# NTSB CEN20CA033: Piper PA18, N530AK, Kerrville, TX, November 23, 2019 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: November 23, 2019, 11:00 local (17:00 UTC) - Place: Kerrville, TX - Coordinates: 29.830627, -95.28936 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=29.8306&lon=-95.2894&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Loss of control in flight](https://openairdocs.org/ntsb-events/240) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report June 16, 2020 - Report: Approved by Office Director - NTSB office: Central Region - NTSB case key (mKey): 100676 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN20CA033 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/100676/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=100676 - Page: https://openairdocs.org/ntsb/CEN20CA033 ## Probable cause The pilot’s loss of airplane control during the landing flare, which resulted in a loss of directional control and ground-loop. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Piper PA-18-150, 160 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=7101828), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Performance/control parameters](https://openairdocs.org/ntsb-findings/01062000): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Piper PA-18-150, 14 cases](https://openairdocs.org/ntsb-findings/01062000/cases.md?model=7101828), [All aircraft, 1,269 cases](https://openairdocs.org/ntsb-findings/01062000/cases.md) - [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Piper PA-18-150, 98 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=7101828), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Piper PA-18-150, 41 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=7101828), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Landing-flare/touchdown: Abnormal runway contact](https://openairdocs.org/ntsb-events/090); cases with it: [Piper PA-18-150, 15 cases](https://openairdocs.org/ntsb-events/090/sequence.md?model=7101828), [All aircraft, 1,506 cases](https://openairdocs.org/ntsb-events/090/sequence.md) - [Landing-flare/touchdown: Loss of control on ground](https://openairdocs.org/ntsb-events/230); cases with it: [Piper PA-18-150, 109 cases](https://openairdocs.org/ntsb-events/230/sequence.md?model=7101828), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) - [Landing-landing roll: Aircraft structural failure](https://openairdocs.org/ntsb-events/337); cases with it: [Piper PA-18-150, 1 case](https://openairdocs.org/ntsb-events/337/sequence.md?model=7101828), [All aircraft, 290 cases](https://openairdocs.org/ntsb-events/337/sequence.md) ## Analysis The pilot reported that, based on the wind reported by the destination airport's AWOS, he decided to conduct a conventional, full-stall, three-point landing. He said the approach was normal and stabilized. When the airplane was about 1 ft above the runway, a wind gust pushed the airplane left. The left main landing gear contacted the runway, and the airplane drifted right. The left shock absorber broke, and the airplane swerved right. The tailwheel unlocked, and the airplane ground looped, which resulted in substantial damage to the left wing. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. ## Factual narrative . The private pilot was on a cross-country flight with one passenger. He stated that based on the wind reported by his destination airport's Automated Weather Observing System (AWOS), he decided to make a conventional, full-stall, 3-point landing. He said he crossed mid-field and entered a left downwind for runway 30. The turn to base and final were normal. When the airplane was about a foot off the runway at stall speed, "an unexpected" wind gust pushed the airplane to the left. The left main landing gear contacted the runway, and the airplane drifted to the right. The left shock absorber broke, and the airplane swerved to the right. The tailwheel unlocked and the airplane ground looped. Damage included a bent left wing and left main landing gear. The pilot did not indicate the wind direction but said it was at 7 knots. AWOS reported that the wind was calm. The pilot did not indicate that there were any mechanical anomalies with the airplane prior to the accident. He noted that the destination airport "has a reputation for gusty wind conditions . . . the gust caught me in a landing configuration where I was unable to maintain directional control at touchdown." The pilot stated that once the tailwheel turns about 15 to 20 degrees, it unlocks automatically and the tailwheel swivels. When the airplane began its turn and reached the point where the tailwheel unlocked, there is no tailwheel steering. ## Aircraft - Registration: [N530AK](https://openairdocs.org/aircraft/N530AK), registered now, S/N 18-4385, built 1956 (OpenAirDocs) - Reported make and model: PIPER PA18 - Registry model: [Piper PA-18-150](https://openairdocs.org/model/piper-pa-18-150) (registry code 7101828) (OpenAirDocs) - Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs) - Category: Airplane - Serial number: 18-4385 - Year built: 1956 - Airframe hours: 4017 - Engines: Lycoming O-360 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, May 30, 2019 - Departed: CXO, Conroe, TX - Destination: ERV, Kerrville, TX - Airport: ERV, Kerrville Municipal, runway 30, 6,004 × 100 ft, asphalt - Equipment: Handheld GPS, Onboard weather, ADS-B, Electronic flight bag or handheld device, Electronic multifunction display, Electronic primary flight display ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 62; injuries: none; private; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review March 24, 2019; seat: front; restraint: 4-point; flight hours: 2,160 total, 53 in this make and model, 1,750 as pilot in command, 108 in the last 90 days, 75 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 7 knots - Visibility: 10 statute miles - Temperature: 64 °F, dew point 39 °F - Altimeter: 30.27 inHg - Observed at: ERV ## Other investigations on N530AK (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 GAA19CA298](https://openairdocs.org/ntsb/GAA19CA298), May 31, 2019: Piper PA18 (N530AK), Sparta, IL, substantial damage. Probable cause: The pilot's failure to maintain directional control during the landing roll, which resulted in a ground-loop. ## Docket (3 files) The files NTSB released with the investigation on February 26, 2020, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=100676. 994 KB in all. - NTSB Form 6120.1-2, Pilot-Operator Aircraft Accident Report (item 1, .PDF, 548 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40480772&FileExtension=.PDF&FileName=NTSB%20Form%206120.1-2,%20Pilot-Operator%20Aircraft%20Accident%20Report-Master.PDF - E-Mail from Pilot (item 2, .PDF, 114 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40480773&FileExtension=.PDF&FileName=E-Mail%20from%20Pilot-Master.PDF - Report Photos (item 3, .PDF, 332 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40480774&FileExtension=.PDF&FileName=Report%20Photos-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.