Go Back  PPRuNe Forums > Flight Deck Forums > Rumours & News
Reload this Page >

Airprox over Central Scotland

Rumours & News Reporting Points that may affect our jobs or lives as professional pilots. Also, items that may be of interest to professional pilots.

Airprox over Central Scotland

Old 22nd Oct 2013, 10:57
  #41 (permalink)  
 
Join Date: Dec 2006
Location: Florida and wherever my laptop is
Posts: 1,350
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by MCDU2
We did ATC avoiding action scenarios a few years back in the sim. Our OPS manual now reflects that the AP is to disconnected in order that an increased bank of turn can be achieved. Our airline is all airbus and hence if you left in the AP at high cruising levels then all you would get is a gentle 1g turn. Interestingly enough we were briefed that a number of other airlines across Europe refuse to allow their pilots to disconnect the AP so to plan on an ATC avoiding action event to become a TCAS RA.
That will be really interesting to the controllers.

First - if you do NOT react at once disconnect the AP and make a standard turn you are hazarding your aircraft and the other aircraft and the passengers on both. But they use the AP to keep their management happy?

Second - If a controller has an aircraft report a TCAS RA while under their control they are removed from their position, have one way interviews with the supervisors and management. This is a career threatening event. All because the flight crew had a management directive to never fly manually?

Looks like managements should justify their case in writing to their passengers.

Last edited by Ian W; 22nd Oct 2013 at 11:02. Reason: mistype
Ian W is offline  
Old 22nd Oct 2013, 11:07
  #42 (permalink)  
 
Join Date: Mar 2007
Location: In my head
Posts: 694
Likes: 0
Received 0 Likes on 0 Posts
Climbing or descending into conflict still a problem in 2013 ? Classic in a safety system so predominantly reliant on exact vertical separation, what ?

It seems the best post mortem timelapse pictures of any growing collision risk in controlled airspace are ATC radar. Radar control is also surely the best ante mortem antedote to this kind of ill - pity that the control AND monitoring gets degraded when there is some pressure applied to change a plan (in this case a pilot's request to climb).

As I read it, the report indicates the onset of this conflict was brought about by a pilot request to climb i.e. a request to the controller to change the controller's current plan for the safe flight of that pilot's aircraft. The report doesn't actually say this was the cause because as an operational event it was seen as routine. As always, it is what happened next which is in our faces.

Ultimately, the plan was changed as requested but clearly on clearance to climb it was being changed to a more risky one which had created ATC workload at the time to accommodate, and then was quickly followed by more ATC workload / monitoring / confusion / concern, then seemingly missed or misinterpreted safety communications, then pilot workload and probable confusion.

The official post mortem risk classifications applied are ICAO C or ERC 102. Take your pick, but essentially a routine request to (risk a) climb was mismanaged all the way into the tabloids today.

There's no question there are pants-down enough reasons for it to be reported in the tabloids. Seems to me the question is, as always, how better can classic pants down scenarios like this be avoided ?

The human condition/temptation to defend or blame individuals is of course not going to improve anything, but personally I don't buy that this was an everyday event to be noted in the database with a date and risk score.
slip and turn is offline  
Old 22nd Oct 2013, 11:40
  #43 (permalink)  
 
Join Date: Jan 2008
Location: Reading, UK
Posts: 15,787
Received 196 Likes on 90 Posts
Whilst recognising the need for anonymity in the report, it may have been useful to see if there was any similarity between the callsigns for these two aircraft.
"Lufthansa 418" and "Speedbird 87".
DaveReidUK is offline  
Old 22nd Oct 2013, 11:49
  #44 (permalink)  
 
Join Date: Feb 2010
Location: farfaraway
Posts: 162
Likes: 0
Received 0 Likes on 0 Posts
To the guys who invented TCAS your lifes work has been truly vindicated
obwan is offline  
Old 22nd Oct 2013, 12:15
  #45 (permalink)  
 
Join Date: May 2000
Location: Living In The Past
Age: 75
Posts: 297
Received 1 Like on 1 Post
I find this comment from the report interesting from a "human factors" point of view :

ATCO(1) reported that his usual method of working was to put the electronic strips of conflicting traffic together and suitably highlighted. On this occasion ATCO(1) had not done this.
No explanation given as to why not. I'll bet my pension that if they'd been paper strips, he would have immediately put the strip holders together & cocked them out as a reminder......
Eric T Cartman is offline  
Old 22nd Oct 2013, 14:18
  #46 (permalink)  
 
Join Date: Dec 2006
Location: Florida and wherever my laptop is
Posts: 1,350
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Eric T Cartman
I find this comment from the report interesting from a "human factors" point of view :



No explanation given as to why not. I'll bet my pension that if they'd been paper strips, he would have immediately put the strip holders together & cocked them out as a reminder......
In the old days with strips they would not have been cleared to the same level. When the lower aircraft then asked to climb the radar controller would then have been given just those two aircraft to separate and would have watched them until they were clearly separated before giving them back to the planner.

Not many here will know what Redbrae and Gailes were
Ian W is offline  
Old 22nd Oct 2013, 14:42
  #47 (permalink)  
 
Join Date: May 2000
Location: Living In The Past
Age: 75
Posts: 297
Received 1 Like on 1 Post
@ Ian W
Gailes Type 7/14 blips were so wide, they'd never have got within 10 miles of each other anyway
I last did Area Radar in 1974 @ Manch but even then, if I'd not established both acft on headings before level changes, I'd had a sharp blow to the back of the head from my mentor. I'm sure there'll be many ATCO's who'll recall the examiner who 'chopped' many people for similar stuff

Last edited by Eric T Cartman; 22nd Oct 2013 at 14:43.
Eric T Cartman is offline  
Old 22nd Oct 2013, 15:59
  #48 (permalink)  
 
Join Date: Jan 2008
Location: The foot of Mt. Belzoni.
Posts: 2,001
Likes: 0
Received 0 Likes on 0 Posts
Wise words Mr.C. Also, as one of our training officers used to point out........"In area control, radar headings normally come in pairs".
ZOOKER is offline  
Old 22nd Oct 2013, 19:40
  #49 (permalink)  
 
Join Date: Oct 1999
Location: Near VTUU or EGPX
Age: 65
Posts: 317
Likes: 0
Received 0 Likes on 0 Posts
If only I had the luxury of concentrating on just 2 aircraft to separate

Comments as to how ATC worked 37+ years ago are not very helpful

This crossing scenario happens often and in this instance was identified, correct lateral avoiding action WAS given and IF the pilots had acted immediately and correctly, as the report states, separation WOULD NOT have been eroded.

Granted, the confliction was not marked on the strips, but it could just have easily been missed using paper.

I am valid on the sector concerned.
The Fat Controller is offline  
Old 22nd Oct 2013, 20:09
  #50 (permalink)  
 
Join Date: Apr 2004
Location: A galaxy far far away
Posts: 109
Likes: 0
Received 0 Likes on 0 Posts
So why didn't the controller give avoiding action to only one of the pilots? (= less chance of confusion over who's told what?)

And why not give lateral avoiding action to one and vertical to the other?

p.s. you may have noticed I'm not qualified in any aspect of ATC (apart from listening to it)
AdLib is offline  
Old 22nd Oct 2013, 21:07
  #51 (permalink)  
 
Join Date: Feb 2008
Location: Ireland
Posts: 31
Likes: 0
Received 0 Likes on 0 Posts
50% of the incidents in the Airprox report involved military aircraft .....
PPRNkof is offline  
Old 22nd Oct 2013, 21:12
  #52 (permalink)  

More than just an ATCO
 
Join Date: Jul 1999
Location: Up someone's nose
Age: 74
Posts: 1,768
Likes: 0
Received 0 Likes on 0 Posts
Comments as to how ATC worked 37+ years ago are not very helpful
Whether you like it or not the way we work today was shaped by those who worked then.
A lot of the advice my generation was given is still valid and worth passing on to today's students. Sadly, it seems that some of it wasn't, or fell on stony ground
Lon More is offline  
Old 22nd Oct 2013, 21:59
  #53 (permalink)  
 
Join Date: Mar 2007
Location: In my head
Posts: 694
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Fat Controller
This crossing scenario happens often and in this instance was identified, correct lateral avoiding action WAS given and IF the pilots had acted immediately and correctly ...
But four pilots each with a brain supposedly plugged in to the radio transmissions of one ATC brain did NOT heed "the correct lateral avoiding action" which was "given". I think we might therefore be entitled to ask when is receipt / compliance with an ATC instruction a "given" (or not) ?

Is it for example:
(a) When a request to climb to a desired level is cleared without any cautionary condition attached about the new level having created a convergence problem ?
(b) When a sudden instruction to turn on the end of a busy series of transmissions to other aircraft is read back correctly ?
(c) When the aircraft addressed with the urgent instruction responds only with a transmission comprising just the digits of its callsign ?
(d) When the onscreen radar track appears to reflect the instruction given ?
(e) When the onscreen radar track appears to reflect the opposite of the instruction given ?

I don't think the report was particularly clear on all this beyond it being clear that the 5 brains involved in communicating and executing the instructions clearly were not ad idem (or was it 6 brains eventually including two ATCOs ?). At best it appears that at one point three pairs of brains were doing their own thing with each being unaware of what the other pairs were doing or expecting to be done.

I don't know if ATCO(1) realised it was a "given" when he ultimately cleared 747(2) to 340 or whether those posters reading the report have realised it, but once at the same level and using the data in the report it would appear that between 1252:00 and 1255:22 when low level STCA was triggered i.e. in 3.35 minutes the two aircraft had converged 14.5nm. That is a closing speed of 260 knots. In the next 38 seconds the aircraft closed a further 3.2nm i.e. an increased closing speed of 303 knots.

In the next 17 seconds before high level STCA alerted, a further 1.7nm separation was lost (that is a further increased closing speed of 360 knots or 185 metres a second with just 9000m left to close or just 48 seconds left until tracks cross).

Now when, as had already been seen in this incident, you factor in that the first attempt to instruct the aircraft to take avoiding action had taken almost a full minute to establish as not happening, we can begin to guess what colour pants ATCOs might favour for these frequent crossing scenarios. I am sure they are more aware of the hazards of the closing speeds involved than any civilian pilot. Question is, when they see one coming, how will they get the message across next time without the fail ?


I have to say, that "Resume own navigation" intruction that followed the first little fiasco was a little ironic (that's the fiasco up to about 1257 which warranted the description "airprox"). Own navigation seems largely to have been what was pervading from the moment 747(2) decided they wanted a better level and were given it!

Then, love-a-duck, just when some of us may have stopped reading the report and breathed a sigh of relief that it obviously all turned out ok with thousands of metres to spare, we get another STCA alert at 1258:20 seemingly caused by 747(2) having drifted down out of their 340 level just a couple of minutes after the first STCA alert! Perhaps they'd decided 340 was feeling a bit crowded / own navigation is the better part of valour etc...

So then, Part 2 of this buggers muddle then also takes the best part of a minute to resolve including two new ATC avoiding action instructions, one of which this time is queried and cancelled when the aircraft seem to have straightened themselves out (TCAS ?).

Anyway, I really do hope this wasn't that typical "not newsworthy" day out some posters would have us believe it was.

Last edited by slip and turn; 22nd Oct 2013 at 22:16. Reason: grammar and doubting and rechecking those astounding closing speeds!
slip and turn is offline  
Old 22nd Oct 2013, 23:09
  #54 (permalink)  
 
Join Date: Feb 2008
Location: Ireland
Posts: 31
Likes: 0
Received 0 Likes on 0 Posts
I actually think the third incident in the report was far more significant. The one involving the F15 Cowboy. The plane nearly lived up to it's name. The Strike Eagle.
PPRNkof is offline  
Old 23rd Oct 2013, 07:43
  #55 (permalink)  
 
Join Date: Dec 2010
Location: S 51 N
Age: 84
Posts: 196
Likes: 0
Received 0 Likes on 0 Posts
slipandturn

Fully agree with what you write, had my problems with some contents of the report too.
Well, I consider myself also being one of those "ATC Dinosauers", but as was mentioned before the basics havenīt changed !
Clearing two flights to the same FL and heading for the same fix at or almost at similar time overhead, was and is an absolute NO GO !!
I have my serious doubts that this conflicting clearance for FL 340 was coordinated correctly, as is stated in the report. Who in heaven would agree on such a flaw knowingly ??
I also see the second violation of separation as the more serious one. Hopefully, the two crews at least had each other in sight ??
Finally the question must be raised wether or not the reception of the avoidance clearances was as clear received and understandable as is assumed in the report. Obviously there is another "sleeping flaw".
Wether this was a "newsworthy" incident or not is not what raised so many comments. Itīs the way those press and news sharks have prepared it for the common public that causes my anger too!!
Annex14 is offline  
Old 23rd Oct 2013, 09:37
  #56 (permalink)  
 
Join Date: May 2000
Location: Living In The Past
Age: 75
Posts: 297
Received 1 Like on 1 Post
@ The Fat Controller
[QUOTE]Comments as to how ATC worked 37+ years ago are not very helpful[/QUOTE

I expect you've heard this famous saying : "Those who cannot remember the past are condemned to repeat it".

Not all the old ways are rubbish now - that's why us old codgers wouldn't do what ATCO(1) did .......

Last edited by Eric T Cartman; 23rd Oct 2013 at 10:43. Reason: added text
Eric T Cartman is offline  
Old 23rd Oct 2013, 10:00
  #57 (permalink)  
 
Join Date: Feb 2007
Location: GLASGOW
Posts: 1,289
Likes: 0
Received 0 Likes on 0 Posts
I actually think the third incident in the report was far more significant. The one involving the F15 Cowboy. The plane nearly lived up to it's name. The Strike Eagle.
Especially the 'when the climb rate exceeds 8000 feet/min

Mode C output is lost when rate of climb exceeds 8000fpm, and the member opined that this may have been the reason.
maxred is offline  
Old 23rd Oct 2013, 10:08
  #58 (permalink)  
 
Join Date: Mar 2010
Location: Often in Jersey, but mainly in the past.
Age: 79
Posts: 7,786
Received 129 Likes on 58 Posts
Originally Posted by Eric T Cartman
I expect you've heard this famous saying : "Those who cannot remember the past are condemned to repeat it".

Not all the old ways are rubbish now - that's why us old codgers wouldn't do what ATCO(1) did .......
Along with others of the Older Generation, I find the concept of clearing both ac to FL340 with the intention of resolving any issues 'later' is anathema.

Lesson "ATC 1.01.03", I would suggest.
MPN11 is offline  
Old 23rd Oct 2013, 13:00
  #59 (permalink)  
 
Join Date: Mar 2007
Location: In my head
Posts: 694
Likes: 0
Received 0 Likes on 0 Posts
PPRNkof raises an interesting comparison which I take the liberty of paraphrasing as "does this incident between two 747s actually matter compared to other types of airprox ?":
I actually think the third incident in the report was far more significant. The one involving the F15 Cowboy. The plane nearly lived up to it's name. The Strike Eagle.
The ARM methodology(?) now in use by UK CAA gives the F15E/J41 airprox an ERC of 502 and the 747/747 an ERC of only 102. I assume there is supposed to be some steady linear progression of measured risk between these two scores and not some logarithmic scale as with decibel measurement

So, as maxred points out, the rate of climb of an unsuspecting F15E is enormous. Not quite as fast as any bullet but far more lethal projectile than any bullet if it hits you.

However, I wonder if the ERC classifications in any way take into account the obviously differing collision profiles presented by larger and smaller types i.e. if we assume in all cases the two conflicting aircraft are targeted to the same "aiming point" what is the likely grouping of the two hotshots when they punch their mark on target? Will the holes in the F15E/J41 target card ever be likely to overlap ? And even if they do, will one sneak through just in time to avoid the other? I think it is quite remote that two 19m long aircraft will be so unlucky as to punch the same mark even if using equally accurate navigational equipment.

However, take two 75m long projectiles and fling those at the target using the same kind of projectile accuracy then I would say there is a much greater likelihood of the punched holes overlapping. There are arguments that might suggest you need to use the relative airspace displacement volumes to calculate something useful, and others which might suggest a calculation based only on the collision area profiles presented by each typewould be more useful.

Either way I venture to suggest that it might be between 300 and 1000 times more likely that if you fire two 76m long 747s at each other from 20 miles or 6 miles or 3 miles that they will in some way hit each other versus a 19m F15 fired at a 19m J41. Anyone know if that kind of factor is included in the calculation of ERCs (which are supposed to provide a useful comparison of which incidents are the most important to learn from first I think!)? Any anti-missile missile scientists care to chip in with something more useful ?

Another factor in the comparative severity of risk might also be measured in terms of likely casualties both in the aircraft and on the ground.

And as we have also seen both in slow motion "why are they not complying / now what are they doing?" with the 747s and in "blink and you missed it" terms with the F15, the lack of adequate time for any intervention is surely a major risk assessment factor.

Does the recently introduced ERC system come close to getting the correct balance, do we think? Is there a corruption in the methodology which may mean that it too easily leads us to ignore lower score civilian operational risks because we are measuring them on the same page of an airprox report against what is essentially an enhanced military risk i.e. measuring both risks with a politically incorrect military mindset ?

Would it take five similar 747 on 747 airprox to gain as much of the CAA's attention as is warranted by the F15/J41 incident or is that not what those relative 102:502 ERC scores mean?

Last edited by slip and turn; 23rd Oct 2013 at 13:21.
slip and turn is offline  
Old 23rd Oct 2013, 13:50
  #60 (permalink)  
 
Join Date: Dec 2006
Location: Florida and wherever my laptop is
Posts: 1,350
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by The Fat Controller
If only I had the luxury of concentrating on just 2 aircraft to separate

Comments as to how ATC worked 37+ years ago are not very helpful

This crossing scenario happens often and in this instance was identified, correct lateral avoiding action WAS given and IF the pilots had acted immediately and correctly, as the report states, separation WOULD NOT have been eroded.

Granted, the confliction was not marked on the strips, but it could just have easily been missed using paper.

I am valid on the sector concerned.
The problem here is what is called open-loop instructions as compared to closed-loop instructions.

With open-loop instructions an aircraft is told (as in this case) turn right heading (sic) 050. Pilot then reaches forward and selects 050 on the FMS. The controller may have in his head what to do next but nobody else does, least of all the crew. Similarly as in this case the lower aircraft was cleared to climb flight level 340 - controller knows something needs to happen after that but its an open loop as he may not have thought ahead or if he has it is only shown by cocked strips - or electronic highlight and an interrupt like a stuck mic or a controller relief and all can go pear shaped rather rapidly.

The trajectory based control systems that are just starting to appear in European airspace are 'closed loop'. An aircraft isn't put onto a heading or told to climb to a level, the trajectory which runs all the way to destination is given constraints (level, position and time windows) that it has to pass through. In this case the controller giving the lower aircraft a level constraint of FL340 would have received an immediate medium term conflict alert with the other aircraft as the new trajectory would be in conflict, so the controller would then have put in a lateral constraint on the trajectory that would have cleared the conflict. So the aircraft would now received a trajectory amendment with a climb and a deconflicting lateral constraint- not unlike an oceanic routeclearance.

Closed loop control is the way of the future systems. It will move air traffic management from the known traffic environment to the known trajectory environment with FMCs sharing their trajectories with the ground systems. It will also enable more efficient 'business trajectories'.

Experience gained 30+ years ago in that airspace being used to create more efficient and probably safer systems for the future.
Ian W is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.