Drum brake is comprised of two brake shoes, a wheel cylinder, an adjuster, an emergency brake mechanism, a back plate, a lot of return springs, and a brake drum as shown in Fig.5-7．

指示空速是修正仪表误差后空速指示器所指示的飞行速度。 A: Indicated Airspeed is the speed of an aircraft as shown in the airspeed indicator when corrected for instrument error. B: Indicated Airspeed is the aircraft speed indicated by airspeed adapter after modified instrument error. C: Indicated Airspeed is the aircraft speed of an aircraft as shown in the airspeed adjuster when corrected for instrument error.