and audio stall warning is activated at an appropriate margin from the stall condition and the upper floor protection is inoperative ladies and gentlemen welcome to my channel captain sq where we're going to discuss on eba systems emergency procedures and supplementary techniques on how to fly the plane a320 normal low alternate law direct law and mechanical backup airbus laws that keep you safe disclaimer always refer to your company manuals this video is merely a guide before we start do destroy the like button comment and subscribe if you want to see more of these videos all right let's start with normal law normal law is indicated to the pilots by the double green symbols on the pfd in normal law regardless of the pilot's input the computers will prevent excessive maneuvers and accedences to keep the aircraft within a safe light envelope flight control normal law covers control in three axis number one pitch number two row number three yaw let's look at flight envelope protection alleviation of maneuver loads in ground mode ground mode in a direct relationship between side stick deflection and elevator deflection without the auto trim ground node automatically sets the trimmable horizontal stabilizer or ths at zero degrees which is within the green band a manually adjusted that settings for takeoff cg has priority when the aircraft reaches 75 knots during the takeoff roll the system reduces maximum up elevator deflection from 30 degrees to 20 degrees ground mode blends into flight mode during the first five seconds after liftoff let us look at flight mode in normal law the site stick sets the elevator and that shares to maintain a load factor proportional to stick deflection as is independent of speed with the side stick and neutral and wings level the system maintains one g in pitch and there is no need for the pilot to trim if he changes speed or configuration which stream is automatic in normal turns with up to 33 degrees of bang the pilot does not have to make any pitch correction once the turn is established nor does he have to introduce your the aircraft does it for you automatic pitch trim freezes in the following situations the pilot enters a manual trim order via the ths the radial height is below 50 feet or 100 feet with autopilot engage and the load factor goes below 0.5 g or above 1.25 g when the angle of attack protection is active the thcs setting is limited neither the pilot nor the system can apply additional nose up trim when high speed or high mark protection is active th s setting is limited between the setting at the aircraft entry into protection and 11 degrees nose when the aircraft exceeds 33 degrees angle of bang thss is limited between the setting at the aircraft entry into this protection and 3.5 degrees nose down control with autopilot engage the elec and sex limit what the autopilot can order with the autopilot engage their side stick has a restraining force keeping it in neutral position if the pilot overcomes this force the autopilot is disconnected the pilot can also disconnect the autopilot by pushing on the rudder pedals 10 degrees out of trim or by moving the pitch stream will beyond a certain threshold all protection of normal law remains active at pitch attitude protection let us move on to the flare mode and the flare mode is essentially a direct stick to elevator relationship with some damping provided by the load factor and the pitch rate feedbacks flight mode changes to flare mode as the aircraft descends below 500 feet radioaltimeter height to land the ths is frozen and the system memorizes the aircraft attitude and it becomes the initial reference for pitch attitude control as the aircraft descends through 30 feet the system begins to reduce the pitch attitude to -2 degrees nose-down over a period of 8 seconds and consequently to flare the aircraft a gentle nose up action is required flat mode transitions to ground mode over the next 5 seconds when pitch attitude is less than 2.5 degrees well let's take a short break and we move on to the alternate law thereafter [Music] all right before we dive in into alternate law i made an error on purpose regarding normal law can you figure it out and if you know the answer do comment below okay let's dive in alternate law well alternate law is like having protected sex the condom breaks now you have to be extra careful as things gets a little sensitive inflight amber access replaces the green double bars on the pfd and an ecam flight control alternate law indicates that the aircraft flight control laws have changed from normal to alternate law alternate law can be with or without protections let's look into pitch control in flight mode in flight the alternate law pitch mode follows a load factor demand law much as the normal law with auto trimming in changes of speed or configuration but it has reduced protections caution there is no pitch attitude protection and in flare mode in pitch alternate law the flight mode changes to the pitch direct law when the pilot selects the landing gear down the flare mode is a direct stick to elevator relationship with manual trimming by the ths and let's look at ground mode under alternate law the ground mode becomes active on the ground 5 seconds after touchdown it is identical to the ground mode of the normal law it is a direct relationship between side stick deflection and elevator deflection without auto trim it automatically sets the trimmable horizontal stabilizer or ths at zero degrees which is inside the green band let's have a look at the lateral control when the aircraft is flying in pitch alternate lord lateral control follows the role direct law it is a direct stick to control surface movement relationship using the ailerons and spoilers 4 and 5. some special knowledge for you guys if spoiler number 4 has failed spoiler number 3 replaces it and if the ailerons have failed all spoilers becomes active for the role roll rate is automatically limited to about 30 degrees per second in clean configuration and 25 degrees per second when sleds are extended the rate of roll is higher than normal law so the aircraft can be very sensitive at first do be careful my friends because there is no bang angle protection okay we have covered pitch and lateral control let us move on to the your alternate law your alternate law the turn coordination function is lost and the pilot controls your with the rudder pedals only the your damping function is available damper authority is limited to plus minus 5 degrees of radar deflection ok so now what protections we have then number one load factor limitations it is similar to normal law which is plus 2.5 gs to minus 1g for clean configuration and plus two g's to zero g's for other configurations number two we have low speed stability function and artificial low speed stability replaces the normal angle of attack protection it is available in all slats and flaps configuration and it is active from about 5 knots up to about 10 knots above stall warning speed depending on the aircraft gross weight and configuration a gentle progressive nose down signal is introduced which tends to keep the speed from falling below these values the pilot can override this demand and the system also introduce bank angle compensation so the aircraft effectively maintains a constant angle of attack the pfd speed scale is modified to show a black red barber pole below the stall warning and audio stall warning is activated at an appropriate margin from the stall condition and the upper floor protection is inoperative number three we have the high speed stability function and above vmo and mmo a nose up demand is introduced to avoid excessive increase in speed the pilot can override this demand in addition the oral overspeed warning which is vmo plus four knots or mmo plus 0.06 mark remains available let's have a look at the alternate law without protections and this is identical to autumn law except that it does not include the low speed stability or the high speed stability it includes only the load factor limitation this topic is rather dry with a lot of numbers and figures so not to worry we are almost at the end of this topic next we will have a look at direct law and being in dire law is kind like having unprotected sex you feel more a little more sensitive but boy you are entering a danger zone here all right direct love the pfd displays message use man pitch stream this message flashes for five seconds and then becomes steady the ecam displays flight control direct law protection loss use small control inputs when the aircraft is in direct law as controls are light and powerful guys at this point the controls are sensitive some pointers here good trimming and pitch is required avoid large changes in truss or sudden speed brake movements and landing in direct law is like landing a conventional aircraft as usual we look into pitch lateral and yaw the three axis the pitch direct law is direct stick to elevator relationship elevated deflection is proportional to side stick movement the maximum elevator deflection varies with the aircraft cg it is a compromise between adequate controllability with the forward cg and not too sensitive control with an rcg just like a compromise between a husband and wife there is no automatic trim so you the pilot must stream manually there is no pitch attitude protection so over speed and stall warning are available which is same as alternate law no protections are operative and the alpha flow function is out as well next we will look at lateral control when the aircraft is flying in pitch alternate law lateral control follows role direct law it is a direct state to control surface movement relationship using ailerons and spoilers four and five special note if the spoilers number four has failed spoiler number three replaces it and the ailerons have failed all spoilers becomes active road rate is automatically limited to about 30 degrees per second in clean configuration and 25 degrees per second when slats are extended the rate of roll is higher than normal low and the aircraft appears to be very sensitive at first there is no bang angle protection does this sound familiar surprise yes you are right lateral control in direct law is the same as alternate law lastly let us look at your mechanical control the pilot controls you're using the rider pedals and your damping and turn coordination functions are lost and there you have it short and sweet message on direct law finally we are at the last end of this series the last mile the last run mechanical backup mechanical backup enables the pilot to control the aircraft during a temporary complete loss of electrical power and therefore loss of all computers guys this is a very very rare occurrence but it is good to know the pfd displays man pitch trim only in raid the pilot edges the pitch by manually applying trim to the ths and the pilot uses the rod pedals as the mechanical backup to laterally control the aircraft this degraded mode is designed to enable the pilots to control the aircraft until the restoration of the other flight system occurs so only the rudder and the ths controls are available however the pilot does have the use of trust increased trust gives no sub pitch and decreased trust gives nose down pitch and is quicker acting than trimming the aircraft itself and caution differential truss will give your and is definitely not recommended very very hard to fly in this state so good luck i have not heard stories about pilots being in mechanical backup stage but if you have do comment on the section below and let us discuss that's it for this video do comment subscribe and like this video and i will see you in the next video also if you have any videos that you like to see do comment in the section below