CEN15LA057

The pilot's engagement of the emergency parking brake during the landing roll, which decreased the airplane's braking performance and prevented it from stopping on the available runway. Contributing to the pilot's decision to engage the emergency parking brake was the expectation of a faster rate of deceleration and considerably shorter wet runway landing distance provided by the airplane flight manual than that experienced by the crew upon touchdown and an actual wet runway friction level lower than the assumed runway fiction level used in the calculation of the stopping distances published in the airplane flight manual.

The pilots of the very light jet were conducting a positioning flight in instrument meteorological conditions. The flight was cleared by air traffic control for the instrument landing system (ILS) approach; upon being cleared for landing, the tower controller reported to the crew that there was no standing water on the runway. Review of the airplane's flight data recorder (FDR) data revealed that the airplane reached 50 ft above touchdown zone elevation (TDZE) at an indicated airspeed of 118 knots (KIAS). The airplane crossed the runway displaced threshold about 112 KIAS, and it touched down on the runway at 104 KIAS with about a 7-knot tailwind. FDR data revealed that, about 1.6 seconds after touchdown of the main landing gear, the nose landing gear touched down and the pilot's brake pedal input increased, with intermediate oscillations, over a period of 7.5 seconds before reaching full pedal deflection. During this time, the airplane achieved its maximum wheel braking friction coefficient and deceleration. The cockpit voice recorder recorded both pilots express concern the that the airplane was not slowing. About 4 seconds after the airplane reached maximum deceleration, the pilot applied the emergency parking brake (EPB). Upon application of the EPB, the wheel speed dropped to zero and the airplane began to skid, which resulted in reverted-rubber hydroplaning, further decreasing the airplane's stopping performance. The airplane continued past the end of the runway, crossed a service road, and came to rest in a drainage ditch. Postaccident examination of the brake system and data downloaded from the brake control unit indicated that it functioned as commanded during the landing. The airplane was not equipped with thrust reversers or spoilers to aid in deceleration. The operator's standard operating procedures required pilots to conduct a go-around if the airspeed at 50 ft above TDZE exceeded 111 kts. Further, the landing distances published in the airplane flight manual (AFM) are based on the airplane slowing to its reference speed (Vref) of 101 KIAS at 50 ft over the runway threshold. The airplane's speed at that time exceeded Vref, which resulted in an increased runway distance required to stop; however, landing distance calculations performed in accordance with the AFM showed that the airplane should still have been able to stop on the available runway. An airplane performance study also showed that the airplane had adequate distance available on which to stop had the pilot continued to apply maximum braking rather than engage the EPB. The application of the EPB resulted in skidding, which increased the stopping distance. Although the runway was not contaminated with standing water at the time of the accident, the performance study revealed that the maximum wheel braking friction coefficient was significantly less than the values derived from the unfactored wet runway landing distances published in the AFM, and was more consistent with the AFM-provided landing distances for runways contaminated with standing water. Federal Aviation Administration Safety Alert for Operators (SAFO) 15009 warns operators that, "the advisory data for wet runway landings may not provide a safe stopping margin under all conditions" and advised them to assume "a braking action of medium or fair when computing time-of-arrival landing performance or [increase] the factor applied to the wet runway time-of-arrival landing performance data." It is likely that, based on the landing data in the AFM, the crew expected a faster rate of deceleration upon application of maximum braking; when that rate of deceleration was not achieved, the pilot chose to engage the EPB, which only further degraded the airplane's braking performance.

HISTORY OF FLIGHT On November 21, 2014, about 1010 central standard time, an Embraer EMB-500 (Phenom 100) airplane, N584JS, overran the runway after landing at Sugar Land Regional Airport (SGR), Sugar Land, Texas. The airline transport-rated pilots were not injured and the airplane was substantially damaged. The airplane was being operated by Superior Air Charter, LLC, Irvine, California (doing business as JetSuite Air), as a 14 Code of Federal Regulations (CFR) Part 91 positioning flight. Instrument meteorological conditions existed at the airport at the time of the accident, and the flight operated on an instrument flight rules flight plan. The flight originated from William P. Hobby Airport (HOU), Houston, Texas. According to the pilots, the purpose of the flight was to reposition the airplane from HOU to SGR. During the approach to SGR, the tower controller provided the pilots vectors to the airport and then told them to expect the instrument landing system (ILS) 35 approach at SGR. After the accident, the copilot reported that the tower controller cleared the flight to land and that there was no standing water on the runway. The copilot added that, during the approach, there was a tailwind of 15 kts that decreased to 9 kts on touchdown. After landing, the pilot, who was flying the airplane, applied the brakes and noted no appreciable deceleration. She then pulled the emergency brakes twice, but the airplane continued past the end of the runway and onto a grassy area. The airplane then crossed a service road and came to rest in a drainage ditch facing opposite the direction of travel with the empennage section partially submerged in water. A review of flight data recorder (FDR) data revealed that, while on the ILS approach to runway 35, the airplane slowed to 120 knots (kts) and that it maintained that airspeed until about 155 ft mean sea level (msl), at which point it slowed to about 118 kts. The airplane remained on the glideslope until about 380 ft msl, when the cockpit voice recorder (CVR) recorded an electronic voice stating "autopilot," consistent with autopilot disconnection. Shortly after, the airplane descended below the glideslope. The airplane crossed the displaced threshold about 100 ft msl and at 112 kts indicated airspeed (KIAS), and touched down at 1010:37, about 1,040 ft from the threshold, at an airspeed of 104 KIAS. During the landing roll, the CVR recorded the pilots concern about the airplane's lack of deceleration. About 1.6 seconds after touchdown, the nose landing gear touched down, and the pilot's brake pedal increased, with intermediate oscillations, over a period of 7.5 seconds and reached full pedal deflection. About 4 seconds later, the emergency/parking brake (EPB) was applied, at which point the wheel speed dropped from 70 to 0 kts, consistent with a locked-wheel skid. Concurrently, the FDR recorded an engine indication and crew alerting system ANTI-SKID FAIL message, consistent with the application of the EPB and locking of the wheels. The airplane departed the runway at 1011:15 at a groundspeed of about 30 KIAS. Shortly after, the FDR recorded accelerations consistent with the impact and airplane coming to a stop. PERSONNEL INFORMATION Pilot The pilot held an airline transport pilot certificate with airplane single-engine land, multi-engine land, and instrument ratings. Additionally, she held an instructor's certificate with airplane single-engine and instrument ratings. She reported that she had 6,311 total flight hours and 1,110 hours in the accident airplane make and model. The captain was issued a Federal Aviation Administration (FAA) first-class medical certificate on July 29, 2014. Copilot The copilot held an airline transport pilot certificate with airplane single-engine land, multi-engine land, and instrument ratings. He reported that he had 4,232 total flight hours and 814 hours in the accident airplane make and model. The copilot was issued an FAA first-class medical certificate on July 26, 2014, with the restriction, "must wear corrective lenses." AIRCRAFT INFORMATION The Embraer EMB-500 Phenom 100 is included in the very light jet (VLJ) class of airplane. The Phenom 100 can seat four passengers in its normal configuration, but it can be configured to carry up to seven passengers. The airplane is equipped with two Pratt & Whitney Canada PW617-F turbofan engines each rated at a takeoff thrust of 1,695 lbs. The accident airplane's serial number was (S/N) 50000140 and was certified as a 14 CFR 23 normal category airplane. The EMB-500 is not equipped with thrust reversers, and prior to serial # 50000325 not equipped with spoilers. All EMB-500s from serial # 50000325 onwards are equipped with spoilers when delivered from the factory. The accident airplane was not equipped with spoilers. Brake System The Phenom 100's hydraulic brake system delivers hydraulic pressure to the brakes via input on the brake pedals. The hydraulic pressure to the brake system is supplied at a maximum of 3,000 pounds per square inch (psi). The copilot's (right seat) brake pedals are mechanically linked to the pilot's (left seat) brake pedals. Each pilot brake pedal is connected to a pedal position transducer (PPT), each of which produces two independent electrical outputs to the brake control unit (BCU) that were proportional to the respective pedal displacement. The BCU controls the main brake system. The brake system is a brake-by-wire system with an antiskid function. There are no hydraulic components on the brake control; therefore, the only pedal force feedback to the pilots is from a force spring installed on the pedals. This provides a consistent pedal resistance regardless of the runway condition and the pressure applied. Wheel speed information is sent to the BCU via two axle-mounted speed transducers. The BCU uses the output from the wheel speed transducers, the PPTs, and two brake line pressure transducers to generate an electrical command to the associated brake control valve (BCV). Anti-skid protection is provided when the BCU detect a skid by monitoring the two-wheel speed transducer signals. If a skid is detected, the BCU sends a signal to the BCV to reduce pressure to the brakes. The antiskid protection cannot be turned off in the cockpit. The Phenom 100 is equipped with an EPB to stop the airplane if the main brake system fails and to provide means to keep the aircraft parked even when the hydraulic power system is turned off. The EPB is operated by a T-handle on the control pedestal. The handle is mechanically linked to the emergency brake valve. Upon using the EPB, the pressure applied is proportional to the handle displacement. No anti-skid protection is available. Certification In general, 14 CFR Part 23 certification regulations require that dry-runway landing distances be published in airplane flight manuals (AFM) and that they be based on performance demonstrated during flight tests on smooth, dry, hard-surfaced runways. Certification regulations do not require the publication of landing distances on other-than-dry runways, although certification applicants may choose to present this information to the regulator. If the applicant provided this information, it would not necessarily be based on flight tests (largely because of the difficulty of achieving a consistent "wet" or "contaminated" runway surface) but rather derived by calculations based on assumptions agreed to by the regulator. The EMB-500 was first certified by the Brazilian regulator (the Agência Nacional de Aviação Civil), which, like the FAA, does not require the publication of landing distances on other-than-dry runways. However, the European Aviation Safety Agency (EASA) does require the publication of landing distances on