Intersection Departures

[surplus1]

I agree with Caveman and Enigma. If you do not have the data available to you, in the cockpit, don't do it.

What you "think" is safe may very well be safe, but you have to be able to "prove" it. You can't do that without "approved" data. All those pages of takeoff performance data in the AFM are essentially useless. You as a pilot cannot calculate obstruction clearance with any degree of accuracy. It is not possible. Why? Because you do NOT know where the "obstructions" are and you have NO MEANS of making that determination.

With respect to the "engineering department", most small alirlines and many large airlines simply do NOT have the in house capability of generating accurate runway analysis charts. That's why they a purchased externally. Don't take anybody's word for it, no matter who they are and yes, that includes the POI. That dude doesn't know a bit more than you do, he simply has a badge. Either you have the approved data or you don't. It's that simple.

Operation without supporting data is not legal, period. That applies to everything, not just intersection departures. You can't land on a runway 3 times as long if your have no data for that runway. You can't "hold short" of an intersection if you have no data (one of the reasons LASHO was thrown out). You can't divert to an airport if you have no data for that airport. You can't run a "charter" to an airport that is not in your analysis book, unless you get the data before you depart. You can't operate with the "gear down", even if you have a "ferry permit" unless you have the data for gear down operations. You can't pull and reset circuit breakers, even when maintenance control tells you to do so on the phone, unless you have an "approved" procedure for that particular CB. You can't use airports or minima that are not in your Ops Specs. Etc., etc., etc. It's all a part of the same basic principle, i.e., you, as Captain, always have to be able to prove that whatever you did, was by the book. If there is no "book", don't do it. Your "ticket" is your only asset; protect it. The life you save may well be your own.

Intersection takeoffs are for the "convenience" ot the Tower. Do not facilitate "their convenience" by risking "your license". It ain't worth it.

Don't forget the "catch all regulation" buried in Part 91. The "careless & reckless" gambit. It is totally subjective but turst me, you don't want to put yourself in the position of having to prove a negative.

Finally, remember this very old axiom: "The runway behind you and the altitude above you are both useless."

 

[Dieterly]

What about if you have the numbers for Maglev, are you the legal to takeoff?

 

[Gator1999]

Typhoon,
For what it's worth on this topic, I just verified with our techinal experts and fleet manager about this topic that using the less restiricted intersection is legal at Mesaba. However, they indicated that different companies may have different policies about being able to use intersections that aren't specified in their RA. Comair and Continental Express pilots that I know say that they can't take an intersection departure that isn't specified in ATOGS or RA. Check with your fleet manager for details at your company. Great topic...

 

[Skyboss]

What about if you have the numbers for Maglev, are you the legal to takeoff?

You can get over it any time now.

 

[Typhoon1244]

Remember, there is a lateral component to obstacle clearance and intermediate intersections may not provide the required lateral safety necessary to meet 121 requirements.

I just learned (from someone who knows more about airports than I do) that the lateral data applies to the entire runway, not particular intersections. In other words, if you're okay laterally to take off at one point on the runway, you're okay laterally from any part of the runway. It's in an Advisory Circular on airport design (I forgot the number)...and I think it's also in Part 139.

(I need to go to the airport and get my flightbag to see what our book says...)

I guess the bottom line is: it depends on the operator

 

[Skyboss]

Glad to help...

It's actually Part 77. You won't find 139 unless you go on line or call a FSDO. 139 is irrelivant, it covers certification of airports and does not discuss approach and departure slopes to the level you're looking for.

The associated AC's are:

70-2E
70/7460-2F

There may be some info in the 150/5200 series AC's, but it will be limited. It has more to do with lighting of obstructions that it does limitations.

I guess the bottom line is: it depends on the operator

I believe thats what I said initially. Glad I could help.

 

[Singlecoil]

I know we can do it where I work. If you have numbers for full length, and some intersection past where you want to depart, you use the highest accelleration height, and the most restrictive weights of the two analyses. Then you are good to blast ahead of that 757 that is taxiing at 10 mph waiting for the numbers from ops.

 

[Caveman]

"Intersection takeoffs are for the "convenience" ot the Tower."

Also, different airplanes have different performance. Just because one type can safely depart an intersection doesn't mean another can. The tower doesn't necessarily know who has data for each intersection.

 

[flywithastick]

Learnt somthing today. Sure never thought about 121 operations making intersection departures. I'm all for flying smart, but it reminds me of what my uncle used to say about runway behind you and fuel left on the ground. Just didn't think it was done with larger planes.

Last (I can't help not mentioning this one), what's with these "engineering departments"? Y'all building runways or using them?! Must be like the "engineering department" that fixes leaky plumbing and broken light switches in hotels.

 

[Typhoon1244]

Sure never thought about 121 operations making intersection departures. I'm all for flying smart, but it reminds me of what my uncle used to say about runway behind you and fuel left on the ground. Just didn't think it was done with larger planes.

In my situation, it involved a 53,000 pound CRJ-200 using 9,000 feet instead of 10,000. The margin for error was pretty wide.

But yeah, big airplanes do this, too. I don't think I've seen Southwest do a full length takeoff anywhere...

 

[Typhoon1244]

I believe thats what I said initially.

Well, not exactly. I asked a performance question, and you gave me a certification answer.

Don't take it too hard, though. You're a lot like Mary Schiavo: even when she has the right answer, nobody takes her seriously because she's a wacko...

 

[dispatchguy]

Learnt somthing today. Sure never thought about 121 operations making intersection departures. I'm all for flying smart, but it reminds me of what my uncle used to say about runway behind you and fuel left on the ground. Just didn't think it was done with larger planes.

Last (I can't help not mentioning this one), what's with these "engineering departments"? Y'all building runways or using them?! Must be like the "engineering department" that fixes leaky plumbing and broken light switches in hotels.

Every airline, whether a major or a very small regional, has an ops engineering department - or someone that holds that responsibility. They generate all the performance data used in flight operations. Even if you dont have a perf engineering department in house, for 121 operators, they still have someone (usually contracted) to perform the function (ref. A009 of the OpSpecs). Even if a line crew cant access them, your dispatcher can get them 24/7 to generate a legal weights table, such as when runways are shortened, or in the case of an intersection departure that tower wants.

 

[wingnutt]

Don't take it too hard, though. You're a lot like Mary Schiavo: even when she has the right answer, nobody takes her seriously because she's a wacko...

roflmao...ba-hahahahahahahahaha

 

[WrightAvia]

Hey, flychicaga...hope school is going well! We'll be tangling out there at MKE soon as you get on the line, as I fly in there alot.

Some day you'll be taxiing to 7 Right in the Saab and some old Vin Diesel looking mofo in a caravan will landing and making Alpha 4 with whimsical ease. That'll be me.

Hope to see you out there soon!

 

[NEDude]

To put it basically, for 121 operators this is airline specific.

I have been at two 121 carriers, at one airline you could not use the intersection unless you had the numbers for that particular one. At the other airline you could use any intersection provided you had the numbers for a more restrictive intersection. Both procedures were spelled out in the particular ops manuals for each airline.

 

[JECKEL]

I think an example of this is "or was" BHM. They had cranes erected on the field for construction. Certain intersection departures did not allow for for the lateral consttraints under part 25.
However, intersections FURTHER down the runway (considered more restrictive, I guess) were allowable because the cranes were no longer a lateral concern.

More restrictive was allowable while less restictive was not.

If you don't have the numbers, don't do it. There is a reason!

 

[GCD]

Having the good fortune to have worked with and learned from the man who sold the performance data computations to Jeppesen, that most of you use, the short answer is no.

Read some of the above for the reasoning. I'm too lazy today.

Gary Owen! 4/7 Cav!

 

[Typhoon1244]

They had cranes erected on the field for construction. Certain intersection departures did not allow for for the lateral consttraints under part 25. However, intersections FURTHER down the runway were allowable because the cranes were no longer a lateral concern.

This must have been an isolated incident since lateral clearances are normally computed for the entire length of the runway, not certain intersections.

For the record: Atlantic Southeast Airlines pilots are authorized to make intersection takeoffs provided they have data for a more restrictive intersection. The problem we were having a while back is that some of our guys were reasoning that if we were legal for, say, 17R at Yankee, we must also be okay to use 17C at Yankee. Not true! Even if the remaining runway distance is equal or longer, you can't substitute one runway's numbers for another. (Frankly, it never even would have occurred to me to try this!)

I wonder why this varies so much from company to company? ASA can, Skywest can't. Eastern could, Sunjet didn't.

 

[ClassG]

Both airlines where I worked, the answer was "NO" simply because you don't HAVE the data on board to prove it, so you don't do it. The same held true if that particular APD PAGE happened to be missing from the performance data. If it wasn't on the aircraft, it wasn't legal. If you knew it was missing, you had it faxed prior to dispatch. If you found it missing after pushback, you used what you had or returned to gate to get it. (At least, that's how it worked in THEORY.)

As for Skyboss - I haven't seen such a Dork around here since Mr. Concorde. You just don't get it, bro. We don't want to be you. We don't want your job. We aren't interested in how much you think pilots should be paid. And when Maglev trains take over the planet we hope they shut your airport down first.

 

[surplus1]

Typhoon

I don't doubt you for a second when you say that your carrier "approves" this procedure. With all due respect, that doesn't make it right.

Many are the airlines that have come up with internally "approved" how-to's, that subsequently were proven to be the product of erroneous thinking on the part of some program manager or flight standards guru and the rubber stamp of the FAA. We are not infallible any of us and the incidence of bogus "approved" procedures for a variety of things is more prevalent than most of us know or are willing to admit. All too often they aren't uncovered until the NTSB gets into the act. When a procedure is questionable, someone should take the time to have it changed to one that is not. You make waves in the process but it needs to be done anyway.

I still say that if you don't have the data for the specific intersection, on board the a/c, you should not accept the departure.

For your own gratification I have a suggestion. Just take another look at that avatar of your beautiful baby boy, then tell the tower "unable" and taxi to the end. The minute or two you might save just isn't worth it. Sometimes one foot of altitude, two degrees of heading, 100 #s of fuel or 5 seconds of time can make all the difference in the world.

Sincerely --- and sorry I said too much.