# NTSB WPR12LA228: Cessna 150L, N11428, Tulare, CA, May 23, 2012 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 23, 2012, 13:40 local (20:40 UTC) - Place: Tulare, CA - Coordinates: 36.26889, -119.510276 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=36.2689&lon=-119.5103&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report August 13, 2013 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - SAIBs cited in the narratives: [SAIB CE-09-35](https://openairdocs.org/saib/CE-09-35) (OpenAirDocs) - NTSB case key (mKey): 83757 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR12LA228 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/83757/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=83757 - Page: https://openairdocs.org/ntsb/WPR12LA228 ## Probable cause A partial loss of engine power, which was likely the result of carburetor icing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Temp/humidity/pressure: conducive to carburetor icing](https://openairdocs.org/ntsb-findings/03031030): Environmental issues › Conditions/weather/phenomena · Effect on equipment (probable cause); cases with it: [Cessna 150L, 7 cases](https://openairdocs.org/ntsb-findings/03031030/cases.md?model=2071826), [All aircraft, 435 cases](https://openairdocs.org/ntsb-findings/03031030/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Cessna 150L, 11 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=2071826), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) ## Analysis The student pilot was maneuvering the airplane at an altitude of about 1,300 feet above ground level when the engine started to sputter. He configured the airplane for a forced landing in an alfalfa field. During the landing roll, the airplane encountered a water-filled ditch and nosed over, coming to rest inverted and sustaining damage to the tail section. Postaccident examination of the engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. In ambient conditions similar to those reported near the accident site, a pilot could expect serious carburetor icing while operating at various power settings. ## Factual narrative On May 23, 2012, about 1340 Pacific daylight time, a Cessna 150L, N11428, experienced a partial loss of engine power and nosed over during a forced landing to a field in Tulare, California. The student pilot, who was the registered owner, was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The student pilot and one passenger were not injured; the airplane sustained substantial damage. The local personal flight departed from Mefford Field Airport, Tulare, about 1300. Visual meteorological conditions prevailed, and no flight plan had been filed. The student pilot stated that after departing from Tulare he was maneuvering the airplane in the local area. At an altitude about 1,300 feet above ground level (agl), the engine started to sputter and he configured the airplane for a forced landing in an alfalfa field below. During the landing rollout, the airplane encountered a water-filled ditch. The airplane nosed over inverted, sustaining damage to the tail section. A review of the airplane’s logbooks revealed the airplane had undergone an annual inspection on October 12, 2011, at a total time of 3,238 hours. The student pilot had prior problems with the carburetor and thought that may have contributed to the sputtering engine. Following the accident, the airplane was sold to the student pilot’s past certified flight instructor (CFI). The CFI reported that he inspected the fuel tanks and found them clear and free of debris. The engine had no evidence of catastrophic mechanical malfunction or failure. The CFI removed the carburetor and did not find any anomalies that would have precluded normal operation. A routine aviation weather report (METAR) generated by an Automated Surface Observation System (ASOS) at the Visalia Municipal Airport, Visalia, California (located about 10 nautical miles southwest from the accident site), indicated that about 5 minutes prior the accident the wind was variable from 320 to 020 degrees at 11 knots with wind gusts at 17 knots; temperature 79 degrees Fahrenheit; dew point 48 degrees Fahrenheit; and altimeter 29.89 inches of mercury. The FAA published Special Airworthiness Information Bulletin (SAIB) CE-09-35 in June 2009, regarding carburetor ice prevention. The SAIB noted that carburetor icing does not just occur in freezing conditions; it can occur at temperatures well above freezing temperatures when there is visible moisture or high humidity. Vaporization of fuel combined with the expansion of air as it flows through the carburetor (the venturi effect) causes sudden cooling. A significant amount of ice can build up within a fraction of a second. The SAIB contained a graph that illustrated the probability of carburetor icing for various temperatures, dew points, and relative humidity conditions. According to the SAIB, a pilot encountering the ambient conditions reported by the Visalia METAR could expect serious carburetor icing while at glide power. ## Aircraft - Registration: [N11428](https://openairdocs.org/deregistered/N11428-2019-07-11), registration cancelled 2019-07-11, S/N 15075412, built 1973 (OpenAirDocs) - Reported make and model: CESSNA 150L - Registry model: [Cessna 150L](https://openairdocs.org/model/cessna-150l) (registry code 2071826) (OpenAirDocs) - Registry engine: [Continental 0-200 series](https://openairdocs.org/engine/continental-0-200-series) (registry code 17020, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 15075412 - Airframe hours: 3238 - Engines: CONT MOTOR O-200 SERIES 100 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, October 12, 2011, 73 hours before - Departed: TLR, Tulare, CA - Destination: TLR, Tulare, CA - Airport: TLR, Mefford Field Airport ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 42; injuries: none; student; medical: class 3, without waivers/limitations; seat: left; flight hours: 81 total ## Weather - Conditions: Visual (VMC), Day - Wind: 350° at 11 knots, gusting 17 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 79 °F, dew point 48 °F - Altimeter: 29.88 inHg - Observed at: VIS, 10 nm away ## Docket (2 files) The files NTSB released with the investigation on June 6, 2013, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=83757. 2.5 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 2.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40370867&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Record of Conversation: Certified Flight Intructor (item 2, .PDF, 112 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40389567&FileExtension=.PDF&FileName=Record%20of%20Conversation%3A%20Certified%20Flight%20Intructor-Redacted.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.