Mode S:
My understanding is that from March next year you must have
a Mode S transponder in airspace classes A-C and in TMZs. A mode C or A
transponder will not be legal. In other airspace (i.e. outside of UK
controlled airspace) it is less clear and not helped by random
statements in mags like Loop that suggest that ALL aircraft must have
Mode S.
Given that the reason for mandating Mode S is to prevent
potential saturation of the transponder RF 'environment' by the replies
---From older mode A/C units, the logical thought is that the use of Mode
A/C transponders will be illegal everywhere, but I cannot find a
statement to that effect. The nearest I can find is that any
transponder fitted after March 2012 must be Mode S.
The alternative is
that once the IFR aircraft are fitted with Mode S, the RF environment
can cope with the remaining few Mode A/C units in our aircraft. If that
is the case then you are ok until you can no longer get it repaired, so
long as you never fly in class A to C airspace or TMZs.
The original
plan was to fit Mode S to everything because CAA would sponsor the
manufacture of a 'lightweight transponder' or LWT. This failed when it
was found that the technology could not be shrunk enough to be viable
in a portable battery powered device. Ever since then the information
to GA users has shrivelled and even now gliders are still being
threatened with Mode S for flights above FL100.
A poorly communicated
piece of legislation.
Ian
|