Now that the 8/900 will use 'offsets' in the FMC, when would you use this feature and why? When do they use it in the real world? The only reason I can think is beacuse of traffic and ATC tell you to. Thanks.

To get around long streches of bad weather and traffic issues, would be the main uses I believe.

Over on the pprune forums, I have read that many pilots use it as a method of traffic avoidance on heavily travelled airways. For example, you might program a 1 mile offset to give yourself an extra margin of safety during cruise, and I'm not sure ATC would even notice. During a Departure or Arrival, I would imagine you would NEVER want to do this.Hope this helps (and prepared to be shot down)!

Hi Jeff,Even if they do notice they can't say anything because airways are 5nm wide. So as long as you stay whithin 5nm offset you are not off route.Bruno Francescoli :-waveStudent Pilot.KOPF PA28-161.

I feel redeemed :) Thanks for the info!Jeff

Ahh. Now I know what they are, lol.I didnt know Airways were 5nm wide...Probably a stupid question but: Are there "one way" airways? What are the different types and what are they all used for? If anyone could answer..Cheers,Ryan

>Ahh. Now I know what they are, lol.>>I didnt know Airways were 5nm wide...>In the US, they aren't. An airway is typically defined as 4 NM each side of the centerline, for a total width of 8 NM.That said, however, a pilot is likely to get called if he's consistently more than a mile or two offset without first coordinating it with ATC.There is a US rule that requires flying the centerline (91.81, I believe).

It is not a good thing to use offset without asking ATC when under radar surveillance. However in areas where there's no radar but at the same time opposite traffic on the same airway this makes sense. A good example is Africa. Above the Atlantic Ocean even though there's no radar you do not need to fly offset because the NATs are one-way anyway...BTW ATC controllers may use offset navigation as a purpose of separation. Say two airplanes are on the same airway opposite to each other, same level. Now the controller tells both airplanes to fly offset 2.5nm to the right. Perfect 5nm separation. However this is extremely rare, but it could be used.Best regards,Markus

ok. Thanks for the info guysRyan