V-Flyer

Quick question, see if any of you folks might know some insight?!

Flew Glasgow-Luton this afternoon, aircraft was already at Glasgow and had seemingly been there for some time, unlike normal low cost 25 minute turn arounds.

Just before take off, the captain announced that due to the cold/fog they'd be holding the aircraft on the brakes under full power for about 30 seconds. So we positioned on the runway, the engines were at full tilt and the brakes held us in place (just about!), brakes off and then we launched down the runway at quite a rate!

Just wondering if anyone might have any idea why this would be done? I guess I'm a little more inquisitive to learn more beyond the captain's explanation!

Can't remember the exact technical reason but I've had many take-offs like that.

I've had this a few times too, lastly on a easjet to Budapest. Apparently it's where the aircraft has been parked up overnight and ensures the engines are all revved up.

That was from the Hungarian Stewardess so could well have been made up with a more advanced technical reason!

More than likely due to ensuring anti-ice fully heated and they can check the various engine readings (n1 for example, being the front fan rate of turn - or something like that).

Essentially, icing is a very serious threat to aircraft - engines, pitots, wings, control surfaces etc - so all good airlines/pilots will make damn sure the aircraft is good to go - most especially if it's been waiting overnight in the cold!


Or, maybe the pilot fancied a "sporty" take off!

Wasn't this the norm years ago? Unless of course I'm only remembering my JNB take offs, due to the altitude they wanted to make sure we weren't going have engine problems.

Certainly take offs used to be more fun - I just used to love the "wack in the back" as the plane accelerated down the run way...

What's happened these days, is that they look to reduce thrust and maximise runway use - "flex takeoffs".

What this means in practice, is that they calculate the thrust they need to takeoff safely within the runway length given temperature, payload, altitude and many other factors.

Drive is to reduce fuel burn and strain on engines, thus reducing maintenance costs.

All about money in the end - with a bit of safety thrown in!!!

Thanks for the responses folks.

The flight was at 16.25, it was very foggy and the outside air temp (according to hire car thermometer was -1c) so I guess making sure the engines are performing to their maximum potential is important in the cold like that.

They wouldn't really have much of a problem with low temps, it's high temps and high pressure that cause a reduction in thrust and a different take off to increase the safety margin. Not sure why he held on the brakes.

The fog and cold temp will actually help the engine, the taxi to the active should be more than enough time for the oil etc to get up to the correct temp range, what could of happened is the aircraft was projected to be over max landing weight, the quick and easy solution is you bring the engines up and burn off some fuel.

If you listen carefully on a take off the pilot will advance the throttles, once the engines are shown to be operating normally and stable the throttles will be advanced again to take off power, this happens in a matter of seconds, modern je engines accelerate very quickly.

Now with that said, did you happen to notice if you turned on to the runway at the end of the runway or at a taxi way, if for some reason they were doing a short field take off the flex power goes out the window and the pilot can give it some gas.

BTW try at least once in your life to do this on a lightly loaded 752, lots of fun.

But a you can see, there are many reasons why this would happen, my bet is the fuel, but the only people who will really know the answer were sitting up front.

We definitely took off at the proper end of the runway.

Basically there is a bunch of different reasons why this kind of takeoff would be preformed. You should have made it a point to talk with the Pilots after you landed - you would have got the exact answer for the specific reason on that occasion. For instance, I've had Pilots tell me they held on the breaks before rolling as they had de-iced the plane and wanted to make sure the engines were clear of de-icing fluid. Other reasons were because the aircraft was close to the max takeoff weight with the runway length in mind. So you see it varies a lot.

@Scrooge I look forward to test that theory of yours. I'm taking a 752 to EWR in March, hopefully it will be a light load.

From where to EWR ?

I took one that went LAS - LAX on National when they were flying, the 752 is one seriously overpowered aircraft !