A Humble ATCO asks....

[Notso Fantastic]

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!

[A4]

Notso

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" 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?

BE

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!

A4

[Roger Dodge]

NotSoFantastic

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).

Nigel

'Twas a B757

A4

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????

[jeppsbore]

Roger Dodge

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?

Cheers JB.

[055166k]

Own Nav?

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.

[Roger Dodge]

JB

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.

055166k

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

[Ignition Override]

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).

[Hand Solo]

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............

[PPRuNe Towers]

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,

Yours faifhfully

CX B744 Captain retired.

[Roger Dodge]

PPrune Towers

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

[DouglasDigby]

If in doubt, perhaps the radar heading option is less likely to cause confusion, especially for crews not necessarily familiar with "unusual" waypoints.