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HORIZONTAL STABILIZER POSITION INDICATION -FUNCTIONAL DESCRIPTION
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TRAILING EDGE FLAPS -INTRODUCTION
General
The trailing edge (TE) flaps improve the takeoff and landing performance of the airplane. When the flaps extend, they increase the lift of the wing. They also help to decrease the airspeed during landings and approaches.
The flaps are part of the high lift control system (HLCS). The HLCS electrically controls the flaps with a fly-by-wire system.
During takeoff and landing, the pilots use the flap lever to command the flaps to move to an extended position. During cruise, the pilots command the flaps to retract to the up position.
Each wing has an inboard flap and an outboard flap. The inboard flap is double-slotted and has a main flap and an aft flap. The outboard flap is single-slotted and is one piece.
Flap Operation
The flaps operate in sequence with the slats. At cruise speed and altitude, flap extension is inhibited.
The load relief function retracts the flaps to prevent structural damage to the flaps at high airspeeds.
The flaps are monitored for skew or asymmetry. When the system detects a skew or asymmetry, the flap drive shuts down.
Abbreviations and Acronyms
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AIMS -airplane information management system
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altn -alternate
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ARINC -Aeronautical Radio, Inc.
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EICAS -engine indication and crew alerting system
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EXT -extend
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FSEU -flap/slat electronics unit
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HLCS -high lift control system
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LVDT -linear variable differential transformer
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MAT -maintenance access terminal
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PDU -power drive unit
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retr -retract
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RVDT -rotary variable differential transformer
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sec -secondary
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TE -trailing edge
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TRAILING EDGE FLAPS -INTRODUCTION
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TRAILING EDGE FLAPS -GENERAL DESCRIPTION
General
The flaps operate in one of three modes:
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Primary mode
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Secondary mode
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Alternate mode.
The primary mode uses hydraulic power to operate the flaps. The secondary and alternate modes use electrical power to operate the flaps.
Primary Mode
The primary mode has a closed-loop control system. The pilot commands the flaps with the flap lever. The flap lever position sensor sends input signals to the FSEUs. The FSEUs use the flap lever position to calculate the flap commands. The FSEUs also receive data from the systems ARINC 629 buses.
The FSEUs send the flap commands to the flap primary control valve. This valve supplies hydraulic power to the flap power drive unit (PDU). The hydraulic motor on the PDU then moves the flap mechanisms.
The flap/slat priority valve controls the amount of hydraulic flow to the flap primary control valve. The flap/slat priority valve gives priority of hydraulic power to the primary flight control system (PFCS) over the HLCS.
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As the flaps move, the flap position sensors send feedback signals to the FSEUs. The FSEUs stop the flap commands when the feedback signals equal the commanded position. 中國航空網 m.k6050.com 航空翻譯 www.aviation.cn 本文鏈接地址：777 AMM 飛機維護手冊 飛行操縱 Flight Controls 2(30)
