Questions about phraseology

[caucatc]

I just read Doc.4444 Phraseology again, I found that controller should say"descend to XX ft" , but so many controllers use "descend and maintain" or "descend to and maintain", can somebody tell me why or what are the differences?
One more question is about the rules to read an aircraft registered number, according to the rule we have in China, if all the registered number is in words, such as ACGDS, I can read ADS for short, but what if some numbers in it? Such as ACGD1, A565T? Is there any rule for that?

[Yurtchenko]

I didnt check the doc 4444 but at school, i was told not to use "to" for flight levels or headings cause it may create confusion between to and 2.

[orgASMic]

National differences? Or just gash controllers embellishing their phraseology?

As a UK ATCO, CAP 413 requires:

"Call sign descend to altitude xxxx feet, QNH xxxx" (or FL or height/QFE).

If I give you a level to fly at, you are expected to maintain it until I or a colleague says differently, you request a change and we agree, or the procedure you are cleared on requires a change.

As for abbreviated call signs, CAP 413 says:

From Table 9

GBFRM becomes G-RM
N31029 becomes N029
N753DA becomes N3DA

[divingduck]

Climb TO, descend TO...ICAO DOC9432

Standard stuff....IFF you follow the ICAO docs.

[Yurtchenko]

National differences.
I checked my manuel.
We also have differences for call sign contractions compared to icao docs.
Obviously my answer wasnt relevant.

[caucatc]

Thanks for the how to read callsign briefly, but where can I find the Doc you mentioned?
As for the "descend to" or "descend and maintain", it seems that there is really a difference in the different countries, becasue we need to speak Chinese also, somebody argues that ICAO listed "descend to" why we have to use "descend and maintain" and when we give clearances in Chinese, we have to say "maintain" also, tough someone thinks that is nonsence.

[Yurtchenko]

You may find the doc on google by looking for "ICAO doc 9432".
Regarding the differences, i will tell you some reasons but only for France.
When you have a safety incident the european ansp is supposed to analyse it and take some actions to prevent a new one. It can be a phraseology change compared the icao requirements or some different actions such as closing a taxiway....
For your climb or descent phraseology, it exists now the enhanced mode S which allows atc to see the pilot level selection on screen radar. In Muac they already use it and it is slowly coming to France.
So if in china you are not enhanced mode S equiped you may have some recommandations to use a special phraseology.
The descend and maintain is may be a recommendation to prevent a level bust if you suspect a conflict with another acft 1000ft below the assigned level.

[hvogt]

Originally Posted by caucatc

One more question is about the rules to read an aircraft registered number, according to the rule we have in China, if all the registered number is in words, such as ACGDS, I can read ADS for short, but what if some numbers in it? Such as ACGD1, A565T? Is there any rule for that?

According to 5.2.1.7.2.2.1 of ICAO Annex 10, Volume 2, abbreviated call signs consist of 'the first character of the registration and at least the last two characters of the call sign' or 'the telephony designator of the aircraft operating agency, followed by at least the last two characters of the call sign'. Since both letters and numbers are characters, the abbreviated call sign for a flight using the registration 'ACGD1' would be 'alpha delta one', respectively 'alpha five tango' for 'A565T'.

[250 kts]

Hitman,

I use it in exactly the same way-and also in order to then hopefully stop the request for further climb or descent.

[Arch Stanton]

Having recently worked alongside both FAA and ICAO controllers this topic was frequently discussed.

The reason either "maintain"(FAA) or "altitude" (UK) is inserted before the level is to prevent confusion. If you omit either of these words you end up with a clearance like this -

"climb to wun zero thousand feet"

...which can easily be misinterpreted to mean "climb 21'000ft"

Unfortunately I don't think ICAO phraseology addresses this problem, and unless your state files a difference, you are stuck with using the slightly less safe ICAO phraseology.

[ATC Watcher]

the slightly less safe ICAO phraseology.

Not quite, after the Flying tigers 747 accident in KL in 1989, ICAO recalled that you must always use the words " altitude" or " FL" before enunciating numbers
it is not climb to " it is "climb to FL ( or altitude) xxx

In the US they use " maintain" probably because it is far easier to pronounce than " altitude" as they have a rather high transition altitude .( my guess )

[hvogt]

Originally Posted by ATC Watcher

Not quite, after the Flying tigers 747 accident in KL in 1989, ICAO recalled that you must always use the words " altitude" or " FL" before enunciating numbers
it is not climb to " it is "climb to FL ( or altitude) xxx

Sorry, ATC Watcher, but Arch Stanton is right. According to 12.3.1.1 and 12.3.1.2 of PANS-ATM, the correct ICAO-phraseology would indeed be 'CLIMB TO FLIGHT LEVEL (number)' or 'CLIMB TO (number) FEET'.

[ATC Watcher]

hvogt :
They changed it again ? Crazy. Did not know.
They probably have forgotten why it was there in the first place ...
The Flying Tigers story may repeat itself one day sadly ...

[Lon More]

Not quite standard but I encouraged my trainees to say, "Climb/Descend FL ,,,"
No "to" in the instruction, no ambiguity possible IMHO

[Glamdring]

Originally Posted by Lon More

Not quite standard but I encouraged my trainees to say, "Climb/Descend FL ,,,"
No "to" in the instruction, no ambiguity possible IMHO

That's what I was taught. But only for Flight Levels, still use "to" for Altitudes.

[Yurtchenko]

I encouraged my trainees to say, "Climb/Descend FL ,,,"
No "to" in the instruction, no ambiguity possible IMHO

So my first post is still alive!!!

[RTN11]

The difference is

Climb/Descend FL...

Climb/Descend TO Altitude ...'

the to is only used when referring to Altitudes, as one of the ways of picking it out, particularly in the descent when you read back the QNH as well so you remember to set it and don't go busting a level or MSA.

Perhaps the climb and maintain has crept in where controllers are trying to tell you that is your last expected cruise level, but it has then become generalised for all climb instructions.

Often non-standard phrases will creep in regarding your final requested level.

[Lon More]

The "Maintain" bit has been around for years. I wonder if it has its origin in the M with the horizontal arrow through it used when marking paper strips? Possibly it ws spoken in as it was written?

See Section 4.2.5 here for the FAA's strip marking symbols including that.