# NTSB CEN15LA292: Cessna 172D, N2320U, Shenandoah, TX, July 3, 2015 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: July 3, 2015, 12:00 local (17:00 UTC) - Place: Shenandoah, TX - Coordinates: 30.185832, -95.447502 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=30.1858&lon=-95.4475&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Fuel related](https://openairdocs.org/ntsb-events/190) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report March 18, 2019 - Report: Approved by Office Director - NTSB office: Central Region - Parties: Continental Motors, Federal Aviation Administration - Houston FSDO - SAIBs cited in the narratives: [SAIB CE-09-35](https://openairdocs.org/saib/CE-09-35) (OpenAirDocs) - NTSB case key (mKey): 91494 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN15LA292 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/91494/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=91494 - Page: https://openairdocs.org/ntsb/CEN15LA292 ## Probable cause The pilot's delayed application of carburetor heat, which resulted in the total loss of engine power due to carburetor icing during cruise flight. ## 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 172D, 1 case](https://openairdocs.org/ntsb-findings/03031030/cases.md?model=2072410), [All aircraft, 435 cases](https://openairdocs.org/ntsb-findings/03031030/cases.md) - [Action: delayed action](https://openairdocs.org/ntsb-findings/02041025): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Cessna 172D, 1 case](https://openairdocs.org/ntsb-findings/02041025/cases.md?model=2072410), [All aircraft, 894 cases](https://openairdocs.org/ntsb-findings/02041025/cases.md) - [Info processing/decision: identification/recognition](https://openairdocs.org/ntsb-findings/02041510): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Cessna 172D, 1 case](https://openairdocs.org/ntsb-findings/02041510/cases.md?model=2072410), [All aircraft, 559 cases](https://openairdocs.org/ntsb-findings/02041510/cases.md) - [Ice/rain protection system: intake anti-ice, deice](https://openairdocs.org/ntsb-findings/01023020): Aircraft › Aircraft systems · Incorrect use/operation (probable cause); cases with it: [Cessna 172D, 1 case](https://openairdocs.org/ntsb-findings/01023020/cases.md?model=2072410), [All aircraft, 108 cases](https://openairdocs.org/ntsb-findings/01023020/cases.md) - [Object/animal/substance](https://openairdocs.org/ntsb-findings/03022000): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Cessna 172D, 1 case](https://openairdocs.org/ntsb-findings/03022000/cases.md?model=2072410), [All aircraft, 224 cases](https://openairdocs.org/ntsb-findings/03022000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Other weather encounter](https://openairdocs.org/ntsb-events/400); cases with it: [Cessna 172D, 1 case](https://openairdocs.org/ntsb-events/400/sequence.md?model=2072410), [All aircraft, 1,127 cases](https://openairdocs.org/ntsb-events/400/sequence.md) - [Enroute-cruise: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Cessna 172D, 1 case](https://openairdocs.org/ntsb-events/060/sequence.md?model=2072410), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md) - [Enroute-cruise: Fuel related](https://openairdocs.org/ntsb-events/190) (defining event); cases with it: [Cessna 172D, 1 case](https://openairdocs.org/ntsb-events/190/sequence.md?model=2072410), [All aircraft, 361 cases](https://openairdocs.org/ntsb-events/190/sequence.md) - [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341); cases with it: [Cessna 172D, 6 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=2072410), [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 172D, 9 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2072410), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-landing roll: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Cessna 172D, 11 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2072410), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) - [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Cessna 172D, 2 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=2072410), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis The private pilot reported that he was conducting a personal flight when the engine began to "sputter and lose power" during cruise flight. He was unable to restore full engine power after applying carburetor heat, selecting a full-rich mixture setting, and verifying that the selector valve was positioned to draw fuel from both tanks. The engine subsequently lost total power, and the pilot made a forced landing to a nearby vacant parking lot. The pilot was unable to stop the airplane during the landing roll before it impacted a concrete curb and nosed over. Postaccident engine examination did not reveal any evidence of preimpact anomalies that would have precluded normal operation. The pilot had topped off the airplane's fuel tanks before departing on the 1-hour flight; the airplane had a fuel endurance of 4.2 hours when the tanks were full. Although the fuel quantity was not measured after the accident, the airplane likely had at least 3 hours of fuel remaining at the time of the accident. The pilot stated that fuel samples drained from each wing fuel tank during his preflight inspection were consistent with 100 low-lead aviation fuel and were not contaminated with water or debris. Additionally, postaccident testing of the fuel source used to refuel the airplane before the flight did not reveal any evidence of water or debris. The weather conditions at the time of the accident were conducive to the formation of carburetor icing at glide and cruise power settings. Based on the available information, it is likely that the engine initially lost power after developing carburetor ice and that the application of carburetor heat was ineffective and possibly exacerbated the problem by introducing less-dense hot air, which likely led to a further drop in rpm. Additionally, the pilot's delay in applying carburetor heat until after the engine began running roughly likely resulted in insufficient exhaust gas temperature to produce hot air in the exhaust muffler, which rendered the use of carburetor heat ineffective at melting the accumulated ice. ## Factual narrative On July 3, 2015, about 1200 central daylight time, a Cessna 172D airplane, N2320U, collided with terrain during a forced landing in Shenandoah, Texas. The pilot sustained minor injuries, and the airplane was substantially damaged. The airplane was owned by the private pilot and operated under Title 14 Code of Federal Regulations Part 91 without a flight plan. Day visual meteorological conditions prevailed for the personal flight that departed Cleveland Municipal Airport (6R3), Cleveland, Texas, about 1100, with the intended destination of Weiser Air Park (EYQ), Houston, Texas.According to the pilot, the airplane's wing tanks were topped off with fuel before he departed on the flight. The pilot stated that fuel samples drained from each wing tank during his preflight were consistent with 100 low-lead aviation fuel and did not contain any water or debris. The pilot did not observe any anomalies with engine operation during his pretakeoff runup. After an uneventful takeoff, the pilot overflew the Lake Livingston area for about 30 minutes before continuing toward his planned destination (EYQ). While established in cruise flight, at 1,600 ft mean sea level, about 10 miles north of David Wayne Hooks Memorial Airport (DWH), the engine experienced a partial loss of engine power. The pilot reported that the engine "suddenly began to sputter and lose power." The pilot applied carburetor heat, selected a full-rich mixture setting, and verified that the fuel selector valve handle was set on BOTH. The pilot's corrective actions did not restore full engine power and he declared an emergency with the tower controller at DWH. The flight was cleared for an immediate landing on runway 17 at DWH; however, shortly after receiving the landing clearance, the engine experienced a total loss of power. The pilot reported that he trimmed the airplane for best glide airspeed and made a forced landing to a vacant parking lot at a nearby sports stadium. He was unable to stop the airplane during landing roll before it collided with a concrete curb. The impact with the curb collapsed the nose landing gear and the airplane subsequently nosed over. The fuselage, wings, and empennage were substantially damaged during the forced landing. A postaccident examination of the airplane and its engine was completed by Federal Aviation Administration inspectors and a representative with the engine manufacturer. Engine control cable continuity was confirmed from the cockpit controls to their respective engine components. The carburetor heat control cable remained attached to the airbox; however, the airbox was crushed during impact, which precluded normal movement of the carburetor heat valve. The fuel selector valve was positioned to draw fuel from both wing fuel tanks. Examination of the fuel gascoloator revealed a small amount of water and no fuel; however, the airplane came to rest inverted at the accident site and was subsequently recovered in an inverted attitude. Further inspectionof the gasoclator did not reveal any particulate contamination. The fuel quantity was not measured at the accident site because the airplane was inverted. The engine, a Continental O-300-D, serial number 28116-D-3-D, remained partially attached to the airframe. The engine was separated from the airframe to facilitate an examination. The engine case remained intact with the accessory components still attached to their respective installation points. The upper spark plugs exhibited features consistent with normal engine operation. Internal engine and valve train continuity were confirmed as the engine crankshaft was rotated. Compression and suction were noted on all cylinders in conjunction with crankshaft rotation. Both magnetos remained attached to the engine case and provided spark on all posts while the crankshaft was rotated. Both impulse couplings released simultaneously when the No. 1 piston was moved to the top-dead-center position during the compression stroke. The correct firing order was observed as the crankshaft was rotated. A borescope inspection of each cylinder did not reveal any anomalies with the cylinders, pistons, valves, or valve seats. The oil filter was crushed during impact; however, removal and inspection of the filter element did not reveal any metal debris. The disassembly of the carburetor revealed no water, corrosion, or debris in the bowl assembly. Functional testing of the carburetor accelerator pump produced a normal fuel discharge. A visual examination of the carburetor fuel inlet screen revealed no evidence of debris. The float and needle valve were attached and moved freely by hand, and the needle valve seat was clean. The propeller remained attached to the engine crankshaft. Both propeller blades were bent aft near each blade tip, and neither blade exhibited spanwise S-shape bends or leading-edge damage. The postaccident examination did not reveal any anomalies that would have precluded normal engine operation during the flight. The fixed-base operator where the airplane was fueled before the flight completed fuel testing after the accident. The fuel testing revealed no evidence of water or debris of their 100 low-lead aviation fuel source. According to the Pilot Operating Handbook for the Cessna 172D, the airplane had a total fuel capacity of 39 gallons (36 gallons usable) and a fuel endurance of 4.2 hours at 2,500 ft msl and 75% engine power. At 1153, about 7 minutes before the accident, the DWH automated surface observing system reported: wind 230° at 4 knots, few clouds at 3,400 ft above ground level (agl), scattered clouds at 4,100 feet agl, 10 mile surface visibility, temperature 32°C; dew point 24°C; and an altimeter setting of 30.00 inches of mercury. According to a carburetor icing probability chart contained in FAA Special Airworthiness Information Bulletin CE-09-35, entitled "Carburetor Icing Prevention", the recorded temperature and dew point were in the range of susceptibility for the formation ofcarburetor icing at glide and cruise power settings. An article on carburetor icing published by Flight Safety Australia stated that if ice forms in the carburetor of a fixed pitch propeller aircraft, the restriction to the induction airflow will reduce power and result in a drop of engine rpm, which might be accompanied or followed by a rough running engine as the fuel/air mixture ratio is upset. Applying carburetor heat introduces less-dense hot air which will cause a further drop in engine rpm. Additionally, the article stated that if a pilot delays applying carburetor heat until after the engine begins running rough, the exhaust gas temperature might be insufficient to produce hot air in the exhaust muffler, which could render the use of carburetor heat ineffective at melting the accumulated ice. ## Aircraft - Registration: [N2320U](https://openairdocs.org/deregistered/N2320U-2018-05-30), registration cancelled 2018-05-30, S/N 17249920, built 1962 (OpenAirDocs) - Reported make and model: CESSNA 172D - Registry model: [Cessna 172D](https://openairdocs.org/model/cessna-172d) (registry code 2072410) (OpenAirDocs) - Registry engine: [Continental 0-300 series](https://openairdocs.org/engine/continental-0-300-series) (registry code 17022, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17249920 - Year built: 1962 - Airframe hours: 5247.1 - Engines: Continental O-300-D 145 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, June 24, 2015, 2 hours before - Departed: 6R3, Cleveland, TX - Destination: EYQ, Houston, TX - Equipment: Stall warning system, Handheld GPS, Electronic flight bag or handheld device ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 63; injuries: minor; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review February 18, 2014; seat: left; restraint: lap only; flight hours: 590 total, 427 in this make and model, 552 as pilot in command, 3 in the last 90 days, 3 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 230° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 90 °F, dew point 75 °F - Altimeter: 30.00 inHg - Observed at: DWH, 9 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 20150703010199A](https://openairdocs.org/incident/20150703010199A), Jul 3, 2015: Cessna 172D, Shenandoah, TX, Substantial damage. Aircraft has just been through annual inspection and this was first flight. Preflight inspection and engine run-up were conducted as usual with no… ## Other investigations on N2320U (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 FTW67F0267](https://openairdocs.org/ntsb/FTW67F0267), Nov 11, 1966: Cessna 172 (N2320U), Fort Worth, TX, substantial damage ## Docket (11 files) The files NTSB released with the investigation on November 8, 2018, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=91494. 5.0 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 261 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40468150&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - FAA Inspector Statement (Jim Moore) (item 2, .PDF, 143 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40468151&FileExtension=.PDF&FileName=FAA%20Inspector%20Statement%20(Jim%20Moore)-Master.PDF - FAA Inspector Statement (Casey Storm) (item 3, .PDF, 68 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40468152&FileExtension=.PDF&FileName=FAA%20Inspector%20Statement%20(Casey%20Storm)-Master.PDF - Engine Examination Report (item 4, .PDF, 2.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40468153&FileExtension=.PDF&FileName=Engine%20Examination%20Report-Master.PDF - Fixed-Base Operator Fuel Source Test Report (item 5, .PDF, 140 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40468154&FileExtension=.PDF&FileName=Fixed-Base%20Operator%20Fuel%20Source%20Test%20Report-Master.PDF - Cessna 172D Pilot Operating Handbook (Excerpts) (item 6, .PDF, 75 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40468155&FileExtension=.PDF&FileName=Cessna%20172D%20Pilot%20Operating%20Handbook%20(Excerpts)-Master.PDF - Weather Reports (item 7, .PDF, 69 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40468156&FileExtension=.PDF&FileName=Weather%20Reports-Master.PDF - FAA Special Airworthiness Information Bulletin No. CE-09-35 (Carburetor Icing Prevention) (item 8, .PDF, 113 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40468157&FileExtension=.PDF&FileName=FAA%20Special%20Airworthiness%20Information%20Bulletin%20No.%20CE-09-35%20(Carburetor%20Icing%20Prevention)-Master.PDF - Flight Safety Australia Article on Carburetor Icing (item 9, .PDF, 263 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40468158&FileExtension=.PDF&FileName=Flight%20Safety%20Australia%20Article%20on%20Carburetor%20Icing-Master.PDF - Security Video of Airplane Landing in Parking Log (item 10, AVI, 925 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40468159&FileExtension=avi&FileName=Security%20Video%20of%20Airplane%20Landing%20in%20Parking%20Log-Master - Statement of Party Representatives to NTSB Investigation (item 11, .PDF, 237 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40468160&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-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.