PPRuNe Forums - LHR 160 till 4dme

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unitedabx

13th August 2018 08:40

Checking info on "MCP selections".

Selected IAS NOT transmiitedonly actual IAS.

Apologies Gents.

LeadSled

13th August 2018 09:01

Folks,
One airline from SE Asia is not happy about config. changes on "short final" so flies with Flap 30, gear down all the way from about 3000 ft, rather defeating the noise minimization aspect of the procedure.
Tootle pip!!

Dan Winterland

14th August 2018 03:52

Quote:

One airline from SE Asia is not happy about config. changes on "short final" so flies with Flap 30, gear down all the way from about 3000 ft,

Many airlines from that part of the world have rigid stabilisation criteria and no mercy when it is found these have been broken. The guys aren't taking a chance of being punished. An unintended consequence of the rules.

vilas

14th August 2018 05:10

Quote:

One airline from SE Asia is not happy about config. changes on "short final"

Short finals is very vague. The airline may be too strict about Stabilized approach by 1000ft. so one can push it up 1500. Three thousand is way too much. I don't know how the airline can accept that.

LeadSled

14th August 2018 07:04

Quote:

Originally Posted by vilas (Post 10223061)

Vilas,
There was a reason why "short final" was in inverted commas.
It was/is not a matter of the airline accepting, but requiring, the aircraft be in the landing configuration, checks complete, at approx. 10nm/3000 agl.
Dan in the previous post "gets it".
Tootle pip!!

RexBanner

14th August 2018 09:39

Quote:

Originally Posted by Max Angle (Post 10210405)

Actually I think the only selected (as opposed to indicated) data that is displayed to the controller is altitude.

Nah they can definitely see what speed you have selected on the MCP. Hence why flying an approach with managed speed into Heathrow (as long as S and F speeds comply with the speed control given) confuses the hell out of them and often they’ll ask you to confirm your speed.

DaveReidUK

14th August 2018 12:46

Quote:

Originally Posted by RexBanner (Post 10223255)

Then allow me to ask you the same question that I asked the previous poster (who subsequently decided that selected speed wasn't displayed, after all):

Quote:

Originally Posted by DaveReidUK (Post 10221462)

Which BDS are you getting selected speed from ?

I can't find anything in the Mode S/EHS spec that has provision for MCP selected speed. While selected altitude has obvious benefits in providing potential early warning of a possible level bust, I'm struggling to see similar benefits for an approach controller who already has access to your IAS and, as noted above, will likely ask you what you're doing if you appear to be ignoring a speed instruction.

Can anybody provide a definitive reference to any recent changes to the Mode S/EHS spec that make this provision?

RexBanner

14th August 2018 12:48

Why are they asking you to confirm your speed then when you’re flying managed speed which, quite coincidentally, is the only time they ask you that question?

KriVa

14th August 2018 13:45

I’m not at LL, but Mode S/ADS-B functionality is the same for everybody, I can confirm we(ATCOs) can’t see your selected speed.
However, if you’re doing something different than preceding or succeeding traffic (even slightly different), it does stand out. So if they ask you to maintain 160, and you keep 165, that difference will be noticeable after a short while, if the others are doing 160 exactly.

DaveReidUK

14th August 2018 15:50

Quote:

Originally Posted by KriVa (Post 10223484)

I’m not at LL, but Mode S/ADS-B functionality is the same for everybody, I can confirm we (ATCOs) can’t see your selected speed.

Thanks for the definitive response and explanation.

Wally777

14th August 2018 19:50

Once had a 63 000kg payload on a B77W and needed to configure fully for landing with F30 at 4000' joining the GP to try and achieve the ATC speeds. - Not ideal.

Skyjob

14th August 2018 23:19

Quote:

Originally Posted by KriVa (Post 10223484)

And this is where the problem is, ATC expect us to fly exact speed of eg 160, but aircraft limitations due eg landing weight prohibit this to be done unless the big anchor is dropped down causing a lot of noise which no one wants.
Better would be a dialog with airlines, so that types unable to fly 160 at MLW are planned for at the appropriate speed they can fly without dropping the gear, eg 165...

737aviator

15th August 2018 19:24

Quote:

Originally Posted by TangoAlphad (Post 10223908)

Happens elsewhere. LGW Atco's know we often want 170-5 as with the short field performance mod we almost always would need to drop gear and F15 for 160. Drop the request with director on checkin and we usually get it.

Dialogue with the airline(s) resulted in STN now requesting 165 to 4 instead of 160, enabling a certain 737 operator to keep the gear up till 4 miles with flaps 5/10.
In other airports that request 160 I'd usually ask if 16x is ok and usually they're happy.

Gonzo

16th August 2018 05:34

Heathrow ATC can only see actual IAS, not selected.

Heathrow AIP entry gives usual speeds to expect, including 160 to 4DME. If this is not acceptable, then as requested in the AIP please inform Director on first contact and we will accommodate a different speed on final.

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