RT phraseology for let downs
 

Hello everybody,

I have an IR(R) but I'm not entirely clear or the correct RT phraseology when wanting a radar service let-down through cloud. I wondered if anyone could clarify this?

Thanks

Not sure what you are asking? If its that you want separation from other visible traffic to Radar during your descent in IMC that is one thing if you want a cloud break remember that off a published approach you can only come down to the MSA for the area you are in and all radar can do is to confirm where you are in that descent and that you are descending to the right MSA and not in the wrong area where the MSA might be higher.

Pace

So let me get this straight; you've managed to get an IR(R) without learning this? How could this happen, surely it would be covered in the syllabus?

Normally people operating VMC on top just ask for Traffic Service(or RIS as it used to be) for the IMC bit.

Yes exactly, radar-vectored cloud break. Is there a specific phrase eg "request radar-vectored cloud break"?

Or is it just a case of having a traffic service and descending not below MSA? I realise a let down using a published IAP is an alternative, but then one would have to travel a distance to commence a relatively lengthy procedure (which of course would be the only suitable thing to do if cloud base is below MSA outside of that procedure).

chevvron - thankfully I know how to request and utilise a traffic service, which I would always do in IMC. It was more a case of seeing if there are other specific RT/ATC requests that I'm not aware of or haven't been taught.

gantshill

It is assumed that you are operating outside of controlled airspace.

It's not "RT" its "RTF".

There is no standard phraseology. If you intend descending below MSA/terrain safe level request a Traffic Service, would be advisable to tell ATC that you are/will be descending. ATC may decline provision of a Traffic Service if radar coverage below MSA / terrain safe level is not considered adequate.

If you do not intend descending below MSA/terrain safe level, a De- confliction Service could be requested. The latter will be terminated / downgraded by ATC if you descend below MSA.

The answers all look like being UK-specific. Is the question, too?

I get a cloud break quite a lot at Leuchars, not really sure of what the legalities or responsibilities of either myself or radar approach are for doing such so i just treat it like asking for a basic service as if I was transitioning through their area , goes something like this:

1. When I can't find a hole to get back down from VFR on top I make for Leuchars Air Base which is nearby and pick up the ATIS at Dundee which is close by Leuchars with both fields being at sea level. as long as the basis are about 1200 or above I know based on the ILS being about a 300 feet per mile drop that I will get down to VFR prior to entering Leuchars zone and be able to get back my home field.

2. If the cloud tops are say 5000 i know again based on the standard ILS GS i will need to fly out over the North Sea about 16 miles to intercept the ILS 26.

3. I call up Leuchars and advise then that I would like a basic service and will be maneuvering from between 16 and 4 miles along the extended centerline of runway 8 between 5000 and 1000 and will remain clear of their zone.

4: Swing onto final,Tune in the ILS, set the timer for 8 minutes, set the decent for 500 FPM and 90 Knots sit back and wait.

5. Turn for home when I get VFR and cancel the basic service with Leuchars.

Edit to add: I guess this way there is no expected or implied responsibilities either way, all I'm getting and all I want from ATC is a basic service and the rest is up to me.

This guy in the attached recording has a different method, probably not recommended:

gantshill, surely a straightforward "request descent to VMC below" would suffice? Whilst you are IMC you could always ask for deconfliction service if you think it's pertinent (subject to the normal conditions, of course).

Very helpful, thanks. I was indeed being UK specific (sorry, should have mentioned). I guess the answer is 1. Use an existing procedure to get into VMC below MSA, or 2. can get traffic/deconfliction service to break cloud above MSA. I guess I was just wondering if there was a third, descending below MSA in cloud safely, not on a published procedure, and I guess the answer is no (unless out to sea!).

Thank you all. Apologies for not being particularly clear!

Would you really descend below MSA over the sea??

No one cares if you call it RT phraseology or RTF :rolleyes: everyone knows what you mean.

OP - You want to ask for a cloud break decent -

"<station> request cloud break descent"

"<callsign> descend to altitude xxxx, QNH/RPS xxxx (xxxhpa)"

"xxxx (xxxhpa) set, descend to altitude xxxx <callsign>"

They will get you to the TSL (terrain safe level) that will be on their radar screen which will depend on the area (1000' above the surface level or to 2000' over mountainous terrain, rounded up to the nearest 100'). At that point if you require further (which you will need to ask for) they will automatically put you on a TS, remind you of your own terrain clearance and then approve your descent. They will not give you levels below the TSL. Any further questions, please ask. I deal with this request by civil and mil aircraft on a daily basis :ok:

Hm, you sure? "RTF" made me wonder what letter comes next, to make the full phrase of "Read the f_____g " manual or datasheet or documentation or whatever. In my training it was R/T though I never understood what the slash stands for. But what does the F stand for?

The above is of course only side-stepping nitpicking. Thanks for a clear answer from the business side!

Great answer

ICAO Doc 8400

RTF = Radio Telephone.

RT, although still commonly used, is technically incorrect, even though it still appears in some current UK CAA publications.

I bet you're fun at parties...

Well I'm really letting my hair down here....

RTG = Radio Telegraphy...

I'm gonna have to loosen my tie now...

TCAS is fun at parties. Just don't expect him to bring a bottle...

I am really sorry... But what does the F stand for?

Not sure this is what you will get - outside CAS you will not get a clearance, they may give a deconfliction service and they will probably advise the MSA but the rest is up to you.

I have read enough AAIB reports of CFIT that would put me off going below MSA without being VFR. Remember that MSA figures exist for a reason!

If you must go below MSA, I would use a nearby airfield with a published approach, once VFR, break off and do what I like below MSA but of course abiding by the low flying rule. Or I would go over the sea, and descend to what I deem is safe (not normally below 1000ft).

The real question is why would you want to descend below MSA without being visual? You normally start to see through the lower parts of the clouds when you get close to the cloudbase, you would still be well above the low flying rule when fully VFR if you continued to descend a further few hundred feet or so.