callsign confusion>TCAS RA

[TC_Ukraine]

Here is situation we had some time ago.
2 747s of Carglolux with callsings CLX749(FL320) and CLX794(FL310) were flying opposite directions. here is an actual picture of event:

CLX749 was about to be in conflict with other converging traffic at FL320 in 100 n.m. so controller asked, if he was able to climb FL 340. CLX749 said that they would like to remain at FL 320.
Minute later, when distance between CLXs was 15 n.m. CLX794 requested FL 330. Controller assumed that is was CLX749...
C: CLX749, climb FL 330.
P: Climbing FL 330, CLX 794.
few seconds later, distance 10 n.m.:
P: CLX794, confirm, climb flight level three three zero now.
C: CLX749, if you prefer maintain flight level three two zero, you may maintain flight level three two zero.
few second later both flights reported about TCAS RA climb/descent. Min separation was 700 feet at 3 miles.

As a result controller has been fired.
Your opinion?

[Ninja Controller]

My opinion is that if the controller was fired as a result of this incident, the ANSP has a poor safety management system which will result in more incidents such as this one, or worse.

Callsign confusion is an issue that can be addressed in many ways but at the end of the day it will always exist. For example, yesterday I had an Easyjet aircraft take the call for a Ryanair aircraft with a completely different callsign. What can you do in such a situation? My thoughts to mitigate against further occurrences would be:

Controller training - Making controllers aware of callsign confusion and the associated traps.
Operator cooperation - Getting operators on board to help avoid putting very similar callsigns out there at the same time.
Technology - It doesn't look like it but does the equipment provide any sort of data link via Mode S or ADS? Such information paired to the right systems could help nip such a problem in the bud. Was there any form of conflict alert to make the controller aware of the potential and actual loss of separation?
Aircrew training - Making aircrew more aware of callsign confusion and the associated traps. Possible CRM issues too?

[DaveReidUK]

What happened to the system that's supposed to ensure that flights with confusingly similar callsigns aren't flightplanned to be anywhere near each other ?

[darkroomsource]

Absolutely crazy...
Maybe when this kind of thing is happening, the controller should say
"CLX794 turn right 20 degrees, CLX749 turn right 20 degrees, both of you turn right 20 degrees for traffic avoidance"
Or maybe
"every body who can hear me, turn right 20 degrees right now for traffic avoidance"

OK, that was cynical, but maybe, if they're going to fire someone over it, the controllers should give both planes instructions in the same sentence as in
"CLX749 that's seven four niner climb flight level 330, CLX794 that's seven niner four maintain flight level 310"


Cargolux should be chastised for using two call signs that are so close to each other on opposing flights.

Did the controller tell the flights that there was a similar call-sign on the radio?

[HEATHROW DIRECTOR]

<<Controller assumed that is was CLX749...>>

Never assume anything - be certain of the facts.

[Sweet Potatos]

So easily done ... Controller should never have been fired.

Callsign confusion happens and is so common these days.
Qatar was particularly bad for similar callsigns in the same bit of airspace at the same time ...

He should have been expecting an issue here though ... but easy to judge from here. I've been stung by a similar situation where an aircraft took another a/c's clearance to be his own - even though it was a climb and maintain instruction and he was descending! Q241 v Q421 .... deep joy.

[Lon More]

Waiting until they were only 15 miles apart was leaving it much too late. If another a/c had made acall he'd have lost separation anyway.
If a trainee had done this with me we'd have had a very long debrief!!!
Allowing for the time to start the turn giving each 20 degrees would have been insufficient by then
Whilst it should not be a firing situation it should have lead to some retraining and a very critical look at the unit's operating procedures

[Chilli Monster]

the ANSP has a poor safety management system which will result in more incidents such as this one, or worse.

Bear in mind this is the same ANSP that classified all its ATCO's as level 4 English, but when one came to work in the sandpit it was immediately apparent a re-assessment was required. Result - level 3.

Not saying this had any bearing on the incident, but worth keeping in mind.

[LEGAL TENDER]

Waiting until they were only 15 miles apart was leaving it much too late. If another a/c had made acall he'd have lost separation anyway.

Not sure you read the scenario correctly?

The 2 a/c were separated, he wanted to climb the higher one to resolve a confliction with a 3rd a/c who's not in the picture, but then the lower of the 2 CLX's asked to climb and he thought this was the higher one.
There were no 20 degrees turns involved.

[ATCast]

Originally Posted by Lon More

Waiting until they were only 15 miles apart was leaving it much too late. If another a/c had made acall he'd have lost separation anyway.

The cause of the separation loss had nothing to do with waiting too long. It had to do with call sign confusion and subsequently instructing one aircraft to climb into the other's path.

This is a nasty combination of callsign confusion and expectation bias.
If he wouldn't have asked CLX749 to climb just a minute ago, his mind would not have been preoccupied and he'd probably would not have confused the two or at least verified the call sign.

In my opinion this could happen again to any other controller. Firing the guy does not help safety at all.
Instead they should showcase this incident to airlines to stress the importance of avoiding call sign similarities.

If anyone from an airline's flight planning office reads this, you might want to read this link.

[TC_Ukraine]

some more info: clx749 (at fl320 ) was expected to climb 340 according its FPL in same sector.
we do have mode-s, but without level bust indication, when pilot sets different FL to autopilot.
STCA started just 10 seconds before TCAS report.

Administration accused controller in:
speaking 130 words /min during comm
instructing westbound clx749 to climb to odd level
poor English, as he confused 749 and 794.

[Talkdownman]

The ATC 'assumption' aside, the Cargolux callsign allocation is asking for trouble. If ATC heads are rolling then Cargolux heads should roll too. Airline ops need to be a bit brighter than that...

[mad_jock]

Having been recently throught this bun fight with commercial and ops.

Can ATC please file MOR and send a ****ogram to company whenever you get even a hint of conflicting callsigns.

As pilots we do file internal reports when we see them. But then the darkside forces come into play. Some airports/handlers have to be forced into doing the season changes and will lie saying they can't do it. OPs get sent round in circles.

Commercial will come out with rubbish that it will screw with the booking systems.

Basically it can go round and round in circles.

If ATC file on it, it becomes an audit item which is brought up in the flight ops audit. Flights ops inspectors take an extremely dim view of open MOR's on this subject. Post holders get an ear full and the problem gets fixed.

So please file on it. More to the point and the reason why we as pilots file ASR's on it. When the inevitable screw up occurs you have a paper trail showing that the issue had been highlighted.

[HEATHROW DIRECTOR]

Aren't "callsign confusion" forms filed now? They were back in the 70s. Also, ATCOs can always as a pilot to change his callsign, perhaps to the aircraft registration, to avoid problems. Or is this not permitted now?

[mad_jock]

We were weeks with the similar callsign and nothing was changed.

Maybe with electronic strips its not as easy to score through the callsign and give it XYZ papa india alpha callsign.

And MOR is the way forward because the company gets it and has to be seen to do something about it.

[throw a dyce]

I hope that the crew of CLX 794 had tea with no biscuits for basically level busting.The controller never instructed CLX794 to climb,the instruction was given to CLX 749.The controller misheard the callsign for whatever reason,but the CLX 794 crew took the wrong call as well.
As for sacking the controller for a mistake,well the ANSP obviously has no idea about human factors.Some would agrue that 700ft and 3 miles is a technical loss,but isn't that why TCAS was developed as a last line of defence.
So what was the background noise levels in the OPS room?
In the last places I worked in there has been full scale arguments,a £5 kettle at 100db used by management,ATSA meeting chatting gallery,and a sing along with plonker ATCO,all drowning out the R/T and that is with the latest headsets.You have to use very plain words to remind these idiots it's an OPS room.

[UpperATC]

Searching for solution

It is quite sad to read that the controller was fired after the incident. I don't know the history of the ATCo, or his "personal file", but if this was the only major mistake, the resulting procedures at that ANSP are disgraceful... Where is the Safety Officer? Safety system? Just culture?
I hope that you have a Union or at least a national ATCA, who will help the controller.

Of course I agree with the previous posts regarding the call sign similarities in the sector. Many steps were taken in the past to avoid it, but the system is still far from perfect. And there are other factors, like huge delays, or unplanned reroutings that compromise the idea sometimes.

But going deeper... I see another issue here. It is the human factor, it is how our brain works. Why?

I see that the controller was looking at the conflict with the 3rd acft, 100NM away. His brain was somewhat locked onto that problem. He started with preplanning, asking the pilot (2nd acft) for higher levels. The answer was negative, and it was surely not a relief for the ATCo. Minutes later, the 1st acft asked for higher level - and here we are... Because his brain was still preoccupied with the conflict ahead, he "heard" what he wanted to hear, his brain seeking for some ease and... the assumption happens. A very common thing in ATC.

Maybe a small issue here is trying to solve the problems to early. Of course identifying the problem, and searching for the best solution is obvious, but 100NM can sometimes be a bit to early. I've seen many mistakes where controllers were focused on the problem that was 6, 7 or more minutes ahead, issued an instruction (climb, turn, descent) and at the same time they totally forgot or missed the conflicting acft, (or the new conflict with the 3rd acft, as a result from the instruction) that was in only 20NM range of the acft being "vectored". Doing step by step, monitor the conflicts that are still 10 or more min away, and rethink the best solution is sometimes better that taking immediate action.

The second thing is identifying and being aware of the possible misunderstanding due to the similar call signs. It is not just similar call signs. Sometimes even just the same company, like CLX call, will be enough for the problem. Same as above - "wrong expectation" -, if the pilot asked for a higher level, was put on stand-by and moments later a new acft from the same company made the inital call and was instructed to continue climb to FL, which was the same as the requested from the pilot nr. 1, it can happen that just that nr. 1 will also read-back "Climbing to level xxx"... We're all humans.

In the case of CLX749 and CLX794, stressing out the call sign when instructing can be a solution, for example;
CLX749, I SAY AGAIN, CLX 7-4-9, CLIMB TO FL330.
Maybe in latter case at least the pilots of the both acft would identify the mistake made by ATCo.

And the administration accused the controller because of the temporary west/east FL allocation?? I'm sure, they were never working surveillance ATC...

[ZOOKER]

I'm surprised that the CLX794 crew couldn't see the opposite direction, 1000' above traffic on their TCAS display, prior to making the request for higher. At cruising speeds/levels you would expect the TCAS to be set at a fairly long range. I know it's not the flight-crews primary duty to monitor the ATC situation from the cockpit, but on most of the post TCAS fam-flights I undertook, they did.

Had this happen several times:-

A/C Bigjet123 approaching level (......). standing by for higher.
ATC Bigjet123 roger, maintain FL(......), traffic crossing 1000ft above you right to left, x miles ahead.
A/C Yes we have that traffic on TCAS, or (even worse), traffic in sight.

I don't know whether this still happens in the UK.

[Rossoneri]

I don't know whether this still happens in the UK

Yes. Not on a frequent basis, but still get a few pilot requests for climb/descent as traffic is just passing 1000ft above/below. Equally frustrating is someone who insists on climbing like a lift as they approached their cleared level, despite being told there will be an a/c directly above them by 1000ft.

[TC_Ukraine]

And the administration accused the controller because of the temporary west/east FL allocation?? I'm sure, they were never working surveillance ATC...

U r right! As they said: "You have so many FLs in RVSM airspace, so controller just had to strictly instruct CLX749 to climb 340, not asking was he able or not."

I hope that you have a Union or at least a national ATCA, who will help the controller.

Union is fully controlled by administration)
According to latest news he's about to become a FISo in uncontrolled airspace. But it's 3rd part of salary he had before. Adm-n says that they saved him from prison. Crazy....