NTSB Factual Report

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 transport pilot certificate with an airplane multiengine land 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.

The SIC estimated that his total flight time was more than 17,000 hours, about 1,500 hours of which were in the accident airplane make and model and 10 hours of which were in the 90 days before the accident. He obtained his type rating in the CL600 in December 2008 from CAE, and his last 14 CFR 61.58 check in the CL600 was performed at CAE in June 2014.

The operator hired the SIC in 2007 as the chief pilot. He had flown with the captain for years. In July 2014, he took a Director of Operations position for another company but continued to be a contract pilot for the operator.

AIRCRAFT INFORMATION

The airplane, serial number (S/N) 3002, was manufactured in 1983 by Canadair Ltd. A Certificate for Airworthiness for Export was issued on September 9, 1983, and 20 days later, the FAA issued a transport-category Standard Airworthiness Certificate. The airplane was powered by two General Electric CF34-3A engines.

The airplane was equipped with steer-by-wire nosewheel system, which was controlled by an electronic control module that operated a hydraulic steering control valve (SCV) in response to the commands via either the handwheel and/or rudder pedals. The SCV controlled an actuator, which through a rack-and-pinion arrangement, rotated a steering cuff. The steering cuff in turn rotated the nosewheels through torque links (or scissors). The steering system was normally switched on continuously during flight and was enabled only when the aircraft was on the ground with WOW input. With no WOW input, the NLG was free castoring.

The airplane was equipped with a normal brake system, and each four-wheel brake system provided one-quarter of the total stopping force in the four-tire set (Nos. 1 and 2 on the left main landing gear [MLG] and Nos. 3 and 4 on the right MLG). Each pilot had a left and right brake pedal, which were mechanically linked at the brake control assembly located beneath the cockpit floor. The brake control assembly contained two brake control valves (BCV) that manipulated hydraulic valves via mechanical inputs. Each of the four BCVs regulated the amount of hydraulic pressure provided to each of the four-wheel brake systems through the antiskid braking system and hydraulic fuses. There were two BCV assemblies installed in the nose hydraulics compartment as a part of the brake control mechanism assembly. The upper BCV controlled the inboard brakes, and hydraulic pressure was supplied by the No. 3 hydraulic system; the lower BCV controlled the outboard brakes, and hydraulic pressure was supplied by the No. 2 hydraulic system. The BCVs were considered on-condition components.

The airplane was equipped with an antiskid braking system that consisted of a skid control unit and two dual antiskid control valves and wheel speed sensors (WSS) located in the axle of each main wheel. The system independently controlled the braking of each main wheel by automatically varying the hydraulic pressure output of each dual BCV before these outputs reached the brakes. WSSs were considered on-condition components. An arming switch on the antiskid panel controlled power to the antiskid valves from the 28-volt direct current main bus via the inboard and outboard antiskid relays and the parking brake microswitch. Therefore, the system cannot be armed when the parking brake is on (parking brake shutoff valve closed). When the parking brake is applied, the INBD FAIL and OUTBD FAIL antiskid warning lights illuminated.

The antiskid system had the following features: (1) modulated skid protection of each wheel via the primary antiskid circuits; (2) locked-wheel protection, which provided a pressure dump signal in the event of a deep skid or failure of a wheel to spin up at touchdown and a coarse backup circuit in the event of a primary antiskid circuit failure; (3) pretouchdown protection which, via input from the WOW circuitry, dumped all the wheels' brake pressure while the airplane was still airborne, but the protection was overridden as soon as the wheels have spun up to allow normal skid-controlled braking; (4) built-in test equipment to provide a check of virtually all the system circuits, both on the ground (before takeoff) and in the air (before landing); and (5) spin-up relays to inhibit thrust reverser deployment until after touchdown.

The airplane was equipped with ground spoilers that were controlled electrically via a control unit located in the underfloor avionics bay, which received electrical signals from the ground spoilers on/off/test switch, spoiler control lever, landing gear control unit, antiskid control unit, and throttle levers. Upon receiving all required signals concurrently, the spoiler control unit transmitted a signal to energize the solenoid valves of a manifold assembly located in each MLG wheel well, which, in turn, directed hydraulic pressure to the extend port of each ground spoiler actuator to extend the spoilers. The ground spoilers are armed for deployment at touchdown by setting the ground spoilers switch to the "on" position and moving the spoiler control lever to the "extend" position. The lever must be pulled up, then moved rearward through an integral gate to achieve the required position. In addition to the lever selection, the throttle levers must be set at idle and the aircraft weight must be on the landing gear (and/or wheels spin-up) before the ground spoilers can deploy.

The airplane was equipped with thrust reversers that redirected engine fan air flow forward over the nose cowl assembly. Thrust reverser selection and control are accomplished primarily by a throttle-quadrant-mounted thrust lever for each engine. Each lever is held in the stow position by a thrust reverser lever stop, which is released by lifting the stop release latch. A deploy switch for each thrust reverser was mounted in the throttle quadrant and was operated by moving the appropriate thrust reverser lever to the "deploy" position.

The airplane was maintained in accordance with the manufacturer's maintenance steering group (MSG) 3 program since January 30, 2009, which consisted of hours- or months-interval inspections of systems or components. Review of the program revealed no requirement to periodically perform an operational test of the antiskid system; however, it contained a general zonal visual inspection every 120 months of the lower internal left nose compartment, which contained the upper and lower BCVs. The zonal inspection did not require inspection of either the upper or lower BCVs input rods extension lengths. The last inspection of that zone was completed on January 18, 2013, at an airframe total time of 15,155.5 hours and 9,303 cycles.

Review of the maintenance records revealed that the airplane's last 800-hour inspection was completed on January 14, 2015, at an airplane total time of 15,737.0 hours and 9,684 cycles. The 800-hour inspection included an operational test of the nosewheel steering electronic control module and the landing gear control unit.

A review of the Aircraft Reporting Form (used by flight crewmembers to report discrepancies) for the 90 days before the accident revealed no discrepancies regarding the brakes, antiskid system, ground spoilers, or thrust reversers.

According to the current status document provided by the operator, there was no record that the upper BCV or No. 1 WSS had been removed, replaced, or repaired since the airplane was manufactured. Maintenance record entries indicated that the No. 1 tire, part number (P/N) 256K43-3, S/N 33097507, was installed on November 10, 2014, at an airframe total time of 15,699.7 hours and 9,657 cycles. At the time of the accident, the airplane had a total time of 15,771.2 and 9,705 cycles.

METEOROLOGICAL INFORMATION

The MKY AWOS reported about the time of the accident wind from 250° at 8 knots, visibility 10 statute miles, few clouds at 9,000 ft, temperature 27°C, dewpoint 20°C, and altimeter setting 30.22 inches of mercury.

The Weather Surveillance Radar 0.5°-elevation scan depicted the conditions from between 3,740 and 10,990 ft over the accident site. The scan images for 1611 and 1626

NTSB Probable Cause

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.