using full length of rwy for t/o
 

What are people's impressions of using full length rwy departures, instead of intersection departures for jets such as the 737/A320 etc....? is it good airmanship or not really needed? (the a/c is not at MTOW and we have a long rwy, no performance limits)

The question is: Why would you want to go from the intersection?

To save time? Are you late already? Are you trying to avoid turning back to get deiced again (not all too likely in Australia)?

Here in MUC, my base, controlers like to put you on an intersection, but I decline every time, eventhough my stopping margine might be around 1000m. Why would I give that away, just to make a controller happy? I even decline if it makes me #1 ahead of three others and I am late already. I just cannot find a reason to justify giving up a safety margin I am so glad to have . when flying the A340 almost every takeoff was with a stopping margin close to 0, so the extra meters my CRJ gives me on most RWYs are gladly accepted.

No need to rush, better be safe...

Nic

ah but...
 

The questioner specifically asks about lightly loaded B737/A320 not a heavy A340. At Brisbane for example the domestic and international terminals are considerably spaced apart. May a little light F70 departing Rwy 01 for Norfolk Island not legitimately trundle to "domestic" intersection A7 rather than "international" A9? Let's say the F70 insists on coming down to A9 and from your lofty vantage point in the A340 you see him rotate after 1500 metres with fully 2000 metres remaining thus delaying you and three B777's behind you. You need the full runway, and he doesn't. Do you congratulate him for the extra three minutes of fuel it has cost you because your take-off run will now be that little bit shorter?

Is it not the case that both aircraft and airports are designed to accommodate a number of options that are both safe and consonant with good airmanship?

I wonder under which pseudonym ssg will now reply

I find it interesting that some pilots won't consider intersection departures (not a criticism, just an observation) yet at the same time are quite happy to perform derated thrust takeoffs. Off wet runways as well!

Modern performance software programs/FMCs have the effect of turning many TOs into balanced field scenarios, leaving you back where you started.

Yes, runway behind you, fuel in the bowser and all that sort of thing but you have to ask what you're actually going to use that extra tarmac for and how likely is it you're going to need it. Tempted by a post-V1/Vr reject? Put it back down after you've left the ground? Taking these sort of options usually ends in a crash, statistically speaking. Sometimes extra choices are not helpful and may lead to bad decision making.

If it's going to save fuel/time, etc. then I'm happy to go from wherever, if the figures say yes. If there's nothing to gain, then full length starts to look attractive.

After V1 it's go. Or not...?
 

Admiral346 . . . your point is well taken and easily understood. It's always ideal to be able to land and to take off using full length on the longest runway at every airport.

But your CRJ is not the only airplane on the airport. And it's not just a matter of eroding your "extra-extra" safety margin, it's also a matter of practical reality. Commensurate with your intersection approved runway analysis, with your CRJ jet on a 4000 meter pavement. . . are you suggesting that you need the extra 1500+ meters beyond your V1 accelerate-stop distance to stop . . . ? :confused:

In our operation (B737) we do not always have performance charts for all intersections, full RWY required in these cases.
With full RWY available I feel a bit more comfortable if the take-off is just at minimum legal separation behind a 'heavy' as a case of N-1 will give me a chance to deal with it while not immediately having to go through some leftovers of the still present wake turbulences of the bigger brothers and sisters.
We do not derate, we use assumed temperature; the full runway allows mostly for a nice reduction and it helps to keep the engines a bit cooler.
The longer runway gives me also a bit of a higher V1/Vr as a result of improved speeds, something which may give you the necessary extra margin for the understatement of todays passenger weights.
And if you do not have to use the full RWY for an RTO, it helps me to stay cooler as well.

Do we get a discount for intersection take-off? No, but you may be asked after parking in the gravel why you accepted it.

The RWY behind you is as useless as ....

In a reasonable way, full length is my option.

Why would you be asked such a question? Do your managers not understand the concept of balanced field performance calculations? If the figures come out to max derate and max assumed temperature from the intersection then you'll either get airborne and avoid the nasty things on the climb out or you'll stop before the gravel. Either that or I've misunderstood performance all along!

This concept of 'just in case' can be absolute nonsense, especially statements like . Okay, so it's your perogative to decline but why if it's perfectly safe? Why not try to make up some of the time when you're late and, thereby, keep those people behind you a bit happier by getting to the destination less late? Why not cause less inconvenience to your fellow pilots if you're in a similar situation to that mentioned in BNE? I'm not for one moment advocating shortcuts or caning the engines to achieve an intersection take-off but, in a situation like MUC, with runways to the moon, refusing an intersection take-off and inconveniencing pax, pilots and controllers just because you'll have even more tarmac in front of you following an RTO is just silly. If you're THAT worried about margins then why derate at all and I do hope you'd never use less than max take-off flap. You can never be too careful eh! Full thrust and flap 15 for all 737s on a runway 4000m long......did someone mention professional pilots or is no-one confident enough in their understanding of performance that they're more scared of lawyers and the 'just in case' monsters?

You either trust your performance calculations, or you don't. I'll take an intersection every time, if it saves me any time at all - and the safety of my flight is guaranteed by my performance calculations.

If you won't accept an intersection on a 4000m runway, does that mean you refuse to fly to any destination with a runway shorter than 4000m? :cool:

Used intersection departures many times with large piston/turbopropellor types (Lockheed Electra, especially), but don't fly a light jet, only very heavy ones, so full length is required.
However if light, and performance data available, seems reasonable to me, conditions permitting.
However, don't paint yourself into a corner in doing so.

:ok:
e.g. - heavy acft on a short leg with few fuel... why not ?

enycalith :ok:

The T/L - Climb tables is where you justify an intersection take-off. If you find yourself in the gravel, you will say that the book issued by the company for the aircraft you are flying said you could do so. That is all the justification you need. Similarly, taking minimum fuel. If you follow your flight planning rules and come up with figure X, how much more makes it safer? One tonne, five or is an arbitary amount of time added instead? And what is the minimum underload you are prepared to accept on a loadsheet? Zero or would you like more? And where would you like the CofG. Within limits or do we want to add some extra margin here as well? Say 2% MAC or would you like more?

The days of the wet finger in the air/palm readers/fortune tellers and lucky rabbit's (unlucky bunny) foot have gone. To make it totally safe, call in sick!

PM

All of the salient technical points have been covered already so i won't repeat, but a good homily i was taught is......

The three most useless things in aviation are;
1 Runway behind you
2 Sky above you
3 Fuel still in the bowser

From Checkboard: On the head. If you abort prior to V1, you will stop before the gravel. If you don't believe that, why do you go to work?

P

It's such a worn out quotation and clearly has very little relevance to modern commercial aviation. You only ever hear it in the bars of flying clubs from the resident 'expert', who likes to say it loudly because he thinks it's so clever and nobody else has ever heard it before.

1. Runway behind you is not useless if you're using balanced field calculations. Something the Cessna expert in the club bar will have little clue about.

2. If sky above me is useless that means I should be flying right up there where the stall and Mmo are coincident. Maybe I'm just being cautious but I really don't think that's the best place for an airliner to hang out, especially with that nasty turbulence stuff that goes 'bump' in the air and suddenly sends your speed one side or the other of the 'hockey sticks'. Having the advantage of height (and, therefore, potential energy) is good for a fighter pilot and it's jolly nice to have if you've lost all your means of propulsion but to advocate the sky above as useless is just trite waffle.

3. Fuel in the bowser. Well, need I say very much at all? If you think getting airborne every time with full tanks in an airliner is the way ahead then (a)you didn't pay too much attention in class and (b)your airline is not going to be around too long.

As you can tell, I'm not too impressed by such a worn-out cliche that is bantered around by people who clearly have not thought it through. You don't HAVE to laugh when the boring old fart in the left seat says it for the 20th time you know :)

If I used full length at my home port, most departures would be delayed because back tracking the runway is required, in either direction.

If I used full length at a frequent port, I'd have to cross two runways to get to one threshold, and one runway to get to the other, with potential delays, all fo no real increase in safety.

Pontius, or should that read "Pompous"....

With reference to your points, i agree fully with what you say, its all basic aviation knowledge. As i stated in my previous post there was little to add to what has already been discussed. You have interpreted the expression too literally, these days its more symbolic of adopting a cautious approach to things. I was merely trying to point out (in an obviously unsuccessful way) that I personally like to use extra safety margins whenever it is appropriate, and available to do so. I fly a nice high performance corporate jet and have never been on the limits performance wise for T/O, cruise or landing so perhaps i am being too cautious...But, unlike you poor airline people, we can go straight to FL450 at max weight in all but high temp conditions (ISA +15 up). Usually we don't go that high though, but theres still a good speed margin up there if we do. Also, in our operation, I can pretty much take as much fuel as i want, I don't have to take what "Mummy" strongly suggests I take and I don't live in fear of a good "spanking" if i take more..........

With reference to the tone of your post.... that phrase about grannies and sucking eggs comes to mind.

Lastly, I really don't care what impresses you or not.

"Pompous"....

What private jet said is true.

Trouble is today, too much emphasis is placed on the automatics and what is "dictated" by the automatics, that the basics seem to be forgotten.

Why use less runway, when more is available?

Why fly low and fast, when it is safer to fly "high" and fast?

Why take less fuel, when it maybe prudent to take more?

Maybe you are one of those robots, that cant function without a "book" to tell you how to function. Maybe you are one of those pilots, that given a set of figures from a computer printout you would treat them as gospel, without a thought, as to the wisdom of cross checking those figures.

Full length runway is always my rule. No intersection takeoffs.
I even get upset when a PF wastes 200 meters to "line-up" nicely.
Takes longer...? I do not mind... I am paid for extra time if applicable.
xxx
:ok:
Happy contrails

Yeah, sorry about that PJ. I re-read my post and it does sound as if I was aiming my comments deliberately at you, which was not my intention. My aim was to address the worn out cliche versus flying modern aircraft in today's commercial market. Clearly my written word is not as precise as is necessary (note to self: must make greater use of 'one' rather than 'you').


Doubleu-anker,

Nah, you'll be glad to know I'm not an automaton who treats computer printouts as gospel. I tend to lean towards the other way of doing things but, in doing so, I make sure I know why I'm trusting the computer when I choose to use it. In other words I try to think about what I'm doing rather than relying on 'that's the way I've always done it' or, even worse, relying on a quotation made way back when the pilots flew in white flying overalls, engines were unreliable and taking less than full tanks wouldn't get one across the English Channel.

The use of less runway has already been discussed in this thread. There are, of course, times when I would use full length (particularly when you get to contaminated performance which, let's face it, is a best guess anyway). What I am saying is you don't ALWAYS need to use it, hence my comment regarding runway behind you being 'useless'. If, for instance, BelArgUSA wants to use the full length then that's fine. He'll have his own reasons for doing so but they'll hopefully be based on something more scientific and knowledgeable than an out-of-date saying.

Who said anything about flying low? I would rather cruise at the optimum cruise altitude. Yes, I know, silly old me using computers again to optimise the operation of my aircraft, thereby saving fuel and standing more chance of keeping my job as my airline stays afloat. What I said is the saying is nonsense regarding sky above you being wasted. That's not optimum operation that's operating at the ceiling, which I don't think is a good idea.

And as for fuel, do I really need to expand? Again, did I mention never taking extra fuel? There will always be occasions when more fuel is 'prudent' and I have no qualms whatsoever about loading it. However, I will (again) use those pesky flight planning computers and all the means at my disposal to ensure that I take a sensible amount extra and certainly do not subscribe to the 'load a bit for Mum' mentality. It may not be quite as much a concern in the Middle East but it certainly makes my job more secure if all the company pilots think about why and how much extra fuel they are going to carry, as opposed to the unthinking cliche which tells us that fuel left in the tanker is wasted :rolleyes:

NZAA has implemented a reccommendation, by some body or other, not to allow intersection departures . As I understand it, this is to do with minimising the risk of runway incursions, or whatever, not to do with perf issues.

The move will probably play hell with domestic ops (next sector) on-time departures but does not worry the long-haulers.