# NTSB CEN23LA170: Luscombe 8F, N1113B, Palmer, TX, April 30, 2023 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: April 30, 2023, 14:50 local (19:50 UTC) - Place: Palmer, TX - Coordinates: 32.478, -96.685422 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=32.4780&lon=-96.6854&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach-VFR pattern final: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: FAA - FSDO - ADs cited in the narratives: [AD 51-10-02](https://openairdocs.org/ad/51-10-02) (OpenAirDocs) - NTSB case key (mKey): 107811 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN23LA170 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/107811/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=107811 - Page: https://openairdocs.org/ntsb/CEN23LA170 ## Probable cause The installation of an unapproved rudder control cable, which resulted in a fatigue failure and subsequent loss of rudder control during cruise flight. Contributing to the accident was the mechanic’s inadequate inspection of the rudder control system. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Flight control system: rudder control system](https://openairdocs.org/ntsb-findings/01022720): Aircraft › Aircraft systems · Fatigue/wear/corrosion (probable cause); cases with it: [Luscombe 8F, 1 case](https://openairdocs.org/ntsb-findings/01022720/cases.md?model=8190114), [All aircraft, 93 cases](https://openairdocs.org/ntsb-findings/01022720/cases.md) - [Flight control system: rudder control system](https://openairdocs.org/ntsb-findings/01022720): Aircraft › Aircraft systems · Incorrect service/maintenance (probable cause); cases with it: [Luscombe 8F, 1 case](https://openairdocs.org/ntsb-findings/01022720/cases.md?model=8190114), [All aircraft, 93 cases](https://openairdocs.org/ntsb-findings/01022720/cases.md) - [Maintenance: scheduled/routine maintenance](https://openairdocs.org/ntsb-findings/02062010): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Luscombe 8F, 1 case](https://openairdocs.org/ntsb-findings/02062010/cases.md?model=8190114), [All aircraft, 320 cases](https://openairdocs.org/ntsb-findings/02062010/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 final: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333) (defining event); cases with it: [Luscombe 8F, 1 case](https://openairdocs.org/ntsb-events/333/sequence.md?model=8190114), [All aircraft, 410 cases](https://openairdocs.org/ntsb-events/333/sequence.md) - [Approach-VFR pattern final: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Luscombe 8F, 2 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=8190114), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing: Landing gear collapse](https://openairdocs.org/ntsb-events/094); cases with it: [Luscombe 8F, 1 case](https://openairdocs.org/ntsb-events/094/sequence.md?model=8190114), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis During the landing approach, the pilot felt the left rudder cable break and subsequently lost rudder control. The pilot placed the airplane into a left-wing-low crab attitude and chose to land in a nearby field. During the landing, the left main landing gear collapsed and the left wing impacted terrain, which resulted in substantial damage. Postaccident examination revealed that the left rudder cable had separated at the pulley under the cabin floor. Examination of the cable revealed that it did not meet the airplane manufacturer’s specifications for the rudder control system, and that the cable displayed evidence of fatigue due to an excessive bending angle at the pulley. Additionally, the rudder assembly was missing an attach link on the left rudder cable return spring between the spring and firewall. The link is used to balance the tension forces on the rudder cables due to the design of the rudder system. The tension forces on the left cable were likely greater than design due to the missing part, which could have increased the risk of fatigue. The mechanic who conducted the most recent annual inspection did not remove the rudder control cables for inspection as required by an airworthiness directive. The mechanic stated that he did not remove the cables due to the time-consuming process and instead actuated the rudder pedals to move the cable and allow inspection around the pulleys and fairleads. It is likely that the degraded condition of the cable would have been discovered during the annual inspection if the mechanic had complied with the AD requirement to remove the cables. Additionally, the mechanic should have identified that the rudder control cable itself did not meet manufacturer specifications, and that the rudder assembly was missing a rudder attach link. Review of the airplane maintenance logbooks did not reveal the origin or installation date of the unapproved cable. ## Factual narrative On April 30, 2023, about 1450 central daylight time, a Luscombe 8F airplane, N1113B, was substantially damaged when it was involved in an accident near Palmer, Texas. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. During an approach to the runway at Dallas South Port Airport (T13), the pilot felt the left rudder cable break and subsequently lost rudder control. The pilot placed the airplane into a left-wing-low crab attitude and choose to land in a nearby field. During the landing, the left main landing gear collapsed and the left wing struck terrain, which resulted in substantial damage to the left wing. Postaccident examination revealed that the left rudder cable separated at the pulley under the cabin floor. The cable was retained and sent to the National Transportation Safety Board Materials Laboratory for analysis, which revealed signatures consistent with severe wear and fatigue. Additionally, the cable had a 1/8-inch 7x7 construction that was not consistent with the original 1/8-inch 7x19 design construction. A review of historical Luscombe manufacturer drawings and current FAA-approved part manufacturer authorization showed that the rudder control system design only incorporated a 1/8-inch 7x19 cable. Examination also revealed a missing rudder attach link on the left rudder cable return spring between the spring and firewall. The link is used to balance the tension forces on the rudder cables due to the design of the rudder system. The left rudder shaft assembly sits aft of the right rudder assembly, and as such, the left rudder return spring requires a spacer attached between the spring and the firewall. The Civil Aeronautics Administration issued Airworthiness Directive (AD) 51-10-02 in 1951 to address reoccurring flight control cable failures in the Luscombe Model 8 fleet. The AD requires that the flight control cables be removed annually from the airplane to the extent necessary to perform the inspection. The AD also references Luscombe Service Bulletin (SB) 1-51, issued in January 1951, regarding fatigue failures of these cables. The mechanic who conducted the last annual inspection stated that he does not remove the cables as required by the AD due to the time-consuming process and instead actuates the rudder pedals to move the cable and allow inspection around the pulleys and fairleads. Review of the airplane maintenance logbooks did not reveal the origin or installation date of the unapproved cable. The airplane owner reported that there was a missing airplane maintenance logbook that recorded maintenance between August 2009 and April 2014. Review of historical manufacturer data also revealed that the installed rudder cable 2-inch pulley under the cabin floor had a cable bending angle of between 27° and 31° from a straight line. The currently available replacement 2-inch pulley, MS24566-3B, has a cable bending angle limitation of 15° for frequently usedaircraft control cables. Additionally, a manufacturer design change was put into production in March 1959 to later serial numbers that increased the size of the pulley to a 3-inch A-120. However, the engineering reasoning behind the design change could not be determined due to a lost engineering order. There was no retroactive SB or AD issued to incorporate the design change on earlier serial numbers. ## Aircraft - Registration: [N1113B](https://openairdocs.org/aircraft/N1113B), registered now, S/N 5740, built 1947 (OpenAirDocs) - Reported make and model: LUSCOMBE 8F - Registry model: [Luscombe 8F](https://openairdocs.org/model/luscombe-8f) (registry code 8190114) (OpenAirDocs) - Registry engine: [Continental C90 series](https://openairdocs.org/engine/continental-c90-series) (registry code 17009, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 5740 - Year built: 1947 - Airframe hours: 3831.3 - Engines: Continental C90-12F 90 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, January 9, 2023 - Departed: 3T0, Gordonville, TX - Destination: T13, Palmer, TX - Equipment: Satellite tracking device, Onboard weather, Electronic flight bag or handheld device, ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 66; injuries: none; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; seat: left; restraint: 4-point; flight hours: 820 total, 573 in this make and model, 820 as pilot in command, 12 in the last 90 days, 10 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 82 °F, dew point 50 °F - Altimeter: 29.89 inHg - Observed at: KJWY, 12 nm away - METAR: KJWY 302000Z AUTO 00000KT 10SM CLR 28/10 A2989 RMK AO2 T02810102 ## 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 20230430018379A](https://openairdocs.org/incident/20230430018379A), Apr 30, 2023: Luscombe 8F, Ferris, TX, Substantial damage. Pilot was practicing touch and goes when shortly after rotation pilot lost rudder control at about 50 feet AGL. Pilot iniatiated an emergency landing in an… ## Other investigations on N1113B (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 DEN90LA117](https://openairdocs.org/ntsb/DEN90LA117), May 26, 1990: Luscombe 8F (N1113B), Morgan, UT, substantial damage. Probable cause: PILOT'S IMPROPER USE OF THE BRAKES DURING LANDING ROLL. ## Docket (10 files) The files NTSB released with the investigation on October 23, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=107811. 15.6 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17167372&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Maintenance records - airframe excerpts (item 2, PDF, 10 pages, 5.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17174831&FileExtension=pdf&FileName=Maintanence%20Logbook%20Excerpts_Redacted-Rel.pdf - Photo array (item 3, PDF, 6 pages, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17166876&FileExtension=pdf&FileName=Photo%20Array-Rel.pdf - Materials laboratory factual report 23-102 (item 4, PDF, 10 pages, 12 photos, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16536582&FileExtension=pdf&FileName=23-102-Rel.pdf - 1947 Luscombe parts manual - rudder system (item 5, PDF, 6 pages, 4.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17168109&FileExtension=pdf&FileName=Luscombe%201947%20Parts%20Manual%20Rudder%20System-Rel.pdf - Examination summary (item 6, PDF, 5 pages, 400 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17167921&FileExtension=pdf&FileName=Examination%20Summary-Rel.pdf - Memorandum for record a�� mechanic (item 7, PDF, 2 pages, 70 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17167749&FileExtension=pdf&FileName=MOR%20-%20Craig%202023%20IA-Rel.pdf - AD 51-10-02 (item 8, PDF, 1 page, 57 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17167392&FileExtension=pdf&FileName=AD%2051-10-02-Rel.pdf - Luscombe sb 1-51 (item 9, PDF, 1 page, 149 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17167539&FileExtension=pdf&FileName=Luscombe_SB1-51-Rel.pdf - Evidence control form - wreckage release (item 10, PDF, 2 pages, 221 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17167856&FileExtension=pdf&FileName=Release%20of%20Bulk%20Wreckage%20Form%20-%20SIGNED%20d.d.%2005-23-2023_Redacted-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.