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wde12

Early Runway Entry Point Procedure

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Hi all,

 

Quick question on what I can best describe as early runway entry ops. I'm thinking of KJFK's 31L for example. Often times on VATSIM or while flying with the an airports' LiveATC on in the background for some kind of "atc feel," I hear instructions to taxi and hold short of a long runway at an early spot (for 31L it's often KD I believe). Thus, you wouldn't end up using the full runway length. For a heavy like the 77W, this can often be a big difference. Now, I don't use Topcat, just the FMC takeoff calculations w/some kind of derate. Either way, just assume that the V! VR V2 speeds are properly calculated for the full runway length.

 

Anyone know how pilots recalculate / accommodate shorter takeoff distances than the runway length that is in the FMC?

 

Thanks in advance.

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Anyone know how pilots recalculate / accommodate shorter takeoff distances than the runway length that is in the FMC?

 

You'd be surprised at what's right under your nose if you pay attention to the TAKEOFF REF page.

 

...particularly line 4L...  :wink:

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Anyone know how pilots recalculate / accommodate shorter takeoff distances than the runway length that is in the FMC?

 

Thanks in advance.

It's not a problem in my world, we DO NOT do intersection takeoffs, everything is FULL length. How did that intersection take off work out for QATAR in KMIA a while back?

 

blaustern

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It's not a problem in my world, we DO NOT do intersection takeoffs, everything is FULL length. How did that intersection take off work out for QATAR in KMIA a while back?

 

That incident pointed more to a miscommunication between the pilots and their tools rather than anything else, honestly. The tool, somewhat confusingly, mentioned that intersection takeoffs were lot available for that runway, even though it listed 09#T1 (the intersection they ended up departing), which (again, confusingly) referred to full length as it was the only option.

 

Anyone with a bit of common sense and a good planner, though, is completely safe, provided the performance data is all in line. One of my favorite runways is 2000x40. The one I routinely use is 5500x100. A midfield departure at that field would actually be longer than the 2000 foot runway I can safely depart elsewhere, but it's suddenly unsafe because it's not full length? No.

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I have flown over JFK numerous times (RW) over the years from Connecticut to New Jersey and south. The routing is perfect for the pilot and departure as it is accomadating and efficient. I have never seen an aircraft do an intersection takeoff on 31L when 31L/R are in use. And the line gets long during peak periods on 31L in particular. The KD spot you are referring to and it appears on the airport diagram as an inner taxiway  and I have seen aircraft in that area waiting while 31L was in use. I can see where access to 04L is also possible, do you recall what Rwy. was used in the taxi instructions?  Any one else??

https://skyvector.com/files/tpp/1512/pdf/00610AD.PDF

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Hi all,

 

Anyone know how pilots recalculate / accommodate shorter takeoff distances than the runway length that is in the FMC?

 

Thanks in advance.

 

Hello, William,

 

I don't know you or whether you are just a simulator pilot, or a new real world beginning pilot, or an "old and bold" pilot. But.....

 

My advice would be not to look for a "quick" way to depart the airport. Get into the habit of using the full length of the runway for every departure.

 

You thereby allow yourself the additional safety of having more runway available off the nose of your aircraft to work with should you encounter an emergency. I advocate never trading expediency to depart using an intersection departure over retaining a safety factor higher than what would be available if an intersection departure is implemented.

 

 

It's not a problem in my world, we DO NOT do intersection takeoffs, everything is FULL length. How did that intersection take off work out for QATAR in KMIA a while back?

 

blaustern

 

We are on the same safety related page, Wilhelm. Our operation prohibits intersection departures as well. Any time a pilot elects to "leave runway behind" instead of using all runway available, they degragate their safety factor and have less options available to them in the event of an emergency.

 

Regardless of whether or not a pilot has the numbers to depart "safely" using less than available runway, they are placing themselves, and more importantly, their passengers, in a less safe environment than otherwise would be available.

 

The Qatar incident at KMIA is more than sufficient to justify not using intersection departures. Among other events that never needed to happen.

 

Our mission in aviation is to make it MORE safe, not to take chances and make it LESS safe.

 

But, there will always be those in our industry that are willing to take risks and roll the dice of chance for expediency.

 

Cheers,

 

Jim Wilkerson

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Good Morning Kyle,

 

I read the preliminary report and it does appear the crew may have been bitten by the failure to expand the screen bug. :)

 

blaustern

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The KD spot you are referring to and it appears on the airport diagram as an inner taxiway  and I have seen aircraft in that area waiting while 31L was in use. I can see where access to 04L is also possible, do you recall what Rwy. was used in the taxi instructions?  Any one else??

 

The K and KD intersection use is per SOP, just as 22R at W is for EWR. It eliminates the need for runway crossings unless required, which, contrary to what is written above, increases safety. Case in point: runway incursions rank much higher on the list worldwide than any other airport-related safety item. Additionally, in situations like this, controllers often split frequencies and runways. This means that, in order to cross a runway, it usually has to be coordinated with another position. If done improperly, the other position could forget about it (since, again, it's not SOP and we all know what happens to risk when people get off established procedures) and cross the traffic while the runway is otherwise in use.

 

In other words:

The procedure removes the practice of intentionally placing aircraft at risk of collision.

 

The Qatar incident at KMIA is more than sufficient to justify not using intersection departures. Among other events that never needed to happen.

 

Except that, again, it does not. It points more to a miscalculation by the pilot, and an error in the planning tool used. The intersection takeoff was a contributing factor, sure, but much like your other, previous (yes I remember) attempts to rationalize hyper-sensitivity, it doesn't actually hold your argument. A 777 could easily depart in that distance. I could take that same 777, put it at the end of the runway (which in your mind is apparently infallible), and give the same aircraft similarly bad data inputs and still take out the lights.

 

Our mission in aviation is to make it MORE safe, not to take chances and make it LESS safe.

 

But, there will always be those in our industry that are willing to take risks and roll the dice of chance for expediency.

 

And you make it more safe by adding a conscious, and competent pilot to the front of the plane. This is done by involving and empowering said pilot to make safety conscious decisions, and not simply rote, drone-like behavior.

 

Example:

Your aircraft can land and depart on 2000', safely. You fly to an airport that is resurfacing its only runway. In order to do so, they've ripped up half of their 8000' runway. This still gives you a 200% margin of error on your landing and takeoff performance. The runway is no longer full length, though, technically. You fly in, and now you need to make a ton of phone calls to get people's opinions on what "full length" means, technically, and, if full length is unavailable, what you should do.

 

...or, if you had a safety conscious pilot instead, that pilot would run the calculations, see that he only needs 2000' of that 4000' (plenty of margin), and continue. The fact that he operated the aircraft safely at a field with a 3500 foot runway the day before lends well to this.

 

If you want to argue the "well we'd use another airport" excuse, then I'll play into it, but only slightly:

The airport under construction is 8000' NOTAMd down to 4000'. All of the other fields within a reasonable distance are 2500' or less.

 

 

 

No matter how you cut it, the pilot in an environment that requires something no matter what is less capable to process actual factors of risk, simply because the decision regarding the risk has been "made" for him. What you're saying is essentially the "don't talk to strangers" approach to aviation. Except in your case, you're just repeating "I said 'don't talk to strangers," when the kid asks "but what about police officers?"

 

There are always exceptions to how things need to be done. In those cases, logic must be applied, and the operation must accommodate those.

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Kyle,

 

One of my retired ATC buddies was telling me that at one time intersection takeoffs were prohibited by "121" aircraft. He didn't know if that was still the case. All I know is I didn't do intersection takeoffs in the military and I didn't do intersection takeoffs in my commercial career.

 

la gracia y la paz mi amigo,

 

blaustern

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One of my retired ATC buddies was telling me that at one time intersection takeoffs were prohibited by "121" aircraft. He didn't know if that was still the case. All I know is I didn't do intersection takeoffs in the military and I didn't do intersection takeoffs in my commercial career.

 

I'd be interested in seeing it. Might it have been a misunderstanding of an OpSpec requirement (which has standing as if it were a reg)? All the operators I know of require you to have performance numbers for whatever the operation might be, so, in other words, you wouldn't see impromptu intersection departures that weren't the SOP for the field because the dispatcher wouldn't have thrown that data into the release. Many international fields have used intersection takeoffs for quite some time, so I'd be surprised to see an actual reg on it.

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Thanks all. I wasn't aware that the line @ 4L on the FMC Takeoff page was also a function vs. simple info (being able to customize the length). Normally I'd be in the FCOM but mistakenly assumed this was something outside that realm. Shoulda known better.

 

Pat/Jim - rest assured, I'm not the one looking for a quick way out. As I believe Kyle posted, I am 100% confident that KJFK uses that intersection for takeoffs (or perhaps one immediately adjacent). I have heard it on ATC and Vatsim has given me that instruction on multiple occasions (to which I requested full length). So my thinking was, okay, there has got to be some kind of calculation feature that crews us in the real world to accommodate this procedure.

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Pat/Jim - rest assured, I'm not the one looking for a quick way out. As I believe Kyle posted, I am 100% confident that KJFK uses that intersection for takeoffs (or perhaps one immediately adjacent). I have heard it on ATC and Vatsim has given me that instruction on multiple occasions (to which I requested full length). So my thinking was, okay, there has got to be some kind of calculation feature that crews us in the real world to accommodate this procedure.

 

Correct - as this is SOP, the dispatcher (DX) will run the takeoff calculation for that intersection on that runway, and it's simply treated as if the runway began at K, KD, or KE (or all three, which would be the case if provided with data for that group - this can be obtained with TOPCAT if you request a runway table, by the way). Any subsequent data runs would then be backed up by the hard numbers from the DX, and discrepancies would (should) mean a call to Ops.

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How did that intersection take off work out for QATAR in KMIA a while back?

The problem wasn't that they took off from an intersection, it was that they took off with bad data as a result of misinterpreting the performance calculation software and losing situational awareness of where they were on the airfield.

 

Would it have worked out any better if they had taken off from full length but entered the wrong weights in to the performance software and thus taken off with equally bad data?

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....   Except that, again, it does not. It points more to a miscalculation by the pilot, and an error in the planning tool used. The intersection takeoff was a contributing factor, sure, but much like your other, previous (yes I remember) attempts to rationalize hyper-sensitivity, it doesn't actually hold your argument. A 777 could easily depart in that distance. I could take that same 777, put it at the end of the runway (which in your mind is apparently infallible), and give the same aircraft similarly bad data inputs and still take out the lights.

 

Hi, Kyle,

 

Now, you have a compounded situation to contend with. Incorrect pilot data and an intersection departure.

 

So, you make an error in your takeoff calculations. So, you didn't catch, nor did your co-pilot, the mistake before power application. You perform an intersection departure. You have an unexpected emergency that requires aborting the departure.

 

Do you have the same available runway remaining to stop the aircraft performing an intersection departure in comparison to using the full length for departure?

 

This question makes the Qatar incident at KMIA more than applicable.

 

Point being ...  you will only miss the runway that was wasted when you need it.

 

Until then, you are rolling the dice performing intersection departures and degrading your safety factor in the process. Putting your passengers and aircraft in a less safe than available operational consideration.

 

Cheers,

 

Jim Wilkerson

 

 

 

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Jim,

 

Let me offer an alternative situation.

 

You calculate your fuel requirement for a trip according to the regulations and load it. You take off (using the full length!) and proceed enroute.

 

Shortly before arrival, an unforecast fog bank descends over your destination and forces you to enter a hold whilst you wait for it to clear up.

 

If you'd taken off with full tanks instead (bearing in mind nobody had predicted the fog), would that have been more or less safe in that situation? As you might come across unforecast weather at any point, why not enhance your safety margin by topping the tanks off every time you depart? Why would you knowingly choose to reduce your options by not brimming the tanks before every departure?

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