Volume 8: The Weird and Wonderful Logic RECORD OF REVISIONS revision n° Issue date Release Description 001 15 June, 2018 1.00 completion 002 10 July, 2018 1.
A318/A319/A320/A321 Professional The Weird and Wonderful Logic Vol 8 8-03-1 10 July 2018 CONTENTS THE WEIRD AND WONDERFUL AIRBUS LOGIC .................................................................................................. 2 AUTOMATION ................................................................................................................................................... 2 FLY BY WIRE ...................................................................................................
A318/A319/A320/A321 Professional The Weird and Wonderful Logic Vol 8 8-03-2 10 July 2018 THE WEIRD AND WONDERFUL AIRBUS LOGIC In the last few years we have seen many pilot who were used to Boeing (and more ‘standard’ logic) have problems understanding the logic of Airbus. We’ll try to discuss the most confusing and often illogical aspects in this document. This is not a highly technical document and people accustomed to Airbus logic will not need it.
A318/A319/A320/A321 Professional The Weird and Wonderful Logic Vol 8 8-03-3 10 July 2018 Another very important aspect of FBW is that when the pilot does not give any input the aircraft will stay on its current flight path. Best explained with an example. Take an Airbus up to 5000 feet, bank it a bit and let go of the side stick. Then go have diner. When you come back the aircraft will still be at the same bank and making large circles in the sky.
A318/A319/A320/A321 Professional The Weird and Wonderful Logic Vol 8 8-03-4 10 July 2018 THOSE PESKY FCU BUTTONS The buttons on the FCU (the Flight Control Unit, on the glare shield) can be pushed or pulled and this leads to endless confusion for new pilots. Yet there is a great way to remember what is what: • • PUSH: you push control from you to the aircraft and go into MANAGED MODE. The aircraft will now fly the route (with altitudes and speed etc) programmed in.
A318/A319/A320/A321 Professional • The Weird and Wonderful Logic Vol 8 8-03-5 10 July 2018 BANK ANGLE PROTECTION: another things your passengers will not like is to look out of the window and stare directly at the ground. Also at high bank angles you will lose a lot of lift and speed and G-loads will increase rapidly. That’s why the Airbus systems will prevent a very steep bank. It will let you bank up to 67° and when you let go of the stick will return to 33°.
A318/A319/A320/A321 Professional The Weird and Wonderful Logic Vol 8 8-03-6 10 July 2018 PHASES In Airbus logic every flight is divided into stages and stages are very important to understand the logic of the Airbus systems. Consider a stage to be a combination of system settings and parameters.
A318/A319/A320/A321 Professional The Weird and Wonderful Logic Vol 8 8-03-7 10 July 2018 MODES Next to phases you got to understand Modes. They are not as complex as Phases as there are only three (I copied this from airbusdrivers.net, a great resource for any Airbus enthusiast) but as they change the way controls work they are important. • • • Ground Mode o Active when aircraft is on the ground.
A318/A319/A320/A321 Professional The Weird and Wonderful Logic Vol 8 8-03-8 10 July 2018 reasonable confidence what the surface-wind is likely to be at the landing threshold, they enter the figure into the approach Performance page. The FMS works out the correct Vapp, which is a threshold IAS based on weight and headwind component. Now: let's take the sea-level ISA case, where IAS=TAS; a Vapp of 130kts; and a predicted headwind of 10kts entered into the Performance page.