I have been out of the system for some time.
You should consider P18 as a part time airway:
NATEB - ADN CDR 1 Fri (or the day preceding a PH) 1500 (1400) to Mon (or the day following a PH) 1000 (0900); Tue-Fri 0530-0900 (0430-0800).May-Sep, Mon-Thu 1900-0900
The convention is that UP18 is a one way airway so when P18 is available it is there for Aberdeen inbounds. However having said that Eastern Airways ( EZE ) use P18 because when the airspace disappears they had an arrangement with Swanwick Mil to provide a Radar service.
During it’s operational hours Flybe used to use it for southbound flights. My last ever live ATC transmission was to BEE24KE a Dash 8 Aberdeen to Leeds. Sadly airline and route no longer exist.
KLM would appear to use it however they were probably just routing direct to the UIR boundary ( saving the planet! ) and they were just passing through the airspace 🤔
P18 was established to protect flights by providing controlled airspace. When the airspace expired I enjoyed telling the aircraft “controlled airspace has left you. What service do you require?”
Hope this helps a little.
Rgds
AyrTC
Last edited by AyrTC; 28th Jun 2021 at 21:02.