Just to clarify, I'm talking about offsetting without a specific clearance from ATC to do so.
tobzalp. There is no problem with 1000 ft separation, but I used the road analogy for a reason. What do the two cars in my analogy have in common?
I know that aircaft such as the B767 and B737-400's (that have IRU's and FMC's without GPS position updates) often have an ANP up around 3 nm when they haven't had a DME or VOR position update for a while. This is always the case on Australian transcontinental flights. For this reason I personally don't see the problem with offsets of less than 1 nm for aircraft that do have GPS updates.
I suppose I am wanting to start a discussion on this subject because at the moment it is not standard practice to offset when outside radar coverage, and I think it should be.
Why do we choose to have two airliners with GPS position updates, flying towards each other at a combined speed of 900 knots outside radar coverage with absolutely no lateral separation (not even a wingspan) and relying soley on vertical separation for collision prevention??