Both cleared to same level inthe hold?
 

Excuse my ignorance but would like to hear some input ref an experience in DXB last week. Was extremely busy arrivals pattern (worst I have seen in 3.5 yrs flying here) and we were cleared to the BUBIN hold, FL280. I was just taking this in mentally when an a/c ahead called that he was also cleared to the same hold at the same level. Yes, I thought, switched on fellow (and I was getting there, too - alarm bells were going off inside the cranium!) The - very busy - ATCO told him firmly that, yes, he was but that he would be dropped furhter before his arrival. Now that turn of events worried me since it was already very busy and the frequency was getting congested and the ATCO might forget or get distracted. I could envisage him turning outbound and me getting a rather too-close look at his paint scheme.

Is this common practice? It was certainly something that I had not heard of before, 2 a/c cleared to the same bit of sky at the same level even though the intention was to onward clear/descend one of them before it became an issue? I heard it used a few times that night and I was a little concerned to say the least. Maybe I just haven't taken it on board before but I have been flying for some 24 years or so and I couldn't help but be curious. Would love some feedback from those that 'push tin'.

Can't tell you about DXB, but speaking generally I would never do it intentionally.

its good that you are vigilant, but distance to "point where two or more planes are cleared to same level" also has to be counted in. Thus there are just two posibilities with your case,
a) ATCO error
b) intent to start descent of preceeding traffic before you come into scene

in both cases you should look out for our mistakes, as we are for yours. To eliminate them that is, not to put anybody on the shame list :)

Intention, believe me, is not to shame anyone! Am just curious as to whether or not this is a common practice (that I have clearly missed in 24 years of flying!). Don't think it was ATCO error, he knew that he had cleared us both to the same level and point and he stated that he intended to drop the preceeding a/c shortly. It just sits somewhat uncomfortably with me....we all speak of 'the holes in the swiss cheese lining up' - is this one that we don't need to line up?

It happens. There are agreements with adjacent units where aircraft are descending to the same level and cleared to the hold. Appropriate (separated) levels are assigned before reaching the hold. It's nothing new.

:rolleyes:

Before we panic Cap'n Smiff....how far was the preceding a/c ahead of you and how many miles were you to run on BUBIN?

Hey, nobody is panicking here - it took me over a week to write about it! Guess I was about 20 miles or so to run and he obviously had less! No idea. Am just interested to see if this is a standard tactic or a 'creative bit of controlling'. It was used a few times that night.

BTW, not adjacent units but the same unit.

I fear the thread's title is a little misleading, it should read: "Both cleared to the hold at the same level".

As captainsmiffy illustrates, a/c were not in the hold yet (was it not DESDI btw, a common DESDI hold level, not BUBIN?), and until a/c have entered the hold, radar separation can be applied, what was done is perfectly legal, and possibly the only option (at the time) at the ATCO's disposal.

I agree that should both a/c have gone 7600 or should ATC have lost radio's, a loud bang may have resulted, but in this airspace, as in most these days, if one were to control without an element of experience/trust/faith/self belief, then air traffic would come to a grinding halt.

'69

Normally you don't clear 2 a/c's to the same point at the same level. Radiocom failure being one of the reasons.

Way back in the early '70s, two aircraft with similar callsigns from the same well known Irish airline were inadvertantly cleared to the same level in the BNN hold. They saw each other, chatted on company frequency, adjusted their position to be exactly 180 deg apart, then told London Control what they were doing!!

No, it was definitely BUBIN at 280 - not a standard level, agreed. (Got a pm from a local controller who pointed that out). Got moved on very quickly to the RASKO hold and then a DARAX arrival, followed by lots of vectors! The FMS programming was going thick and fast, I can tell you!

It was the thought of R/T failure that prompted this initial post....

Don't get me wrong, I think that the boys and gals on duty that night did a sterling job, given the amount of traffic and I think that, on both sides, the 'experience, trust, faith and self-belief' was there in spades. I do think that this airspace is now creaking under the weight of traffic currently coming in and out and i just get a little concerned when people start alluding to the fact that 'maybe both cleared to the same level to hold' was his only option. That says, surely, that we are already too busy?

Just an aside, flew back with another guy who insisted on taking min fuel to DXB - and even found ways of cutting this back - and he justified this by saying that his diversion fuel gave him his 20 mins extra if he committed to DXB and that if he dropped below xxxx kilos then he would simply declare a PAN/MAYDAY as required and get in first! Personally I thought that he was mad but he did it anyway (nice CRM). It actually worked out fine that night but, had it been the night that i was referring to earlier, then this sort of thinking is going to screw the system big time!
I did point out to him during the approach that things could get quite interesting if the last 10 guys that he had flown with all adopted the same approach to fuel planning as he did on the same night at the same time!

SOP in the London TMA. The LAM arrivals are all cleared to FL150 level by Saber and if the world then went 'pop' they would all enter the Lam hold at FL150. The same applies to the other 3 arrival stacks. It is mitigated by the LAM etc stack controller descending them to a proceedurely safe level before the hold is entered. If things start to get a bit 'hairy' and and levels up to FL150 are either not being cleared quickly enough or LL APC are unable to take sufficient from the said stack the 'standing agreement' of FL150 must be ammended.

Cleared to hold and actually in the holding pattern are two vastly different situations. Personally I refer the OP's described scenario as "anticipated separation". They're at the same level now, but when it matters they won't be.

As an aside, the chances of two aircraft, that one is trying to separate, having a radio failure at the same time is so remote that it isn't even worth considering.

Chance of total ATC radio fail isn't so remote though :uhoh:

"As an aside, the chances of two aircraft, that one is trying to separate, having a radio failure at the same time is so remote that it isn't even worth considering."

I have seen a radar replay of that very thing happening, so I would say it is worth considering!

As a simple principle, clearances should be fail safe wherever and for as long as possible. This was hammered into me from day one of training and has always seemed sensible. To clear two aircraft to the same holding fix at the same level just adds another opportunity for it all to go wrong.

Don't worry about the probability of multiple radio failures - it takes far less to distract the controller. And as Defruiter says, multiple radio failures do happen - I suspect I have watched the same radar recording and it wasn't fun imagining how the controller felt.

'Anticipated separation' and all the other examples of 'It'll be OK, I'll keep an eye on it' seem to have featured disproportionately in incidents that I have been involved in reviewing or investigating.

Fully agree :ok:


If we go to the numbers, a debateable issue that will end up with discussing the definition of the word failure and the quality of radio equipment at different places in the world.

In practice, which means two aircraft that it is impossible to reach, with enough clarity to deconflict, on the frequency during a short but critical time period - it is not even very rare (by my admittedly very subjective opinion/definition). Fact is that this happens and has led to accidents/incidents in the past, at least one quite famous by the way.

A lot of opinions, definitions & speculations you might say but the fact remains.

By the way I dont judge the controller at the time in any way. Anticipated clearences might not be one of the safest ways of operation in general but without the whole picture its valueless to speculate.

I must say I personally do find the statement of Bluesky slightly worrying.
But I also chose to not draw any parallells to attitude or imagination related skills from a forum entry and leave it at that - a slight feeling of worry.

If you start to apply the "what if" principle to aviation we wouldn't be flying. What if the engine catches fire? What if the thing gets hijacked? What if the cargo catches fire? What if I clear him to a level and he busts the level? What if he strays onto the active runway? What if ad nauseam

Compare the above mentioned incidents to the amount of incidents because of multiple radio and/or radar failures.

Actually, Bluesky, i play the 'what if?' game every time I drag my weary butt into the sky! Every single time we brief what we will reject for and up to what speed and then we brief what we would do post-v1, despite getting checked every 6 months (and, often in between), with, say, an engine failure or engine fire. Every commercial pilot does/should. It is part of the reason why aviation is so inherently safe these days.....the other reason is that you guys are doing an equally conscientious and good job on your side of the screens. Which brings me back, full circle, to a debate on is this practice safe? I wasn't really even thinking of a radio failure, per se, which is undoubtedley a problem (as pointed out) - the big thing that night was the sheer level of traffic and that surely provides its own big-enough distraction? From conversation with local controllers we were already cleared to hold at a non-standard level and then moved to a point that i'd never even heard of to hold shortly thereafter. My concern is that, sooner or later, something will 'give' - I just hope, for everybodies sake, that this doesn't happen whilst 2 a/c are cleared inbound to the same hold at the same level.....happy new year!