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NORMAL LAW

47 important questions on NORMAL LAW

What happens when the speed/Mach increases above VMO/MMO?

When the speed/Mach increases above VMO/MMO, an overspeed ECAM warning is triggered. If the airspeed/Mach increases to the protection activation speed, the autopilot will disengage and the EFCS will send a pitch up command to the flight controls to prevent further acceleration. If necessary, the EFCS will permit exceeding this speed for maneuvering for TCAS resolution advisory. With stick released, the speed will return to VMO/MMO.

What happens to the side stick input in the protection range according to the Normal Law?

In the protection range, the Normal Law input is modified and side stick input is an á input, instead of a load factor input, in other words, side stick will adjust á instead of 1g load.

What is the bank angle limit in Normal Law?

In Normal Law, bank angle is normally limited to 33°. If the pilot holds full lateral side stick, Normal Law provides positive spiral stability and the bank angle will increase to a maximum angle of 67°. The Flight Director (FD) command bars will disappear if the angle of bank exceeds 45°.

What does normal law provide in terms of high angle of attack protection?

Normal law provides high angle of attack protection to prevent stalling and to facilitate temporary optimal performance for evasion/escape maneuvers during Windshear, TCAS, or GPWS recovery. The high angle of attack protection takes priority over all other types of pitch protection. High angle of attack protection is displayed on the PFD speed scale.

What occurs if the pilot releases the side stick at VÁMAX?

If the pilot releases the side stick at VÁMAX, the speed will return to, and maintain VÁPROT.

What occurs if the side stick is released when the bank angle exceeds 33°?

If the side stick is released at any time when the bank angle exceeds 33°, the aircraft will return to and maintain 33° bank angle. The FD command bars will be displayed again when the angle of bank reduces to less than 40°.

What are the structural load limits while the aircraft is clean?

The structural load limits are: +2.5g to -1g.

When is auto trim inhibited?

Auto trim is inhibited above 33° of bank. If VaPROT is active, the bank angle is limited to 45°.

How is thrust and angle of attack protection described?

As speed decreases it approaches VLS, which is the Lowest Selectable speed and if A/THR is engaged the A/THR will apply thrust to maintain that speed. This protection is strictly an automated protection by A/THR to maintain VLS and is independent of angle of attack (á).

What is the value for á between VÁPROT and VÁMAX?

Between VÁPROT and VÁMAX is the value for á, depending on the configuration that will activate the A/THR.

What does the autopilot provide inputs to during Auto flight?

The autopilot provides inputs to the EFCS to command an attitude that is normal for a transport category aircraft. Additionally, automatic pitch trim and yaw damping function throughout this mode.

What happens to the structural load limits when either slats or flaps are extended?

The structural load limits are reduced to: +2g to 0g.

What feature is called ALPHA FLOOR?

This feature is called ALPHA FLOOR. It is a thrust feature only - not a flight control feature.

What happens if A/THR is not operating?

If the A/THR is inoperative or not engaged, the speed can be reduced to a higher á protection regime (V4PROT), which is shown at the top of the amber/black band (barber pole). If the autopilot is engaged, it will disconnect if V4PROT +1 is reached.

What is the bank angle limit with high speed protection active?

With the high speed protection active, the bank angle limit is reduced from 67° to 45°, and the system maintains a positive spiral stability to 0° bank angle, so that if the side stick is released the aircraft returns to wings level. We have described the operation of Normal Law.

During the GROUND mode operation, how are the flight controls moved from the 'at rest' position?

During the GROUND mode operation, the flight controls are moved from the 'at rest' position in direct proportion to the side stick displacement from the neutral hands off position.

When does the FLARE mode engage?

The FLARE mode engages when descending through 50' AGL just before landing.

When is the Load Alleviation Function (LAF) available?

The Load Alleviation Function (LAF) is available only in Normal Law and only in clean configuration.

What is the next level of protection after V4PROT?

The next level of protection is VÁMAX. If V4PROT is reached while using the side stick, the speed can be reduced to a lower speed and a higher á until VÁMAX is reached. The EFCS will not maintain á more than VÁMAX, even if the pilot holds the side stick full aft. During this condition, nose up pitch trim is inhibited.

When will an accelerated feature of ALPHA FLOOR activate?

An accelerated feature of ALPHA FLOOR will activate if full back side stick is applied and the nose up pitch limit is reached regardless of the á.

What does the EFCS process in the Flight Controls Introduction module?

The EFCS processes inputs that are programmed to position the flight controls according to pre-set limitations and instructions known as LAWS.

What is the 'at rest' position for the rudder and elevators?

The 'at rest' position is "trail" for the rudder and elevators but the ailerons will be in the "droop" position.

What will the EFCS memorize at 50' AGL?

The EFCS will memorize the pitch attitude at 50' AGL, and that becomes the initial reference for pitch attitude control.

What does the Load Alleviation Function (LAF) use to alleviate wing structural loads?

The function uses the ailerons only, or can use both the ailerons and the two outboard spoilers.

How is the Normal Law input modified in the protection range?

In the protection range, the Normal Law input is modified and side stick input is á input, instead of a load factor input, in other words.

What will the FMA indicate until the conditions for ALPHA FLOOR no longer exist?

The FMA will indicate A. FLOOR until the conditions for ALPHA FLOOR no longer exist, then the FMA will indicate TOGA LOCK.

How many Flight Control Laws are used by the EFCS?

There are three Flight Control Laws that are used by the EFCS; these Laws are Normal, Alternate, and Direct.

Before takeoff, what must the pilot manually set due to the absence of auto trim function?

Before takeoff, there is no auto trim function so the pilot must manually set the takeoff THS setting.

What command is required to flare the aircraft?

To flare the aircraft, this situation will require a gentle nose-up command on the side stick.

How does the Load Alleviation Function (LAF) operate in smooth air?

In smooth air, only the ailerons are deflected upward to alleviate wing loads.

How can TOGA LOCK be disconnected?

A method for disconnecting TOGA LOCK is to select the thrust levers to Idle (this will disconnect A/THR), select A/THR pushbutton on, and then place the thrust levers to CLB.

What happens to the THS after landing?

After landing, the THS normally automatically re-sets to 0°, but the re-set will stop if the pitch attitude increases above +2.5°.

What does Normal law provide in terms of speed protection?

Normal law provides high speed protection. It is designed to prevent the aircraft from exceeding maximum design speed.

What are the three modes of Normal Law?

Normal Law has three modes that are shown in this logic diagram. These modes are: GROUND, FLIGHT, and FLARE.

During takeoff, what happens to the elevator up deflection limit as the aircraft passes through 75 knots?

During takeoff, the aircraft is in the GROUND mode and the elevator up deflection limit of 30° is reduced to 20° as the aircraft passes through 75 knots.

When does the pitch limit protection apply?

The pitch limit protection applies either when the input is provided by the sidesticks or the autopilot.

How are protection limits displayed on the PFD speed scale?

Protection limits are displayed on the PFD speed scale. VMO/MMO is represented as the bottom of the red/black barber pole.

When does the FLIGHT mode blend in after takeoff?

The FLIGHT mode blends in after takeoff with a gradual transition from the GROUND mode.

What do two parallel green dashes indicate?

Two parallel green dashes indicate the speed/Mach at which the protection is activated.

What do the green parallel dash symbols on the PFD represent?

They display the pitch attitude protection limits for 30° nose up and 15° nose down.

What determines pitch and roll rate during Manual flight?

During Manual flight the amount of side stick displacement determines pitch and roll rate.

What does the protection limit in Normal Law?

This protection limits control surface deflections to ensure structural limits are not exceeded.

What will the EFCS do at lower speeds regarding pitch limit?

At lower speeds, the EFCS will reduce the nose up pitch limit to 25° (clean) or 20° (Config FULL) but the symbols will not change.

What limits the pitch attitude during Manual flight?

The pitch attitude is limited by the pitch attitude protection.

What does Normal law provide to prevent stalling?

Normal law also provides high angle of attack protection to prevent stalling and to facilitate temporary optimal performance for evasion/escape maneuvers during Windshear, TCAS, or GPWS recovery.

How is the angle of bank checked during Manual flight?

The angle of bank is checked at a maximum normal angle (33°) by the spiral stability changing from neutral to positive with a maximum angle of bank of 67°.

What are both pitch and roll limited by during Manual flight?

Both pitch and roll are limited by the Load Factor limitation.

The question on the page originate from the summary of the following study material:

a320 FLIGHT CONTROLS

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