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时间:2011-03-30 15:02来源:蓝天飞行翻译 作者:航空
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G.  Flap Takeoff Warning Switch - The warning horn is sounded if the landing gear or flaps are not down with EPR less than 1.6 on both engines. The flap takeoff warning switch has dual sets of contacts, one set is used in the landing warning system, the other in the takeoff warning system. The switch is installed on the flap control valve follow-up mechanism and is actuated when the flaps are not in the takeoff range (Fig. 1). The takeoff flap switch is bypassed by an EPR logic circuit in the engine accessory unit when the EPR is less than 1.6 (Fig. 2). The EPR detector is connected to the EPR transmitter and indicating circuit. Two test switches and EPR indicating lights on the front of the engine accessory unit allow ground testing the EPR function (Ref Chapter 77, Engine Pressure Ratio Indicating System).
H.  Warning Horn Reset Switch - The warning horn reset (HORN CUTOUT) switch is located on the aisle stand. The reset switch may be used at the crew's discretion to silence the warning horn for either or both engine thrust levers by energizing circuits in the landing gear electrical module. The circuit is reset automatically when a thrust lever is advanced (Fig. 1).
4.  Takeoff Warning System
A.  The takeoff warning system warns the pilot if flaps, stabilizer and speed brakes are not in their respective takeoff positions prior to takeoff. If either thrust lever is advanced to takeoff power, an intermittent warning horn in the control cabin will sound if either the flaps or stabilizer are not in the takeoff range or the speed brakes are not down. The horn can only be silenced by correcting the configuration or retarding the thrust lever. On airplanes with SB 31-1073, the takeoff warning system warns the pilot if the parking brake is not released before takeoff thrust is applied.
B.  The flight controls warning switches are parallel-wired. In series with these switches are an air ground sensing circuit and a circuit that arms the takeoff warning system. The air ground safety sensor deactivates the warning circuit when the airplane is airborne (weight off the landing gear). The air/ground sensing and control circuits are in the landing gear accessory unit module (Ref Chapter 32, Landing Gear Position Indicating System).
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C.  A thrust lever actuated takeoff warning switch is installed on the engine No. 1 and 2 thrust lever switch mechanisms located in the ceiling of the electronic equipment compartment (Fig. 1). When either thrust lever is advanced to a takeoff power setting, a cam in a mechanism actuates the corresponding takeoff warning switch. The takeoff warning system is armed when either thrust lever is advanced to a position which actuates the corresponding takeoff warning switch and provides an EPR of 1.4 or greater. The EPR logic/sensing circuits are in the engine accessory unit.
D.  Flap Takeoff Warning Switch - The flap takeoff warning switch is installed on the flap control valve follow-up mechanism (Fig. 1). It is actuated by a cam on the control valve follow-up drum shaft when the trailing edge flaps are outside the takeoff range. Contacts on the switch are also part of the landing gear warning system.
E.  Stabilizer Takeoff Warning Switches - The two stabilizer takeoff warning switches are installed in the stabilizer actuator compartment and actuated by cams on the stabilizer center section leading edge structure (Fig. 1). The upper switch actuates when the stabilizer is outside the takeoff (green band) range in the leading edge up (APL NOSE DN) direction. The lower switch actuates when the stabilizer is outside the takeoff (green band) range in the leading edge down (APL NOSE UP) direction.
F.  Speed Brake Takeoff Warning Switch - The speed brake takeoff warning switch is installed on the upper forward portion of the control stand. The switch is actuated when the speed brake control lever is lifted out of the down and locked detent.
5.  Cabin Altitude Warning System
A.  The cabin altitude warning system provides an audible signal when cabin pressure approaches an altitude detrimental to passenger comfort.
B.  The cabin altitude warning system consists of a pressure switch, a cutout switch and a cutout relay. The system provides an intermittent sound signal when cabin altitude exceeds approximately 10,000 feet. The cutout switch and relay are installed in the cabin altimeter and rate of climb module on the P5 overhead panel.
C.  The pressure switch is an aneroid type switch. When pressure sensed in the cabin port reaches approximately 10,000 feet, the difference in pressure inside and outside the bellows closes the switch contacts and provides a ground for the aural warning devices box. The switch is installed on the underside of the control cabin floor ahead of the control stand.
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