# NTSB WPR16LA017: Luscombe 8A, N25100, Prescott, AZ, October 24, 2015 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: October 24, 2015, 15:10 local (22:10 UTC) - Place: Prescott, AZ - Coordinates: 34.654724, -112.419166 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=34.6547&lon=-112.4192&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Runway excursion](https://openairdocs.org/ntsb-events/300) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report May 23, 2017 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 92226 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR16LA017 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/92226/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=92226 - Page: https://openairdocs.org/ntsb/WPR16LA017 ## Probable cause The pilot's failure to maintain directional control during landing, and his inability to recover due to a malfunction of the tailwheel. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: nose/tail landing gear](https://openairdocs.org/ntsb-findings/01023220): Aircraft › Aircraft systems · Malfunction (probable cause); cases with it: [Luscombe 8A, 2 cases](https://openairdocs.org/ntsb-findings/01023220/cases.md?model=8190104), [All aircraft, 185 cases](https://openairdocs.org/ntsb-findings/01023220/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Luscombe 8A, 39 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=8190104), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing-landing roll: Runway excursion](https://openairdocs.org/ntsb-events/300) (defining event); cases with it: [Luscombe 8A, 18 cases](https://openairdocs.org/ntsb-events/300/sequence.md?model=8190104), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) ## Analysis The commercial pilot of the tailwheel-equipped airplane stated that, upon touching down in a three-point attitude, the airplane veered left. The pilot attempted to correct with rudder, but the airplane continued left and ground looped. Examination revealed that the tailwheel had rotated 180°, leaving its control chains crossed over one another. Under this condition, the tailwheel direction of movement would be opposite that commanded by the pilot. Further examination revealed that the tailwheel steering arms were bent upward, allowing the wheel to rotate past its travel stops and into the reversed condition. It is likely that, as the pilot initially lost control and the airplane began to ground loop, the wheel passed beyond its travel limits, causing the controls to become reversed, which made recovery unlikely. ## Factual narrative On October 24, 2015, about 1510 mountain standard time, a Luscombe 8A, N25100, experienced a loss of directional control during the landing roll, and ground looped at the Ernest A. Love Field Airport, Prescott, Arizona. The pilot, who owned the airplane, was operating the airplane under the provisions of 14 Code of Federal Regulations Part 91. The certified flight instructor and his passenger were not injured; the airplane sustained substantial damage. The personal cross-country flight departed from Gallup Municipal Airport, Gallup, New Mexico, about 1245 with a planned destination of Prescott. Visual meteorological conditions prevailed and a company flight plan had been filed.In a written report, the pilot stated that as he entered the vicinity of the destination airport, he maneuvered the airplane for a straight-in approach to runway 21L. The approach was slightly higher than his normal glide slope, and the pilot configured the airplane into a left slip in an effort to lose altitude. After becoming established, he maintained a left crab angle to compensate for an approximate 7 kt left crosswind. He configured the airplane for a three-point landing and touched down on the centerline. The airplane continued the landing roll until decelerating to about 15 mph at which point it began to veer to the left. The pilot input full rudder control to try to counteract the veer, but despite his attempts, the airplane ground looped. During the accident sequence, the airplane incurred substantial damage to the wing. The pilot opined that the loss of control was precipitated by a tail wheel malfunction. According to Federal Aviation Administration (FAA) records, the pilot purchased the airplane on the day of the accident; he reported having amassed about 200 hours of flight time in the same make and model. The Luscombe 8A was equipped with a Scott 3-24B tailwheel (now Scott 2000), with a steerable six-inch rubber tire with full-swivel capability. The rudder control horns were connected via chains to the assembly, which uses spring pressure to hold a set of steering arms into machined flats on the wheel fork. As the wheel pivots to its travel limit, it comes into contact with a stop on the fork bracket, which releases the assembly, allowing the wheel to castor freely. According to the Scott 3-24B Handbook, "The tail wheel assemblies provide directional control throughout full rudder travel of the aircraft while the tailwheel is in contact with the ground. The assemblies will automatically full-swivel only well after the maximum point of air rudder control is reached in either direction…The tailwheel steering and release mechanism is so designed that 65-degrees of tailwheel turn (or travel) is provided either right or left from neutral steering position before the mechanism begins to release." The airplane came to rest on the edge of the runway with the right landing gear collapsed and folded under the fuselage. The tailwheel steering chains remained affixed totheir respective rudder horns as well as their respective steering arms mounted on the tailwheel body. However, the tailwheel had rotated over 180-degrees and was canted to the left leaving the chains crossed over one another. Additionally, the steering arms appeared bent upwards. A complete report with accompanying photographs are attached to the public docket for this accident. An FAA certified airframe and powerplant mechanic examined the tailwheel. He stated the examination revealed that the tailwheel was turned around 180-degrees from its normal configuration. The right steering arm was bent upwards, and he observed that it was able to clear over the stop, allowing the steering head to continue to the reversed position, rather than unlock to caster freely. Under this condition, the tailwheel direction of movement would be opposite that commanded by the pilot, rather than free-castering as designed. He additionally noted that the leaf spring assembly was loose, allowing a possible shudder to develop. Following the examination, he repaired the assembly, and the steering arms were reconfigured to their correct straight position, enabling them to contact the stops and release the wheel to freely caster with the steering chains remaining on their respective side. ## Aircraft - Registration: [N25100](https://openairdocs.org/aircraft/N25100), registered now, S/N 1024, built 1939 (OpenAirDocs) - Reported make and model: LUSCOMBE 8A (A) - Registry model: [Luscombe 8A](https://openairdocs.org/model/luscombe-8a) (registry code 8190104) (OpenAirDocs) - Registry engine: [Continental A&C65 series](https://openairdocs.org/engine/continental-a-c65-series) (registry code 17003, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 1024 - Year built: 1939 - Engines: Continental C85-12F 85 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Special light-sport (Special); Standard, Normal - Last inspection: Annual, November 4, 2014, 10 hours before - Departed: KGUP, Gallup, NM - Destination: KPRC, Prescott, AZ - Flight plan: Company VFR - Airport: KPRC, Ernest A Love Field Airport, runway 21L, 7,619 × 150 ft, asphalt - Equipment: Handheld GPS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 72; injuries: none; commercial, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; last flight review October 16, 2015; seat: left; restraint: lap only; flight hours: 11,000 total, 200 in this make and model, 10,800 as pilot in command, 11.8 in the last 90 days, 11.8 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: variable at 4 knots - Lowest ceiling: none - Temperature: 72 °F, dew point 34 °F - Altimeter: 30.12 inHg - Observed at: KPRC ## 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 20151024022649A](https://openairdocs.org/incident/20151024022649A), Oct 24, 2015: Luscombe 8A, Prescott, AZ, Substantial damage. The pilot had just earlier purchased N25100 and was operating it as a sport aircraft. Pilot states that the landing on runway 21L at prc was normal and during… ## Other investigations on N25100 (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 GAA19CA568](https://openairdocs.org/ntsb/GAA19CA568), Aug 30, 2019: Luscombe 8 (N25100), Prescott, AZ, substantial damage. Probable cause: The pilot's loss of directional control and subsequent overapplication of rudder pedal, which resulted in a runway excursion and the right wing striking the ground. ## Docket (3 files) The files NTSB released with the investigation on April 5, 2017, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=92226. 2.7 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40450740&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Tailwheel Examination Notes (item 2, .PDF, 9 photos, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40450741&FileExtension=.PDF&FileName=Tailwheel%20Examination%20Notes-Master.PDF - Video of Tailwheel Function (item 3, .PDF, 164 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40450742&FileExtension=.PDF&FileName=Video%20of%20Tailwheel%20Function-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.