Mode Charlie and Class D Airspace

[martinidoc]

I recently requested an IFR clearance to transit Teeside in a club aircraft which only transponds mode alpha. This was denied, because of the lack of mode C.

Two day later in the same Mode A aircraft, I requested a VFR transit through Leeds which was denied because of traffic density, but I was offered (and accepted) an IFR clearance.

Which is correct, or is this a matter of ATC discretion, based upon workload?

I realise I could probably get the answer by wading through the ANO, but I'm sure one of you could answer the question very quickly

Thanks

[Chilli Monster]

There is no requirement to deny a transit (at the moment) due to a lack of mode 'C'. If you're IFR you're at a known level anyway, so the only time you may cause a problem is during a long climb or descent (not likely in an airfields class 'D' - they're not that high ) when the Controller will use the mode 'C' to establish whether you have vacated a level without asking.

Sounds to me like you were unlucky at Teeside - possibly due to workload.

[almost professional]

Sounds like an excuse to me-could understand if no transponder at all (though would have to be pretty busy to refuse transit totally under those circumstances-only time I have ever directly refused transit was for unreadable radio) having mode C makes life easier , not having it does not make life impossible-just need to keep the strip marking up!
As for refusing a VFR clearance but offering IFR?, making a rod for your own back

[Legs11]

by the book

for the record the carriage of transponders is a requirement within UK controlled airspace below FL100 when operating under IFR (but not VFR) with the capability for Mode A and Mode C with altitude reporting.

You should be able to select Mode C simultaneously with Mode A unless otherwise instructed by the ATS unit - whether this be for malfunction reasons or whatever

An exception exists for aircraft below FL100 in CAS receiving an approved crossing service.

OK so that's the legal, however I would suggest that most controllers would cope unless very busy and whilst not knowing if NM or NV have any local instructions, I reckon Chilli's right and you were just unlucky at Teeside

[Samwise]

More SSR confusion

I would like to add to Leggs11's comments.

According to the UK AIP (page ENR 1-5-1, I think) ATC may authorise a/c to transit controlled airspace IFR without mode C, on an occasional basis, and subject to traffic. However this authorisation shall not be given to aircraft that regularly require access to the particular airspace.

This is from memory, certainly not verbatim, but you get the gist!

Interpret this as you will.

[VectorLine]

and you even got the page from memory? Mr memory man or spend too much time reading the AIP?

[ecj]

It certainly makes life easier for me using TCAS if they do have mode C as well. Mode A usually only leaves you guessing, and in class F & G airspace [ north of 55N ] I take sufficient lateral separation to avoid the machine going off. TRAFFIC TRAFFIC