N46MF

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 stated that 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.”