# NTSB CEN11LA361: Flournoy Martin R Flournoy MR S1S, N457CF, Colorado Springs, CO, May 22, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 22, 2011, 16:30 local (22:30 UTC) - Place: Colorado Springs, CO - Coordinates: 38.940555, -104.568611 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.9406&lon=-104.5686&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Landing gear collapse](https://openairdocs.org/ntsb-events/094) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report November 17, 2011 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA/FSDO - NTSB case key (mKey): 79252 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN11LA361 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/79252/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=79252 - Page: https://openairdocs.org/ntsb/CEN11LA361 ## Probable cause The pilot’s loss of directional control during the landing rollout due to failure of the tailwheel assembly for undetermined reasons. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: nose/tail gear attach section](https://openairdocs.org/ntsb-findings/01023221): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Flournoy Martin R FLOURNOY MR S1S, 1 case](https://openairdocs.org/ntsb-findings/01023221/cases.md?model=05610EG), [All aircraft, 29 cases](https://openairdocs.org/ntsb-findings/01023221/cases.md) - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Flournoy Martin R FLOURNOY MR S1S, 1 case](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=05610EG), [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. - [Landing-landing roll: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [Flournoy Martin R FLOURNOY MR S1S, 1 case](https://openairdocs.org/ntsb-events/094/sequence.md?model=05610EG), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) - [Landing-landing roll: Loss of control on ground](https://openairdocs.org/ntsb-events/230); cases with it: [Flournoy Martin R FLOURNOY MR S1S, 1 case](https://openairdocs.org/ntsb-events/230/sequence.md?model=05610EG), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) ## Analysis The pilot reported that he made a normal touchdown, but during the rollout the airplane began to yaw to the left. He attempted to correct his loss of directional control by applying full right rudder and right brake. Despite his efforts to straighten the airplane's path, the airplane began to bounce/skip to the side and subsequently ground looped. During the impact sequence, the lower right wing tip, aileron and aft section of the fuselage sustained substantial damage. Postaccident examination of the airplane revealed that the tailwheel spring attach bolt had pulled through the fuselage structure where it was mounted. The bolt was intact and there was no obvious damage to the threads. It could not be determined why the bolt separated prior to the accident. ## Factual narrative On May 22, 2011, at 1630 mountain daylight time, N457CF, an experimental Flournoy MR S1S airplane, ground-looped during landing on Runway 15 at Meadowlake Airport (KFLY), Colorado Springs, Colorado. The airplane was registered to and operated by the commercial rated pilot, who was not injured. Visual meteorological conditions prevailed and no flight plan was filed for the local flight conducted under 14 CFR Part 91. According to the pilot, after a normal touchdown, he felt the tail drop about 6-inches followed by a loud grinding noise. As the airplane began to decelerate, it began to yaw to the left. The pilot applied full right rudder and right brake, but was unable to stop the yaw to the left. The airplane continued to rotate to the left and began to bounce/skip to the side and roll. The lower right wing struck the ground and the engine came to an abrupt stop. The pilot reported that the right main landing gear strut, entire brake assembly, wheel, tire, and wheel pant were damaged. The lower right wing tip and aileron sustained substantial damage from impacting the ground. The tailwheel separated from the airplane and there was substantial damage to the rudder and aft section of the fuselage. The propeller was also damaged. An inspector with the Federal Aviation Administration (FAA) performed an examination of the airplane and discovered that the tailwheel spring attach bolt had pulled through the fuselage structure where it was mounted. The bolt was intact and there was no obvious damage to the threads. It could not be determined as to why the bolt separated. Weather at Meadowlake airport at 1630 was reported as clear skies, visibility 10 miles, and wind from 100 degrees at 5 knots. ## Aircraft - Registration: [N457CF](https://openairdocs.org/aircraft/N457CF), registered now, S/N 08 (OpenAirDocs) - Reported make and model: FLOURNOY MARTIN R FLOURNOY MR S1S - Registry model: [Flournoy Martin R FLOURNOY MR S1S](https://openairdocs.org/model/flournoy-martin-r-flournoy-mr-s1s) (registry code 05610EG) (OpenAirDocs) - Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 08 - Airframe hours: 808 - Engines: LYCOMING O&VO-360 SER 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Matt Tanner Aviation LLC - Registered owner: Matt Tanner Aviation LLC - Airworthiness certificate: Special, Experimental (Special); Standard, Normal - Last inspection: Condition, October 1, 2010 - Departed: KFLY, Colorado Springs, CO - Destination: KFLY, Colorado Springs, CO - Airport: KFLY, Meadow Lake, runway 15, 6,000 × 60 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 31; injuries: none; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, without waivers/limitations; last flight review February 1, 2011; seat: single; flight hours: 3,600 total, 370 in this make and model, 3,500 as pilot in command, 150 in the last 90 days, 60 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 100° at 5 knots - Visibility: 10 statute miles - Temperature: 70 °F, dew point 39 °F - Altimeter: 29.97 inHg - Observed at: KFLY ## 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 20110522008749A](https://openairdocs.org/incident/20110522008749A), May 22, 2011: Flournoy Martin R FLOURNOY MR S1S, Peyton, CO, Substantial damage. On may 22, 2011 at approximately 1630 mountain daylight time, a single engine pitts S1S, N457CF, was substantially damaged following the loss of the tail wheel… ## Docket (2 files) The files NTSB released with the investigation on October 3, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=79252. 324 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 257 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40354464&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Record of Conversation with FAA (item 2, .PDF, 67 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40354465&FileExtension=.PDF&FileName=Record%20of%20Conversation%20with%20FAA-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.