# NTSB FTW99LA228: Aviat S1-11B, N540DM, Katy, TX, August 14, 1999 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 14, 1999, 18:30 local (23:30 UTC) - Place: Katy, TX - Coordinates: 29.75035, -95.740905 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=29.7504&lon=-95.7409&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report September 12, 2000 - Report: Approved by Office Director - NTSB case key (mKey): 47092 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW99LA228 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/47092/pdf - Page: https://openairdocs.org/ntsb/FTW99LA228 ## Probable cause The pilot's inability to maintain directional control of the tailwheel equipped biplane following the failure of the left brake master cylinder. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, landing - roll - landing gear,normal brake system - failure (cause) - brakes(normal) - not attained, pilot in command - directional control - not possible, pilot in command (cause) - Loss of control - on ground/water, landing - roll ## Analysis The pilot was unable to maintain directional control of the aerobatic biplane during the landing roll due to failure of the brake master cylinder for the left brake. He reported that he had been operating in the designated aerobatic box above the airport for approximately 15 minutes, and while recovering from a hammer head stall, the propeller and engine oversped, and suspecting engine damage, he elected to execute a precautionary landing on runway 27. The airplane touched down about mid-field on the 4,300 foot grass/sod runway. The pilot applied brakes to exit the runway; however, the left brake failed, and the airplane 'made a violent turn to the right.' The tailwheel-equipped airplane nosed over and came to rest in the inverted position. The FAA inspector verified that the master cylinder for the left brake had failed, and braking was not possible. The 1998 model airplane had accumulated a total of 160 hours since new. ## Factual narrative On August 14, 1999, at 1830 central daylight time, an Aviat-Pitts S1-11B biplane, N540DM, was substantially damaged following a loss of control during the landing roll at the Sack-O-Grande Airport near Katy, Texas. The instrument rated commercial pilot, sole occupant of the airplane, was not injured. The airplane was owned and operated by the pilot. Visual meteorological conditions prevailed for the Title 14 CFR Part 91 personal flight for which a flight plan was not filed. The local flight originated approximately 15 minutes prior to the accident. The 1,400-hour pilot reported to the FAA inspector, who traveled to the accident site, that he had been operating in the designated aerobatic box above the airport for approximately 15 minutes. He added that "while recovering from a hammer head stall, the propeller and engine over sped," and suspecting engine damage, he elected to execute a precautionary landing on runway 27. The pilot stated that the airplane touched down about mid-field on the 4,300 foot grass/sod runway. The airplane was decelerating through 40 knots when he applied brakes to exit the runway; however, the left brake failed, and the airplane "made a violent turn to the right." The left wing tip impacted the ground, and the tailwheel-equipped airplane nosed over and came to rest in the inverted position. The pilot was able to exit the biplane without assistance. Examination of the wreckage by the FAA inspector revealed that the rudder and vertical stabilizer were crushed, the fuselage was wrinkled, and the left main landing gear was folded under the fuselage. The inspector verified that the master cylinder for the left brake had failed, and braking was not possible. He added that the 1998 airplane had accumulated a total of 160 hours since new. The pilot reported that an examination of the engine revealed signs that an engine overspeed had occurred, necessitating the replacement of the engine. ## Aircraft - Registration: N540DM (not matched to a registry record) - Reported make and model: Aviat S1-11B - Category: Airplane - Serial number: 4003 - Airframe hours: 160 - Engines: Lycoming AEIO-540 260 horsepower reciprocating - Damage: Substantial damage - Flight: Part 91 - Registered owner: David Z. Mafrige - Airworthiness certificate: Standard, Aerobatic - Last inspection: Annual, January 28, 1999, 35 hours before - Departed: 9X59 - Airport: 9X59, Sack-O-Grande, runway 27, 4,300 × 80 ft, grass/turf ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 36; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: center; flight hours: 1,400 total, 410 in this make and model, 1,200 as pilot in command, 60 in the last 90 days, 20 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 270° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: none ## 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 19990814012679A](https://openairdocs.org/incident/19990814012679A), Aug 14, 1999: Amtr S111B, Katy, TX, Substantial damage. Acft experienced engine problems, and the pilot attempted to make an emergency landing at Sack-o-Grande Acroport, the acft experienced brake failure on… 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.