# NTSB CEN20LA055: Aero Commander 100, N5573M, Mullin, TX, January 4, 2020 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: January 4, 2020, 16:00 local (22:00 UTC) - Place: Mullin, TX - Coordinates: 31.650278, -98.654167 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=31.6503&lon=-98.6542&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: FAA San Antonio FSDO - NTSB case key (mKey): 100769 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN20LA055 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/100769/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=100769 - Page: https://openairdocs.org/ntsb/CEN20LA055 ## Probable cause A total loss of engine power for reasons that could not be determined based on the available information. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating)](https://openairdocs.org/ntsb-findings/01058500): Aircraft › Aircraft power plant · Unknown/Not determined (probable cause); cases with it: [Aero Commander 100, 1 case](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=0140202), [All aircraft, 497 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md) - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Aero Commander 100, 3 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=0140202), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach: Unknown or undetermined](https://openairdocs.org/ntsb-events/000); cases with it: [Aero Commander 100, 2 cases](https://openairdocs.org/ntsb-events/000/sequence.md?model=0140202), [All aircraft, 1,703 cases](https://openairdocs.org/ntsb-events/000/sequence.md) - [Approach: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Aero Commander 100, 1 case](https://openairdocs.org/ntsb-events/341/sequence.md?model=0140202), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Approach: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Aero Commander 100, 4 cases](https://openairdocs.org/ntsb-events/060/sequence.md?model=0140202), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md) - [Approach: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Aero Commander 100, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=0140202), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Approach: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490); cases with it: [Aero Commander 100, 1 case](https://openairdocs.org/ntsb-events/490/sequence.md?model=0140202), [All aircraft, 1,309 cases](https://openairdocs.org/ntsb-events/490/sequence.md) ## Analysis The flight instructor and student pilot were conducting a cross-country flight. During a gradual descent to the destination airstrip, the engine lost total power, and the airplane sustained substantial damage during the subsequent forced landing. The airplane was recovered from the accident site and an engine examination and test run revealed no anomalies. Examination of the fuel selector revealed that either the fuel selector handle or the pointer was installed 180° out of position. When the selector handle was selected to BOTH, the valve was completely closed, in what should have been the OFF position. When the selector handle was selected to OFF, the valve was open, in what should have been the BOTH position. The temperature and dewpoint for the accident time and accident site were not conducive to the formation of carburetor icing. It is possible that if the fuel selector was manipulated to the BOTH position during the flight, the fuel may have been prevented from reaching the engine due to the incorrect installation of the selector handle. However, the examination could not determine whether it was the selector handle or the pointer that was installed incorrectly. Based on the available evidence, the reason for the total loss of engine power could not be determined. ## Factual narrative On January 4, 2020, about 1600 central standard time, an Aero Commander 100 airplane, N5573M, sustained substantial damage when it was involved in an accident near Mullin, Texas. The student pilot and flight instructor were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The flight instructor reported that he and the student departed on the 75-nautical-mile flight with 40 gallons of fuel onboard. About 3 miles from the destination airstrip, they initiated a slow descent to a private airstrip. The student completed the Descent and the Before Landing checklist. About 3,000 ft above mean sea level, the engine lost total power. The instructor immediately took control of the airplane and ensured that the fuel selector switch was selected for both fuel tanks, the carburetor heat was applied, and the mixture control was at the full-rich position. He trimmed the airplane for its best glide speed and the student completed a mayday call. The instructor switched fuel tanks; however, the engine did not respond, and the propeller was “wind milling.” The instructor performed a forced landing to a flat, plowed dirt field, during which the right wingtip impacted a tree and the airplane nosed over. The airplane sustained substantial damage to the fuselage, both wings, and the empennage. The fuel system was breached during the accident and the exact amount of fuel onboard at the time of the loss of engine power could not be determined. The airplane was recovered from the accident site and an engine run was performed. The engine successfully ran for several minutes at various power settings when a fuel source was plumbed to the engine. No mechanical anomalies were found during the engine run. Examination of the fuel selector revealed that either the fuel selector handle or the pointer was installed 180° out of position. When the selector handle was selected to BOTH, the valve was completely closed, in what should have been the OFF position. When the selector handle was selected to OFF, the valve was open, in what should have been the BOTH position. The hole on the end of the pointer that slid over the shaft featured a round side and a flat side, which helps to correctly orient the pointer during installation. The hole was sufficiently worn that the pointer would fit over the shaft in both directions. The examination could not determine if the selector handle or the pointer was installed incorrectly. The temperature and dewpoint for the accident time and accident site were not conducive to the formation of carburetor icing. ## Aircraft - Registration: [N5573M](https://openairdocs.org/deregistered/N5573M-2022-12-31), registration cancelled 2022-12-31, S/N 107, built 1967 (OpenAirDocs) - Reported make and model: Aero Commander 100 (UNDESIGNAT) - Registry model: [Aero Commander 100](https://openairdocs.org/model/aero-commander-100) (registry code 0140202) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 107 - Year built: 1967 - Airframe hours: 2335.38 - Engines: Lycoming Engines O-320-A2B 150 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, June 28, 2019 - Departed: ABI, Abilene, TX - Destination: Mullin, TX - Airport: Private Airstrip - Equipment: Stall warning system, Handheld GPS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 33; injuries: none; commercial, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review April 22, 2019; seat: right; restraint: lap only; flight hours: 1,756 total, 10 in this make and model, 1,659 as pilot in command, 25 in the last 90 days, 10 in the last 30 days - Student pilot; age 42; injuries: none; student; medical: class 3, with waivers/limitations; seat: left; restraint: lap only; flight hours: 77.1 total, 57.9 in this make and model, 70.5 as pilot in command, 39.5 in the last 90 days, 18.7 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 260° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 68 °F, dew point 30 °F - Altimeter: 30.28 inHg - Observed at: KMKN, 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 20200104000859A](https://openairdocs.org/incident/20200104000859A), Jan 4, 2020: Aero Commander 100, Mullin, TX, Substantial damage. Pilot and student departed abilene regional airport in abilene, Texas. The purpose of the flight was for student to satisfy solo tower controlled airport… ## Docket (6 files) The files NTSB released with the investigation on September 23, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=100769. 23.1 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 11.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11575476&FileExtension=pdf&FileName=NTSB%20Form%206120_1%20Redacted-Rel.pdf - Accident photographs (item 2, PDF, 6 pages, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11575486&FileExtension=pdf&FileName=Accident%20Photographs-Rel.pdf - Airplane and maintenance documents (item 3, PDF, 5 pages, 9.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11575410&FileExtension=pdf&FileName=N5573M%20Airplane%20Documents%20Redacted-Rel.pdf - NTSB engine run report (item 4, PDF, 1 page, 80 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11574901&FileExtension=pdf&FileName=CEN20LA005%20NTSB%20Engine%20Run%20Report-Rel.pdf - NTSB airframe examination report (item 5, PDF, 4 pages, 671 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11645960&FileExtension=pdf&FileName=CEN20LA005%20NTSB%20Airframe%20Examination%20Report-Rel.pdf - FAA carburetor icing probability graph (item 6, PDF, 1 page, 335 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11575561&FileExtension=pdf&FileName=Carburetor%20Icing%20Probability%20Graph-Rel.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.