Offsetting-An ATC perspective
In radar airspace. I think it very much a bad idea. Your 1 or 2nm offset may infact put you in conflict with another route. The controller is expecting you to fly a particular track and makes judgements based on your predicted track only to find you a mile or so closer to that other aircraft that you were going to slide nicely 5nm past.
Outside radar coverage:-
Not such a bad idea. Especially in areas where you don't particulary trust ATC. But here are some things for ADS/CPDLC aircraft to consider (Australian airspace)
i) When you fly an offset it is immediately known to ATC. Personally I don't give a hoot. The current rules do not allow me to ignore the fact that you are flying an offset
and because I know you are flying an offset I have to take that into consideration when working out seperation problems and this adds considerable complexity and delays to the calculation.
ii) When flying an offset the data from your ADS does not automatically update the data into the ATC computer as it would if you are flying on the route (because you are not on track it doesn't recognise that you have over flown any waypoints). You will probably be asked to give CPDLC positions.
A Singapore Airlines pilot told be the other day that it was company policy to fly an offset. Is this an official policy or just a policy of the pilots or was he telling me porkies?
Another pilot the other day was complaining to a colleague about not being able to get a particular level despite him being about 10nm away (outside radar coverage). He said that his GPS was accurrate to 50m and why should he be held up. My colleague's response was "So you would be happy to have another aircraft 50m from you?" This shut him up but I thought it was an interesting question. Just how close are you prepared to have another aircraft from you. Pilots often complain when they can't have what they want, but the line has to be drawn somewhere!