Taxy clearance

[goddammit]

In light of uk MATS Pt1 Amendment 64, when is a clearance limit not a clearance limit?
Surely by mitigating an incursion by SOMETIMES adding 'hold short', you are increasing the risk of an incursion when it's not added.
And that's before i get started on the downside of not providing a thoroughly consistent ats across a unit , and across units!!

[2 sheds]

Goddammit

Absolutely - it defies any logic and leaves it open for the ATCO to be accused of not having crystal balls when a runway incursion does occur and this additional phrase has not been used. WIH do we have unique alphanumeric designators for taxiway holding positions?
If it's any consolation, this very point has been raised at CATC to be queried with SRG - so, watch this space.

[peatair]

When is a clearance limit not a clearance limit? Good question. Following on from the Manchester "incident" in 2004 the CAA issued FODCOM 25/04 (dated 17th November 2004). In this it states - para 5.7 - that "The receipt of a clearance to taxi beyond a runway does not automatically include the authorisation to cross that runway. Each taxi clearance beyond a runway should contain an explicit clearance to cross the runway or an instruction to hold short of that runway."

In other words, a so-called "clearance" to a point may not actually be a true "clearance." This is, in my view, nonsense. It is high time that there was a return to the true meaning of a clearance and clearance limit. Surely, a clearance is an authorisation to proceed to the point specified as the clearance limit.

All this seems to me to go back to the Manchester incident. Serious questions remain as to how that configuration came to be licensed by CAA. They are, in my view, seeking to avoid the issue by placing caveats on the meaning of a clearance.

[2 sheds]

Peatair

Can you give a reference to find the FODCOM 25/04?

What you quote from it is completely the opposite to common sense, the meaning of the English language and indeed to what is indicated in MATS Part 1. (However, if I remember correctly, ICAO (PANS-ATM) does give an example of a clearance limit beyond a runway, followed by "hold short of (that runway)"!!!

[HEATHROW DIRECTOR]

<<hold short>>

Brain not too clear on this but I believe we were banned from using that phrase at Heathrow years ago. A vehicle had been told to "hold short" and promptly hurtled across the runway. Driver said he thought ATC had said "haul short", which he thought was some sort of "aviation-speak" for "shift your ass"!! I personally used to clear aircraft to a point before a runway with no suggestion that they were cleared beyond.

[No_Speed_Restriction]

Correct me if im wrong but i thought that ICAO specifies that a taxy to clearance implies crossing of runways to reach the appropriate holding point.

[Spitoon]

For 2 sheds - FODCOM 25/04 (http://www.caa.co.uk/docs/33/FOD200425.pdf).

Same stuff in ATSIN 53 (http://www.caa.co.uk/docs/33/ATS053.pdf).

[ILS 119.5]

If you have doubts then use your own phraseology to ensure the a/c stops where it is supposed to do. MATS PT1 says you can. Any further problems then file a 1261 or a CHIRP. Easy.
Sometimes it is better if you are controlling the a/c then you know where it is going to stop. We all treat each other as professionals and assume that we all know what each other is doing. Not the case. If you have to say to an a/c "are you sure about your taxy instructions", don't worry. MATS PT1 says you can, safety is first.

[peatair]

2 Sheds - the reference is
http://www.caa.co.uk/publications/publicationdetails.asp?id=1477

CAA Website under Publications and then Flight Operations and then FODCOMs.

[mm_flynn]

I have not looked up the wording in the FAA regs - however, I am pretty sure a taxi clearance like -

"taxi via a2, b1, k for runway 24" that does not include "Hold Short of xxx",

clears a pilot to taxi to, but not onto runway 24, crossing all intersecting runways (other than runway 24).

From reading the posts in this thread I have the impression that the US approach is ICAO standard and that the UK has a difference in introducing an implied clearance limit prior to each runway intersection.

Have I gotten confused or is this a significant difference in the meaning of a clearance between US and UK.


Mike

[bookworm]

Have I gotten confused or is this a significant difference in the meaning of a clearance between US and UK.

No, I think the only thing that's confused is FODCOM 25/04 and ATSIN 53, which give advice that specifically contradicts MATS Part 1.

A clearance to a point beyond a runway does authorise the aircraft to cross the runway.

In the UK, ATC is required to provide explicit instructions to cross intervening runways in those circumstances. As a belt-and-braces approach, if the crew does not hear those explicit instructions to cross, it should request clarification. But it doesn't change the meaning of the clearance.

I don't think goddammit's original concern is warranted, though it's a good issue to raise. The omission of "hold short" does not change the clearance, which is defined by the holding point.

Examples: (A1 is beyond runway 23, A2 is short of it)

Taxi to holding point A1, cross runway 23.
Taxi to A1 crossing 23 on the way

Taxi to holding point A2, cross runway 23.
Query the instruction: it's inconsistent

Taxi to holding point A1, hold short of runway 23.
Query the instruction: it's inconsistent

Taxi to holding point A2, hold short of runway 23.
Taxi to A2 and hold short of 23

Taxi to holding point A1.
Query the instruction: you expected a "cross runway 23".

Taxi to holding point A2.
Taxi to A2 and hold short of 23. ATC doesn't have to include an explicit "hold short".

[MrApproach]

I recall us having this argument in Australia some time ago and for a while the ICAO intent was adopted. That is a clearance to taxi to the holding point included clearance to cross any runways en route. It was later decided that this was too much of a cultural change (as is the current attempt to introduce Class E airspace) so we reverted back to the more sensible concept that a runway crossing has to be specific. (as per your FODCOM) In this case we use the FODCOM phraseology.

In other cases we use tyhe ICAO words for example, "B717 on final, behind that aircraft line up behind"and "Go ahead" as ageneral invitation to transmit. We are also allowed to use anticipation more broadly with our landing and take off clearances. Not as broadly as the US but not as restrictively as the UK.

ICAO standardisation is essential but when English speaking countries have been using a form of words for fifty years it's very hard to overcome the cultural inertia. (By the way, how is your change to metrics going? Swopped those miles for kilometres yet? If you see what I mean.)

[Squadgy]

As an aside, does anyone know why ATSIN 53 was only addressed to ATC units and not to FIS units who may also be issuing taxy clearances, including those which may cross runways?

[goddammit]

An underhand way to increase the lack of consistency:O

[2 sheds]

Bookworm

As an aside, but further to your examples, some time ago the UK amended the taxi phraseology to specifically exclude to word "to", hence it now should be (in UK) "taxi_holding point A2, etc".

The reasoning was that any use of the word "to" could, in the wrong circumstances, be mistaken for "two" and therefore it was omitted. However, it would have been very useful if some publicity had been generated about this and it not just snuck into an amendment page with a miniscule indication in the margin!

[bookworm]

A good point, 2 sheds, and a sensible amendment.

I've never quite worked out why "to", though outlawed for flight levels, is still used with altitudes these days. While I can just about imagine someone misinterpreting "climb 4000 ft" as an invitation to add 4000 ft to their current altitude, I can't imagine "climb altitude 4000 ft" being misinterpreted any more than "climb flight level 40".

Of course there's always a possibility that, when given the instruction "Taxi holding point A", some bright spark will get out, attach a rope to the holding point sign and tow it across the airfield... ;)