-
when the alpha protection is active,
-
when the load factor is higher than 1.25g,
-
when the bank angle is above 33 deg,
-in case of low speed protection (alternate law).
(4)
Protections
(a)
Alpha (A0A) protection In the normal law, when an angle-of-attack threshold is reached (ALPHA PROT), the C* law is replaced by an alpha protection law. In this case, an angle-of-attack value, proportional to the side stick position, is calculated. The ALPHA PROT value is associated to a null order of the side stick. The ALPHA MAX value is associated to a full nose-up order of the side stick. This protection is de-activated by a pitch-down side stick order.
(b)
High-speed protection If a Vc or Mach threshold is reached, a positive load factor demand is added to the C* law. This positive load factor demand is proportional to the difference between the actual Vc or Mach and the related threshold. This value is limited and decreases the pilot's authority in nose down direction. This protection is active from takeoff to landing.
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(c)
Longitudinal attitude protection Pilot pitch-up commands are reduced linearly from a factor of 1 (theta max - 5.) to zero at (theta max and above). Similarly, pitch-down commands are factored from 1 at (theta min + 5.) to zero at (theta min and below). Pitch attitude feedback is phased in outside (theta min/theta max). theta max = 30. at conf. 0 to 3 theta max = 25. in full.
(d)
Load factor limitation A maneuver protection is introduced in the C* law and restricts the load factor within the limits below :
-clean configuration : - 1 g, + 2.5 g, (CONF 0 - CONF 1)
-flaps extended : 0, + 2g. (CONF 1+F, 2, 3, F)
(5) Operation in normal conditions The pitch laws are activated as described in the table below.
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Pitch Normal Law
-------------------------------------------------------------------------------| | | NORMAL LAW | | | | PHASE |TRANSITION|---------------------------| | | | | | GROUND | FLARE | C* LAW | THS | A0A | | | | LAW | LAW | | COMMAND |PROTECTION | |---------------|----------|----------|-------|--------|----------|-----------| | GROUND | | YES | | | 0. | | | | | | | | | FINAL | | | | | | | | | MANUAL | | | |Take off | | | | | SETTING | | | | | | | | | | | | | | | | | | | | | FLIGHT | FLIGHT | SMOOTHLY | |SMOOTHLY| AUTOTRIM | AUTHORIZED| | | | AND | WASHED | |INTRODU-| WHEN | 1s AFTER | | | |Theta > 8.| OUT OVER | |CED OVER| z > 5 ft | FLIGHT | | | | | 5s | | 5s | | | | | | | | | | | | | | | | | | | | | | BEFORE | z < 50ft | | YES | | INHIBITED| | | LANDING | | | | | | | | | | | | | | | | | |Landing | | | | | | | | | | | | | | | | | GROUND | GROUND | YES | | | 0. | | | | | CONFIRMED| | | | | | | | | 5s AND | | | | | | | | |Theta < | | | | | | | | | 2.5. | | | | | | | | | | | | | | | | GO AROUND | | | YES | | FROZEN | | | BELOW | | | | | | | | 50 ft | z > 50ft | | |SMOOTHLY| | | | | | | |RESTORED| | | | | | | |OVER 5s | | | -------------------------------------------------------------------------------
B. Lateral Control
(1) General The normal law for the lateral control includes the roll and yaw axis control. The ailerons and the spoilers 2, 3, 4 and 5 are the roll control surfaces. The main characteristics of the lateral control law are as follows:
-side stick movement in roll processed as a roll rate demand,
-turn coordination automatically ensured,
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-lateral attitude limitation provided.
(2) Lateral normal law
Two phases must be considered:
-flight,
-ground.
The ground law is activated 0.5s after landing with longitudinal
attitude lower than 8..
The flight law is activated 0.5s after take-off with longitudinal
attitude higher than 8..
(a) Flight law The side stick movement in roll controls a roll rate in which the gains are function of Vc and of the configuration. The maximum roll rate is 15./s. The characteristics of the roll law are:
-in turn configuration, lateral attitude maintained up to 32. with side stick at zero,
-lateral attitude limited to 67. for full side stick deflection,
-automatic turn coordination,
-Dutch roll damping,
-minimization of sideslip.
(b) Ground law All feedbacks are inhibited. The side stick movement directly controls the roll control surfaces (ailerons and spoilers). The rudder is mechanically controlled by the pedals with the yaw damper function always active.
R **ON A/C 001-049, 051-099, 101-149, 151-199, 201-299, 401-499, 中國航空網 www.k6050.com 航空翻譯 www.aviation.cn 本文鏈接地址：A320飛機維護手冊 AMM FLIGHT CONTROLS 飛行操縱9(3)
