Likelihood of clearance

[bookworm]

Generally, I think the operational freedom offered by the UK airspace system for IFR flights in class G works well, with ad hoc clearances through controlled airspace as required. Yesterday, it didn't work quite so well, and I'm wondering if I'm missing a trick.

Tuesday, a trip from Cambridge to Bristol-Filton. Cloud base about 1500 ft, tops at about 3500 ft, I have the choice of a nasty scud run VFR below the layer or climbing above it. I tell Cambridge I'd like an IFR departure at 4000 ft towards WCO. The base of the Luton CTA on that leg is 3500 ft so it requires a clearance through. This way round it works seamlessly, clearance issued as requested shortly after first contact with Luton, and a handover to Brize on passing WCO.

Wednesday, the return trip. Cloud base about 3000 ft, tops at about 4500 ft. VFR below the cloud all the way would be quite feasible, but, while the vis below cloud is not brilliant, it's a nice day and the traffic density below the cloud is likely to be much higher with lots of primary and non-Mode-C traffic: so prudent risk management suggests that FL50 in clear air is the level to be at. Works perfectly as far as Oxford, with a RIS from Filton then Brize.

Now I have a choice to make. If Luton will clear me at 5000 ft through the CTA, the obvious thing to do is stay on top. If they won't, I need to be below 3500 ft below the cloud to get under the CTA. I ask Brize if they will handover to Luton: no, they have no landline to Luton (strange that, are there a lot of one-way telephone lines? ;)).

So I freecall Luton with about 10 miles to run to WCO, and request transit at 5000 ft. Nope, and I'm offered only a Flight Information Service, and I'm now passing WCO. Fair enough, Luton sounds busy -- and even if 129.55 is quiet that doesn't mean much. But now I have a dilemma. I can't stay at 5000 ft because of the Luton CTA, I'm above a layer, and I have only a FIS. So I'm faced with a descent through a layer of cloud without a radar service, in the failry busy airspace south of Cranfield. The exposure is no more than a couple of minutes, so the risk is acceptable. I would rather have done so under Brize's radar service, but I've burned that bridge now.

So, what should I have done?

File airways? It's only slightly longer but it feels like an imposition on TC to L9 and a STAR through the TMA for a short flight.

Could I have called Luton on box 2 while still getting a service from Brize to ask about the likelihood of a clearance? (Could I buy Brize a telephone to allow them to make the call for me? ;))

Should I have asked Luton for a RAS for 2 minutes while descending through cloud?

Please don't misunderstand: no complaints, I'm just trying to work out how I can best manage the risk.

[eyeinthesky]

It sounds like you were subject to the luck of the draw. Transits are available subject to controller workload, and they may well have been to busy. Also, you need to be aware of some of the SIDs departing Luton to the north route through that area an 5000ft might be an inconvenient level.

As for what you should have done:

Call Luton on Box 2: Give it a try, but they might refuse a transit anyway until you are under their control. Give that they did refuse you on the way back, it might not have made much difference

Ask for a RAS: If they are too busy to accept you for transit then they are probably too busy to give you a RAS.

Having established that Luton will only give you a FIS, you could return to Brize and ask them for a RIS for the descent. After all, there is no real need to get a FIS from Luton when Cranfield and Cambridge can do that.

Of course, none of this takes account of the fact that they were probably different controllers who might have different views on the acceptance of transits...

[loubylou]

Why had you burned your bridges with Brize? If Luton couldn't accomodate you - then I can't see why you felt you couldn't go back to Brize.
Or - as you say, call Luton on box 2.
Maybe there isn't a direct line between the two airfields, but the previous controller may have been being uber helpful and looked up the number to call via a BT line, and maybe the other guy was too busy, had to go through a switch board or something like that :p

But - as you say the beauty of the UK system is that it is flexible, but the downside is that controllers don't have to provide the service you may want!!!!

louby

[Chilli Monster]

Maybe there isn't a direct line between the two airfields, but the previous controller may have been being uber helpful and looked up the number to call via a BT line, and maybe the other guy was too busy, had to go through a switch board or something like that

Nobody here heard of the ATOTN? (Being an adjacent unit I suspect the number was handy).

[bookworm]

Why had you burned your bridges with Brize? If Luton couldn't accomodate you - then I can't see why you felt you couldn't go back to Brize.

Because it took a few minutes for Luton to respond to my initial call (again, no complaints, the controller obviously had other priorities), and by the time it was clear that I would not get a clearance to cross the Luton CTA, I was too close to it to go back to Brize, re-establish the service with a new squawk and make the descent under a RAS.

Or - as you say, call Luton on box 2.

Yes, I'm coming to the conclusion that that would have been the right thing to do, though it could have been a bit involved with maintaining the Brize squawk while getting identified by Luton.

I'm not sure there's a good answer to this one.

After all, there is no real need to get a FIS from Luton when Cranfield and Cambridge can do that.

You reminded me of another option, which would have been to route north of the Luton CTA over Cranfield maintaining FL50. Generally I don't like to do that if Luton can offer a service, as Cranfield is without radar but it might have been the best option. (Bring back Bedford, I say ;))

[TC_LTN]

Did you do it again today? Did you get a different response?

[bookworm]

Did you do it again today? Did you get a different response?

I'm afraid I didn't. Did you change your policies or procedures in some way?

[TC_LTN]

I was on TC Luton yesterday morning (Friday) and gave someone a transit both ways on exactly the same route under RAS/RCS at 4,000 Alt. but because traffic levels allowed that. Nothing to do with a policy or procedure change.

[bookworm]

Not me but thank you to you and your colleagues for the great flexibility you offer. It's very helpful when heading SW from Cambridge through a difficult area.

Out of interest, is 4000 ft fundamentally easier than 5000 ft because of arrivals or departures?

[TC_LTN]

4000 ft rather than 5000 ft is generally easier to accommodate on that track.