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RECONFIGURATION LAWS

42 important questions on RECONFIGURATION LAWS

How can roll control be maintained with Mechanical back-up control?

Roll control can be maintained by using the interconnected Rudder Pedals.

What is available in Alternate Law Yaw if a computer, hydraulic power, and actuator are available?

Only the yaw damping function is available if a computer, and the corresponding hydraulic power and actuator are available; damper authority is limited to ± 5° rudder deflection. Rudder trim may be available.

What protections are lost when operating in Alternate Law without Reduced Protections?

Low Speed and High Speed Protection are lost when operating in Alternate Law without Reduced Protections. All other features, protections, and MODES are identical to Alternate Law with Reduced Protections.

What is required for Direct Law capability in Pitch?

To have Direct Law capability, at least one of the Pitch and Roll computers must be operating and the assigned servojacks must have hydraulic and electrical control power available.

How can pitch control be maintained with Mechanical back-up control?

Pitch control can be maintained by use of the interconnected Trimmable Horizontal Stabilizer (THS) trim wheels.

What is Low Speed Stability and when is it active?

Low Speed Stability is available for all slat/flap configurations, and is active from + 5 knots to + 10 knots above VSW (VSW is a function of both gross weight and slats/flaps configuration).

Under what condition are speed protections lost according to Page 22?

These Speed Protections are lost if there is not at least one SFCC slat channel input and two reliable airspeed sources available to the active EFCS.

What happens to EFCS when inputs are insufficient to support Normal Law or Alternate Law?

The available EFCS will direct the system to reconfigure to Direct Law if the inputs to the EFCS are insufficient to support Normal Law or Alternate Law.

Until when is the Mechanical back-up control operation provided?

This operation is provided as a back-up control until one or more EFCS computer(s) can be reset.

What protections are available during Direct Law?

There are no protections and only Manual Stabilizer Trim is available during Direct Law.

What are the three phases of flight in Alternate Law with Reduced Protections?

Alternate Law with Reduced Protections has three modes for three phases of flight. These phases of flight are FLIGHT, FLARE, and GROUND.

How is Sidestick authority affected in Low Speed Stability?

The Sidestick authority is reduced by a gentle progressive nose down signal that is introduced, which tends to keep the speed from falling below these values.

What is the relationship of Roll Direct Law during Alternate Law?

Roll Direct Law is in effect during Alternate Law; it is a direct stick-to-surface-position relationship and identical to the Roll Direct Law for Direct Pitch Law operation.

What is available during Alternate Law according to Page 6?

Automatic Stabilizer Trim is available during Alternate Law. Depending on the failure, the Auto Pilot may be available until 3 sec. after the landing gear is down.

What happens in the FLIGHT mode during manual flight in Alternate Law?

In the FLIGHT mode, during manual flight in Alternate Law, the amount of side stick displacement determines pitch rate and follows a load-factor demand law as Normal Law does, but it has less built-in protection (reduced protections) with no High Angle of Attack or Pitch Attitude Protections.

What additional features are activated in Low Speed Stability?

The pilot can override these demands. In addition, audio stall warnings are activated at a margin above stall speed (VS) and the PFD speed scale is modified to display a black/red barber pole below VSW.

How are system gains set according to Page 25?

System gains are set automatically to correspond to slat/flap configuration. With the aircraft in the clean configuration, the maximum roll rate is 30°/sec (twice the Normal Law 15°/sec) and with slats extended, it is 25°/sec.

What is lost in Direct Law Yaw?

Yaw Turn coordination and yaw damping are lost; yaw inputs are through the rudder pedals. Rudder trim may be available.

What are Reconfiguration Laws and when do they occur?

Reconfiguration Laws occur during some equipment failures and abnormal flight conditions.

What does Page 7 say about Alternate Law and the Pitch axis?

When we speak of Alternate Law, we are addressing the Pitch axis only. During the Reconfiguration Laws, the Roll axis will always be in Direct Law if Sidestick input is available to the Roll Control surfaces. The Yaw axis will have Alternate Yaw Damping if yaw damping capability is available but Turn Coordination will be lost.

What protections are lost in Abnormal Attitude Law?

When operating in Abnormal Attitude Law, the Low Speed and High Speed Protections are lost.

Is there an Alternate lateral control mode for roll in Alternate Law?

There is no Alternate lateral control mode so the roll mode will change to the Roll Direct Law with no Bank Angle Protection.

When is High Speed Stability available and what happens to Sidestick authority?

High Speed Stability is available above VMO or MMO, the Sidestick authority is reduced when a nose up demand is introduced to avoid an excessive increase in speed.

What does the Roll Direct Law use to limit roll rate?

To limit roll rate, the Roll Direct Law uses only ailerons and two roll spoilers. If a spoiler or the ailerons have failed, other roll spoilers become active. Bank Angle Protection is not provided.

How many Reconfiguration Laws are there and what are they?

There are three Reconfiguration Laws: Alternate Law with and without Reduced Protections; Direct Law; and finally Mechanical Back-up.

What remains available in High Speed Stability?

The pilot can override this demand. In addition, the aural overspeed warning remains available.

How are Speed Protections described under Alternate Law on Page 8?

For Alternate Law, the Speed Protections are similar to the Normal Law Speed Protections but can be exceeded. The Normal Law Speed Protections are replaced by Alternate Law "Low Speed" and "High Speed" Protections. These protections require additional Sidestick input to exceed the protections.

What happens to the Pitch Alternate Law Sidestick authority as the aircraft approaches stall warning speed?

The Pitch Alternate Law Sidestick authority is reduced as the aircraft approaches stall warning speed (VSW) for Low Speed Stability because the EFCS will command nose down and bank angle compensation for constant á.

What happens to control authority in Abnormal Attitude Law?

All other features, protections, and MODES are identical to Alternate Law with Reduced Protections except there is no reversion to Direct Law when the landing gear is extended. This feature is to ensure full control authority during upset and is not recoverable until after landing.

What can the ELAC 1 and 2 computers control during Reconfiguration Laws?

ELAC 1 and 2 can control the Elevators, Stabilizer, and Ailerons.

What protections are lost in Alternate Law according to Page 8?

Pitch Attitude, Bank Angle, and High Angle of Attack Protections are all lost and not replaced by a protection. The Load Factor Limitation in Alternate Law is similar to that under Normal Law.

How is Sidestick authority affected as the aircraft approaches maximum operating speed?

Similarly, Sidestick authority is reduced as the aircraft approaches maximum operating speed (VMO), or maximum operating MACH (MMO) for High Speed Stability because the EFCS will command nose down.

What is FLARE MODE and when does it activate?

In pitch alternate law the flight mode changes to the FLARE mode when the pilot selects landing gear down.

When does the system apply Abnormal Attitude Law in pitch and roll?

The system applies this Abnormal Attitude Law in pitch and roll if the aircraft exceeds any of these limits in flight.

What is required for Alternate Law capability regarding Pitch and Roll computers?

At least one of the Pitch and Roll computers must be operating and the assigned servojacks must have hydraulic and electrical control power available.

What does Page 9 state about Alternate Law with Reduced Protections?

Alternate Law with Reduced Protections...

Describe the relationship in FLARE MODE.

The flare mode is a direct stick-to-elevator relationship.

What will the available computer(s) do if inputs are insufficient to support Normal Law?

The available computer(s) will direct the system to reconfigure to Alternate Law if the inputs to the computer(s) are insufficient to support Normal Law.

What will be described on Page 10 regarding Alternate Law?

We’ll first describe Alternate Law with Reduced Protections. Differences for Alternate Law without Reduced Protections and Abnormal Attitude Laws will be discussed later.

What is GROUND MODE and when does it become active?

Alternate GROUND mode operation, is identical to Normal Law GROUND mode and becomes active on the ground after touchdown.

How many phases does Alternate Law with Reduced Protections have according to Page 11?

Alternate Law with Reduced Protections has three modes for three phases of flight.

What happens during the transition from GROUND mode to FLIGHT mode?

Transition from ground mode to FLIGHT mode is not normal, but if it is necessary to Go-around after touchdown, the aircraft will transition to the Flight mode after the landing gear is up.

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

a320 FLIGHT CONTROLS

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