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andalusi

How to perform an intersection departure?

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As the title says I`m wondering how to takeoff from an intersection?

Because in my opinion the V1 and Vr speeds changed in that way.

 

I know there is an entry on the second takeoff-page. But entering less distance won't change the speeds.

 

Anyone out there who may help?


Andreas

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I find intersections are too short to take off from. I always use runways. :Kiss:


John Veldthuis

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The only way to calculate takeoff speeds at intersections is with a tool like TOPCAT.


Joe Sherrill

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Andreas: I dont believe that the FMC takes runway length into account at all, I think it only uses balanced field. It is up to pilot to get take-off speeds from a different source or to validate that runway length is longer than balanced field length.

 

TO SHIFT (or RWY REMAIN, whichever the bird has) is used for FMC to derermine its position relative to runway threshold, as it automatically updates its position on TOGA thrust.


--Peter Fabian 
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TO SHIFT (or RWY REMAIN, whichever the bird has) is used for FMC to derermine its position relative to runway threshold, as it automatically updates its position on TOGA thrust.

 

Is this entered via a taxiway identifier or by a distance? As the weather gets nicer in Seattle, KSEA typically will have takeoffs from the 34s, and it's extremely common to take off from the Q intersection of 34L (similar to 32L T10 at KORD).


Jon Skiffington

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By distance. Truth be told I have no idea if it is in meters or feet in NGX and if it is runway remaining or TO shift.


--Peter Fabian 
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Hi folks,

 

are intersection take offs requested by pilots, too? E.g. to overtake the long row of waiting aircraft at the beginning of the runway?


Andreas Berg
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Is this entered via a taxiway identifier or by a distance? As the weather gets nicer in Seattle, KSEA typically will have takeoffs from the 34s, and it's extremely common to take off from the Q intersection of 34L (similar to 32L T10 at KORD).

Caution: RW info. Maybe not useful, but might be interesting to someone.

 

I did that very thing last week. I had 34C in the box, and SEA has been randomly (seemingly) closing runways, so they switched us to 34R/Q

 

On Takeoff 1pg on LSK6L, you can enter the intersection. The box has that data from ACARS, and presto - off you go. Check the route and legs on the SID and your speeds; easy breezy.


Matt Cee

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Hi folks,

 

are intersection take offs requested by pilots, too? E.g. to overtake the long row of waiting aircraft at the beginning of the runway?

 

If that is your only purpose don't count on it. But intersection departures aer used frequently by ATC to optimise the traffic flow.

 

EGLL is a prime example, they optimise their departure sequence based on route, speed and wake category, since all of these affect the required departure separation. But to add more spice you also have slot times which can cause an aircraft to jump considerably up and down the line to avoid having to wait at the hold while the computer in brussels finds a new slot.

 

 

So intersection departures are not so much a tool used by pilots as by ATC, even though a pilot can obviously request one, but if the only reason is to skip the line it's likely to be denied anyway :)


Regards

Johan Grauers

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FYI intersection takeoffs are pretty much banned by a lot of airlines now - there's been some incidents with them in the past where the speed stuff was wrong, issues with runway incursions etc.


Ryan Maziarz
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I already thought that ATC don't let you simply overtake...

And slots are an issue:

Last week my real LH2731 had to clear EDDT08R after line up and sitting there for a couple of minutes.

The pilot told us the slot had expired.

We had to queue again and instead of clogging 08R, we taxied to 08L and waited for the next slot assignment.

No intersection T/O for me... 8^)


Andreas Berg
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Hello all

 

I think you have to expect that ahead of time in order to perform proper safety checks on V speeds and power settings. It basically boils down to something that Boeing has actually forbitten PMDG from publishing and that is the FPPM manual (pretty sure a legal/liability issue so however great the product, WILL remain an incomplete simulation without everything that it takes to actually use as in real life so no claims can be made other than entertainment; also certain parts of the real manuals have been left out from the delivered manuals, specially the load sheet). There is the required information, specifically the RWY limited weight - a complex graph for each possible TO configuration.

 

If you are too heavy for the given remaining RWY and atmospheric conditions you cannot do it. But if you had a high enaugh assumed temperature, chances are you can use higher TO power and perform an intersection TO.

 

Ionut "John" Micu

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I use a "calculator" one member created with Excel here. And instead of TORA I enter the distance from the taxi point to end of the runway. So instead of TORA of say 10072 feet I enter 8038. Then it calculates my Vspeeds.


Dmitrij Nazarenko

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FYI intersection takeoffs are pretty much banned by a lot of airlines now - there's been some incidents with them in the past where the speed stuff was wrong, issues with runway incursions etc.

 

Hmmmm, I'm curious to know the source of your information. I'm not saying you're wrong, but your information could be inaccurate depending on the circumstances. For example, we run intersection departures on a daily basis with multiple airlines (even when the full length is available). Now, some are unable to take those intersections based on weight, temperature, departure runway and so on. However in any case, intersection departures are not banned by any airlines that at least operate out of Las Vegas. Prime example, when we depart 7L, our primary departure point for air carriers is 7L @ A8 or D.

 

Again I'm not saying your info may be wrong, just not 100% accurate.


Jeremy "BZ" Bucholz

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FYI intersection takeoffs are pretty much banned by a lot of airlines now - there's been some incidents with them in the past where the speed stuff was wrong, issues with runway incursions etc.

 

That may be the case, but I can think of two airports I fly out of regularly that use intersection departures: KSEA 34R/Q and KORD 32L/T10.


Jon Skiffington

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