# NTSB CEN24LA085: Learjet 35, N46MF, San Marcos, TX, January 2, 2024 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: January 2, 2024, 17:10 local (23:10 UTC) - Place: San Marcos, TX - Coordinates: 29.885406, -97.855343 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=29.8854&lon=-97.8553&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: 5 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: Bombardier Aviation, FAA FSDO - NTSB case key (mKey): 193628 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN24LA085 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/193628/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=193628 - Page: https://openairdocs.org/ntsb/CEN24LA085 ## Probable cause The captain’s failure to perform a go-around following an unstable approach while landing with a gusty tailwind, which resulted in the airplane touching down long on the wet runway with insufficient distance to stop. Contributing to the accident was the crew’s unawareness of the prevailing winds and first officer’s decision to not call a go-around. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Knowledge: knowledge of meteorologic cond](https://openairdocs.org/ntsb-findings/02032020): Personnel issues › Experience/knowledge · Flight crew; cases with it: [Gates Learjet 35A, 1 case](https://openairdocs.org/ntsb-findings/02032020/cases.md?model=5170602), [All aircraft, 30 cases](https://openairdocs.org/ntsb-findings/02032020/cases.md) - [Wind: tailwind](https://openairdocs.org/ntsb-findings/03034015): Environmental issues › Conditions/weather/phenomena · Awareness of condition; cases with it: [Gates Learjet 35A, 1 case](https://openairdocs.org/ntsb-findings/03034015/cases.md?model=5170602), [All aircraft, 594 cases](https://openairdocs.org/ntsb-findings/03034015/cases.md) - [Wind: tailwind](https://openairdocs.org/ntsb-findings/03034015): Environmental issues › Conditions/weather/phenomena · Effect on operation; cases with it: [Gates Learjet 35A, 1 case](https://openairdocs.org/ntsb-findings/03034015/cases.md?model=5170602), [All aircraft, 594 cases](https://openairdocs.org/ntsb-findings/03034015/cases.md) - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Gates Learjet 35A, 3 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=5170602), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Copilot; cases with it: [Gates Learjet 35A, 3 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=5170602), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/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: [Gates Learjet 35A, 4 cases](https://openairdocs.org/ntsb-events/300/sequence.md?model=5170602), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) ## Analysis While in cruise flight approaching the descent for landing, the crew received automated weather information that was about an hour old that reported wind from the northeast. The crew selected the precision approach to the airport, which landed toward the southeast. Unknown to the crew, the wind had shifted from the northeast to a tailwind from the northwest and had increased in velocity with gusts. They did not request current weather during the descent, and no weather information was provided by the tower controller. Recorded data for the approach revealed that the airplane had a 15-knot tailwind and a steep descent rate before the landing, which exceeded the company’s general operation manual’s criteria for a stabilized approach. Data showed the airplane touched down at 124 knots about halfway down runway 13, which was wet, with about 2,600 ft remaining. The captain applied the brakes and reported that they were unresponsive. The airplane overran the runway and traveled into a grass field. The nose landing gear separated from the airplane, resulting in substantial damage to the fuselage. The first officer (FO) stated that he perceived that the airplane had hydroplaned on landing. A performance study conducted for the accident flight using available airplane and weather information revealed the landing distance for the airplane on a wet/contaminated runway was 4,550 ft; runway 13 was 5,601 ft. The calculated landing reference speed to included “half the gust factor” was 125 knots. The manufacturer’s flight manual lists the maximum tailwind component as 10 knots. The landing data for the flight could not be calculated since the actual tailwind component at the time of the landing exceeded 10 knots. ## Factual narrative On January 2, 2024, about 1710 central standard time, a Learjet 35A, N45MF, was substantially damaged when it was involved in an accident near San Marcos, Texas. The two pilots and three passengers were not injured. The airplane was operated under the provisions of Title 14 Code of Federal Regulations Part 135 as an air medical transport flight. The airplane departed Albuquerque International Sunport Airport (ABQ), Albuquerque, New Mexico, about 1448 mountain standard time with the captain flying, and flew to San Marcos Regional Airport (HYI), Austin, Texas. A review of air traffic control radio transmissions, ADS-B data, pilot statements, and weather information revealed that while the airplane was en route to its destination, the crew checked the weather with the airplane’s Garmin 750 system. The crew also listened to the airport’s Automatic Terminal Information Service, which reported wind from 310° at 12 knots, gusts to 24 knots, visibility 9 miles, lightning in the vicinity, and an overcast ceiling at 900 ft. The pilot briefed the ILS 13 instrument approach and was informed by the approach controller that they were using the RNAV GPS approach to runway 8 or 35. Thinking they heard someone make a missed approach, the captain requested to use the ILS approach to runway 13. After receiving vectors, the captain intercepted the approach course and began to fly the approach. When the crew checked in with HYI tower, the tower acknowledged them and later cleared them to land on runway 13. No updated weather was provided to the flight crew by the tower controller over the radio and the flight crew did not request a wind check. The captain reported that the airplane broke out of the clouds about 500 ft above the ground and that the visibility was poor. The first officer (FO) called out that the runway end identifier lights were in sight, which the captain then also saw along with the runway. The captain flew the airplane to the runway, touched down, applied the brakes, and deployed the spoilers. After he applied normal pressure to the brakes, the airplane showed no signs of deceleration on the wet runway. The captain pushed harder on the brakes with no improvement to the braking action. He called to the FO that the airplane had “no brakes” and seeing the airplane was going to overrun the end of the runway, veered left to avoid damaging the localizer antenna. The airplane departed the end of the runway and traveled into a grass field. The nose landing gear separated from the airplane, resulting in substantial damage to the fuselage. The FO reported that during the approach, the captain had difficulty maintaining course alignment due to the autopilot “not working the way it was supposed to.” The FO advised the captain to hand fly the approach and not continue attempting to configure the autopilot. Later on the approach, the FO called out having the airport and the precision approach path indicators in sight at the airplane’s “12 o’clock” and statedthat the landing was assured. The captain did not respond, so the FO asked if the captain could see the runway, to which the captain responded no. He informed the captain the runway was “down” and the captain saw the runway. The captain then “abruptly chopped power and descended to land at a rapid pace.” After the airplane touched down the FO perceived that they were hydroplaning, and the airplane ran off the end of the runway. The FO stated that a go-around should have been initiated before the landing. A review of weather information for the airport found that at 1600 CST, about 70 minutes before the accident, the automated weather reporting facility at the airport recorded wind from 070° at 8 knots, visibility 10 miles, thunderstorms in the vicinity, and light rain. About an hour later at 1706 CST, the automated weather observation facility at the airport reported a wind from 310° at 12 knots gusting to 24 knots, visibility 9 miles, and an overcast ceiling at 900 ft. Recorded data for the approach found that the airplane had about 15 knots of tailwind and a descent rate that exceeded 2,000 ft/min about 10 seconds before the landing. The descent rate reduced to 1,000 ft/min about 3 seconds before touchdown. The airplane touched down at 124 knots calibrated airspeed about halfway down the runway, with about 2,600 ft remaining. A performance study conducted for the accident flight using available airplane and weather information revealed that the landing distance for the airplane on a wet/contaminated runway was 4,550 ft. Of note, runway 13 was 5,601 ft. The calculated base landing reference speed would be 119 knots, which then would have been increased for “half the gust factor” to 125 knots. The manufacturer’s flight manual lists the maximum tailwind component as 10 knots, so landing data could not be accurately calculated for the accident flight. A review of the flight’s general operations manual found the criteria for a stabilized approach as “one of the key features of safe approaches and landings. It is characterized by a constant-angle, constant-rate of descent approach profile ending near the touchdown point, where the landing maneuver begins. A stabilized approach is the safest profile in all but special cases, in which another profile may be required by unusual conditions.” The manual stated the flight should be stabilized by 1,000 ft above touchdown in instrument meteorological conditions. Also, it states that “[i]f an unexpected, sustained rate of descent greater than 1,000 fpm is encountered during the approach, a missed approach should be performed.” ## Aircraft - Registration: [N46MF](https://openairdocs.org/aircraft/N46MF), registered now, S/N 377, built 1981 (OpenAirDocs) - Reported make and model: LEARJET 35 (A) - Registry model: [Gates Learjet 35A](https://openairdocs.org/model/gates-learjet-35a) (registry code 5170602) (OpenAirDocs) - Registry engine: [AiResearch TFE731 series](https://openairdocs.org/engine/airesearch-tfe731-series) (registry code 01518, turbo-jet) (OpenAirDocs) - Category: Airplane - Serial number: 377 - Year built: 1981 - Airframe hours: 14813 - Engines: Honeywell TFE731-2C-2B 3500 lbs thrust turbo fan; Honeywell TFE731-2C-2B 3500 lbs thrust turbo fan - Damage: Substantial damage - Flight: Other work use, Part 135 - Operator: Med Flight Air Ambulance Inc - Registered owner: Med Flight Air Ambulance Inc - Airworthiness certificate: Standard, Transport - Last inspection: AAIP, October 5, 2023 - Departed: ABQ, Albuquerque, NM - Destination: Same as departure - Flight plan: IFR - Airport: HYI, San Marcos Rgnl, runway 13, 5,601 × 100 ft, asphalt - Equipment: ADS-B, Stall warning system, Onboard weather, Electronic flight bag or handheld device, Auto-pilot, Angle of attack indicator ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 71; injuries: none; airline transport, flight instructor; airplane ratings: single-engine sea, multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; last flight review December 8, 2023; seat: left; restraint: 4-point; flight hours: 11,000 total, 2,200 in this make and model, 7,400 as pilot in command, 65 in the last 90 days, 25 in the last 30 days, 6 in the last 24 hours - Pilot; age 27; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: helicopter; medical: class 1, without waivers/limitations; last flight review September 14, 2023; seat: right; restraint: 4-point; flight hours: 789 total, 165 in this make and model, 338 as pilot in command, 101 in the last 90 days, 16 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Instrument (IMC), Day - Wind: 310° at 12 knots, gusting 24 - Visibility: 9 statute miles - Lowest ceiling: 900 ft overcast - Temperature: 50 °F, dew point 48 °F - Altimeter: 30.07 inHg - Observed at: KHYI, 1 nm away - METAR: KHYI 022306Z 31012G24KT 9SM OVC009 10/09 A3007 RMK AO2 LTG DSNT N RAE2257 CIG 006V011 ## 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 20240102001369A](https://openairdocs.org/incident/20240102001369A), Jan 2, 2024: Gates Learjet Corp. 35A, San Marcos, TX, Substantial damage. Aircraft was conducting the ILS runway 13 approach into San Marcos regional airport. During this approach, the aircraft entered VMC at what the pilots estimate… ## Docket (12 files) The files NTSB released with the investigation on February 26, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=193628. 18.8 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18016375&FileExtension=pdf&FileName=NTSB%20form%20CEN24LA085%20COPY_Redacted-Rel.pdf - Captain's statement (item 2, PDF, 1 page, 209 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18016509&FileExtension=pdf&FileName=P.%20Kinzelman%20Statement%20(PIC)-Rel.pdf - First officer's statement (item 3, PDF, 1 page, 252 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18016331&FileExtension=pdf&FileName=T.%20Quinton%20Statement%20(SIC)-Rel.pdf - Photos (item 4, PDF, 3 pages, 2 photos, 886 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18017179&FileExtension=pdf&FileName=Photos%202%20CEN24LA085-Rel.pdf - Weather information (item 5, PDF, 4 pages, 385 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18018934&FileExtension=pdf&FileName=Weather%20Information-Rel.pdf - Airplane performance study (item 6, PDF, 13 pages, 4.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17354652&FileExtension=pdf&FileName=CEN24LA085_airplane_performance_study_v4-Rel.pdf - FAA ADS-B data (item 7, XLSX, 6.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17354417&FileExtension=xlsx&FileName=20240102_A5985B_537245596_ADSB-Rel.xlsx - Cockpit voice recorder - specialista��s factual report (item 8, PDF, 21 pages, 275 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18321402&FileExtension=pdf&FileName=CEN24LA085_CVR%20Report_RELEASE-Rel.pdf - Crew emails to FAA (item 9, PDF, 7 pages, 964 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18023352&FileExtension=pdf&FileName=Crew%20Email%20Statements_Redacted-Rel.pdf - Lear 35A flight manual excerpt (item 10, PDF, 9 pages, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18023616&FileExtension=pdf&FileName=Lear35A%20AFM%20sections-Rel.pdf - Gom stabilized approach criteria (item 11, PDF, 1 page, 309 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18026345&FileExtension=pdf&FileName=GOM%20(Rev%208)%20Stabilized%20Appr-Rel.pdf - Statement of party representatives to NTSB investigation (item 12, PDF, 1 page, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18023466&FileExtension=pdf&FileName=CEN24LA085%20Party%20Form_Redacted-Rel.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.