motors - NTSB case key (mKey): 65762 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DFW07LA108 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/65762/pdf - Page: https://openairdocs.org/ntsb/DFW07LA108 ## Probable cause Separation of the exhaust stack and resulting vapor lock. A contributing factor was the none suitable terrain for the forced landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, maneuvering - aerial application - exhaust system,stack - failure (cause) - Loss of engine power(partial) - nonmechanical, maneuvering - fluid,fuel - vapor lock (cause) - Forced landing, emergency descent/landing - Nose over, emergency descent/landing - terrain condition - none suitable (contributing factor) ## Analysis As the agricultural pilot was pulling up from a low level pass, he smelled something "like wires burning" and observed the engine's fuel pressure drop. The pilot selected the auxiliary fuel pump's "EMERGENCY" position and five to ten seconds later the engine lost partial power. Not able to maintain altitude, the pilot elected to land the airplane to a rolling wheat field. During landing, the airplane nosed over and came to rest in an inverted position. An examination of the airplane revealed that, prior to impact, the engine exhaust stack had separated from the muffler. Hot exhaust gasses, that are normally vented overboard, were directed to the airplanes firewall, resulting in thermal damaged to electrical wiring and a vapor condition in the fuel gascolator. The pilot attempted to purge the vapor to no avail. No other pre impact anomalies were noted with the engine or the fuel system that would have prevented normal operating power. ## Factual narrative On May 11, 2007, about 1250 central daylight time, a single-engine Cessna A188A airplane, N4413Q, was substantially damaged during a forced landing following a partial loss of engine power near Clinton, Oklahoma. The airline transport pilot, the sole occupant, sustained serious injuries. The airplane was registered to and operated by the pilot. Visual meteorological conditions prevailed and a flight plan was not filed for the 14 Code of Federal Regulations part 137 aerial application flight. The local flight originated from Clinton Regional Airport (CLK), Clinton, Oklahoma at 1157. According to the pilot, age 35, as he was pulling up from a low level pass, he smelled something "like wires burning" and observed the engine's fuel pressure drop to approximately six gallons per hour (GPH). The pilot selected the auxiliary fuel pump's "EMERGENCY" position which resulted in an increase in fuel pressure to about 22 GPH. Approximately five to ten seconds later the engine's fuel pressure again dropped to approximately six gallons per hour. Not able to maintain altitude, the pilot elected to land the airplane to a rolling wheat field. Prior to landing, the pilot shut off the engine magnetos and master switch. During landing, the airplane nosed over and came to rest in an inverted position. A post impact fire did not occur. A Federal Aviation Administration (FAA) inspector responded to the accident site. According to the inspector, the airplane sustained substantial damage to the vertical stabilizer and both wings. The inspector further reported that aviation fuel was found in the airplane's main fuel tanks and in the engine's fuel manifold. The NTSB investigator-in-charge (IIC) and a representative from Teledyne Continental Motors examined the airplane following its recovery. The examination revealed that prior to impact, the engine exhaust stack had separated from the muffler. The electrical wiring attached to the firewall in the area behind the muffler was found thermally damaged. The fuel gascolator was also attached to the firewall in this area. No other pre impact anomalies were noted with the engine or the fuel system that would have prevented normal operating power. According to the Cessna Agwagon Owners Manual dated 1970/71, page 2-12, "...if fuel vapor is affecting engine operation, the vapor may be purged by placing the switch in the "EMERGENCY" position while leaning the mixture as required to prevent excessively rich mixture. Successful vapor purging is evidenced by smooth engine operation and steady and normal fuel flow indications with the auxiliary fuel pump switch "OFF."" ## Aircraft - Registration: [N4413Q](https://openairdocs.org/deregistered/N4413Q-2008-12-30), registration cancelled 2008-12-30, S/N 18800813, built 1971 (OpenAirDocs) - Reported make and model: Cessna A188A - Registry model: [Cessna A188A](https://openairdocs.org/model/cessna-a188a) (registry code 2073008) (OpenAirDocs) - Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18800813 - Airframe hours: 5678 - Engines: Continental IO-520-D 300 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: Chad Wright - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, March 1, 2007 - Departed: CLK, Clinton, OK ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 35; injuries: serious; flight instructor, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review September 1, 2006; seat: single; flight hours: 7,230 total, 650 in this make and model, 6,050 as pilot in command, 105 in the last 90 days, 73 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 20° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: 7,000 ft broken - Temperature: 73 °F, dew point 64 °F - Altimeter: 30.11 inHg - Observed at: CLK, 3 nm away ## Other investigations on N4413Q (1) 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 MKC84LA251](https://openairdocs.org/ntsb/MKC84LA251), Aug 15, 1984: Cessna A188A (N4413Q), Goodland, KS, destroyed 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.