UK - MODE S and battling level busts
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UK - MODE S and battling level busts
Just a quick question for the guys in manch and london who have the lovely tool of mode s,The scenario... if you gave a cleared flight level to an a/c and they read back the correct flight level to you but dial in the incorrect one on the a/c and you pick it up what is the procedure for this taking into account you pick up the mistake before a level bust do you just re-confirm cleared level? Or is there an sop? and another question once you have given the fl do you check on the scope every time that the a/c had set it correctly?
Thanks in advance guys
Thanks in advance guys
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'Check selected level and confirm climb/descend FL xxx'
The only other thing i do differently is instead of giving a level, then transferring to next sector, if workload allows then i will wait to see if they have the correct level. Saves the pilot taking the first call, leaning across to set new level and get called back with a freq while still setting the level!
LOA
The only other thing i do differently is instead of giving a level, then transferring to next sector, if workload allows then i will wait to see if they have the correct level. Saves the pilot taking the first call, leaning across to set new level and get called back with a freq while still setting the level!
LOA
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Not quite the greatest thing since sliced bread though.I can see what the selected level is thanks to "mode s",but if it's low pressure and crews don't select 1013mb when cleared to a flight level,it can lead ATCO's into a false sense of security that the a/c will level at the instructed Flight Level.Been there,done that!No substitute for monitoring rate of climb against traffic 1000' above cleared level.(assuming we have time to do so!)
Out of interest, how fast does the display update?. On a two crew aircraft you can assume that the level is dialled up within a second of the call being received so how long does it take after issuing the clearance before you see the selected level change on the screen.
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Can take up to 25 seconds says the book, but in practice i dont think i've ever had to wait more than about 10 -15. Usually about 5 or so. Whats off putting is when it catches you halfway through the change eg, drop from 220 to 130, and SFL promptly changes to (say) 120.... Usually its correct at the next refresh, or you get a call obviously! More often than not, if it does pick it up as you are changing it it'll say something blatantly wrong that doesnt end in a zero.
And if you fly a saab with a dodgy txpdr, we know to ignore the sfl!
And if you fly a saab with a dodgy txpdr, we know to ignore the sfl!
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Now for the nerd answer!
Assuming taking from point where has been dialled in on MCP and register has been passed to the aircraft transponder:
Slowest Mode S ENHS radar feeding the TMA is 8 second scan rate. So if pilot changes just after last detection, worst case 8 seconds before radar downlinks the SFL register.
Radar allows for up to 2 seconds between detection and output to allow for the longer time required by the primary radar to process its data and the combined data to be output.
Data to get to centre is measured in milliseconds, so will discount.
Data processing works on 4 second cycles, so worst delay there is 4 seconds.
Maximum time to present to controller should be 8+2+4 = 14 seconds. In practise is much less as multiple radar sources extracting data.
RS
Assuming taking from point where has been dialled in on MCP and register has been passed to the aircraft transponder:
Slowest Mode S ENHS radar feeding the TMA is 8 second scan rate. So if pilot changes just after last detection, worst case 8 seconds before radar downlinks the SFL register.
Radar allows for up to 2 seconds between detection and output to allow for the longer time required by the primary radar to process its data and the combined data to be output.
Data to get to centre is measured in milliseconds, so will discount.
Data processing works on 4 second cycles, so worst delay there is 4 seconds.
Maximum time to present to controller should be 8+2+4 = 14 seconds. In practise is much less as multiple radar sources extracting data.
RS
...if it's low pressure and crews don't select 1013mb when cleared to a flight level,it can lead ATCO's into a false sense of security that the a/c will level at the instructed Flight Level....Been there,done that!
Surely controllers have been trained that Selected Altitude is ONLY used to confirm a vertical clearance has been received and correctly understood.
There is no guarantee whatsover that an aircraft approaching its selected level will level out other than the normal faith in flight crew competence. The aircraft may be being flown by hand for example - the value being entered into the MCP only as a matter of procedure.
No substitute for monitoring rate of climb against traffic 1000' above cleared level.(assuming we have time to do so
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Sorry, have to disagree.
Pilot selected baro IS DOWNLINKED via Mode S where it is available. Barometric pressure setting is part of BDS 4,0 - the transponder comm-B register that also contains Selected Altitude. Unfortunately, European policy makers in their infinite wisdom decided not to mandate the baro setting as part of Enhanced Surveillance.
As such it is not displayable to ATC as it could not be counted as being reliable data.
A shame really, as it could be a useful piece of data to provide a controller tool to indicate a pilot operating on wrong QNH when transitioning from 1013mb.
RS
Pilot selected baro IS DOWNLINKED via Mode S where it is available. Barometric pressure setting is part of BDS 4,0 - the transponder comm-B register that also contains Selected Altitude. Unfortunately, European policy makers in their infinite wisdom decided not to mandate the baro setting as part of Enhanced Surveillance.
As such it is not displayable to ATC as it could not be counted as being reliable data.A shame really, as it could be a useful piece of data to provide a controller tool to indicate a pilot operating on wrong QNH when transitioning from 1013mb.
RS
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As an ATCO working in the LTMA, I would not want the Altimeter subscale setting on my radar - enough clutter as it is. What we have is useful. We don't need anymore! It doesn't happen that often, and spotting these things is one of the many things an ATCO gets highly trained and well paid to do.
Selected frequency, again is not needed and would clutter up the screens too much.
Mode S is a safety enhancement tool, not a replacement for good ATC practices.
Don't Hang Up
That's not how Mode S is used. The SFL is used to check that a pilot selects the FL you have instructed him/her. It is a confidence check. ATCOs still monitor a/c on radar!!
All Mode S does (and does it very well) is add another safety level, and in the case of SFL, helps prevent some of the level busts we previously had by confirming the SFL correlates with the instructed level.
ATCOs still prevent level busts caused by pilots manually flying the aircraft and going to the wrong level or by busting a level due to incorrecty QNH. With Mode S, we now prevent some level bust from happening before they even get near to it!
Selected frequency, again is not needed and would clutter up the screens too much.
Mode S is a safety enhancement tool, not a replacement for good ATC practices.
Don't Hang Up
Slightly disturbed by this.
Surely controllers have been trained that Selected Altitude is ONLY used to confirm a vertical clearance has been received and correctly understood.
Surely controllers have been trained that Selected Altitude is ONLY used to confirm a vertical clearance has been received and correctly understood.
All Mode S does (and does it very well) is add another safety level, and in the case of SFL, helps prevent some of the level busts we previously had by confirming the SFL correlates with the instructed level.
ATCOs still prevent level busts caused by pilots manually flying the aircraft and going to the wrong level or by busting a level due to incorrecty QNH. With Mode S, we now prevent some level bust from happening before they even get near to it!
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Anotherthing spot on there - I should have said about the frequency selected that I believe it wont be in the data block (that would def be too much clutter!), but available in the box where you can look at all available parameters, which isnt used that often anyway but occasionally comes in handy! I presume TC have that box minimised too most of the time?
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landedoutagain -
That option makes more sense. I think I can categorically state that no one in the LTMA has the Mode S box permanently open.
In fact, the only time I use it nowadays is to show visitors what we can see - i.e. instantaneous ROC/ROD etc.
The NODE interface is such a pain anyways - trying to highlight the a target aircraft can be onerous because of the highlight toggle on/off on the master palette. I find that when I want a solid box i.e. to select an aircraft (say to force it into a stack list) I have the highlight selected so get a blue hatched box... or vice versa if I'm trying to do something else
The problem with the next frequency is that it would need to be input manually into the system because depending on adjacent sector configurations at that point in time etc, the frequency could be different.
I suppose working a T&P system would give more scope for that, but to be honest at TC it's (the frequency thingy) not needed.
I think LAC have the ability for a quick look on taget aircraft for the next frequency, but obviously they work on electronic offers and the T&P system.
That option makes more sense. I think I can categorically state that no one in the LTMA has the Mode S box permanently open.
In fact, the only time I use it nowadays is to show visitors what we can see - i.e. instantaneous ROC/ROD etc.
The NODE interface is such a pain anyways - trying to highlight the a target aircraft can be onerous because of the highlight toggle on/off on the master palette. I find that when I want a solid box i.e. to select an aircraft (say to force it into a stack list) I have the highlight selected so get a blue hatched box... or vice versa if I'm trying to do something else
The problem with the next frequency is that it would need to be input manually into the system because depending on adjacent sector configurations at that point in time etc, the frequency could be different.
I suppose working a T&P system would give more scope for that, but to be honest at TC it's (the frequency thingy) not needed.
I think LAC have the ability for a quick look on taget aircraft for the next frequency, but obviously they work on electronic offers and the T&P system.
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The problem with the next frequency is that it would need to be input manually into the system because depending on adjacent sector configurations at that point in time etc, the frequency could be different.
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Cheers for clearing that up - completely my mistake getting two totally different things mixed up!!
Only problem with knowing the frequency they have gone to/dialled up in the event of PLOC, is
a. Are the numbers they have dialled actually a frequency
and
b. Do you recognise who they belong to, so you can call them!
Possibly not much use IMHO
(Vote NO)
Only problem with knowing the frequency they have gone to/dialled up in the event of PLOC, is
a. Are the numbers they have dialled actually a frequency
and
b. Do you recognise who they belong to, so you can call them!
Possibly not much use IMHO
(Vote NO)
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Can I suggest that whoever is busy inventing weird and wonderful applications with requirements for new DAPS come and talk to those that actually provide the mechanism that gets them off the aircraft.
If you want another more than a couple more new DAPs, you are going to have to start saying goodbye to some others!
RS
If you want another more than a couple more new DAPs, you are going to have to start saying goodbye to some others!
RS