View Full Version : A Humble ATCO asks....
22nd Oct 2003, 18:32
I need some advice as to SOP's amongst you good airline types.
Whilst working a LL BPK departure, having given the climb to FL150 and with the a/c 5 miles south of BPK (easterlt R/W's in use), I cleared the a/c to route direct DIDGO, (expecting a track of about 060 degrees), and transferred it to the next sector.
Imagine my surprise when the a/c then tracked 090 straight towards the LAM hold (which only had one a/c in it fortunately), for a good 10 miles before turning to track 040 (I don't know whether this turn was instigated by the next sector).
Any ideas people, because if LAM had been busy, this could have had a different result!!! My understanding is that if you are given a direct routing then you will route there directly from where you are. Is this not always the case???
22nd Oct 2003, 19:08
Your assumption is correct, when cleared 'direct to xxx' we do as instructed.
Talking of FMC equipped aircraft though two possibilities come to mind.
Finger trouble and executing 'direct to yyy instead of xxx' or more commonly if on a radar heading executing 'direct to xxx' and then omitting to select LNAV thereby disconnecting the HDG mode that the aircraft was previously in.
No excuse and poor airmanship but it does happen.
22nd Oct 2003, 19:14
Just a guess. DIDGO didn't appear on their flight plan, was not in their FMC on the legs page, (if they tried to put it in as a fix they may have mis-spelt it!), had to get the chart out, no not the High Level, the Low Level, after frantic search found DIDGO, typed it in and hit 'execute', sat back and breathed sigh of relief, totally unaware of the distress they caused you, Roger! Well, possibly something like that anyway!;). Is DIDGO a compulsory report point?
I've seen people take all the non-compulsory report points from the FMC to tidy it up and bring it into line with the CFP, which usually doesn't show them, only to find themselves being cleared to one of the deleted non-compulsory points! Win some, lose some.
22nd Oct 2003, 19:31
Thanks for your replies. DIDGO is on the route, however, having read the above I think that maybe the LNAV theory may well be correct in this case. :confused:
22nd Oct 2003, 23:21
Talking about direct routings and Australians remind me of a case I had some 10 years back one night when a QF 747-400 attempted the world record between London and Sydney non-stop.
We were trying to get the guy the most direct route possible from KOK ( towards Iran was the furtherst we could coordinate at the time ) when I asked the pilot what would be his heading if I cleared him Sydney direct
he asked his FMS which replied 358 ! ( a 120 degr turn to the North ) and the capt could not understand why.
We thought the FMS was crazy over such long distances and left it to that. It took a few hours and looking at a globe to understand what great circle really means.... (If you are going right down under on a sphere, it does not matter which route you take....)
22nd Oct 2003, 23:31
What type was the A/C? I have had E145's take wild headings after been given a direct several times, the crew citing finger trouble.
Are some sets more difficult to use than others?
22nd Oct 2003, 23:32
As one wag once said:
"The most boring job in aviation would be squatting in a shack on the North Pole giving aircraft True Bearings"!
22nd Oct 2003, 23:53
'Twas a 757
Understood, but why would the a/c change it's initial track (040) to 090 rather than the expected 060, before flying the expected 060 (If that makes sense):ugh:
23rd Oct 2003, 00:03
Rodger Dodge just to keep it simple and expedient and to avoid any delay for the expected immediate turn, you could have and should have instructed: "Turn left/right, Heading 060 and then proceed direct to DINGO." This would have allowed the crew, if necessary, time to enter or select the waypoint. Keep in mind that crews not familiar with the area, or foreign crews who come into your airspace with a vocabulary of 200 English words, may not immediately get the correct spelling of the Waypoint and may have to search for it on the chart.
23rd Oct 2003, 00:06
I hear what you are saying but disagree. In a busy TMA environment, everybody's life is made a whole lot easier by less transmissions. Therefore to instruct the a/c to turn onto a heading, and then instruct it to route direct is a wasted transmission.
The waypoint is on the route and I was not dealing with a foreign crew or airline.
23rd Oct 2003, 00:10
Rodger Dodge your point is well taken. What it comes down to is how soon do you expect a turn? 10 seconds? Is it still safe after turning in 20 seconds? If you expect an immediate turn I would definitely recommend issuing an initial heading.
23rd Oct 2003, 00:30
Getting back to the original question.
If the pilot decided to go direct to the VOR on the FMC and the possibility exists of two or three VOR's with the same letters, he may have executed the incorrect one which turned the aircraft onto a new heading. Observing the mistake, he pulled heading to the approximate new track, and again input a direct to the the correct VOR, thus causing the aircraft to track on the original prposed course.: :ooh:
23rd Oct 2003, 01:25
Was it a Boeing or 'Bus?
Arbii don't tend to suffer from the "forgot LNAV" problem, since when you select "Direct To" in the FMS, off it goes, engaging LNAV (or NAV in Airbus speak) straight away.
Sounds good, but sometimes a bit quick! There is no "confirm" or "execute" (a la Boeing), and if you do DIR to a mistypen Wypt, or the screen shifts as you select it and get a Wypt earlier or later, you are immedaitely turning towards whatever went in. 1 step v Boeing's 3 (Enter, Execute, engage LNAV if in Hdg).
23rd Oct 2003, 01:47
I was refering to a BUS, A340:cool:
23rd Oct 2003, 02:53
Arr.. but my reply was to RD - who started this.
Unless VORs have started started spouting 5 letter idents, and/or they've anchored a beacon at DIDGO (in the middle of the N Sea I think!), I don't think it is a mistaken VOR ident <G>
23rd Oct 2003, 03:46
"LNAV", "NAV", "FMC", "FMS", "Direct to", "Forgot", "Engage", "Confirm", "Delete", "Execute", "Oh!Boll*x!".
Blimey!! I had no idea that it is now so complicated to turn an Aircraft through a few degrees! ;)
If you're flying a SID through a very busy TMA why should there be ANY delay in executing a "DIR TO"? When I'm given a DT I do it immediately, probably within 2 - 5 seconds.
How did this aircraft head off in the wrong direction for 10 miles!? Were the crew doing the crossword or finishing their breakfast? I know I wasn't there etc etc ...... but this is very worrying. As RD points out, what if LAM had been a bit more full?
If you can't find the waypoint (possibly because you've "tidied up" the departure in the FMS :rolleyes: ) just ask the controller to spell it! Delving into a chart whilst plundering straight on in the TMA defies belief.
Out of interest is DIDGO on an FIR boundary? I always underline the boundary waypoints on the plog as it's highly likely that long directs will be to the boundary of the FIR - saves seaching rapidly for the point and gives a good "heads up".
PS The newer busses give the option to "undo" a direct to if you get a bit of finger truoble.:D
23rd Oct 2003, 05:44
Even I don't do the crossword or finish my breakfast on a SID out of London when you haven't even passed BPK! Maybe you are experienced on the Bus. Boeings seem to require more button pressing to get things done. I think the philosophy may have been to give you more time not to make a mistake. A very heavy jet not all that manoeuvrable- a minor mistake, peculiarities of the FMS......not everybody in the world is always up to your speed!
23rd Oct 2003, 12:59
Do you ever operate in USA airspace? Well if you do I'm sure you will know that it is expedient to have your high and low level charts out, as well as any area charts as you will frequently get clearance to obscure waypoints. The pressure really comes on when, on the Eastern seaboard, in winter, fog and snow everywhere and you are required to divert. Putting your alternate in Route 2 will be of limited help until you are at a reasonably high level, until then you can expect directions to waypoints you have never previously heard of and you may just find the charts useful. On a multi crew aircraft this shouldn't be a problem, one just has to remember rule #1, fly the aircraft.
Obviously when on one's home turf and in familiar surroundings a lot of what is on the charts will be committed to memory as well but I believe the charts should be available and not still snug in the Jeppesen holder in a bag behind your seat!;).
23rd Oct 2003, 16:01
Quick, Quick,error, error! Don't forget Cali.
23rd Oct 2003, 16:17
BE- valid point, but there is such an amazing profusion of waypoints in the States, and Direct to clearances can involve such large distances, and the writing on those Jeppeson charts is so small and it's dark and one's eyes get grottier each year, that it is common to ask them to spell it anyway!
Hope my reply didn't come across as arrogant - it certainly wasn't intended that way. My point was that in such a busy TMA as London then we all need to be on our toes lest things become a bit too exciting if we don't turn when Mr ATC expects us to.
Must confess, not famil with the Boeing, but it can't take THAT much longer to execute a direct to..... but I like the philosophy of "more time not to make a mistake" :D People are happy to ask for wx avoidance so why not ask the ATC'er to spell the point (if you can get a word in.......) if you unsure?
No I don't operate to the US (yet?)... however I do have my charts out and available. As above, my point was that whilst in the TMA then the time taken to initiate a turn can be critical. On an airway in the cruise you have more time to look at the charts but if you're not sure whilst in the TMA then I believe it is prudent to ask...... if you don't then you'll certainly be given a heading by a possibly perplexed controller whose STCA has just shouted at him!
23rd Oct 2003, 17:41
I understand what you are saying, but in this case, the 'gentle' turn to get there was about 40 degrees and put the a/c 50 degrees off the anticipated track. I have since spoken to the controller who worked the a/c after me, and the subsequent turn was controller initiated (to get the a/c heading towards DIDGO).
'Twas a B757
DIDGO lies within the London FIR
So the plot thickens..... I feel convinced that this was an FMS problem which worries me slightly. I will certainly be more careful in choosing from which point to send an a/c direct.
In this case it may well have been better for me to plonk the a/c onto a heading and transfer it, thus it would have been beyond BPK before the direct routing would have been given by the next controller .
It might be worth trying the same thing again (obviously with the a/c already above any a/c holding at LAM) and observing the results, could this be a problem with DIDGO????:confused:
23rd Oct 2003, 19:13
As an aside to what went wrong with that particular flight can I ask why would you send an aircraft direct to DIDGO when there is Clacton VOR and REDFA FIR boundry presumably on route, both of which would almost certainly be programmed in the FMS and would be listed on the plog. Don't get me wrong, this is not a criticism but a genuine question.
As my name suggests I do a bit of flight planning and fairly regularly crews return cursing that they had been given a direct routing to an obscure intersection when there logical VOR's or reporting points nearby, not just in the Uk, I just wondered why?
23rd Oct 2003, 20:48
In dense and complex airspace which tends to be heavily sectorised I question the wisdom of releasing an aircraft on to its own navigation when more likely than not the next controller will have to re-apply a heading. Of course I don't know the particular circumstances, but transferring an aircraft on a heading is quick, easy, and safe.......the next controller can make any "own-nav "decision looking at the bigger traffic picture. Just a personal thought! In order to help the pilot route to the desired location without delay and multiple button-pushing you could offer the magnetic track required and the distance to run as per MATS 1.
24th Oct 2003, 14:58
I sent the a/c dct DIDGO simply to save the a/c track mileage (and therefore time, money etc etc). REDFA was not on the flight planned route and CLN would have involved the a/c flying more out of its way.
In order to help the pilot route to the desired location without delay and multiple button-pushing you could offer the magnetic track required and the distance to run as per MATS 1.
Time dear boy :p
25th Oct 2003, 12:16
It happens to us, quite often.
Many thousands of airline pilots in 108,000 (+) MTOW jets have no FMCs, and controllers in the US only recently seem to often forget that we are "slash Alpha". We can normally guess within plus or minus 10 degrees which heading is required, at least until the westerly winter winds increase in velocity in a few weeks.
Hey Meeester, "we don't need no stinkin" microchips in (or under) our cockpits. Just chocolate chip cookies from 'Subway', the finest in airport or (layover, i.e. MKE, JAX) gas station dining: only 15 miles from the white beaches.
There are two totally different kinds of aviation these days in the transport communities, which encompass two entirely different workloads (other than during initial training and IOE)-you see, huge numbers of us must actually FLY each leg, and our planes need us there all of the time.:} (coffee stains and in-flight dessert).
27th Oct 2003, 05:34
Hmmm. Does anyone have a chart handy to check what track they'd have been on if they'd gone direct REFSO by mistake? It's a more common direct routing than DIDGO when heading east from London and if you've got a tired crew then............
28th Oct 2003, 18:08
Posted on behalf of one of our readers:
Dear Roger Dodge,
Not covered in the responses so far to your post of 22 Oct was a possibility that I have experienced with a similar FMC on the B744 as follows. Once the new "direct to" clearance is acknowledged the PNF (Pilot not Flying) line selects the desired new waypoint which writes it into the scratch pad. He then places it to the top of the legs page by selecting the top line select key and then (normally after confirmation by the PF [Pilot Flying] ) selects execute.
It takes as long to do as it takes to read but can be done quicker if no-one checks the new leg on the map on the Nav Display. So if you cleared the subject aircraft just as he was approaching BPK, in the time he acknowledged you and then selected DIDGO or at least the line where he thought it was, the FMC could have moved one waypoint closer to destination. The result is that the aircraft is now going direct to the waypoint AFTER DIDGO! Does this concur with the 090 heading flown?
Long haul and familiarity with the systems coupled with tiredness drops the "check before action step" out of the loop and consequently I have seen the above scenario on more than one occasion. Even if the FMC did not transition to the next waypoint at the time of selection, the "fat finger of fate" is still capable of missing the correct one and usually just before the caffeine unfurrows the now puzzled brow, the "on the ball" ATCO has adjusted the track.
I am, for the moment, retired and regret that I cannot show you how easy this and other scenarios can be effected in electronic airspace but feel sure your refreshingly enquiring mind will find the answers you require. Suffice to say that any external instruction whilst approaching a waypoint, approaching a level, or during a configuration change may test the multi tasking abilities of the average male pilot.
Remembering fondly the peerless UK air traffic control, I remain,
CX B744 Captain retired.
28th Oct 2003, 18:52
Would you please pass my thanks to CX for his very informative missive. He has cleared the matter up as far as I am concerned. I have now found a far better point on the route to send the a/c to direct which means that they only need fly one side of a triangle to get to it, so everybody is happy :D :D
28th Oct 2003, 19:21
If in doubt, perhaps the radar heading option is less likely to cause confusion, especially for crews not necessarily familiar with "unusual" waypoints.