Descent rates in holds

[InTheAir]

In the hold, say for example at LAM. What sort of descent rates do pilots use?

[Chalky]

I use 1000 fpm. You're in no particular hurry to get down, but you don't want to be too slow because the controller wants to get the next one in the stack down a level as soon as possible.

[CaptainSquelch]

Same

Sq

[InTheAir]

aah, it was a stupid question anyway :)

Cheers!

[eyeinthesky]

Bear in mind three things:

1) The AIP demands at least 500 fpm.

2) If you report leaving a level we are legally allowed to clear another aircraft to that level. So don't say 'leaving' unless you actually are (i.e. not before you've pushed the level change button or whatever).

3) Technically we are not allowed to use Mode C info in the hold (although many do), so if you call out of a level and the next one is in a continuous descent we may not spot the closure if you are too slow descending.



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"Take-off is optional, Landing is mandatory"

[Cough]

Other side of things - Going down too quickly can give a TCAS alert (probably nothing more than TRAFFIC)

1000'/min sounds about right.

CCCccc....ough

[Chalky]

eyeinthesky

<<If you report leaving a level we are legally allowed to clear another aircraft to that level. So don't say 'leaving' unless you actually are (i.e. not before you've pushed the level change button or whatever).>>

It has long been my understanding that we shouldn't advise you we are out of a level until at least 200-300ft below it. Is this not the case?

Chalky

[eyeinthesky]

Chalky: That may be common (and sensible) practice, but I'm not sure if it's written down anywhere. Bearing in mind that we are not technically allowed to use radar in the hold, we are talking about a procedural service, where everything is based upon reports. So if you say you are leaving then we can give the level to somebody else. If you leave it to 2-300 feet then I suppose to report that you HAVE LEFT would be more appropriate. If it is crucial you might be asked for a 'Report passing'. I have certainly almost been caught out by a (foreign) airline saying 'Leaving' and then taking some 30-40 seconds to do so.

Don't confuse the 2-300 feet with the 400 feet we would need to see on radar (outside the hold, of course!) before we can allocate your level to someone else who is not 3 or 5 miles away laterally.



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"Take-off is optional, Landing is mandatory"

[eyeinthesky]

Further to yesterday's post:

The AIP says you should not report out of a level until the altimeter shows that you have left a level and 'is continuing in the required direction' or something



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"Take-off is optional, Landing is mandatory"

[HEATHROW DIRECTOR]

eyeinthesky.. Your comments about the use of SSR in the hold prompted some interesting discussions in TC the other afternoon. Upwards of a dozen of us - ranging from long experienced people, including examiners, OJTIs, LCEs, etc, to young whizz-kids who know the book backwards - all readily admitted that we use SSR on a regular basis in the hold to determine when levels are free. So, the inevitable question: Where does it say we can't? SSR is totally different to primary radar, on which the rule about the use of radar separation in the hold was probably based when it was written a hundred years ago. There is no sensible reason why SSR should not be used, provided it isn't garbling. NODEL in TC has a facility to expand certain holding patterns precisely so that garbling may be reduced and the labels read clearly. If that facility has been provided - no doubt at vast expense - surely it means we can use it? As I'm sure you'll agree, the whole of the UK would stop if we had to get level checks every time we dropped someone in a hold..

The other point, which several controllers brought up, is that the SSR info is more reliable than crew reports. Everyone of us can relate stories of crews reporting vacating a level but not doing so for at least thirty seconds - it happens every minute of every working day. Without SSR there would have been many, many dangerous situations. The opinion was that it's actually far safer to use SSR than R/T in checking level vacations.

Maybe time for a Part 1 clarification?

[This message has been edited by HEATHROW DIRECTOR (edited 07 July 2001).]

[eyeinthesky]

HD: It was a while back that I last checked and it may have been changed, but I'm pretty certain either the TC MATS Pt 2 or MATS 1 said you weren't allowed to use Mode C in the hold. It was about three years ago...

[Mister Slot]

eyeinthesky re. point two in your first post -

Many, many moons ago I was taught (during line training in my first position with a major international carrier) that one should not call "reaching" until within 300' of the assigned FL/Alt. and should not call "leaving" until at least 300' out the current FL/Alt. I don't know if that was/is written in some tome somewhere, but it nevertheless strikes me as good advice.

With regard to pilots asking for descent and subsequently not initiating said manoeuvre until some time/distance has elapsed - that can be easily explained. Many FMC's give timely warning that top of descent is approaching (typically 14nm/2 min.) and warn the crew accordingly with a message such as "RESET MCP ALT". For a variety of reasons (not least poor training and lack of situational awareness) the crew will immediately request descent, programme the autopilot et al and wait for another minute or two (several nautical miles) for the aircraft to comply automatically.
.

[ 08 July 2001: Message edited by: Mister Slot ]

[Chalky]

eyeinthesky,

According to a new NATS leaflet "... always ensure that ... we don't call out of a flight level until at least 200ft below it"

Chalky