Why do some pilots consider speed control to be optional??

[PSR]

Hi there,

I am an area controller in the UK and I have a question for pilots. This has begun to annoy me now as it seems to be happening more and more. I give a pilot a speed to fly and the pilot ignores the instruction. Either he/she doesn't fly the speed at all, or they choose to comply at a point that suits them etc. Heading/level instructions are not optional. Nor is speed control, so why do some pilots continually refuse to fly the assigned speed??

I am aware that if aircraft are not given descent early enough then they may be unable to comply with level restrictions and speed control at the same time. I always make allowances for this by informing the pilot which constraint to comply with first (I know there are plenty of controllers out there that don't and then moan about it afterwards when the pilot is unable to do as requested).

The scenario I had today was a very short haul flight (B734) cruising at FL170 and had been cleared when ready to FL130. I asked the pilot his speed, he said 320kts. A few minutes later I asked him to slow to 300kts, which was readback correctly. 5 minutes later the aircraft is still showing the same groundspeed and is catching up the aircraft in front (hence giving the speed restriction in the first place), so I checked the mode S which still said 320kts! I queried this with the pilot, to which he said he was planning on 300kts for the descent. He then reduced his speed and separation between him and the aircraft in front was not lost.

Perhaps I am missing something here, but to me there seems little room for confusion. In this scenario all that resulted was it increased my workload, clogged up the RT even more, and the pilot was still stuck behind the aircraft in front of him so achieved nothing by ignoring the restriction.

I know the vast majority of pilots comply with the speeds that have been assigned, but the few that don't really do increase our workload considerably as we have to issue more instructions (headings, stop descents etc) to achieve exactly the same result.

Perhaps someone can shed some light on this from the point of view of pilots.

[Dream Land]

My own opinion is that this is an airmanship issue, experienced crews will smartly adjust speed when within 30 DME.

[Capt Pit Bull]

Unfortunately a small but significant percentage of flight crew are obsessed about maintaining high speed and direct routings even when the situation clearly doesn't favour it.

Obviously impossible to comment on this example without seeing an exact transcript of the RT. (and maybe the cvr!)

But broadly you might want to prepare yourself for the fact that if you say anything remotely ambiguous it will, by this small percentage, be interpreted as faster / more direct. When it comes to descent and speed reduction, you could do worse then add the word 'now' even if strictly speaking it is not required by standard RT.

(standard rt could probably do with an overhaul in regards to descent and speed control, but I've been saying this for years).

[dhardesthard]

Speed control.

I totally agree with you that the pilot should immediately comply with the instruction to slow down. The only thing that I can think of is that the pilot thinks that you may not notice him closing in on the preceding A/C and hopes to get away with cheating. He is probably looking at the conflicting A/C on his TCAS and doing his "own thing". Suggest you throw in the phrase "Immediate speed reduction required". Good luck.

[dhardesthard]

Within 30 DME of what?

If the controller did not want you to reduce speed immediately he would say so. Where did 30 DME come from? Would one apply your 30 DME rule to a heading change?

[PENKO]

The only reason I have observed (I'm being very diplomatic here) for pilots to be reluctant to slow down is when they perceive themselves as being high on profile.

Pilots hate being high and hate speed brakes even more so they use increased speed to correct the situation. Being told to slow down means they will end up even higher on profile, definitely needing the speedbrakes, so they temptation to cheat a little is very great, especially since a speed reduction is not well defined: I can slow down from 320 to 250 in twenty seconds, but I can also do it in 2 minutes...

This is in no way an excuse

[Kingfisher]

If separation is compromised a couple of laps round the hold should cure the problem. You have to be cruel to be kind

[Lord Spandex Masher]

PSR,

Professionalism, The lack of.

[Defruiter]

It's just as bad in the approach environment too, and it's only getting worse. I may as well be banging my head against a brick wall the majority of the time. (It also annoys me that a lot of pilots also fail to read back the speed instructions. It's a mandatory read back just like heading and level instructions!)

[Fly26]

I think some people are pressured to make up time and feel pushing the limits a bit shaves off a few minutes here and there...I think the lack of speed control in other countries by ATC allows crews to take advantage...therefore discipline after a long day when entering back into say London Airspace sometimes lapses. its a shame...poor discipline and wanting to get home.

[heloguy412]

A long in the tooth pilot once told me, "ATC is advisory only."

[judge.oversteer]

PSR

Yes, PSR, good post.
Have to admit that I have done that lots of the time, especially speed control regarding flap/auw with the B744, ie 230/235 kts or 180/185 kts.
Headings; no, not really, depends on the wind.
Sorry but...
Ciao.

Ps. sorry PSR, just realised your post pertained to Area Control, but my comments are stil valid.

[quarefellah]

Are speed INCREASE instructions correct/mandatory?

Hi All,
While we are on the subject, can someone please clarify the situation w.r.t. speed increase instructions. I understood that ATC were not permitted to INSTRUCT a speed increase but rather could only REQUEST one. I find this practice common in certain European FIRs but notably not the UK.
Also I was given to understand that (UK) controllers expect a speed reduction to be made at a rate of 1kt/sec. Is that correct and where is the reference?

[theshed]

As i fly very often in the UK on short haul trips in a 734 I can only say sorry.

But I must admit anytime i'm in the aircraft speed instructions have and would be complied with.

Perhaps it was a simple mistake.

In my company for the most part we try to make your lives as easy as we can especially as, lets face it you guys can make a Jersey as short or as long as you like for us......

[PSR]

Theshed, that's very good of you to say and is much appreciated. It may well have been a simple mistake. We all make mistakes afterall so I can hardly condemn anyone for that.

That said, it's really just an example to highlight what we regularly see from other airlines.

[ZeBedie]

I don't think there's much scope for discussion - you're given a speed - you fly it. If controllers start MORing the offenders then maybe things will improve? I hope they do because I don't want to share the sky with people who choose not to comply with their clearance.

And I think the original complaint was posted in the right place because many people would have missed it in the ATC forum.

[Basil]

Worth repeating:
No matter what trainers, captains, managers say; speedbrakes are not a cosmetic enhancement. When necessary, use them!

[The Ancient Geek]

I don't think there's much scope for discussion - you're given a speed - you fly it.

In most cases yes.
But Harare approach can yell at me as many times as he wants to maintain 210 knots, it was never going to happen in a Twotter.

[eagerbeaver1]

Maybe they forgot? Maybe they were very tired, maybe they got distracted. Maybe it was the second sector of a six sector day - late already. There could be many reasons.

We could all offer mitigating arguments.

I just did as was told, I didn't have the radar screen and couldn't see the bigger picture.

NATS are the finest ATC in the world.

[Exascot]

There is no excuse if he read back correctly.

"ATC is advisory only."

My wife is a retired ATCO, can I quote you on that because I always obey? Well mostly