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Old 27th Jun 2009, 11:28
  #100 (permalink)  
Join Date: Aug 2002
Location: Switzerland, Singapore
Posts: 1,305
Well, in fact, there are two different AL's. But alternate in the correct sense doesn't exist at all! Funny to here that after so much squak?

AL is just a transitionary phase from normal to direct law. Actually, when you are in AL, you are direct law in roll and some (un)protected condition in pitch. To make it easier, AI called this mode AL. But generally speaking, there are only 2 laws, normal and direct. Which is completly logical: Eighter the computer does it, or you!

To make it even more complicated, there are two different AL! If you are still with me, continue to read: There is AL with protections and AL without. Pretty simple, when your computers still can deliver protections, they do, if they cannot, they don't. So it goes back again to the "AL doesn't exist" from above.

So, your question is: Do you have over- and underspeed protection in alternate law? Well, it depends. If you are in AL with reduced protection (that's what you mean by AL1 I guess), you still have low and high speed stability, and you have load factor stability. So in other words, you have it all (pitch-wise). In AL without proctection, you only have only load factor stability.

Or, in other words: In AL1 you still have all. Well, nearly all. In fact, you don't have anything. The trap is in the word "reduced" protection. As soon as you are in AL, the nice little green double bars at the speed tapes disappear, and amber X's are painted. This is a clear sign that you are not protected against high or low speed conditions. So you have to live with it.

If someone is still able to follow me, you are an Airbus pilot

Dani is offline