【单选题】According to gyroscopic precession, if the rotor disc wants to tilt forward, which direction the pitch angle has to increase? Assuming the main rotor rotates counterclockwise,and 3-o'clock is on the r...
【单选题】A small fuel spillage has occurred during helicopter refueling. After the leak has been stopped and fire-control personnel have been notified and are standing by,the next step is to().
【简答题】Hardly ________ the helicopter ________ when the waiting crowd ran toward it. A) has ... landed B) had ... landed C) would ... land D) was ... landing