Intersection Takeoff Question

bc2209

bc2209

Well-Known Member
I had a flight out to Marine Corps Air Station Yuma yesterday and after having lunch we taxied out and were cleared for an intersection takeoff.

My question is how can I assure that the intersection takeoff clearance will have enough adequate runway length given density altitude, weight, etc.?

ATC did not provide runway length details after giving us our clearance. Is this something I can always ask for given whichever taxi way were depart at?
 
You typically won't see available runway length from every taxiway charted on an airport diagram, but you've got the overall runway length and you can infer the length from the taxiway you're at. If it's questionable, err on the side of safety.
 
I believe, I very well could be wrong. Tower can only give you an intersection take off if they have the distance remaining available to them. I've asked for intersection departures and been denied because they didn't know how much was remaining from that particular intersection.
 
Without getting into all the what ifs and wherefores, you need to know "exactly" how your airplane will perform from any intersection takeoff. Tower is more than happy to offer intersection takeoffs thinking they are doing you a favor, but it is up to you to determine if your takeoff performance comfortably fits within the intersection takeoff runway length. If you're not sure, just tell tower you require full length. I know you already know this, but I mention it just as a reminder to others that tower has no idea what your airplane is capable of..... they are just trying to be nice or get you out in front of the heavy that is taxiing out for the full length. It might be good to explore intersection data possibilities before heading out to the runway so a last minute offer won't catch you by surprise.... Great question.
 
Back in the day when I was a tower flower whenever we gave an aircraft an intersection dept we had to give the rwy distance remaining.
 
I thought it was a requirment as well.. When you pull up the ATIS at the bigger airports they'll usually give you the distance remaining from a certain intersection if they're departing from them.
 
I would hope it goes without saying but available runway length should always be independently confirmed by the flight crew.

Also, in the case of an intersection take-off, I double-check that I'm on the correct taxiway.
 
queeno said:
Back in the day when I was a tower flower whenever we gave an aircraft an intersection dept we had to give the rwy distance remaining.
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It's required. I have never gotten an intersection takeoff without tower giving me the runway available. It isn't on the chart, and if you are concerned about performance, I wouldn't take one without confirming unless I had a death wish.
 
Look for one of these?

images
 
Its also worth mentioning that even if your numbers work for the runway, there's no guarantee that your second segment etc will still be met. A real performance Nazi would only take off from the exact GPS coordinates on their APG paperwork. I am, BTW, not a real performance Nazi.
 
Boris Badenov said:
Its also worth mentioning that even if your numbers work for the runway, there's no guarantee that your second segment etc will still be met. A real performance Nazi would only take off from the exact GPS coordinates on their APG paperwork. I am, BTW, not a real performance Nazi.
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Ehhhh, what?
 
Boris Badenov said:
Its also worth mentioning that even if your numbers work for the runway, there's no guarantee that your second segment etc will still be met. A real performance Nazi would only take off from the exact GPS coordinates on their APG paperwork. I am, BTW, not a real performance Nazi.
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If I forget my reading glasses, can I just ask for the longest runway?
 
Pilot Fighter said:
I would hope it goes without saying but available runway length should always be independently confirmed by the flight crew.
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How does one do that?

Let me clarify... I get a TLR that includes some intersection departures. It gives performance numbers from that intersection but does not give distance available from the intersection. I can also send a data request to Aerodata via the ACARS for pretty much any runway/intersection combo. When that data comes back it gives performance numbers AND the amount of pavement available. However, using just the paper TLR I have no way of knowing the actual distance. Does that matter if I have performance numbers for that intersection?

Also, interesting story from the other day...

8L in HNL was shortened by 3000 feet due to construction on the eastern end of the runway for about 5 days. During that time period the company elected to update our ACARS data manager which meant for about 3 hours we wouldn't be able to get takeoff data via the ACARS and instead would have to use the performance books in each airplane. (we also had TLR data but for some reason it wasn't showing the shortened runway so we couldn't use it.) There are three "normal" takeoff points on 8L. Full length (12,000 feet), RB (which is about a 500 foot reduction) and L which gives you about 7500 feet of runway. The performance book gives data for each of these points. HOWEVER... with the runway being shortened by 3000 feet all of that data was invalid. We got a message from Flight Ops saying that we could use the data for a Lima intersection departure (~7500 feet available) and just take off full length (which gave us 9000 feet of runway). At first brush this sounds fine but like @Boris Badenov said, this doesn't take into account the second stage climb. In theory you are taking off from a point further back (full length instead of Lima) from where the data is for so you SHOULD be ok, but there are a whole lot of what ifs and unknowns with that.

We just went to 8R.
 
BobDDuck said:
How does one do that?

Let me clarify... I get a TLR that includes some intersection departures. It gives performance numbers from that intersection but does not give distance available from the intersection. I can also send a data request to Aerodata via the ACARS for pretty much any runway/intersection combo. When that data comes back it gives performance numbers AND the amount of pavement available. However, using just the paper TLR I have no way of knowing the actual distance. Does that matter if I have performance numbers for that intersection?

Also, interesting story from the other day...

8L in HNL was shortened by 3000 feet due to construction on the eastern end of the runway for about 5 days. During that time period the company elected to update our ACARS data manager which meant for about 3 hours we wouldn't be able to get takeoff data via the ACARS and instead would have to use the performance books in each airplane. (we also had TLR data but for some reason it wasn't showing the shortened runway so we couldn't use it.) There are three "normal" takeoff points on 8L. Full length (12,000 feet), RB (which is about a 500 foot reduction) and L which gives you about 7500 feet of runway. The performance book gives data for each of these points. HOWEVER... with the runway being shortened by 3000 feet all of that data was invalid. We got a message from Flight Ops saying that we could use the data for a Lima intersection departure (~7500 feet available) and just take off full length (which gave us 9000 feet of runway). At first brush this sounds fine but like @Boris Badenov said, this doesn't take into account the second stage climb. In theory you are taking off from a point further back (full length instead of Lima) from where the data is for so you SHOULD be ok, but there are a whole lot of what ifs and unknowns with that.

We just went to 8R.
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Great post.

The point I was trying to communicate was don't rely soley on control when you have other resources at your disposal.

I'm aware of the gotchas.
 
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