What's this UK G/A 185kts lark?

[Bearcat]

OK controllers blind me with education again. I note all approaches in UK are restricted to 185kts max and likewise in the G/A. Pal did a G/A in LHR recently and restricted speed to 185kts in the level off....he felt controller was not happy with him back at 185kts and smartly asked him to speed up to 220kts for the sequence.

My question to you is is this 185kts a pain in the ar@e for you as it is for us....reason why i ask is at that speed on both the boeings and airbus one is selecting a non std intermediate flap setting to maintain the 185kts....get it wrong and one possibly ends up in flap overspeeds etc.

The normal sequence for us is to clean up which I much prefer.

Thanks in advance for all your inputs.

Bearcat (A320 Capt):ok:

[Del Prado]

Sorry, I've never been aware of a 185kts rule for go-arounds but as a radar controller I'd be happy to receive a go-around between 180 and 230 knots. There's a real appreciation that it's a high workload moment for the crew and I can't think of a controller that would b*~~*ck a pilot (except maybe one;) )
It's also a high workload time for us, maybe that's why the controller sounded like he was pi**ed off with your 'friend'?


I post this with a caveat that I'm not the best at bookwork, maybe someone else knows about a 185 speed limit.

[120.4]

In 17 years doing Gatwick and Heathrow I have never heard of a 185kt restriction on the approach or go-around and we would find that restrictive. On approach we typically slow you out of 220 for 180kts with about 18nm to go and then 160kts down the approach when spacing is established. If it is appropriate we would keep you faster e.g. straight in's of Lambourne in the early afternoon could often be kept at 250kts until about 18nm.

I believe it would have to be a very unusual set of circumstances for any ATCO to put a speed restriction on a go-around.

Having said that... a well known former Gatwick ATCO did once tell an aircraft to "take off quickly then fly slowly" when trying to launch the second of 2 in a tight gap.

Point 4

[DFC]

The UK 185Kt restriction applies to turns during the missed approach. If you do not have to turn or you have completed the turn then you can accelerate to the final missed approach speed or any other suitable lesser speed in preparation for a hold, vectors or another approach.

Thus on a straigh ahead missed approach, the 185Kt restriction does not apply.

If a turn is specified then as soon as the turn is completed the restriction no longer applies and you accelerate to the desired speed.

Regards,

DFC

[TopBunk]

The UK 185Kt restriction applies to turns during the missed approach.

Sorry DFC but where does it say that? Then again I've only been flying in and out of LHR using Aread/Thales charts since the 1980's for a large local carrier. As I understand it, SIDS are drawn at 210kts for the turns (although even then it is an implicit restriction and not explicit. AFAIK there is NO EXPLICIT SPEED RESTRICTION other than the 250kts/min clean below 10,000ft.

[moleslayer]

Sorry DFC but where does it say that? Then again I've only been flying in and out of LHR using Aread/Thales charts since the 1980's for a large local carrier. As I understand it, SIDS are drawn at 210kts for the turns (although even then it is an implicit restriction and not explicit. AFAIK there is NO EXPLICIT SPEED RESTRICTION other than the 250kts/min clean below 10,000ft.

DFC has nearly got it correct..................

Generally, ICAO Doc 8168 Pans Ops Criteria specifies max and min speeds for various manoeuvres based upon aircraft category, which I am sure we all know is based on Vat (speed at threshold). These can be found in the 'Grey Supplement' published by Aerad (EAG), under section AER90.

However, member states are permitted to make changes to these.
The UK AIP (Air Pilot), lists a number of "Differences From ICAO Standards"
Check out Section GEN 1.7 which refers specifically to Doc 8168 - Procedures for Air Navigation Services - Aircraft Operations Volume II (Construction of Visual and Instrument Flight Procedures).

The reference for Part III, Chapter 1 (1.9.2) States :-
PROCEDURE SPEED RESTRICTIONS. Unless otherwise stated, procedures are speed restricted to a maximum IAS of 185 kt.

Therefore, as a go-around follows a missed approach 'PROCEDURE', technically, speed should be not more than 185kt, otherwise airspace protected clearance cannot be maintained ! Aerad (EAG) charts are drawn to give protection when flown at 180kt + or -5kt, hence the 185 max.

On a practical level, DFC was correct when he said it only applied when a turn was involved.This of course includes Approach PROCEDURES.

moley.

[120.4]

Moleslayer

This is new to me. If I have understood correctly, the reference refers to the construction of procedures? This suggests to me that the purpose of the 185kts is to guarantee airspace and route separations when in a procedural environment. Of course, the LTMA is a radar, not a procedural environment - We do radar not procedural approaches, suggesting that as ATC is responsible for "construction" of the approach circuit, ATC takes responsibility for the speed; 185kts is not applicable.

The missed approach might be different because it is not directly under ATC control. It is a procedure from the cockpit point of view although it is being separated using radar. I must say I have always expected a missed approach to accelerate back up to its clean speed. Is that incorrect?

Point 4

[DFC]

TopBunk,

You young guys should take some reading material to ionto the top bunk perhaps? :)

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Molesalyer,

The reference for Part III, Chapter 1 (1.9.2) States :-
PROCEDURE SPEED RESTRICTIONS. Unless otherwise stated, procedures are speed restricted to a maximum IAS of 185 kt.

Therefore, as a go-around follows a missed approach 'PROCEDURE', technically, speed should be not more than 185kt, otherwise airspace protected clearance cannot be maintained ! Aerad (EAG) charts are drawn to give protection when flown at 180kt + or -5kt, hence the 185 max.


Part III deals with RNav procedures and Satellite based procedures.

Not what we are talking about here but you are close.

You need to read GEN 1-7-52 It is in the first difference box;

Chapter 7
7.3.2
Procedure Construction and Obstacle Clearance Criteria for Instrument
Approach Procedures (cont)
Missed Approach Segment
Turn parameters - IAS. Unless otherwise specified, all missed approach turns
are limited to 185 kt IAS maximum.

Thus once again I say that the restriction only applies to turns made during a missed approach. If it is a straight ahead missed approach procedure then the 185 Kt limit will not apply. See Gatwick as a good example - the limit is published as 250Kt to prevent use of the final missed approach speed of 265Kt for CAT D aircraft.

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120.4,

It is a containment issue for airspace and obstacle clearance. As I have said above, it only applies until the turn is completed and the aircraft should then be accelerated. Provided that the aircraft is clear of obstacles, pilots will not object to accelerating provided you (ATC) accept responsibility for the airspace containment issue and traffic.

We do radar not procedural approaches, suggesting that as ATC is responsible for "construction" of the approach circuit

No. You take responsibility for positioning the aircraft onto the procedure using radar. If you check, you will find that the speeds you can use at various points in the circuit especially the final approach reflect the requirement of PANS-OPS.

Regards,

DFC

[moleslayer]

Yes, 185kt is not applicable to a radar vectored approach, otherwise we would all have been in breach of the law at LHR for years ! And yes your assumption that this refers to a PROCEDURAL approach is correct. But remember that you are interested in separation criteria, so are we pilots of course, but we are also wholly responsible for terrain clearance at ALL times. Therefore, on a go-around where we are following a published PROCEDURE under IFR, we MUST legally comply with the speed limits to ensure we remain within the protected area as calculated by the charts' designer. In effect DFC was correct when he said that once any turns were completed, an accel. to clean speed would be ok. However I would be VERY careful when operating in airspace where terrain is a factor, as accelerating with reduced thrust after say an engine failure, would demand a level segment before further climb. Terrain might then become an issue, and further low speed climb to at least MSA may be more appropriate.
moley.

DFC..........sorry mate , just read your post.......i'm agreeing with you, just trying to put it in a radar controller friendly way. :)

[120.4]

Thanks guys

I hadn't been aware of any technical limitations to the speeds we can use on the various points of the circuit. I had always thought we use the standard 220, 180, 160kt speeds because they best suit the ATC/Aircrew purpose on the various legs. We regularly use higher speeds when it suits us.

The speed/terrain point makes complete sense now.

So to go back to the beginning of the thread do we agree that radar controlled approaches are not technically restricted to 185kts and missed approaches can accelerate above 185kts once terrain has been taken account of? The latter being true, I would expect/hope that a G/A would accelerate up to about 220kts when appropriate.

Point 4

[moleslayer]

Yes 120.4...................

Only when the aircraft is flown along a published procedure is it req'd to maintain 185kt max.(usually critical for approach procedures involving turns).

For a Go-Around, once the procedure has been completed the aircraft may be accelerated to enroute climb-speed, but the flight crew are ALWAYS wholly responsible for terrain clearance at ALL times !!

moley.

[TopBunk]

TopBunk,
You young guys should take some reading material to ionto the top bunk perhaps? :)

I am now older (but not necessarily wiser:hmm: ) and have migrated to the 'Bottom Bunk':)

Interesting stuff though....