Time on position reporting
Thread Starter
Join Date: Jul 2002
Location: Earth
Posts: 37
Likes: 0
Received 0 Likes
on
0 Posts
Time on position reporting
What is the relevance of the "time" in position reporting? If the aircraft is at the reported position at the time of the report, what additional value does the time provide?
Position reports shall contain the following elements of information:
a) Aircraft identification
b) Position
c) Time
d) Level
e) Next position and ETA
Correct example with time:
BIGJET 347 Wicken 47 FL 280 Marlow 57
Incorrect example without time:
BIGJET 347 Wicken FL 280 Marlow 57
Position reports shall contain the following elements of information:
a) Aircraft identification
b) Position
c) Time
d) Level
e) Next position and ETA
Correct example with time:
BIGJET 347 Wicken 47 FL 280 Marlow 57
Incorrect example without time:
BIGJET 347 Wicken FL 280 Marlow 57
Join Date: Jul 2004
Location: On the wireless...
Posts: 1,901
Likes: 0
Received 0 Likes
on
0 Posts
What is the relevance of the "time" in position reporting? If the aircraft is at the reported position at the time of the report, what additional value does the time provide?
It also saves the Procedural Controller from having to look at the clock!
I'd say that the reason is standardisation.
Even on VHF you will usually be making the report after passing the reporting point and, on HF, probably some time after passing it (if ever with, e.g. Yangon).
The controller or radio operator taking the report expects a standard format and doesn't want to look at a clock in the middle of recording the report.
Even on VHF you will usually be making the report after passing the reporting point and, on HF, probably some time after passing it (if ever with, e.g. Yangon).
The controller or radio operator taking the report expects a standard format and doesn't want to look at a clock in the middle of recording the report.
Join Date: Oct 2000
Location: Berkshire, UK
Age: 79
Posts: 8,268
Likes: 0
Received 0 Likes
on
0 Posts
In a fully procedural environment, ATC has it's own estimated times for each reporting point calculated from upper winds, etc., so the aircraft reports are simply a cross-check. When I was an Area controller abroad the ATC estimates usually won because a number of the local RPs were intersections and nav gear wasn't so hot in those days.
Join Date: Mar 2002
Location: Euroland
Posts: 2,814
Likes: 0
Received 0 Likes
on
0 Posts
As one passes overhead a waypoint one should;
1. Fly the aircraft as accurately as possible over the waypoint and record the time of passing on the OFP
2. Make appropriate adjustments to navigation settings and heading to follow the required track between that waypoint and the next
3. Make a position report if required.
As can be seen, item 3 will be a short period after the actual time of passing over the reporting point. If there are other stations transmitting at the time when one it first trying to make the position report, it may be longer between the time of passing over the waypoint and making the report on R/T.
In many cases, one isd making the report to a radio operator who will pass on your message to the appropriate ATC unit.
Therefore since even if you have autopilot and FMS, you will be busy noting the time on the OFP as you pass over the waypoint (and possibly also making a met observation), even in clear communications, it will usually be a few seconds or more later that you make the report.
Should you pass the waypoint at 09:05:28 = 09:05, unless you make a report and have it received in less than 2 seconds, ATC will receive the report at 09:06 or later. Do you want them recording the time as the time you passed the waypoint or the time you make an R/T report???
At a fix (and always):
Aviate - fly accurately
Navigate - record the time and establish outbound to the next fix
Communicate - make position report.
1. Fly the aircraft as accurately as possible over the waypoint and record the time of passing on the OFP
2. Make appropriate adjustments to navigation settings and heading to follow the required track between that waypoint and the next
3. Make a position report if required.
As can be seen, item 3 will be a short period after the actual time of passing over the reporting point. If there are other stations transmitting at the time when one it first trying to make the position report, it may be longer between the time of passing over the waypoint and making the report on R/T.
In many cases, one isd making the report to a radio operator who will pass on your message to the appropriate ATC unit.
Therefore since even if you have autopilot and FMS, you will be busy noting the time on the OFP as you pass over the waypoint (and possibly also making a met observation), even in clear communications, it will usually be a few seconds or more later that you make the report.
Should you pass the waypoint at 09:05:28 = 09:05, unless you make a report and have it received in less than 2 seconds, ATC will receive the report at 09:06 or later. Do you want them recording the time as the time you passed the waypoint or the time you make an R/T report???
At a fix (and always):
Aviate - fly accurately
Navigate - record the time and establish outbound to the next fix
Communicate - make position report.
And as to why the correct time might actually be important, in the absence of radar, or other accurate means of position fixing that are usable by ATC, the required separation standard is calculated using those block times between reporting points. Introduce a couple of apparently minor inaccuracies..just a minute or two at each end, say, and someone else does the same thing, you could possibly end up with half the required space between 2 a/c at the same level.
On a slight tangent...
I have always thought this practice to be quite illogical. Does anyone know of any authoritative reference for this? What is taught, if anything, to aircrew for recording times when only to the "nearer" minute?
2 s
Should you pass the waypoint at 09:05:28 = 09:05, unless you make a report and have it received in less than 2 seconds, ATC will receive the report at 09:06 or later.
2 s
Join Date: Oct 2000
Location: Berkshire, UK
Age: 79
Posts: 8,268
Likes: 0
Received 0 Likes
on
0 Posts
<<Should you pass the waypoint at 09:05:28 = 09:05, unless you make a report and have it received in less than 2 seconds, ATC will receive the report at 09:06 or later. Do you want them recording the time as the time you passed the waypoint or the time you make an R/T report???
>>
Not going to make a ha'porth of difference. Where I worked, clocks weren't that accurate any way.
>>
Not going to make a ha'porth of difference. Where I worked, clocks weren't that accurate any way.
One point that doesn't seem to have been mentioned is that you may not be able to make the position report because there is other traffic making calls on the frequency. And/or in the case particularly of HF you cannot establish communication immediately and may have to try other frequencies.
Takes me back to the days of flying through Iranian airspace in the 1970s when we sometimes had to relay a position report through 2 other a/c due to the lack of VHF cover.
Takes me back to the days of flying through Iranian airspace in the 1970s when we sometimes had to relay a position report through 2 other a/c due to the lack of VHF cover.
Join Date: Mar 2002
Location: Euroland
Posts: 2,814
Likes: 0
Received 0 Likes
on
0 Posts
Not going to make a ha'porth of difference. Where I worked, clocks weren't that accurate any way.
As Tarq57 said, if the separation required is 15 minutes and one flight makes the position report at 1016, the other aircraft can not cross before 1031. If it has laready passed an estimate of 1030, you now have to tell it to cross the fix not before 1031 as well as providing essential traffic information. A minor inconvenience but unnecessary if the first flight actually crossed the fix at 1015 but failed to note the time.
I have always thought this practice to be quite illogical. Does anyone know of any authoritative reference for this? What is taught, if anything, to aircrew for recording times when only to the "nearer" minute?
You are only required to transmitt the seconds in an R/T report when specifically asked for. Therefore it is logical that the time transmitted is rounded to the nearest minute.
Rounding is taught in Primary School. Do we really have to teach it again to pilots?
References are;
Annex 5 - Units of measurament
Annex 2 - Rules of the Air
DOC 4444 - PANS ATM
fireflybob,
I did point that out earlier. There is also the provision that from an ATC point of view if the report is not received within a reasonable time of when expected then it is sought and this in itself prevents the call being delayed too much when it is essential for separation.
DFC - nice list of publications, but no reference that I am aware of. Please correct me if I have missed it. I would not necessarily agree that it is logical to "round" time to the nearer minute, the way that we describe it is an indication of time elapsed since a reference (midnight). Q.v. rounding of pressure measurements and temperature.
2 s
2 s
Guest
Posts: n/a
Coming to DFC's defence - although I am sure there is no need to - what is a list of documents.....if not a set of references?
FWIW, the first doc that I would head for this topic is Annex 11 which, in fact, is really quite helpful. It says:
FWIW, the first doc that I would head for this topic is Annex 11 which, in fact, is really quite helpful. It says:
2.24 Time in air traffic services
2.24.1 Air traffic services units shall use Coordinated Universal Time (UTC) and shall express the time in hours and minutes and, when required, seconds of the 24-hour day beginning at midnight.
2.24.2 Air traffic services units shall be equipped with clocks indicating the time in hours, minutes and seconds, clearly visible from each operating position in the unit concerned.
2.24.3 Air traffic services unit clocks and other time recording devices shall be checked as necessary to ensure correct time to within plus or minus 30 seconds of UTC.
Wherever data link communications are utilized by an air traffic services unit, clocks and other time-recording devices shall be checked as necessary to ensure correct time to within 1 second of UTC.
2.24.4 The correct time shall be obtained from a standard time station or, if not possible, from another unit which has obtained the correct time from such station.
2.24.5 Aerodrome control towers shall, prior to an aircraft taxiing for take-off, provide the pilot with the correct time, unless arrangements have been made for the pilot to obtain it from other sources. Air traffic services units shall, in addition, provide aircraft with the correct time on request. Time checks shall be given to the nearest half minute.
HTH.
2.24.1 Air traffic services units shall use Coordinated Universal Time (UTC) and shall express the time in hours and minutes and, when required, seconds of the 24-hour day beginning at midnight.
2.24.2 Air traffic services units shall be equipped with clocks indicating the time in hours, minutes and seconds, clearly visible from each operating position in the unit concerned.
2.24.3 Air traffic services unit clocks and other time recording devices shall be checked as necessary to ensure correct time to within plus or minus 30 seconds of UTC.
Wherever data link communications are utilized by an air traffic services unit, clocks and other time-recording devices shall be checked as necessary to ensure correct time to within 1 second of UTC.
2.24.4 The correct time shall be obtained from a standard time station or, if not possible, from another unit which has obtained the correct time from such station.
2.24.5 Aerodrome control towers shall, prior to an aircraft taxiing for take-off, provide the pilot with the correct time, unless arrangements have been made for the pilot to obtain it from other sources. Air traffic services units shall, in addition, provide aircraft with the correct time on request. Time checks shall be given to the nearest half minute.
Join Date: Nov 2009
Location: Poland
Posts: 127
Likes: 0
Received 0 Likes
on
0 Posts
Please note that the time accuracy is half a minute. So time from 0'00'' up to 0'14'' should be rounded to 00, from 0'15'' to 0'29'' - to "00 and a half" and so on. ;-) Of course nobody does that.
I've always wondered how does it look from the pilot's side, how do they check the clock. If they do anything to prove that their clock is at least remotely accurate, giving them a timecheck rouded to a full minute is in my opinion obsolete.
I've always wondered how does it look from the pilot's side, how do they check the clock. If they do anything to prove that their clock is at least remotely accurate, giving them a timecheck rouded to a full minute is in my opinion obsolete.
Join Date: May 2001
Posts: 10,815
Likes: 0
Received 0 Likes
on
0 Posts
We get the time from the GPS and in the SOP's I have used for the first flight of the day is to check off the GPS to ensure the aircraft clocks were the same as that. I am sure newer aircraft have it auto sync to the GPS.
The area centers are always pretty much the same as that. Some towers though are out by up to 5 mins. Leads to all sorts of financial arguments when the airfield wants to charge for out of hours and the tower reckon its 21:01 and the weight on wheels in the FMC records it as 20:59.
The area centers are always pretty much the same as that. Some towers though are out by up to 5 mins. Leads to all sorts of financial arguments when the airfield wants to charge for out of hours and the tower reckon its 21:01 and the weight on wheels in the FMC records it as 20:59.
Thread Starter
Join Date: Jul 2002
Location: Earth
Posts: 37
Likes: 0
Received 0 Likes
on
0 Posts
Thank you all for your responses.
Just to be clear... if the clearance to leave holding is at time 06 what is the earliest moment it is approved to do so. Is it 05:46 or 06:00?
Just to be clear... if the clearance to leave holding is at time 06 what is the earliest moment it is approved to do so. Is it 05:46 or 06:00?
All this debate about time reminds of an amusing incident in my early days of flying long haul when we flying from Karachi to Calcutta. Of course in those days we didn't have the all singing/dancing clocks of today's jet age which automatically synchonise to UTC via GPS but steam driven clocks which had to be wound and set correctly.
We often listened in to the BBC World Service to get the pips and synchronise the clocks and, of course, listen to the news. I had just done a time check on the pips and called ATC to give a position report. The controller said "Airways time is XXXX, confirm time over AAA was YYYY?" The "Airways Time" was about 5 minutes wrong! When we advised the controller that we had just checked our clocks against the pips, he still insisted his time check was right and we were wrong! Happy Days
We often listened in to the BBC World Service to get the pips and synchronise the clocks and, of course, listen to the news. I had just done a time check on the pips and called ATC to give a position report. The controller said "Airways time is XXXX, confirm time over AAA was YYYY?" The "Airways Time" was about 5 minutes wrong! When we advised the controller that we had just checked our clocks against the pips, he still insisted his time check was right and we were wrong! Happy Days
Thread Starter
Join Date: Jul 2002
Location: Earth
Posts: 37
Likes: 0
Received 0 Likes
on
0 Posts
Maybe my question wasn't clear.
Lets say time now is 12:00:00 and an aircraft is at a holding pattern. The aircraft receives a clearance to leave the holding at time 06. When can the aircraft leave the holding? Is it 12:05:46 or 12:06:00?
Lets say time now is 12:00:00 and an aircraft is at a holding pattern. The aircraft receives a clearance to leave the holding at time 06. When can the aircraft leave the holding? Is it 12:05:46 or 12:06:00?