Glasgow and Prestwick SIDs and STARs

[Albaman]

I am aware that certain SIDs and STARs were changed with effect from 11 December 2014. I am curious what prompted these changes although I understand the Dean Cross VOR was withdrawn from the same date.

Specifically, I see that the former New Galloway and Turnberry SIDs have been truncated at NORBO - what is the benefit in the SID terminating closer to the departure point ?

Finally, I've always wondered, why do such changes always happen on a Thursday?

Any information would, as always, be much appreciated.

[DaveReidUK]

Finally, I've always wondered, why do such changes always happen on a Thursday?Aeronautical Information Publication - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Aeronautical_Information_Publication#AIRAC_effective_dates_. 2828-day_cycle.29)

[Crazy Voyager]

The shortening of SIDs has to do with fuel planning, and has happened at many UK airports this year (Luton, Heathrow, Gatwick, Manchester, Prestwick and probably a few more).

When the flight planning is made the airline has to plan to remain at the initial level for the duration of the SID. Flying heavy at low level is in turn very inefficent. Most SIDs were much longer than the actual level segment was ever going to be, so by shortening the SIDs the airlines could plan for a more realistic portion of low level flight. Thereby reducing the amount of fuel needed.

It's probably a reasonably minor saving per flight, but when you do it for thousands of flights a year the numbers quickly stack up.

[Albaman]

Many thanks for the replies.