Level busts - quantity / order of ATC instructions
Thread Starter
Joined: Dec 1999
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From: England
Level busts - quantity / order of ATC instructions
Hi
The subject of level busts is never far away from any of us. We have recently been discussing it at our company and considering how mistakes can happen.
One area that I have always thought was a POTENTIAL cause for problems is the quantity and order of ATC instructions that are given in a single transmission.
For those of you controlling us, is there any limit on how many instructions can be given at one?
"Jersey 345, turn right heading 080 degrees, climb flight level 70,speed maximum 250 Kts. Contact solent radar 120.225" Is this seen as a goog amount of information to transmit in one package?
What about if you are descending an aircraft to it's first altitude and so need to transmit the local QNH?
Is there any written guidance on this, or is it down to professional judgement on your part?
Secondly, is there any prescribed order that instructions should be braodcast in? This may sound like an odd query, but I know that my company tells us to set the cleared level in the autopilot before setiing any heading / direct to or speed clearances. This is because level busts are rightly seen as so dangerous. However, since receiving this advice I have noticed that "laterlal" clearances are always given before "vertical clearances". As I said earlier, I have been wondering whether this order is in accordance with some ATC regulations or merely custom.
Any comments on this gratefully received.
All the best.
The subject of level busts is never far away from any of us. We have recently been discussing it at our company and considering how mistakes can happen.
One area that I have always thought was a POTENTIAL cause for problems is the quantity and order of ATC instructions that are given in a single transmission.
For those of you controlling us, is there any limit on how many instructions can be given at one?
"Jersey 345, turn right heading 080 degrees, climb flight level 70,speed maximum 250 Kts. Contact solent radar 120.225" Is this seen as a goog amount of information to transmit in one package?
What about if you are descending an aircraft to it's first altitude and so need to transmit the local QNH?
Is there any written guidance on this, or is it down to professional judgement on your part?
Secondly, is there any prescribed order that instructions should be braodcast in? This may sound like an odd query, but I know that my company tells us to set the cleared level in the autopilot before setiing any heading / direct to or speed clearances. This is because level busts are rightly seen as so dangerous. However, since receiving this advice I have noticed that "laterlal" clearances are always given before "vertical clearances". As I said earlier, I have been wondering whether this order is in accordance with some ATC regulations or merely custom.
Any comments on this gratefully received.
All the best.
Joined: Sep 2005
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From: Sea Level
Order of ATC instructions
Messages should not contain more than three specific phrases comprising a
clearance, instruction or pertinent information. In cases of doubt, e.g. a foreign pilot having difficulty with the English language or an inexperienced pilot unsure of the procedures, the number of items should be reduced and if necessary passed, and acknowledged, singly.
This is an extract from the CAP 493 Manual of Air Traffic Services part 1. Not always easy to do when really busy but hope this helps.
clearance, instruction or pertinent information. In cases of doubt, e.g. a foreign pilot having difficulty with the English language or an inexperienced pilot unsure of the procedures, the number of items should be reduced and if necessary passed, and acknowledged, singly.
This is an extract from the CAP 493 Manual of Air Traffic Services part 1. Not always easy to do when really busy but hope this helps.
Naughty but Nice
Joined: Dec 2001
Posts: 194
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From: Southern England
"Any thoughts on the order with which multiple instructions are given?"
Not really, except that any that are for legal or separation purposes would come first, any that then give best service to the aircraft involved, or my plan (
) come later.
Other replies good, particularly from Radar 707, we should never give a frequency change with anything else that requires a mandatory readback.
Cheers,
N
"Keep smiling, it makes people wonder what you're up to..."
Not really, except that any that are for legal or separation purposes would come first, any that then give best service to the aircraft involved, or my plan (
) come later.Other replies good, particularly from Radar 707, we should never give a frequency change with anything else that requires a mandatory readback.
Cheers,
N
"Keep smiling, it makes people wonder what you're up to..."
Joined: Aug 2001
Posts: 1,924
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From: UK
Regarding the order of items in an ATC transmission, I normally try to give information first, and instructions last:-
"C/S vectoring for the ILS R/W 27 information Bravo, fly heading 060 degrees, descend to Altitude 4000 feet QNH 997mb"
Hopefully it helps make the mandatory read back a bit easier, but interested to hear pilots' opinions and preferences.
During very busy periods, I may transmit just the turn and level instruction, and follow up with the 'information' in another transmission, on an opportunity basis.
"C/S vectoring for the ILS R/W 27 information Bravo, fly heading 060 degrees, descend to Altitude 4000 feet QNH 997mb"
Hopefully it helps make the mandatory read back a bit easier, but interested to hear pilots' opinions and preferences.
During very busy periods, I may transmit just the turn and level instruction, and follow up with the 'information' in another transmission, on an opportunity basis.
Joined: May 2001
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Just a personal opinion.
Thats 4 manditory readback items. RWY, Heading, alt and QNH
And involves two changes to flight path and an altimeter change with its associated cross checks.
At that stage of the proccedings (below FL100) the paper work is away so the PNF has to remember it all.
Personally i find it easier if you seperated the changes in flight path, heading changes from the level changes then it's easier for the PNF to cross check the PF has set the correct values.
You will proberly find that the read back is more snappy as well so the total time for 2 sets of instructions with 2 readbacks is less than the 1 with full read back, with the bonus of less mistakes or "say again"
Thats 4 manditory readback items. RWY, Heading, alt and QNH
And involves two changes to flight path and an altimeter change with its associated cross checks.
At that stage of the proccedings (below FL100) the paper work is away so the PNF has to remember it all.
Personally i find it easier if you seperated the changes in flight path, heading changes from the level changes then it's easier for the PNF to cross check the PF has set the correct values.
You will proberly find that the read back is more snappy as well so the total time for 2 sets of instructions with 2 readbacks is less than the 1 with full read back, with the bonus of less mistakes or "say again"
Joined: Oct 2002
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From: frozen norff
Although passing information and then instructions is a better way, saying too much can overload pilots. I would reduce what spekesoftly says to the instructions first, wait for the correct readback, give the pilots a few seconds
to carry out said instructions, and then pass information.
to carry out said instructions, and then pass information.
Joined: Jan 2004
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From: Brisbane, Australia
"C/S vectoring for the ILS R/W 27 information Bravo, fly heading 060 degrees, descend to Altitude 4000 feet QNH 997mb"
For example:
ATC: "Qantas 26, Glenn 2 arrival, Blaka transition, maintain F350"
ACFT: "Qantas 26, Glenn 2 arrival, Blaka transition, maintain F350"
ATC: "Qantas 26, for sequencing, cross Blaka at time 26 at 250 knots"
ACFT: "Qantas 26, Blaka at 26, 250 knots."
Seems that a little more air time taken up with transmissions, but more likely to get the correct readback.
BTW, do you still say millibars in the UK? Hasn't it been hectopascals for some time. And why do you say millibars when giving QNH? Surely it's a lot different to giving it in inches to our recalcitrant american friends who know nothing of the metric system.
Joined: Oct 2004
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From: surrey
I was taught in the military when flying and in ATC, give the most important piece of info last - it sticks in the mind that way.
i.e. "Squawk 3730, Flight information Service, QNH 1012"
And never more than three bits of info at once, with something to break up the numbers, as in the above example.
Seemingly it's a human factors thing.
i.e. "Squawk 3730, Flight information Service, QNH 1012"
And never more than three bits of info at once, with something to break up the numbers, as in the above example.
Seemingly it's a human factors thing.
I'm Just A Lawnmower
Joined: Aug 2002
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From: Over the hills and faraway
BTW, do you still say millibars in the UK? Hasn't it been hectopascals for some time. And why do you say millibars when giving QNH? Surely it's a lot different to giving it in inches to our recalcitrant american friends who know nothing of the metric system
Joined: Nov 2000
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From: Greystation
butter side up, CAP 493 appendix E page 10, 6.2:-
Transfer of communication instructions should be passed in a single message. Items which require a readback should not precede the frequency or channel change instruction.
Transfer of communication instructions should be passed in a single message. Items which require a readback should not precede the frequency or channel change instruction.
Joined: Mar 2002
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From: Sunny Warwickshire
5miles u beat me to it.
As for saying millibars when passing QNH / QFE below 1000 I seem to remember that it came about because when we weren't saying it some of our American cousins got confused and would set 2992 instead of 992 etc. and this was introduced to reduce the chance of a level bust occurring
As for saying millibars when passing QNH / QFE below 1000 I seem to remember that it came about because when we weren't saying it some of our American cousins got confused and would set 2992 instead of 992 etc. and this was introduced to reduce the chance of a level bust occurring
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From: North America
Originally Posted by DirtyPierre
Surely it's a lot different to giving it in inches to our recalcitrant american friends who know nothing of the metric system.
Joined: Jan 2001
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From: home
At Lgw quite often you get "ABC 1234 turn left heading 270 descend altitude 4000 QNH 995" followed immediately by "ABC 1234 contact LGW approach 126.82". As soon as we get cleared to an altitude there is a set routine of selecting new altitude, setting the QNH, and crosschecking this. This frequency change often disturbs this routine with the risk of serious consequences. UK ATC still the best in the world imho.
Joined: Jul 2002
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From: Its warm here!!!!!!
Right way,
You know the best way of letting us on the ground monkeys understand better what happens in a cockpit? Fam flights. I am an instructor at a centre and think I would be able to pass on better knowledge and provide a better service if I know more about what and when you are doing things.
This kind of forum provides some idea but face to face is always better. We have recently done TRM courses and it made me at least realise the team is the unit, surrounding units and the aircraft all to acceive a goal. Push for fam flights and centre/airfield visits.
Thats me off the soap box for about an hour!!!!!!!!!!!!
You know the best way of letting us on the ground monkeys understand better what happens in a cockpit? Fam flights. I am an instructor at a centre and think I would be able to pass on better knowledge and provide a better service if I know more about what and when you are doing things.
This kind of forum provides some idea but face to face is always better. We have recently done TRM courses and it made me at least realise the team is the unit, surrounding units and the aircraft all to acceive a goal. Push for fam flights and centre/airfield visits.
Thats me off the soap box for about an hour!!!!!!!!!!!!
Joined: Nov 2005
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From: USA
Originally Posted by Northerner
"Any thoughts on the order with which multiple instructions are given?"
Not really, except that any that are for legal or separation purposes would come first, any that then give best service to the aircraft involved, or my plan ( ) come later.
Not really, except that any that are for legal or separation purposes would come first, any that then give best service to the aircraft involved, or my plan (
) come later.412.1 Issue clearance items, as appropriate, in the following order:
A. Prefix
B. Aircraft Identification
C. Clearance limit.
D. SID
E. Route.
F. Altitude.
G. Mach-number.
H. Departure, en route, approach, or holding instructions.
I. Special instructions or information.
J. Traffic information.
412.1 Note: It is important that an IFR clearance contain positive and concise data phrased in a consistent manner. This is especially true of a clearance that will be relayed through a communication agency, since the clearance must be relayed verbatim.
So, yes, route before altitude.
the "as appropriate" in the manop does give us some room to maneuvre within the rule. Any unnecessary items are omitted, and sometimes they are rearranged slightly.
For example, "abc 123, maintain FL 330 Through fl 320, cleared direct yzz flight planned route" can't really give him the "through fl 320" if he hasn't been cleared past 310 yet.
Item I, special information, is often bumped to the front as well, or sent in a separate transmission.