[James Chan]

The flight procedures at Redhill state that all users must have a serviceable alt-reporting transponder or words to that effect. Aircraft not equipped may be allowed subject to prior approval.

Does that mean a TMZ should be indicated on the chart where the ATZ is?

[Lerk]

No, because a TMZ requires Mode S doesn't it?

[xtophe]

No, because a TMZ requires Mode S doesn't it?

Not necessarly. The Farnborough ones require only A+C.

[pullup]

The requirement to enter the Stansted TMZ is a Mode S transponder if you do not wish to communicate with Essex Radar. No actual clearance is required.
If you are not equipped with Mode S then a positive clearance is required either from Essex Radar or Farnborough.
Is this not standard for any TMZ?

[ak7274]

Transponder Mandatory Zones require Mode S, meaning they do not have to contact anyone to enter.
Farnborough doesn't have a TMZ.
At least not accord to their AIP, my Paper chart and Sky Demon.

[xtophe]

Farnborough CTA 8 and 9 are Class E + TMZ

Edit: will be in 16 days

[pullup]

No, because a TMZ requires Mode S doesn't it?

Not necessarly. The Farnborough ones require only A+C.

A mode S transponder is required to enter a TMZ. No radio call required.
If you do not have mode S then a clearance to enter the TMZ is required from the controlling authority.

[PaulB]

No, because a TMZ requires Mode S doesn't it?

Not necessarly. The Farnborough ones require only A+C.

A mode S transponder is required to enter a TMZ. No radio call required.
If you do not have mode S then a clearance to enter the TMZ is required from the controlling authority.

Which bit of the AIP is that in? (Just been looking but couldn't find it. SERA.6005 allows the ANSP to specify)

[xtophe]

Code: Select allFarnborough CTA 8 is a TMZ (Transponder Mandatory Zone). Carriage and operation of a transponder with Mode A code and Mode C altitude (or equivalent Mode S) is mandatory. Provisions for non-equipped aircraft are promulgated by the controlling authority 01252-526015 (ATC-Radar).

That's the wording in the AIP which will be valid from the 27th Feb in ENR2.1 for Farnborough cTA 8 and 9.

[PaulB]

I was meaning the more general bit that describes RMZs and TMZs.

[Tim Dawson]

Interesting you should pick up that wording about the TMZ for the new Farnborough airspace. Personally I think that is wrong. Mentioning that it “is a TMZ” in the remarks attached to the definition of a piece of controlled airspace most definitely does not make it a TMZ.

Someone has forgotten to actually define the TMZs anywhere.

[xtophe]

Someone has forgotten to actually define the TMZs anywhere.

There are definition and requirement for mode S in GEN 1.5 para 5.3.

But the Farnborough CTAs are not listed there.

So either the Farnborough TMZ are non-existent as not properly defined
or
GEN1.5 is only for TMZ requiring mode S. The others are the default definition coming from SERA.

[Tim Dawson]

I think they are technically non existent as not properly defined.

That’s probably independent of any mode S question though, just an interesting aside.

[xtophe]

It seems there are also Holyhead CTA 15 and 16 which are defined as Class E + TMZ in ENR2.1 but are not in GEN1.5

Doncaster CTA13 also E+TMZ is in GEN1.5

In ENR2.1 all the notes about TMZ say "a transponder with Mode A code and Mode C altitude (or equivalent Mode S)" and so are at odds with GEN1.5

[patowalker]

https://publicapps.caa.co.uk/docs/33/20 ... AndTMZ.pdf