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Herc708
24th Mar 2012, 15:39
Why TYPE rather than CATEGORY ? What is the point of reporting aircraft type when it is surely better to report the aircraft CATEGORY (A,B,C,D) instead

ATC cannot judge the performance of an aircraft from its TYPE only - any instructions should be based on performance considerations which are captured by the aircraft CATEGORY only

There are airports which offer SID's (e.g. DUB) which are dependent on aircraft CATEGORY (it says it on the SID plate) - but the ATIS states report Aircraft TYPE. ATC end up issuing incorrect SID's, Speeds, Climb Rates based on erroneous information

HEATHROW DIRECTOR
24th Mar 2012, 16:09
In the approach environment it's for wake turbulence separation purposes. Airlines have a habit of substituting aircraft types at short notice so for example when ATC expects a Boeing 757, a Boeing 767 turns up. On departure, when a pilot notifies a different type to that flight planned, the change is notified to all ATC agencies.

10 DME ARC
24th Mar 2012, 16:12
"Report aircraft type" is mainly used on arriving ATIS's so that the aircraft actually operating the flight can be seen to match the FPL type. This can make a lot of difference to the ATCO putting a/c together on Approach. For example out here in ME we have lots of airlines who operate Heavy, Medium and even Light aircraft on same routes.
So a late a/c swap could mean, if not noticed, the wrong vortex gap being given on final approach and all the possibilities this could create!!

vespasia
24th Mar 2012, 16:38
ATC cannot judge the performance of an aircraft from its TYPE only

With all due respect, utter tosh:=

There's a world of difference between types in the same category, and any good controller can use that information to help.

Knowing aircraft performance is at the heart of good controlling, certainly from a tower point of view - a Citation is in the same category as a Cherokee (light) - try treating those two the same and see what happens! The same goes for an A340-300 and a B747 and for many other examples - in fact, I'm hard pushed to find 2 aircraft in the same category that I can'tthink of a difference in performance for!

Additionally, the information is used to check the accuracy of flight progress data - which is used by a whole host of agencies from SAR to route charging.

HEATHROW DIRECTOR
24th Mar 2012, 16:47
<<ATC cannot judge the performance of an aircraft from its TYPE only>>

I assume you are not an aviation professional, but they certainly can, as explained by the previous contributor.

Talkdownman
24th Mar 2012, 17:03
aircraft CATEGORY (A,B,C,D) instead
Also there are not only Performance Categories but also Flight Priority Categories.
Any ATCO worth his/her salt is going to be pretty familiar with aircraft type performance. Not only that, aircraft operator performance too! So let's keep it simple...give us your Callsign and Type and we'll do the rest...

hangten
24th Mar 2012, 17:59
It is certainly not unheard of for repetitive flight plans not to be updated after an aircraft type change.

To add to my colleagues, also from a tower perspective, your aircraft type can be important for ground restrictions, specifically taxiways and parking stands. Generally a discrepancy will be spotted on the deck, once in view of the tower, but it's not impossible to sneak the wrong aircraft all the way into the sky before anyone realises. Inbound of course, the wake turbulence category is important long before you're identifiable to the tower.

blissbak
24th Mar 2012, 19:12
I don't really get it, the departure airport TWR should notice and fix any mismatch.

Avoiding_Action
24th Mar 2012, 19:25
You would think so but it doesn't always happen. I was recently working an aircraft and only discovered that it was a different aircraft type when it requested climb to RVSM levels and the filed aircraft type was non-RVSM.

ZOOKER
24th Mar 2012, 19:42
blissbak,
not necessarily.
2 examples spring to mind.
A long time ago, (in a VCR, far, far away), I told an a/c at the holding point, "After the landing Britannia 737, line up R/W...."
Both the flight crew and I were surprised when a KLM DC9 dropped out of the Sc.
Many years later, in a TMA radar environment I was, apparently, working a PIA B742 which was flight-planned as a B777. This thing had flown all the way from OPRN, and no one en-route knew the aircraft's type.
A year or so ago, my unit was working a DC87, and just for fun, I said to a UCE, "if that a/c lost an engine, how many would it have left?".
"No idea" was the response.
Sadly, (and I don't mean this dis-respectfully in any way), some of the 'financially incentivized', (whoops, management-speak), folks in ATC today, have little knowledge of the air traffic they are actually controlling.

I don't mean every ATCO should be a fanatical 'plane-spotter', (God forbid), but the reference books should be available, and used appropriately.

In between stints in ATC, I spent 3 years at uni, studying, among other things, palaeontology, - fascinating stuff. Taxonomy was part of the course. Basically, things are given specific names so that 'no doubt exists as to what is being referred to'. A T-REX and a tortoise are both in the category 'Reptiles', but are completely different beasties. So types beat categories hands-down. :ok:

vespasia
24th Mar 2012, 19:47
I don't really get it, the departure airport TWR should notice and fix any mismatch.

If we're in low vis procedures I might never see the aircraft, so unless the crew report the type to me how am I supposed to notice the mismatch?:ugh:

Talkdownman
24th Mar 2012, 20:46
some of the 'financially incentivized', (whoops, management-speak), folks in ATC today, have little knowledge of the air traffic they are actually controlling
Tucano, working a nats unit: "Mayday, engine failure"
nats unit: "Which engine has failed?"

Some BA 757/767 crews were dual rated. Not unheard of for crew to pass wrong aircraft type (and thus Wake Vortex Category). Only major difference was, apparently, a step up into the flight deck on the 76.

Herc708
25th Mar 2012, 00:33
HD : Assumptions are one of aviations worst enemies. Ironically, it was my last visit to LHR a few months ago which raised this issue again - your ATC (ex?) colleague asked me a question which I would have expected him to have known the answer

The problem is that the Jepps all refer to CATEGORY not TYPE e.g. do this if you are Category A,B and do something else if you are Category C,D etc. How does ATC issue an intruction, e.g. a SID, if an aircraft reports a TYPE on first contact when the SID's are assigned based on CATEGORY

Gonzo
25th Mar 2012, 04:20
I can only speak for LHR, but procedure-wise, it makes no difference what performance category you are, so it makes sense to report a/c type.

In fact, even if a/c category did matter, we'd probably still get you to report type as that's more important to us, for the above reasons.

If you get allocated a SID which according to your plates you cannot fly, then you should inform ATC at the time, and take reporting action to ensure the situation is resolved in the long term.

HEATHROW DIRECTOR
25th Mar 2012, 08:36
Wise words from Gonzo, as always. Understandablt as he is a current Heathrow ATCO. It's only in recent times - and long since I retired - that I've heard about these categories! I managed a liftetime in ATC in such ignorance so I am drawn to the conclusion that they matter little to ATC whereas the aircraft type is of great importance.
Herc708..... you don't by chance drive the type of aircraft suggested by your handle?

2 sheds
25th Mar 2012, 09:09
A long time ago, (in a VCR, far, far away), I told an a/c at the holding point, "After the landing Britannia 737, line up R/W...."
Both the flight crew and I were surprised when a KLM DC9 dropped out of the Sc.
Ahem...shouldn't you be able to see them both before issuing...?

2 s

Gonzo
25th Mar 2012, 09:50
2 sheds, I was thinking the same.....

.....however, at LHR we now have a procedure where we can issue a conditional line up clearance (only for a departure following a departure) without being able to see both aircraft using A-SMGCS.

Spitoon
25th Mar 2012, 11:02
Assumptions are one of aviations worst enemies.An oft-quoted adage and one that should be stored in the mind to be brought out at appropriate times. But it seems to me that you may be making some assumptions about how ATC works, Herc.

The reason that ATC sometimes wants to know the aircraft type is because that is what is important for applying ATC procedures in that environment. There are lots of different classifications and groupings used in aviation and they each have their purpose and their place. As many controllers have already pointed out, a performance category or whatever is not usually relevant to controllers in an approach environment...despite the fact that you clearly think it should be.

That is not to say that things can't or shouldn't change if the need is there. There are a number of mechanisms available to anyone involved in the business of aviation to raise concerns about procedures etc. If those concerns are valid (and not addressed in some way elsewhere in the system), change follows.

But there is another adage that springs to mind - if it ain't broke, don't try to fix it.

Tarq57
25th Mar 2012, 11:38
There are few different categories used by ATC.
There's approach classification A through D ( or is it E?), based on Vs, pertinent to app and circling minima.

There's the well known wake turbulence categories L M H, and J.

There's the Code A through E, based on wingspan, pertinent to ground ops/parking/twy restrictions.

At our unit, there's also a perfomance-based table of aircraft groups that fit a similar approach speed/missed approach speed (4, altogether), used for determining the distance required for a departing ahead of an arrival in Below Circling conditions. (Also refer to aircraft approach classification.)

There's a similar but separate list used for determining departure separations following a preceding departure. These two lists are similar, but different, and must be consulted as appropriate.

A fair percentage of aircraft are in a common or expected grouping across several different types of classification. (Eg; most 'heavies' are also class D and code E, and would be in the same performance group on our separation lists.) Some are not. Enough that it matters.

I'm guessing other units might well have their own specific purpose-built lists of aircraft groupings.

Please give us the type, if it's requested.
We'll work out which of the various classifications we need apply, depending on the conditions, depending on specific aerodrome restrictions. and depending on other preceding or following traffic.
Thank You.

eyeinthesky
25th Mar 2012, 21:23
QUOTE
Tucano, working a nats unit: "Mayday, engine failure"
nats unit: "Which engine has failed?"
UNQUOTE

I heard it was something like:

TUCANO: "Mayday Mayday Mayday, engine failure
ATC: "How many persons on board and which engine?"
TUCANO (with great presence of mind): "Me, and it" :D

ZOOKER
25th Mar 2012, 21:54
Gonzo,
we had a similar procedure about 30 years ago. We had no GMR, SMR, ASMI, or A-SMGCS. We simply asked our 'customers' to use their MK.1 eyeballs.
Please do not think I'm in any way being disrespectful. If you don't believe me check with your GM. :ok:
Oh, hang on, he was on 'B' Watch then. :E

vespasia
26th Mar 2012, 08:56
We simply asked our 'customers' to use their MK.1 eyeballs

Procedure still in place at Gatwick:ok: The use of the ASMGCS satisfies the requirement for me to see both aircraft, but not the requirement for the 2nd ac to see the first, so I still need to ask as above. Long live the MK 1 eyeball;)

hangten
26th Mar 2012, 12:06
There's the Code A through E, based on wingspan, pertinent to ground ops/parking/twy restrictions.

I think (I'm not referring to any paper here) that the A380 is all on it's own in Code F now too.

Gonzo
26th Mar 2012, 15:25
.....and the B747-8.