History of Flight
The accident occurred on March 7, 2022, at about 1045 eastern standard time. The Cessna 525B, registration N22AU, was operated by Executive Flight Services, LLC under Part 135. The two pilots were uninjured. The flight crew reported a stabilized approach to runway 15 at Martin State Airport following a positioning flight from Washington Dulles International Airport. They added 5 knots to Vref due to gusting wind. Landing performance data indicated a required 3,000 ft of runway; the pilots reported landing in the touchdown zone of the 6,997 ft runway. During rollout, the pilot observed no braking action. The copilot also applied brakes without effect. They attempted to locate the emergency brake under the pilot's instrument panel but failed, then used the parking brake. The airplane departed the runway, traveled 450 ft, and struck the airport perimeter fence.
A witness in the control tower parking lot reported the airplane appeared to land very long, near taxiway J about 3,900 ft past the threshold. ADS-B data, onboard flight data, and video footage revealed the airplane touched down about 2,000 ft beyond the approach end at approximately 110 knots.
Personnel and Aircraft
The left-seat pilot held an airline transport certificate with over 2,780 total hours, including 248 hours in type. Recurrent training was completed in October 2021. The copilot had over 7,500 total hours with 115 hours in type; recurrent training occurred in December 2021.
The Cessna 525B is a medium-size business jet with two Williams International FJ44-3A turbofan engines. It lacked thrust reversers but had an antiskid braking system. The emergency brake system used a pneumatic storage bottle and lever. The published checklist included a caution for no braking conditions: "IF DURING LANDING A NO BRAKING CONDITION IS ENCOUNTERED, OPERATE THE EMERGENCY BRAKING SYSTEM. MAINTENANCE IS REQUIRED BEFORE THE NEXT FLIGHT." Emergency procedures directed removing feet from brake pedals and pulling the emergency brake handle.
Meteorological and Airport Information
At 1053 EST, MTN reported wind from 210° at 12 knots gusting to 21 knots, visibility 10 miles, clear skies, temperature 23°C, dew point 13°C, altimeter 29.79 inHg. Crosswind component was 10.4 knots with a 6-knot headwind; gust conditions increased to 18 knots crosswind and 10.5 knots headwind. Runway 15 at MTN is 6,997 ft long.
Wreckage and Brake System Examination
The airplane left light skid marks on the last 100 ft of runway, then three wheel marks through grass for about 450 ft before impacting the fence. The wings and fuselage sustained substantial damage.
Postaccident examination of the brake system: The emergency brake pneumatic bottle had been removed by the operator postaccident on an unknown date and was not available for inspection; the operator reported it was fully charged before removal. Visual inspection of main landing gear brakes revealed no anomalies, no hydraulic leaks, and proper servicing of the brake reservoir and accumulator. The parking brake was set; wear pins indicated serviceable brakes. The on-ground mode antiskid functional test showed normal operation: the PWR BRK LOW PRESS annunciator illuminated and then extinguished as the accumulator charged. Both brakes held pressure. The antiskid system test with transducers functioned normally. Tires were at about 80% treadwear. No preaccident mechanical malfunctions or failures were identified.
Performance Study
A performance study indicated main gear touchdown at about 110 knots airspeed (104 knots groundspeed) about 2,000 ft from the runway threshold, within the first third of landing distance. However, during rollout with flaps and speed brakes deployed, the airplane experienced a prolonged period of low equivalent retarding force at the wheel/runway interface. Deceleration was primarily from aerodynamic drag and free-rolling wheel friction. The airplane did not slow to a safe taxi speed over roughly 5,000 ft of pavement. The low retarding force substantially reduced deceleration, preventing the airplane from stopping before the runway end. It overran at about 58 knots groundspeed.
Based on landing weight and flap setting, the maximum landing distance required was 2,900 ft, similar to the crew's estimate. The actual average deceleration was about 1.25 knots per second, significantly less than the expected maximum of 5–6 knots per second.
Flight Recorders
The airplane was equipped with a Cessna Aircraft Recording System (AReS) and Cockpit Voice Recorder (CVR). Data were processed by Textron/Cessna and NTSB respectively.