# NTSB CEN14LA165: Beech P35, N9532Y, Wichita Falls, TX, March 18, 2014 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: March 18, 2014, 10:20 local (15:20 UTC) - Place: Wichita Falls, TX - Coordinates: 33.860553, -98.49028 - Nearby events: https://openairdocs.org/map.md?lat=33.8606&lon=-98.4903&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach-VFR pattern base: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: Minor injuries - Injuries: 1 minor, 1 uninjured - Status: Completed, report December 15, 2014 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA Lubbock FSDO, Continental Motors - NTSB case key (mKey): 88939 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN14LA165 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/88939/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=88939 - Page: https://openairdocs.org/ntsb/CEN14LA165 ## Probable cause The loss of engine power due to the misrigging of the fuel mixture control. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine fuel and control: fuel control/carburetor](https://openairdocs.org/ntsb-findings/01057322): Aircraft › Aircraft power plant · Malfunction (probable cause); cases with it: [Beech P35, 1 case](https://openairdocs.org/ntsb-findings/01057322/cases.md?model=1151530), [All aircraft, 195 cases](https://openairdocs.org/ntsb-findings/01057322/cases.md) - [Engine fuel and control: fuel control/carburetor](https://openairdocs.org/ntsb-findings/01057322): Aircraft › Aircraft power plant · Fatigue/wear/corrosion (probable cause); cases with it: [Beech P35, 1 case](https://openairdocs.org/ntsb-findings/01057322/cases.md?model=1151530), [All aircraft, 195 cases](https://openairdocs.org/ntsb-findings/01057322/cases.md) - [Engine fuel and control: fuel control/carburetor](https://openairdocs.org/ntsb-findings/01057322): Aircraft › Aircraft power plant · Incorrect service/maintenance (probable cause); cases with it: [Beech P35, 1 case](https://openairdocs.org/ntsb-findings/01057322/cases.md?model=1151530), [All aircraft, 195 cases](https://openairdocs.org/ntsb-findings/01057322/cases.md) - [Action: incorrect action performance](https://openairdocs.org/ntsb-findings/02041015): Personnel issues › Action/decision · Other (probable cause); cases with it: [Beech P35, 2 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md?model=1151530), [All aircraft, 1,386 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach-VFR pattern base: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Beech P35, 3 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=1151530), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing-landing roll: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Beech P35, 7 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=1151530), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot reported that, while turning from the downwind to the base leg to prepare for a short-field landing on the runway, he reduced the throttle. He then applied throttle to increase the power when the airplane was about 600 feet above ground level; however, the engine did not respond, and the pilot subsequently executed a forced landing to a field. During the landing, both wings sustained substantial damage. During an engine test run with the cockpit fuel mixture control in the full-forward position, the engine would lose power when the throttle was advanced past 2,000 rpm. When the cockpit fuel mixture control was pulled out about 1 inch, the engine would develop 2,700 rpm (full power) when the throttle was advanced. The examination of the engine revealed that the lean mixture stop pin in the fuel metering unit was loose and could be removed by hand. Wear was observed on the inside of the fuel mixture actuating arm and on the mixture stop on the rotating shaft. The fuel metering unit's rich mixture stop pin was missing, which allowed the actuating arm to travel past the full-rich mixture position. A bench test of the fuel mixture control demonstrated that extension past the rich mixture stop pin reduced the fuel flow to the engine. This condition indicates that the airplane's fuel mixture control was misrigged, which resulted in the rich mixture stop pin dislodging from the fuel metering unit. It could not be determined when the fuel mixture control was misrigged. ## Factual narrative On March 18, 2014, about 1020 central daylight time, a Beech P35 airplane, N5932Y, sustained substantial damage after a loss of engine power while landing at the Kickapoo Downtown Airport (CWC), Wichita Falls, Texas. The pilot received minor injuries and the instructor pilot was not injured. The airplane was registered to and operated by a private individual under the provisions of the 14 Code of Federal Regulations Part 91 as an instructional flight. Visual meteorological conditions prevailed for the flight, which was not on a flight plan. The flight originated from CWC about 0930. The pilot reported that he had turned from the downwind leg to the base leg and was preparing for a short-field landing on runway 17 (4,450 feet by 75 feet, asphalt). He had reduced the throttle during the turn to base leg, but when he applied throttle to increase the power, the engine did not respond. The airplane's altitude was about 600 feet above ground level, and the pilot executed a forced landing to a field containing mesquite bushes. The airplane sustained leading edge damage to both wings during landing. The on-site examination of the airplane by Federal Aviation Administration inspectors revealed that the airplane had 50 gallons of fuel on board. No damage to the engine was observed. The airplane wreckage was transported to an aircraft storage facility for further examination and an engine run. The Beech P35 Bonanza, serial number D-7017, was manufactured in 1962. The engine was a 260-horsepower Continental IO-470-LCN, manufactured in 1981. The last annual maintenance inspection was conducted on January 1, 2014, with at total aircraft time of 5,896 hours. At the time of the accident, the engine had 4,210 total hours with 326 hours since the last major overhaul. The airplane had flown 21 hours since the annual maintenance inspection. On May 28, 2014, an engine run was conducted. The bent propeller was removed from the engine and replaced with a stock propeller. A 5 gallon fuel container was connected to the left side of the fuel selector. No other work was performed and the engine was run on the airframe. The engine was started and allowed to warm up. The throttle was then advanced to 1,700 rpm and a magneto check was performed. Each magneto had a 75 rpm drop during the magneto check. The throttle was then advanced to full throttle with the mixture full rich. When the throttle was advanced over 2,000 rpm, the engine would begin to lose power. During the first engine run, an attempt was made to shut down the engine, but the cockpit mixture control was stuck in the full rich position. The actuating arm on the fuel metering unit was over center and had to be moved by hand to the lean position. The rich mixture stop pin on the fuel metering unit was missing, allowing the mixture actuating arm to travel past the full rich mixture position and over center. The engine was run a second time with the mixture control in the cockpit pulled out about one inch. Thethrottle was advanced and the engine then ran at 2,700 rpm (full power). The engine was then shut down using the cockpit mixture control. The fuel metering unit was removed and examined. The rich mixture stop pin was missing from the fuel metering unit and could not be located. The lean mixture stop pin was loose in the fixture and could be removed by hand. Wear was observed on the inside of the fuel mixture actuating arm and on the mixture stop on the rotating shaft. The fuel screen was clean and clear. The fuel metering unit was sent to Continental Motors, Inc for further testing. On September 9, 2014, the fuel metering unit was reassembled, examined and tested at Continental Motors, Inc. The examination revealed that the rich mixture stop pin was missing and had signatures of wear in the pin socket. The fuel metering unit was flow tested and it functioned properly through its full range of operation, although some leakage was observed. Upon completion of the production test, the mixture control was extended past the stop pin limits in one-half stop pin diameter increments. The first extension reduced fuel flow from 124.9 pounds per hour (pph) to 113.4 pph. The next extension reduced flow from 133.9 to 88.9 pph. The amount of over extension the aircraft mixture control cable produced is unknown. The test demonstrated that the extension past the rich mixture stop pin reduced the fuel flow to the engine. ## Aircraft - Registration: [N9532Y](https://openairdocs.org/deregistered/N9532Y-2015-04-30), registration cancelled 2015-04-30, S/N D-7017, built 1962 (OpenAirDocs) - Reported make and model: BEECH P35 - Registry model: [Beech P35](https://openairdocs.org/model/beech-p35) (registry code 1151530) (OpenAirDocs) - Registry engine: [Continental I0-470 series](https://openairdocs.org/engine/continental-i0-470-series) (registry code 17027, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: D-7017 - Year built: 1962 - Airframe hours: 5896 - Engines: Continental IO-470 260 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Beavers Glenn A - Registered owner: Beavers Glenn A - Airworthiness certificate: Standard, Normal - Last inspection: Annual, January 1, 2014 - Departed: CWC, Wichita Falls, TX - Destination: CWC, Wichita Falls, TX - Airport: CWC, Kickapoo Downtown Airport, runway 17, 4,450 × 75 ft, concrete ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 79; injuries: minor; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; seat: left; flight hours: 12,813 total, 2,000 in this make and model, 32 in the last 90 days, 13 in the last 30 days, 1 in the last 24 hours - Flight instructor; age 67; injuries: none; airline transport, flight instructor; last flight review May 1, 2013; seat: right; restraint: 4-point; flight hours: 8,500 total, 60 in this make and model, 30 in the last 90 days, 20 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 220° at 19 knots, gusting 24 - Visibility: 10 statute miles - Lowest ceiling: 25,000 ft broken - Temperature: 61 °F, dew point 28 °F - Altimeter: 29.48 inHg - Observed at: SPS, 8 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 20140318003109A](https://openairdocs.org/incident/20140318003109A), Mar 18, 2014: Beech P35, Wichita Falls, TX, Substantial damage. On March 18, 2014, at 1020 local, a Beech BE-35-P35 aircraft bearing registration number N9532Y, registered to the pilot, lost power on short approach and… ## Other investigations on N9532Y (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 UNK65X1169](https://openairdocs.org/ntsb/UNK65X1169), Dec 28, 1964: Beechraft P35 (N9532Y), Allegan, MI, substantial damage ## Docket (16 files) The files NTSB released with the investigation on November 10, 2014, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=88939. 11.8 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 2.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418718&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Maintenance Records (item 2, .PDF, 5.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418719&FileExtension=.PDF&FileName=Maintenance%20Records-Redacted.PDF - Air Salvage of Dallas (ASOD) Engine Run Results (item 3, .PDF, 934 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418720&FileExtension=.PDF&FileName=Air%20Salvage%20of%20Dallas%20(ASOD)%20Engine%20Run%20Results-Master.PDF - Party Form (item 4, .PDF, 75 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418733&FileExtension=.PDF&FileName=Party%20Form-Redacted.PDF - Wreckage Release (item 5, .PDF, 213 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418721&FileExtension=.PDF&FileName=Wreckage%20Release-Redacted.PDF - Photo 1 - Wreckage in Hangar (item 6, .PDF, 175 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418722&FileExtension=.PDF&FileName=Photo%201%20-%20Wreckage%20in%20Hangar-Master.PDF - Photo 2 - Engine Run at ASOD (item 7, .PDF, 187 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418723&FileExtension=.PDF&FileName=Photo%202%20-%20Engine%20Run%20at%20ASOD-Master.PDF - Photo 3 - Sparkplugs (item 8, .PDF, 199 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418724&FileExtension=.PDF&FileName=Photo%203%20-%20Sparkplugs-Master.PDF - Photo 4 - Fuel Metering Unit (item 9, .PDF, 183 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418725&FileExtension=.PDF&FileName=Photo%204%20-%20Fuel%20Metering%20Unit-Master.PDF - Photo 5 - Actuating Arm Over Center (item 10, .PDF, 332 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418726&FileExtension=.PDF&FileName=Photo%205%20-%20Actuating%20Arm%20Over%20Center-Master.PDF - Photo 6 - Actuating Arm Over Center (item 11, .PDF, 355 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418727&FileExtension=.PDF&FileName=Photo%206%20-%20Actuating%20Arm%20Over%20Center-Master.PDF - Photo 7 - Fuel Metering Unit (item 12, .PDF, 324 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418728&FileExtension=.PDF&FileName=Photo%207%20-%20Fuel%20Metering%20Unit-Master.PDF - Photo 8 - Rich Mixture Stop Missing (item 13, .PDF, 250 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418729&FileExtension=.PDF&FileName=Photo%208%20-%20Rich%20Mixture%20Stop%20Missing-Master.PDF - Photo 9 - Actuator Arm (item 14, .PDF, 229 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418730&FileExtension=.PDF&FileName=Photo%209%20-%20Actuator%20Arm-Master.PDF - Photo 10 - Fuel Metering Unit With Wear (item 15, .PDF, 223 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418731&FileExtension=.PDF&FileName=Photo%2010%20-%20Fuel%20Metering%20Unit%20With%20Wear-Master.PDF - Photo 11 - Fuel Metering Unit Test at Continental (item 16, .PDF, 238 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418732&FileExtension=.PDF&FileName=Photo%2011%20-%20Fuel%20Metering%20Unit%20Test%20at%20Continental-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.