# NTSB CEN12LA087: Aviat A-1B, N252U, Gainesville, TX, November 23, 2011

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: November 23, 2011, 16:30 local (22:30 UTC)
- Place: Gainesville, TX
- Coordinates: 33.629131, -97.150611 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=33.6291&lon=-97.1506&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Defining event: [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report August 15, 2012
- Report: Approved by Office Director
- NTSB office: Central Region
- Parties: FAA FSDO
- NTSB case key (mKey): 82410
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN12LA087
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/82410/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=82410
- Page: https://openairdocs.org/ntsb/CEN12LA087

## Probable cause

The right main gear tire contacting the brake caliper, which resulted in an uncommanded brake effect on the wheel.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Landing gear system: brake](https://openairdocs.org/ntsb-findings/01023242): Aircraft › Aircraft systems · Malfunction (probable cause); cases with it: [Aviat A-1B, 1 case](https://openairdocs.org/ntsb-findings/01023242/cases.md?model=2210406), [All aircraft, 297 cases](https://openairdocs.org/ntsb-findings/01023242/cases.md)
- [Aircraft capability: braking capability](https://openairdocs.org/ntsb-findings/01061050): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible (probable cause); cases with it: [Aviat A-1B, 2 cases](https://openairdocs.org/ntsb-findings/01061050/cases.md?model=2210406), [All aircraft, 57 cases](https://openairdocs.org/ntsb-findings/01061050/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: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Aviat A-1B, 5 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2210406), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md)
- [Landing-landing roll: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330); cases with it: [Aviat A-1B, 1 case](https://openairdocs.org/ntsb-events/330/sequence.md?model=2210406), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md)
- [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096) (defining event); cases with it: [Aviat A-1B, 19 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=2210406), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md)

## Analysis

The pilot performed a landing on a remote sandbar in the tailwheel-equipped airplane. The pilot stated that, on landing, the airplane started a slow turn to the right. He added that it appeared the right brake had locked-up and that he tried to correct the turn by adding full left rudder, left aileron, and full aft elevator. The pilot was unable to correct the turn, and the airplane nosed over coming to rest in the inverted position. After the airplane was recovered, it was noted that the airplane’s wheels were free to rotate. A “witness mark” was found on the right tire corresponding to the brake caliper. The airplane was equipped with low pressure, oversized bush wheels. The event is consistent with low tire pressure and/or a side load on the tire, which allowed it to come into contact with the brake caliper. The result of tire/caliper contact would be a dragging or brake effect on the wheel.

## Factual narrative

On November 23, 2011, about 1630 central standard time, an Aviat Aircraft Inc. “Husky” A-1B airplane, N252U, nosed over after landing on a sandbar near Gainesville, Texas. The commercial rated pilot, sole occupant, was not injured. The airplane was substantially damaged during the accident. The aircraft was registered to and operated by C&M Kuhn, LLC under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which operated without a flight plan. The flight departed KT31, McKinney, Texas at 1430. The pilot reported, during a landing on a sandbar that the airplane began a slow turn to the right. He added that it appeared that the right brake locked-up and he tried to correct the right turn by adding full left rudder, left aileron, and full aft elevator. However, the airplane nosed over and came to rest on its back. The airplane sustained substantial damage to the vertical stabilizer, wings, and wing strut. The airplane was lifted from the sandbar by helicopter, to nearby airfield. The airplane remained on its back while the recovery crew disassembled the airplane for transport. The crew noted that the main landing gear wheels were free to rotate. Once the airplane was at the salvage yard, a mechanic inspected the airplane. The airplane was equipped with oversized Alaskan Bush wheels, under Supplemental Type Certificate (STC) SA01015SE. The mechanic also noted that there was a circular, “witness mark” on the right tire that corresponded to the brake caliper. The mechanic stated that with low tire pressure and a side load, the tire could come in contact with the brake caliper.

## Aircraft

- Registration: [N252U](https://openairdocs.org/aircraft/N252U), registered now, S/N 2143, built 2001 (OpenAirDocs)
- Reported make and model: AVIAT AIRCRAFT INC A-1B
- Registry model: [Aviat A-1B](https://openairdocs.org/model/aviat-a-1b) (registry code 2210406) (OpenAirDocs)
- Registry engine: [Lycoming 0-360-A1D](https://openairdocs.org/engine/lycoming-0-360-a1d) (registry code 41504, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 2143
- Airframe hours: 633
- Engines: LYCOMING O-360-A1D 180 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: C & M Kuhn LLC
- Registered owner: C & M Kuhn LLC
- Last inspection: Annual, August 1, 2011
- Departed: T31, McKinney, TX
- Destination: KADS, Addison, TX

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 26; injuries: none; private, flight instructor, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review April 1, 2011; seat: front; flight hours: 2,400 total, 500 in this make and model, 2,250 as pilot in command, 105 in the last 90 days, 30 in the last 30 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 130° at 3 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 59 °F, dew point 46 °F
- Altimeter: 30.26 inHg
- Observed at: KGLE, 12 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 20111123027839A](https://openairdocs.org/incident/20111123027839A), Nov 23, 2011: Aviat Aircraft Inc A-1B, Marietta, OK, Substantial damage. Pilot stated he was attempting to land on a sand bar beside the red river. During the roll out, the right brake was locked and as the aircraft slowed it…

## Docket (6 files)

The files NTSB released with the investigation on June 28, 2012, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=82410. 8.7 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40370501&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF
- Weather Reports and Records (item 2, .PDF, 378 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40370502&FileExtension=.PDF&FileName=Weather%20Reports%20and%20Records-Master.PDF
- Other Pertinent Forms and Reports (Memo) (item 3, .PDF, 71 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40370970&FileExtension=.PDF&FileName=Other%20Pertinent%20Forms%20and%20Reports%20%20(Memo)-Master.PDF
- Photo 1: Wrecked airplane (non NTSB photo) (item 4, .PDF, 2.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40370963&FileExtension=.PDF&FileName=Photo%201%3A%20Wrecked%20airplane%20%20%20%20%20(non%20NTSB%20photo)-Master.PDF
- Photo 2: Wrecked airplane on sandbar (non NTSB photo) (item 5, .PDF, 2.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40370964&FileExtension=.PDF&FileName=Photo%202%3A%20Wrecked%20airplane%20on%20sandbar%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20(non%20NTSB%20photo)-Master.PDF
- Photo 3: Damaged N252U (non NTSB photo) (item 6, .PDF, 2.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40370966&FileExtension=.PDF&FileName=Photo%203%3A%20Damaged%20N252U%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20(non%20NTSB%20photo)-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.

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