ERA15LA140

The failure of a spring inside the No. 2 brake’s upper brake control valve and the fracture of the coupling subassembly of the No. 1 wheel speed sensor during landing, which resulted in the loss of braking action, and the pilot-in-command’s (PIC) deactivation of the antiskid system even though there were no antiskid failure annunciations, which resulted in the rupture of the Nos. 1, 3, and 4 tires, further loss of braking action, and subsequent landing overrun. Contributing to accident were the PIC’s improper landing flare, which resulted in landing several hundred feet beyond the aiming point marking, and his unsuccessful attempts to deploy the thrust reversers for reasons that could not be determined because postaccident operational testing did not reveal any anomalies that would have precluded normal operation.Contributing to the passenger’s injury was his leaving his seat intentionally while the airplane was in motion.

Earlier on the day of the accident, the pilot-in-command (PIC) and second-in-command (SIC) had landed the airplane on a 5,008-ft-long, asphalt-grooved runway. After touchdown with the flaps fully extended, the ground spoilers and thrust reversers were deployed, and normal braking occurred. The PIC, who was the flying pilot, and the SIC subsequently departed on an executive/corporate flight with a flight attendant, the airplane owner, and five passengers onboard. The PIC reported that he flew a visual approach to the dry, 5,000-ft-long runway while maintaining a normal glidepath at Vref plus 4 or 5 knots at the runway threshold with the flaps fully extended. He added that the touchdown was "firm" and between about 300 to 500 ft beyond the aiming point marking. After touchdown, the PIC tried unsuccessfully to deploy the ground spoilers. He applied "moderate" brake pressure when the nose landing gear (NLG) contacted the runway, but felt no deceleration. He also attempted to deploy the thrust reversers without success. The PIC then informed the SIC that there was no braking energy, released the brakes, and turned off the antiskid system. He then reapplied heavy braking but did not feel any deceleration, and he again tried to deploy the thrust reversers without success. He maintained directional control using the nosewheel steering and manually modulated the brakes. However, the airplane did not slow as expected. While approaching the runway end and realizing that he was not going to be able to stop the airplane on the runway, the PIC intentionally veered the airplane right to avoid water ahead. However, the airplane exited the runway end into sand, and the NLG collapsed. The airplane then came to rest about 250 ft past the departure end of the runway. The passengers exited the airplane, and shortly after, airport personnel arrived and rendered assistance. The airplane owner, who was a passenger in the cabin, stated that he left his seat and moved toward the cabin door when he realized that the airplane would not stop on the runway, and he sustained serious injuries. Examination of the airplane revealed that there was minimal pressure at the No. 2 (left inboard) brake due to failure of a spring in the upper brake control valve (BCV), and the coupling subassembly of the No. 1 wheel speed sensor (WSS) was fractured. A representative from the airplane manufacturer reported that, during certification of the brake system, the failure of the BCV spring was considered acceptably low and would be evident to flight crewmembers within five landings of the failure. Because the airplane did not pull while braking during the previous landing earlier that day to a similar length runway, the spring likely failed during the accident landing. Although the PIC was unable to manually deploy the ground spoilers and thrust reversers during the landing roll, they functioned normally during the landing earlier that day and during postaccident operational testing and examination, with no systems failures or malfunctions noted. Additionally, there were no malfunctions or failures with the weight-on-wheels system found during postaccident examinations that would have precluded normal operation. Therefore, the PIC's unsuccessful attempts to deploy the ground spoilers and thrust reversers were likely due to errors made while multitasking when presented with an unexpected situation (inadequate deceleration) with little runway remaining. Airplane stopping distance calculations based on the airplane's reported weight, weather conditions, calculated and PIC-reported Vref speed, flap extension, and estimated touchdown point (300 to 500 ft beyond the aiming point marking as reported by the PIC and SIC and corroborated by security camera footage) and assuming the nonuse of the ground spoilers and thrust reversers, operational antiskid and steering systems, and the loss of one brake per side (symmetric half braking) showed that the airplane would have required 690 ft of additional runway; under the same conditions but with thrust reversers used, the airplane still would have required 27 ft of additional runway. Even though there were no antiskid failure annunciations, the PIC switched off the antiskid system, which led to the rupture of the Nos. 1, 3, and 4 tires and likely fractured the No. 1 WSS's coupling subassembly, both of which would have further contributed to the loss of braking action. Therefore, the combination of the failure of a spring in the No. 2 brake's upper BCV and the fracture of the coupling subassembly of the No. 1 WSS, the pilot's failure to attain the proper touchdown point, the slightly excess speed, and the subsequent failure of three of the tires resulted in there being insufficient runway remaining to avoid a runway overrun. Although the BCV manufacturer reported that there was 1 previous case involving a failed BCV spring and 43 instances of units with relaxed springs within the BCVs, none of these failed or relaxed springs would have been detected by maintenance personnel because a focused inspection of the BCV was not required.

HISTORY OF FLIGHT On March 1, 2015, about 1615 eastern standard time, a Bombardier Canadair CL-600-2A12 airplane, N600NP, experienced a landing overrun and subsequent collapse of the nose landing gear at Marco Island Airport (MKY), Marco Island, Florida. The two pilots, one flight attendant, and four passengers were not injured; one passenger sustained serious injuries; and one passenger sustained minor injuries. The airplane was substantially damaged. The airplane was being operated as a 14 Code of Federal Regulations (CFR) Part 91 executive/corporate flight. An instrument flight rules flight plan was filed, and visual meteorological conditions prevailed at MKY about the time of the accident. The flight originated about 1554 from Florida Keys Marathon Airport (MTH), Marathon, Florida. Earlier on the day of the accident, the pilot-in-command (PIC) and second-in-command (SIC) landed the airplane on a 5,008-ft-long, asphalt-grooved runway at MTH. After touchdown with the flaps fully extended, the ground spoilers and thrust reversers were deployed, and normal braking occurred. The flight crewmembers reported no discrepancies pertaining to the normal brake system, antiskid system, thrust reversers, or ground spoilers. The PIC, who was seated in the left seat, stated that, after takeoff from MTH, they proceeded to MKY and obtained information from the automated weather observing station (AWOS), which indicated the wind was from 250° at 5 knots. Before the approach, the pilots reviewed the speeds and landing distance; the calculated required landing distance assuming a Vref of 133 knots was 3,166 ft for a dry runway and 4,166 ft for a wet runway; runway 17 was 5,000 ft long. About 10 miles south of MKY, they had the runway in sight and then requested and were approved for a visual approach from Fort Myers Approach Control. The airplane then entered the downwind leg of the airport traffic pattern from the south while slowing; the flaps were extended to 20°. The PIC noted that there was rain about 2 to 3 miles east of MKY but that the runway appeared to be dry. Because of the rain, the PIC chose to fly the traffic pattern closer to the runway (0.5 mile) on the downwind leg, which he extended 1 mile to avoid the rain. When the airplane was abeam the approach end of runway 17, the SIC extended the landing gear and the flaps to 30°. The pilots then performed the Landing checklist and the antiskid test, which was normal. The PIC then armed the thrust reversers and made a "teardrop turn" to the final approach leg of the airport traffic pattern. The airplane owner, who was pilot-rated and seated in the cabin, recalled a greater bank angle on the turn from downwind to final. During the approach, the flaps were extended to 45°, and while flying Vref plus 10 knots, the airplane encountered a couple of wind gusts. The SIC checked the AWOS again, but the wind information was the same. The flight did not encounter rain during the approach, and at 50 ft above ground level (agl), the automated callout occurred. The PIC maintained a normal glidepath at Vref plus 4 or 5 knots at the runway threshold, at which point, he placed the thrust levers in the" idle" position. The owner later reported that, while over the runway, it felt like they were floating slightly longer than normal. The PIC reported that the touchdown was "firm" occurring between 300 and 500 ft beyond the "aiming point marking." After touchdown, he tried to extend the ground spoilers without success. He later attributed that to the complex process requiring the lever to be pulled up then moved rearward through an integral gate. When the nose landing gear (NLG) contacted the runway, he applied forward control yoke pressure and brake pressure but felt no deceleration. He indicated that he also attempted to deploy the thrust reversers but did not believe they deployed and did not see any thrust reverser deploy lights. He further stated that each piggyback lever never unlocked and that he could not get the levers into the reverse position. The owner later reported that he heard what he thought was a "tire go" during the landing roll, that he felt "heavy braking," and that he became concerned when he did not feel or hear the thrust reversers deploy. The PIC added that he applied "moderate" brake pressure but did not feel any deceleration, which the SIC characterized the landing roll as similar to skidding on ice. The PIC informed the SIC there was no braking energy, released the brakes, turned off the antiskid, and then "re-applied the brakes pressing hard." The SIC also reported he too applied the brakes because he felt no deceleration. The PIC reported he did not feel any deceleration and again tried to deploy the thrust reversers without success. He maintained the runway centerline using the nosewheel steering and began modulating the brakes. However, the airplane did not slow as expected. After the PIC realized that he was not going to be able to stop the airplane on the runway and because there was water beyond the runway end, he intentionally veered the airplane to the right. The SIC reported the airplane departed the runway travelling about 35 knots, and rolled about 250 ft into sand. The airplane owner, who had stood up to go to the cabin entry door when it became clear to him that the airplane was not going to stop on the runway, was bounced against the sidewall between the Nos. 1 and 2 seats on the airplane's left side and sustained serious injuries. The PIC ordered an emergency evacuation and secured the engines. At that time, the piggyback levers were still up; he then pushed them down, pulled the firewall shutoff valves, and secured the auxiliary power unit. The passengers exited the airplane, and power was secured. Shortly after, airport personnel arrived and rendered assistance. Subsequently, a passenger occupying the cockpit jumpseat complained of back pain and was taken to a hospital for treatment. The PIC later confirmed that he used nosewheel steering to maintain the runway centerline, and that, during the landing roll, he did not detect any abnormal issues with the nosewheel steering. The SIC later reported that there was no antiskid or weight-on-wheels (WOW) annunciations or failed lights and no warnings from the enhanced ground proximity warning system (EGPWS). He indicated that he and the PIC did not discuss whether to go-around because the problem became evident when the airplane was too far down the runway. PERSONNEL INFORMATION PIC The PIC held a Federal Aviation Administration (FAA) airline transport pilot certificate with a multiengine airplane rating and type ratings in several aircraft, including the CL-600. He also held a commercial pilot certificate with an airplane single-engine land rating and a flight instructor certificate with airplane single-engine, airplane multiengine, and instrument airplane ratings. He was issued a first-class medical certificate on January 15, 2015, with the limitation that he "must wear corrective lenses," which he was wearing at the time of the accident. The PIC's total flight time was 8,988 hours, 840 hours of which were in the accident airplane make and model, 625 hours of which were as PIC in the accident airplane. In the 90 days before the accident, his total flight time was 65 hours, 25 hours of which were as PIC and 40 hours of which were as SIC. He obtained his initial type rating in the CL-600 in March 2011 from CAE SimuFlite (CAE), Fort Worth, Texas. His last 14 CFR 135.297 check was performed in a Level D simulator at CAE on February 3, 2015, and his last 14 CFR 135.293 check in a CL600 was performed at CAE in August 2014. The operator hired the PIC in February 2009 as a captain. After obtaining his PIC type rating in the CL-600 in March 2011, he flew a rotation of different aircraft for 2 years. From May 2013 to the accident date, he only flew the CL-600. SIC The SIC held an FAA airline tra