Continious descend approach LHR

[V1GO]

I'm operating into LHR frequently. Some people told me lately that on the arrival into LHR the descend is strictly monitored. Apparently the Airport authority is checking the "level segment" below 5500FT.If longer than 2NM the company is giving some negative points. I heard that most companies have a compliance rate of about 78%.
Can anybody provide me with some more info on this matter? Are these figures correct? Do they apply for all A/C types (L/M/H)?

Thanks,


:cool:

[HEATHROW DIRECTOR]

I can't tell you much I'm afraid but I know the airport authority do monitor the tracks of aircraft. In ATC we are frequently shown maps of tracks flown by a/c under radar control which have infringed night noise restrictions with gentle nudges that we mustn't do it. In this case the maps refer to turning on inside 10nm (6am on westerlies, 7am on easterlies). We're also supposed to descend traffic only to 6000 ft until it's within 20 miles from touchdown during night hours. Unfortunately, the geniuses who make these rules also expect us to land 45+ at the same time, which isn't actually possible!

[Duke of Burgundy]

V1GO - All approaches into Heathrow Gatwick and Stansted are monitored for compliance with Continuous Descent Approach (CDA) procedures at all times.

CDAs are seen by the government as a key factor in noise reduction in the vicinity of the three London airports.

For monitoring purposes, a descent is deemed to have been continuous provided that no segment of level flight longer than 2.5 nm occurs below 6000ft QNH.

Level flight is interpreted as any segment of flight having a height change of not more than 50ft over a track distance of 2nm or more as recorded in the airport Noise and Track-Keeping system.

Due to constraints of the tracking system and differences in elevation of the airports, CDA achievment is monitored from a height of 5500ft aal.

It is recognised that CDAs to runway 05 at Stansted are not possible at the moment due to airspace constraints and to a lesser extent there are restrictions at Gatwick.

Hope this helps.

:confused: :confused:

[Recover]

This is relevant, honest!!

We all (I believe) appreciate the 500 fpm minimum climb and descent rates out in the wide airspace and the reasons for it. However, when is this 'requirement' considered to end? In a certain large BRITISH company, it is written in blood that thou shalt not disobey this rule and the route checkers make great deals of this. However, then we come to the constant descents....told you it was relevant.

Due to varying winds, decaying brain cells and pure stupidity, I often get my initial 'stab' at a descent rate not quite right and find that I'm either stalking the G/S from above or worse (in the case of CDAs) from below. Very often I then have to reduce my RoD to less than 500 fpm. Now in my mind there is no danger in that. I'm not about to clout someone on the final part of G/S intercept (or something, much more significant, has gone very wrong) and the spacing with other a/c has been sorted out by you geniuses on the ground.

So, tell me, is it written in the Book of ATC when the 500 fpm 'rule' ends........it would be great to bring it up at the next route check :p

And........


Recover

[120.4]

Recover:

I am not certain about this but I was under the impression that the 500' ceased once one was out of the hold and onto the intermediate approach. If anybody knows better I would like to know myself.

In my experience, British Midland stand head and shoulders above most when it comes to following CDAs. They are so consistently good at it that I have often wondered if their company ops. people bash it into them during their 6 month recurrent. Is that so?

However, CDAs are great until you have to cross over the 'other' approach when landing on both runways. Getting over the top of a slow descender (especially if its a heavy and vortex is involved) tends to force a late and rushed descent for the succeeding. It becomes time critical, demanding r/t priority and it is easy to forget to 'turn in' the next one. To make it easier for me, I usually explain my problem and ask for a good rate to 4000' (or better still, 3000' if I can get it off Thames) thereby throwing away the CDA!

So as HD says, CDAs and 45 an hour don't go together easily.

Point 4
:)

[V1GO]

Thanks Duke of Burgundy and the others,

As to my knowledge, my company is not aware of the CDA's procedures in LHR and other London airports. I'll inform them accordingly.

Is there some kind of a sanction or penalty if the compliance rate of a certain company is below the average or so? I would think so, why should they otherwise bother to monitor all flights.

Thanks for the extra info.

:cool:

[Duke of Burgundy]

Recover - The requirement to inform ATC if your rate of descent either is or will be less than 500fpm ceases at the Transition Altitude.

This was changed last October or thereabouts specifically to permit achievment of Continuous Descent Approaches.

You will find the reference in the ENR section of the UK AIP somewhere around page 1-1-3-1 if my memory serves me correctly.

Regards DoB

[NigelOnDraft]

DoB

<<You will find the reference in the ENR section of the UK AIP somewhere around page 1-1-3-1 if my memory serves me correctly>>

Blah... and no chance I and many others have read / even if we did, "picked up" on this...

However, thanks for the info, good gen and if anyone asks me where the reference is, I'll answer honestly - its on pPrune!

NoD

[HEATHROW DIRECTOR]

The Duke's assurance that all approached are monitored for CDA compliance leads me to wonder if those responsible understand the complexities of a busy TMA? Countless times every day, even every hour, it is necessary for ATC to descend aircraft early or late, thereby preventing CDAs. It's often necessary for us to employ intermediate altitudes on the descent because of other traffic which results in a/c flying level for several miles at 5000 ft. Yesterday we had a guy flying up and down over Heathrow at 6000 ft doing survey work - all departures were stopped off at 5000 ft, ie 1000 ft below their SID level and we had to start descent early on some inbounds and late on others. As has been mentioned elsewhere, during the 6-7am "rush" it is impossible to achieve the REQUIRED landing rate and CDAs so what does the monitoring system make of all this? Are the airlines penalised fofr obeying ATC instructions??

[V1GO]

Yes, Heathrow Director I fully agree with you!

Can somebody please clarify the statement of H.D. :
"Are the airlines penalised for obeying ATC instructions??"
"What do they do with the statistics of the CDA compliance rate?"

Thanks again,

Save flying

:cool:

[moleslayer]

Three bright RED balloons in tight formation flying thro' the 09L centreline certainly put paid to my
CDA yesterday. Very pretty though, another one on the deck at
White Waltham. Anyone know what they were up to, were they on special VFR across the zone, or in contact with Director.
Any clues 120.4 or HD ?

[ATCO Two]

Hi moleslayer,

The airships were on SVFR clearances working 119.9, having routed through the London Control Zone on the heliroutes.

[Recover]

Thanks for the info guys, it's always nice to know what SHOULD happen rather than follow the whim of another route checker who's has another good idea (in his own mind).

Duke, I'm not being picky but you specifically mention transition ALTITUDE and DESCENT. Should that be transition level fro a descent or does it specifically refer to the region's transition altitude. Genuine question!!

I'm looking forward to seeing their faces :)


And........


Recover

[M.Mouse]

Recover

Two rules:

1) Route checkers are always right

2) If you think they are wrong refer to Rule 1.

Seriously though it is the sort of information that ought to be promulgated. Why not have a chat in the office safer than telling a route checker you know better than he does.:D :D :D

[Duke of Burgundy]

Recover - Sorry if I didn`t make myself clear.

When you are in the en-route or holding phase of a flight above the Transition Altitude, ie in the London TMA above 6000ft, then you should inform the controller if your rate of climb or descent during a level change either is or will be less than 500fpm.

This is not a prohibition on such rates of climb or descent which may be necessary for other reasons.

When you have been cleared to descend from a flight level to an altitude, then on passing through the Transition Altitude the obligation to inform ATC of a rate of descent which will be or is less than 500fpm ceases.

This is in order to allow you to comply with the Continuous Descent Approach Procedure.

Hope this is better.

Regards DoB

[moleslayer]

Duke..........I think? what Recover was getting at is that when descending from a Flight Level to an Altitude, we initially pass through the Transition LAYER .This of course is variable depending on the pressure, whereas the TransAlt. is fixed at 6000ft.
Why is the TransLvl. not included in the ATIS @LHR as at other international aerodromes?

[Euroc5175]

Adherence to CDAs is measured by British Airports Authority (using data supplied from NATS radars). I believe the system is called GEMS.

I believe that non-adherence to CDAs results in letters being sent to the airlines to enquire why.....certainly persistent offenders are notified :p

RNAV Approaches are being introduced at some European airfields where traffic density permits. These approaches incorporate a 3D profile, containing a CDA, which is flown by the FMS when in the appropriate autopilot mode.

[Duke of Burgundy]

moleslayer - Yes I am aware of the Transition Level and Transition Layer, but they are not relevant to this discussion.

What I have said so far on the subject of CDAs is accurate.

In the approach phase when an aircraft is descended from a Flight Level to an altitude, the procedure in the UK is that on vacating the Flight Level the pilot will set the aerodrome QNH unless he has been requested to report passing any intervening Flight Levels after which he will set the QNH.

On climb out when cleared from an altitude to a Flight Level, that is the point at which the Standard Pressure Setting should be selected unless any intervening altitude reports have been requested.

The Transition Level at Heathrow has never been promulgated as it is not a datum which is relevant to the operation. It would, however, be available on request.

Regards DoB

[Recover]

Duke,

Thanks again for that. It's now clear in my mind and enabled me to pull off a corker of a CDA today.......at last :)



M. Mouse,

You know I'm only kidding about the Rte Checkers (well, most of them anyway) but this is a great thing to have tucked behind your ear for later use. As for getting it changed.......you do work for the same company don't you!! Without a steering group and implementation committee there's no way you'd change the way we used to do it on the VC10/Trident ;)


And.......



Recover

[NorthernSky]

Recover,

Perhaps you might ponder why your Megaplanes product doesn't know about this 500fpm requirement? My present main type is the only aircraft I have ever flown which would fail an Instrument Rating FLOWN AUTOMATICALLY! It comes from Seattle btw.

Just another dig at the folks over there who don't build very good aircraft! (And the NG speed control algorythms in desent are a disgrace! Thank God I don't have to fly the BBJ!).

[golfyankeesierra]

Interesting thread this one. I just read in our chief pilots monthly about this and we are told that our CDA rate is 69 - 74 %. But then I always thought the minimum descentrate in the TMA is 1000fpm and a snappy decent helps ATC out.
I think you 'll see our average going up quickly after this info!
And anyway, flying a smooth and stable CDA is much more satisfactory then those stepdescents.

[Young Paul]

BMI (mainline?) don't do it in six monthly checks - but do generally do at least 3 approaches into LHR every two working days (and 4-5 days a week) so get lots of practice.

CDA's are detailed in the RACAL/THALES booklets, and presumably in the Jepps as well, and my understanding is that these are extracts from the AIP. As a matter of airmanship, pilots ought to know what the requirements are for each airfield they operate to, and adjust their procedures accordingly. This specifies things like noise abatement profiles, use of APU on the ground, standard speeds in the TMA etc etc. How do people manage to operate without reference to them?! Or from another perspective, why do pilots think they are being told miles to touchdown?