LARS - Available up to FL95 or FL100?

LARS is available up to and including FL100 as per the answers marked correct in AirQuiz.

It used to be up to FL95 though, which is why some books still report this. At the time of writing, April 2012, not all of the publications had caught up with this change.

The service is available to all aircraft flying outside Controlled Airspace up to and including FL 100, within the limits of radar/radio cover. The service will be provided within approximately 30 nm of each participating ATS Unit. Unless a participating ATS Unit is H24, the service will normally be available between Winter 0800 and 1700, Summer 0700 and 1600, Mondays to Fridays. However, as some participating Units may remain open to serve evening, night or weekend flying, pilots are recommended to call for the service irrespective of the published hours of ATS. If no reply is received after three consecutive calls, it should be assumed that the service is not available.

See also page 23 of the CAA VFR guide, 2011 edition. Under the heading of LARS, it states that the service is available to all aircraft flying outside Controlled Airspace up to and including FL 100, within the limits of radar/radio cover. (Note that as a secondary source of information, it is just copying what is said in the AIP.)

Some PPL textbooks and also CAP 413 hasn't caught up with this change yet, at least not by Edition 20. (It is probably on the change list for next edition, but as the book is more about radio procedures it probably didn't warrant a reissue of the edition just for this amendment.)

References:

You can get ENR 1.6 from the NATS website. See section 3.1.1.

CAA VFR Guide http://www.caa.co.uk/docs/64/VFR_Guide_2011.pdf

Atmospheric Picture

FL45, English Channel.