A R ION MILLING

BACKGROUND INSTRUCTION

BACKGROUND

Conducting an autoland from an ILS approach is the only occasion where we don’t take control of the aircraft with the autopilot disconnected and land it manually. If we disconnect the AP at the MDA or DH on an ILS the aircraft is moving on a stable trajectory and all that is required is to flare and reduce the thrust to land.

As a basic rule for all approaches, not later than 1000 ft AGL, the PF should have one hand on the THRUST LEVERS and the other one on the side stick.

This should apply irrespective of Auto Pilot and Auto Thrust selection.

During the final visual segment of the approach it is very important not to over control with the sidestick. The aircraft will maintain pitch and roll attitudes resisting any atmospheric disturbance until 50 ft when the landing mode becomes active. Landing mode is only a pitch mode and roll control is the same as normal law until the wheels are on the ground.

When reaching 50 ft RA, the pitch law blends into flare mode. The system memorises the attitude at 50 ft, and that attitude becomes the initial reference for pitch attitude control. As the aircraft descends through 30 ft, the system reduces (over 8 seconds) the pitch attitude to minus 2º. Consequently as the speed reduces, the pilot will have to pull back on the side stick to maintain a constant path. The Flare technique is thus very conventional.

At approximately 20 ft the thrust levers should be moved to the idle detent.

The RETARD call out (at 20 ft / 10 ft for an Autoland) is a reminder for the pilot to retard the thrust levers, if he hasn’t already done so. Remember that if Auto Thrust is engaged it will remain engaged until the thrust levers reach the idle detent. Consequently, if you are late in retarding the thrust levers in a MANUAL landing, the A/THR will add thrust during the Flare to keep the A/C on target speed. Therefore the correct technique is to move the thrust levers smartly to the idle position when you no longer need the engine thrust during the flare.

In order to assess the Flare and the A/C position versus the ground, look out well ahead of the A/C.

The typical pitch increment in Flare is approximately 4° which leads to a - 1°

flight path angle associated to a 10 kts speed decay in the manoeuvre.

Common faults are too high speed drop below VAPP (pitch up to avoid high sink rate), prolonged hold off to do grease the landing, and flare too high and consequently no control of the de-rotation once the main wheels are on the ground.

De-rotation should be commenced as soon as the main wheels have touched.

The aircraft has a tendency to nose down naturally as the aft stick applied for the flare is relaxed towards neutral. A comfortable nose wheel touc hdown will be achieved if the stick is maintained just aft of neutral during de-rotation.

There is a tendency to pitch-up due to the effect of the spoilers extending behind the Centre of Gravity. Smoothly control the de-rotation. Tail strike occurs (A320) at 13.5º or 11.5º (landing gear compressed), so pitch attitude should be monitored in the flare.

The recommended technique for a crosswind landing is (during the flare) to apply rudder to align the A/C on the runway centre line and counteract the rolling tendency with side stick (with possibly very slight wing down into a strong wind).

NOTE:

In a strong crosswind, a full decrab might lead to a significant into wind aileron input causing a significant bank angle.The pilot must be aware that there are aircraft geometry limitations in pitch and in bank not only to prevent incurring a tailstrike but to prevent scrapping the engine pod, the flaps or the wing tip. In such conditions, a partial decrab is preferable.

At touch down the ground spoilers will deploy automatically which may give a slight pitch up as mentioned above. Automatic ground spoiler deployment will occur with both main landing gear compressed or with one MLG on the

ground and reverse thrust selected. Ground spoiler deployment will enable autobrake operation (if selected). The green DECEL light on the AUTO / BRK panel enable the crew to monitor whether the selected rate of deceleration is achieved. Remember that the autobrake can operate without the DECEL light illuminating. The DECEL light means that the desired rate of deceleration is being achieved, which may not be the case when the Braking Action is poor.

During the Roll Out use the rudder pedals to keep the aircraft on the runway centreline.

Initially the rudder will be aerodynamically effective and below around 100 kts the Nose Wheel Steering function commanded by the pedals will take over.

Do not try and control the roll out with the NWS tiller.

In case of crosswind various precautions need to be considered. These include avoiding deflecting the stick into wind. It will not assist in aircraft control but has adverse side effects on braking. Side stick input creates a down force on the wheels on the into wind side due to the aileron deflection

and spoiler activation, and it creates a differential drag effect due to spoiler retraction on the out of wind side. These differential effects favour the weather-cocking tendency of the aircraft.

In cases of lateral control problem in high crosswind landings reduce the reverse thrust to idle.

At lower speeds, on wet and contaminated runways the directional control of the A/C may be more difficult. If necessary use differential braking.

The Ground Spoilers, the Thrust Reversers and the Wheel Brakes are the three means of retardation on the ground.

The Ground Spoilers contribute to the aircraft deceleration by aerodynamic drag and they increase considerably the wheel braking efficiency by

increasing the load on the wheels.

The thrust reversers have a significant braking effect at higher speeds, but below about 70 kts their efficiency drops rapidly. Their efficiency is

independent to the runway condition. The Maximum reverse thrust is obtained between N1 values of 70% to 85%. In an emergency situation it is permissible to keep Maximum Reverse thrust down to aircraft stop.

The Actual Landing distances demonstrated in flight test and provided in the FCOM and QRH does not include the use of reversers (which constitute a safety margin).

The wheel brakes are the main factors in aircraft deceleration on ground. The brake force from wheels are a function of -

- the load on the wheels,

- the effectiveness of the brakes and anti skid system, - the contact area of the tires with the runway,

- the friction coefficient between the tires and the runway.

Thus the braking efficiency depends upon the A/C speed, the load on wheels, the wheel speed (free rolling, skidding or locked wheels), the runway condition and also the brake temperature and wear.

The antiskid system maintains the skidding factor close to the point providing maximum friction force. With maximum manual braking and with anti skid operative the typical deceleration rate is 10 kts/sec (or .5g).

With Carbon brakes, the wear is directly linked to the number of pedal applications. Pressing the pedals and modulating the pressure without

releasing the pedals is therefore a recommended technique for minimizing the brake wear.

You may use either Manual braking or Autobrake. Autobrake may be used in LO or MED for landing, (MAX is only used for take-off). Auto brake controls a given deceleration rate (LO: 0.15g and MED: 0.3g). The DECEL light

indicates that the selected deceleration rate is being achieved. In other words the DECEL light is not an indicator of the Autobrake operation, but that the selected decele ration rate is being achieved.

Use of Autobrake minimises the number of brake applications and so the brake wear. Consequently it is recommended to use it when available, unless not needed.

To disconnect the Autobrake, pressure needs to be applied to one brake pedal only. However the normal method of disarming the Autobrake is by even pressure on both brake pedals. The auto brake may also be

disconnected by action on the respective AUTO / BRK pushbutton (not recommended as both pilots should be heads up during the landing roll) or by pushing down the speedbrake control lever. Autobrake should be

disconnected before 20 kts is reached.

Max reverse (or idle reverse depending on airport regulations or airline policy) should be selected immediately after main gear touchdown. Reduce reverse thrust to idle at 70 kts.

Idle reverse may remain selected until the airplane is at taxi speed. The PNF should monitor spoiler deployment (ECAM WHEEL page), operation of reverse thrust (E/WD) and the operation of Autobrake (green DECEL light on AUTO/BRK panel) and notify the PF of any abnormal indications

INSTRUCTION

It is an important concept that the aircraft should be aligned with the centreline of the runway during the landing. If the CM2 is flying and you are looking through the main window of CM1 you may think that CM2 is not aligned very well. This is a feature of the projected visual where both pilots see exactly the same picture. If the CM1 is positioned exactly over the centreline, then CM2 will also be positioned exactly over the centreline.

If they have problems landing check they are looking at the far end of the runway during the flare.