A Humble ATCO asks....
 

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???

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.

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.

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:

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....)

R D

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?

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"!

Arkady

'Twas a 757

NotSoFantastic

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:

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.

Glueball

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.

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.

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:

RD...

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).

NoD

I was refering to a BUS, A340:cool:

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>

"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".

A4 :)

PS The newer busses give the option to "undo" a direct to if you get a bit of finger truoble.:D

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!

A4
 

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!;).

Quick, Quick,error, error! Don't forget Cali.