and high speed limit the effectiveness of the friction brakes located on the gear. When thrust is reversed, passengers will hear a sudden increase in engine noise, particularly seated just forward of the engines.A potencia reversa, tambem chamada de empuxo reverso, e o desviotemporario do ar de exaustao do motor de uma aeronave tal que o impulsoproduzido e direcionado para frente; isto age contra o deslocamento da aeronave,proporcionando desaceleracao. As potencias dos reversores sao usadas por muitos avioes a jato para ajudar adesacelerar exatamente apos o toque no solo, reduzindo o desgaste nos freios epermitindo encurtar distancias de pouso. O empuxo reverso e tipicamenteaplicado imediatamente apos o toque da roda do nariz no solo, frequentemente acompanhadode [abertura] dos spoilers, para melhorar a desaceleracao no inicio da rolagem dopouso quando a forca residual de sustentacao aerodinamica [para cima] e a alta velocidadelimitam a eficacia de friccao dos freios localizados no trem de pouso. Quando oimpulso e invertido, passageiros ouvirao um subito aumento no ruido do motor,particularmente aqueles sentados a frente dos motores.Thrust reverser provide a deceleration force that is independent of runway condition.Thrust-reverser efficiency is higher at high airspeed.Therefore, thrust reversers must be selected as early as possible after touchdown.Thrust reverser should be returned to reverse idle at low airspeed to prevent engine stall or foreign object damage and stowed at taxi speed.Nevertheless, maximum reverse thrust can be maintained to a complete stop in an emergency.Potencia reversora fornece uma forca dedesaceleracao que e independente da condicao de pista. Aeficiencia da potencia reversora e maiorem velocidade alta. Portanto,[os gatilhos] dos reversores devem ser selecionados tao cedo quanto possivelapos o toque da roda do nariz no solo. Os[gatilhos] de potencia dos reversores devem ser retornados para marcha-lenta(idle) em velocidade baixa para evitar que o motor afogue ou seja danificado por [ingestao] de objetos estranhose parado [o funcionamento] em velocidade de taxi. Naoobstante, a potencia maxima reversa pode ser mantida ate uma parada completa emuma emergencia.Factos Affecting BrakingThe following factors have affected braking in runway excursions or runway overruns: - Failure to arm ground spoilers, with thrust reversers deactivated (e. g., reliance on a thrust-reverser signal for ground-spoilers extension, as applicable).- Failure to use any braking devices (i. e., reliance on the incorrect technique of maintaining a nose-high attitude after touchdown to achieve aerodynamic braking.The nose-whell should be lowered onto the runway as soon as possible to increase weight-on-wheels and activate aircraft systems associated with the nose-landing-gear squat switches.- Asymmetric thrust (i. e., one engine above idle in forward thrust or one engine failing to go into reverse thrust.- Brake unit inoperative (e. g., reported as a "cold brake", i.e., a brake whose temperature is lower, by a specified amount, than the other brakes on the same landing gear.- Spongy pedals (air in the hydraulic wheel-braking system.- Anti-skid tachometer malfunction.- Failure to adequately recover from loss of the normal braking system.- Late selection of thrust reversers.- No takeover or late takeover from autobrakes, when required.- No switching or late switching from normal braking to alternate braking or to emergency braking in response to abnormal braking.- Crosswind