Air Traffic Controller Discussion With a Global Perspective
By Rob Barton 1216141
#529003 Hello all,

Small question for you.

If a pilot is given clearance to line up and wait, should the pilot taxi and hold to the runway threshold seeing as the runway in question has a displaced threshold?

I've checked EASA regs and it seems to be the case but I got told off last night by a controller for doing so as he thought I was taking off.

Thanks in advance for your help.

Rob
By Simon Kelsey 810049
#529005 The three most useless things in aviation: altitude above you, fuel on the bowser and runway behind you :wink:

The short answer is no (be interested in that EASA reference though!) - just enter the runway and line up where you are. Remember the displaced threshold is for landing - the area prior to the displaced threshold can and should be used for takeoff, assuming it's not marked otherwise.

To think about it another way - if you were lining up at an intersection beyond the threshold, would you taxi back along the runway to the threshold if you hadn't been explicitly cleared to do so?
By Andreas Fuchs 810809
#529008 Hi Rob,

Simon already gave you the answer that is valid in 99% of cases. I would like to add that during low visibility conditions/operations pilots are to identify the runway by seeing its markings (numbers). For doing so, it will be necessary to slowly taxi forward to the displaced threshold and then wait there, when you can read the runway identifier.
By Mats Edvin Aaro 1227980
#529021 Depends, there are different versions of displaced thresholds.

First off, you have permanently displaced threshold (the most common one), which is marked with centered white arrows before a line of small arrows and a thick solid white line, which marks the start of the runway (threshold). This is available for taxi and takeoff, but not for landing.

Then you have the blastpad/stopway area (officially called Pre Threshold Marking Area) which is marked with something called chevrons. They are yellow arrows which span on the width of the runway. This is not authorized for aircraft movement, and is in some airports used as a stopway (sometimes equipped with an arrestor bed). These exist when the paved area of a runway not suitable for aircraft movement exceed 60m.

You also have different variations of these as well as others (permanent vs. temporary displacements, taxiways etc).

And for those nerds out there: http://ww1.jeppesen.com/documents/aviat ... -signs.pdf
By Andreas Fuchs 810809
#529023 Hi Mats,

no, you are missing the point. Under low visibility conditions ("LVP in force") it may be necessary to positively identify the runway and the only way is to read the numbers/identifiers. In my company it is therefore mandatory to taxi to the displaced threshold to read the identifier, this is not optional.
By Mats Edvin Aaro 1227980
#529024 I'm a little confused as to which part of my post you considered wrong Andreas.. Can you elaborate?

I can't see where LVP conditions come into effect here?
By Andreas Fuchs 810809
#529026 Hi Mats,

you wrote
Depends, there are different versions of displaced thresholds.

while my point is: it does not depend on this. In LowVis I always have to taxi forward to the threshold, no matter whether I could legally use the runway ahead of the displaced threshold or not.

Maybe I misunderstood your post?
By Andreas Fuchs 810809
#529029 That never happens, our business jets get airborne within a few feet. It is our law that we identify the runway and also assess the RVR ourselves by counting lights. The correct distance between centerline lights may also only be available from the original threshold. There are a few reasons and above it all "it's like this".
By Dhruv Kalra 878508
#529037
Andreas Fuchs 810809 wrote:That never happens, our business jets get airborne within a few feet. It is our law that we identify the runway and also assess the RVR ourselves by counting lights. The correct distance between centerline lights may also only be available from the original threshold. There are a few reasons and above it all "it's like this".

If you’re waiting until you’re actually on the runway to positively identify that you’ve lined up on the correct surface, you’re likely too late.

There are countless runway identification markings prior to the hold short line, including surface painted hold short numbers and runway identification signs adjacent. I’m with Martin above - it seems counter-productive to waste usable runway which is factored into your takeoff and climb gradient performance calculations.
Last edited by Dhruv Kalra 878508 on Wed Nov 28, 2018 4:40 am, edited 1 time in total.
By Andreas Fuchs 810809
#529038 Hey Dhruv,

I am doing this for a living, I think I know what I am talking about. Our operations manual is dictating that we follow this procedure.

When you have a runway that is 7,000ft or 10,000ft long and your plane needs 3,000ft takeoff distance (=start of takeoff roll until reaching 50ft above runway), then it does not matter if you are missing out 1,000ft or runway. This is - of course - factored into the t/o and climb performance.
By Dhruv Kalra 878508
#529039
Andreas Fuchs 810809 wrote:Hey Dhruv,

I am doing this for a living, I think I know what I am talking about. Our operations manual is dictating that we follow this procedure.

When you have a runway that is 7,000ft or 10,000ft long and your plane needs 3,000ft takeoff distance (=start of takeoff roll until reaching 50ft above runway), then it does not matter if you are missing out 1,000ft or runway. This is - of course - factored into the t/o and climb performance.

I did it for a living for 3500-odd flight hours, and now I'm a controller. I think I know what I'm talking about, too.

It may be different on your side of the Atlantic, but I guarantee that if you start a taxi down a runway to get to the end of the displaced threshold at a place like 31L at JFK (where the threshold is displaced 3200-odd feet) after being given LUAW, you're going to alarm the ASDE-X safety logic and give a local controller a heart attack. Also, what happens if you're issued an intersection departure and can't read the numbers since they're behind you?
By Andreas Fuchs 810809
#529046 Simple: I will not accept that intersection, because I can't. Obviously, in JFK, I'd request intersection K or KD to avoid the scenario that you described. Aviation is not black&white, there are many different shades of grey. But hey, I will be in the SIM in January and I will take this up to our instructors.