747s and TNCM...

[okini]

Obviously the 747 are more than too big for the short runway of princess juliana airport. What do you guys think? Why do they fly those heavy babes to TNCM? Whats the point????. Sonner or later a big accident is going to happen on that island if they keep landing those 747s there. On every landing and takeoff they use all of the runway. So why not just fly 757, a330s, 777, 767 etc ONLY to st marteen? Aint those big enough to do the job? so yeah basically I wonder why A340s and 747s fly to St marteen.

Thanks.

[MCM]

Why is an accident going to happen if they keep flying big aircraft there?

The 747 has a perfectly good stopping capablity, and the runway is long enough to cope.

Sure, its shorter than the average runway for a 747, but it more than meets the requirements, otherwise they wouldn't be landing there.

[AA 1818]

Firstly - welcome to the forums!!!

Secondly, your location berates us to think back to one of the world's most interesting airports - one that has given us unparalleled, amazing, gut-wrenching approaches, where landings were solely graded on a 'pass/fail' scale. Take a look at some of the most popular pictures on this site (or, for that matter any aviation site) and I can guarantee that if pilots can land a 747 at Kai Tak, then they could easily do the same at Princess Juliana.

Thirdly - the size of aircraft (and by that measure - aircraft) used is wholly dependant on range and capacity. As much as it might be 'safer' to land smaller aircraft at the airport, it is not necessarily economically sound. Now, before I get slammed for that last comment, I said 'safer', which is relative in this conversation. I believe that with the amount of training that operators receive, and the capabilities of both the 747 and A340 lines, the operations of these aircraft are incredibly safe.

[Gabriel]

Obviously the 747 are more than too big for the short runway of princess juliana airport. What do you guys think? Why do they fly those heavy babes to TNCM? Whats the point????. Sonner or later a big accident is going to happen on that island if they keep landing those 747s there. On every landing and takeoff they use all of the runway. So why not just fly 757, a330s, 777, 767 etc ONLY to st marteen? Aint those big enough to do the job? so yeah basically I wonder why A340s and 747s fly to St marteen.

Thanks.

A lot of times airplanes take off and land in runways that are exactly what's required and not 1 inch longer. Including 757, and even 737.

For a given airplane, the required distance depends on the weight. Just ensure that the plane is light enough for the runway to be legal and that's it.

[MCM]

Just to give a general idea for landings:

Taking a landing distance available of roughly 2100m, in nil wind and 30 degrees celsius temperature, the 747 can land at just under 280 tonnes. That is 35 tonnes above the maximum zero fuel weight, and only a fraction under the maximum landing weight.

Or to put it another way:

Given a maximum zero fuel weight of approximately 245 tonne (depending on model), and a landed fuel of somewhere in the ballpark of 10 tonnes, that means a realistically maximum landing weight of 255 tonne (in most operations it would be not be this high). This gives a landing distance roughly 200m shorter than the runway - and this INCLUDES all of the regulatory buffers etc.

Yes, it is a short runway, and it is tighter than most runways you would use, but it is more than usable for normal operations.

For departures, you are just weight limited to the takeoff distance available - so it doesn't matter if the runway is 2000m or 3000m... you are still achieving the same ultimate performance, just that you can't lift as much weight.

[okini]

ok then thank you for the answers =D

[brianw999]

...and then there's the European "mini St Maarten" on Skiathos where A321's and 757's regularly take off with minimum fuel and refuel normally at Thessalonica to continue their journey. I remember landing there once in a 757-200. You could almost hear the pilot shouting "pump the brakes 'Arry, pump the bloody brakes !!"
As someone here said...if the weight/ambient temperature etc. versus available runway length = an allowable takeoff/landing then there's no problem.

[LH-B744]

Yes, there are runways that don't seem to be "usual" landing places for the heavies. But training is everything, and I'll remember for the whole rest of my life, what Mr. Sullenberger did (keyword: life-saver).
So, why do you use 747 and not 777... Landing is not the big difference, but you do have to take off where you landed before, don't you.
B744 range is more than 7,000 nautical miles, so B773ER is a good comparison. But imho, B773ER can't compete with B744 concerning quickstart ability.

[mpe]

Obviously the 747 are more than too big for the short runway of princess juliana airport. What do you guys think? Why do they fly those heavy babes to TNCM? Whats the point????. Sonner or later a big accident is going to happen on that island if they keep landing those 747s there. On every landing and takeoff they use all of the runway. So why not just fly 757, a330s, 777, 767 etc ONLY to st marteen? Aint those big enough to do the job? so yeah basically I wonder why A340s and 747s fly to St marteen.

The 747 has 16 wheels on the main landing gear, hence 16 sets of brakes. By comparison the 777 has 12, the 767&757 have 8 and the 737 has only 4.
On the Airbus side the A320 appears to come in both 4 and 8 MLG wheel versions. The A330 has 8 MLG wheels, the A340 has 10 MLG wheels, but it appears possible to have the middle set remain stowed. Finally the A380 has 20 MLG wheels.

If the runway were unsuitable for a 747 (or A340) then pilots would not attempt to use it.

[WILCO737]

We pilots have a lot of charts where it is said how much runway you need to land. There are different definitions though. The runway needs to be longer than the FAR required field length for landing. So for a special weight, special enviromental conditions you need so much runway. If the runway is shorter: you cannot land; if the runway is longer than that: you are able to land.
Of course the shorter the runway, the less mistakes you can or should do. The shortest runway I have landed with an MD11F on was EMA (2715M) long. You could land there with MLAW (222,9 tons) but that gives you a safety margin of 60m or something like that. If it was raining, you cannot land at MLAW anymore. So using that chart and considering all the factors the crew decide if they can and will land or not.
You have a so called 'touch down- zone' you have to land in. It is usually 3000 feet long, but with a 6000 foot long runway, this zone is shorter and you don't want to land on the last foot of the touchdown zone on a short runway. On a 16000 foot runway you can do that. So if you do not touch down at the 1000 foot marker (which is our goal to touch down) you'd better go around and try again or go somewhere else.
I hope that helps a bit more to understand the problem. So it is not really something about aircraft type, more about the conditions around. The 340 is capapable of doing a lot, same with 330, 777s, 767s and of course 747s. There will be weight restrictions for sure departing from TNCM, but it is possible as we see everyday. But it is not a take off with huge safety margins, I am sure many times it is at its max. But even then there are safety margins from the manufacturer.

Happy landings

P.S.: oops, the post got longer than I thought - sorry about that

[Shanwick]

Okini I'am trying to figure out why you think that 747'are too big for SXM.I take it that you ask the question after seeing some photos from there.
If it was the landing photos such as below refer to Wilco737 answer.....I know that the KLM pilot here was taking it to the extreme as regards not touching down late

If you had in mind take off shots such as the one below it may be a bit more diffucult to explain.A few of us did try to tease it out in a thread a while back.
To give a very basic explanation as to why Corsair 747's(no evidence of KLM doing this)of leaving it very late to rotate on departures from the westerly runway is....given conditions re.temperature,wind and close to max load for the runway length the Pilot may elect to rotate very late as there is nothing to loose in the sense that there are no obstacles at the far end.If an abort was required he should have done this at the given reference speed to stop before the end.
In short the aircraft could become airborne earlier but he delays it after he must roate or abort maybe to have an increased air speed once the wheels lift off.If something went wrong with the aircraft after a V1 delaying the rotate is not going to make much difference...as long as he rotates before the piano keys

[WILCO737]

It is pretty much the same for the take off. We can calculate a max allowable weight for take off which can be significantly lower than the structural max take off weight. For TNCM the allowable TOW will be pretty low. You get then a V1 at which you still can stop the airplane on the remaining runway, if faster, you have to take off. On such short runways, the V1 will be pretty low. The rotation itself cannot and will not be delayed. The Vr is the speed where the airplane is safe to lift off and fly (not the total minimum speed, that would be the VMCA or the 'minimum unstick speed').
You have to cross the runway end at an height 35' on a dry runway and 15' on a wet runway. And on short runways you do that. I can tell you, it looks scary, but it works.

P.S.: this is only a simplified explanation, I didn't want to go to much into detail

[Gabriel]

You have to cross the runway end at an height 35' on a dry runway. And on short runways you do that.

That would be with an engine failed. With all engines running, rotating as prescribed should lead to reaching 35ft at the 85% of the runway length IIRC.

[WILCO737]

That would be with an engine failed. With all engines running, rotating as prescribed should lead to reaching 35ft at the 85% of the runway length IIRC.

Yes, during engine failure at the worst case time to have that failure.
For me it was clear that this would be the case otherwise you wouldn't lift off anymore at all. I mean if you cross the threshold with all engines running at 15 feet, you will roll over the threshold if you have an engine failure
Thanks for clarification.

P.S.: still a simplified explanation

[Crunk415balla]

I think the fact you think you live in Kai Tak is more dangerous than 747s operating into an airport which they have been flying into for years and years on a regular basis without incident.