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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
737-300/400/500MAINTENANCE MANUAL
D. The sensor consists of a synchro transmitter, mounted to the fuselage skin from the inside of the airplane. Index pins are provided to assure correct alignment. An airflow vane is mounted on the synchro shaft, external to the airplane. The airflow vane contains an electrical heater, used during flight to prevent icing.
10. Flap Position Sensor____________________
A. The flap position sensor provides the A/T with a measurement of the flap position. The flap position is used to compute the minimum safe speed and the maximum angle-of-attack. Flap position is also used in the generation of control logic.
B. The flap position sensor is mounted aft of the rear spar, and approximately centered on the left outboard flap. Lower the flaps for access.
C. The flap position sensor is a synchro transmitter having dual output windings. The sensor is mounted on the flap gear drive by 4 screws. Electrical interface with the sensor is through an electrical connector mounted on the end of the synchro case.
11. Power Lever Angle (PLA) Synchro_______________________________
A. The PLA synchros provide a measurement of the throttle input command to the engines. The signal is used by the Autothrottle for throttle position feedback.
B. The PLA synchro is mounted on the engine fuel control box, on the lower left side of each engine. The synchro is attached to the fuel control box by two bolts. Electrical interface is through an integral wire bundle, terminated in an electrical connector.
12. Autothrottle Flight Modes (Fig. 3)_________________________
A. A/T mode selection must be compatible with the DFCS mode engaged. If the F/D is OFF, and the A/P is OFF or PCWS, either N1 or SPEED can be selected for the Autothrottle.
B. As a basic rule, with a DFCS pitch mode selected, and the A/T ON, airspeed is directly controlled by either engine thrust (N1) or pitch attitude, but not both at the same time.
C. TAKEOFF - airspeed is maintained by following the F/D pitch commands, and the A/T sets engine thrust (N1), either full or reduced.
D. CLIMB - when the DFCS is maintaining airspeed (MCP SPD or VNAV SPD), the A/T maintains CLB N1 LIMIT. When the DFCS maintains vertical speed, the A/T maintains MCP SPD.
E. ALT ACQ - the DFCS acquires the selected altitude, and the A/T maintains either MCP SPD, or if the DFCS climb is accomplished in VNAV SPD, the A/T maintains FMC SPD.
F. CRUISE - the DFCS maintains the selected altitude, and the A/T maintains MCP SPD or FMC SPD.
G. DESCENT - with the DFCS controlling vertical speed, the A/T maintains MCP SPD. If the DFCS is in a speed mode (MCP SPD or VNAV PATH), the A/T retards the throttle levers to the aft stop, and then inhibits throttle control (RETARD-ARM).
H. APPROACH - after G/S engage, the DFCS controls the descent rate to maintain the glide slope, and the A/T maintains the selected approach airspeed (MCP SPD). At less than 27 feet radio altitude, the A/T retards the throttles to the aft stop (RETARD-ARM), then disengages 2 seconds after touchdown.
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22-31-00
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A 737-300/400/500MAINTENANCE MANUAL
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：737-300 400 500 AMM 飞机维护手册 自动飞行 AUTOFLIGHT 2(137)
