My question: is it allowed for a commercial jetliner (or any aircraft, for that matter) to directly accelerate after taxi, without a stop on the runway? Or is it simply „tolerated by law“, but not necessarily „best practise“? Is this country-specific (or airport-specific)?
I just experienced this twice just recently, once in Madrid and once in Ibiza. (But not for the first time either)
Interestingly I did not find any answer (or even the question) on the internet, but knowing that some real-world pilots read here in the forum I am pretty sure to find some opinions / answers here.
This would depend on the airport and tower.
I do this frequently IRL with my job where I don’t stop. Uncontrolled airports mostly but I have also done it at smaller controlled airports with tower permission.
I also do it quite often in MSFS.
I don’t think I ever remember a tower telling us to do a rolling or standing takeoff. I was aircrew on a C-17 and it was always the pilots decision on what to do. We tended to do rolling takeoffs if we were light and standing takeoffs when we were heavier but that was not a hard fast rule either. Not sure what drives passenger aircraft on which one to do. Unless we were told to line up and wait vs being cleared for takeoff before entering the runway. Which means we had to stop on the runway so we would do a standing takeoff.
the way I recall a GA flight instructor’s recommendation was that you would maybe do it differently if it was the first flight of the day for the aircraft. In that case (or if taking off on a short field) you would lock the brakes and throttle up to ensure proper instrument readings and engine sounds - standing takeoff.
but if the flight was a return trip (same day) and you had the runway length you could do the rolling takeoff - but he said that in his case personally, he always did the standing takeoff every time. He wanted to hear the engine near full power and watch the instruments for a minute before committing to the TO. He figured he wasn’t in any hurry to practice an engine failure on takeoff procedure…also it isn’t like folks are honking at you to ‘hurry up’ not that that would make a difference
Airliners are - supposedly - so well maintained, depending on the airline ‘culture’, it’s generally safe to do a rolling start and is not frowned upon on crazy busy airports, for one. Depends though what the company big dogs think concerning the practice. At KLM it used to be considered ‘entertaining’, then again young pilot KLM culture is a tad adolescent.
Sure, but it’s not outside law. They got the takeoff clearance during taxi roll and just lining up and start takeoff roll without stopping. If they line up via a highspeed taxi, they begin accelerating smooth at the end of the highspeed entry and go, when on the runway.
It’s not dangerous or something. It’s just a sign of a non busy time, and the crew is ready to go,
For both Part 135 (charter/air taxi) and 121 (scheduled air carriers) it is primarily a function of the company’s OpSpecs. Due to the relatively short runway and high field elevation at my airport, it is company policy for the air carriers to enter the runway, line up, apply brakes, stop, then apply take-off thrust to start their take-off roll. For many of the GA guys, once they get take-off clearance from the tower, they simply roll onto the runway from the taxiway connector, slow roll to line up on centerline then power up and go without stopping. Either way, it is not illegal per Federal Aviation Regulations to do a rolling take-off like this more of a function of OpSpecs and pilot/crew preference.
Sometimes, aircraft may be told something like “no delay” when they are given a takeoff clearance due to an aircraft on final that may be a little close.
In another scenario – and I’m sure this is probably not what you were thinking of – when GA aircraft are taking off on a grass runway, you’re actually trained to not stop when turning into the runway so you don’t lose your momentum and get stuck. If you see a GA aircraft do that on a paved runway, they may be practicing what’s called a “soft field takeoff”.
The takeoff numbers calculated for jet aircraft will have data for both rolling and a static takeoff. These days it is all figured by computer / tablet, it is just a matter of selecting the “rolling” option. Similar to selecting a wet / contaminated runway, inop thrust reverser, etc.
There will be a small penalty for a rolling takeoff, but as long as you meet the runway and climb requirements, the rolling takeoff technique is smoother on the passengers. But the pilots definitely know how many feet of runway is required and the additive for doing a rolling vs static takeoff.
Thank you all for your very informative replies! So I understand first and foremost, a “rolling start” (that seems to be the term I was really looking for here) is not against any “international safety regulations” (I was hoping it wasn’t, just having experienced two such rolling starts, and yes, both times with some “many times a day, short flight” kind of flights, specifically between Madrid and Ibiza).
Then it also mostly depends on “company procedures”, and of course the actual take-off conditions, including whether this is a repeated flight on a given day.
But in any case this generally does not “shortcut” any take-off safety procedures, such as making sure that the engines are starting fine or that some instruments do some final alignment (?) with the runway (I do understand that the GPS / navigation systems should already have been properly “aligned” / initialised at the parking spot, before taxiiing).
P.S. I just marked the last response here as “Solution”, but any of your responses may have been marked as such - so thanks again!
Quite recently on a Lüfthansa flight to Munich not only did I not realise we had actually taken off but it was only as we turned to the gates that I realised we had already landed. As a simmer I have always wondered how I could miss both events? The weather wasn’t even that good with plenty of buffeting on approach.
I guess the wine selection on that flight must have been pretty decent then.
Even in real life as a passenger it’s very often that I experience a rolling start, where the aircraft just taxi into the runway, and without even stopping just apply take off thrust and off we go.
I assumed that they’ve done their take-off checklist while entering the runway and they already have clearance for takeoff, so all they need to do is just line up at the centerline and immediately apply take off thrust.
I do this in the sim as well. If I completed all the checklist before I even line up with the runway, I just straight on take off without stopping. The only time I stop on the runway is when I haven’t completed the checklist or that I don’t have clearance, such as when another aircraft in front of me just took off and I was told to taxi into position and hold on the runway. Then I taxi and stop, even when all my checklist are already done. Once I get take off clearance from ATC, that’s when I apply the take off thrust from a stopped position on the runway.
So it depends on the situation, really.
As is typical in aviation there is no simple answer to to some of these questions.
Normally you would want to check that the engines are accelerating correctly, especially on a twin engined aircraft with wing mounted engines, by applying say 50% thrust with the brakes applied before commencing take off with full power. If one of your engines failed after you had applied full power at standstill you would probably depart the runway sideways due to the asymmetric thrust.
If the runway is short, think London City, then you would prefer to ensure that take off thrust is obtained before releasing the brakes. So 50% power to check the engines and then take off power just before brake release.
If you lined up at a busy airport and didn’t take off quickly, or you had accepted a ‘cleared immediate take off’ instruction from ATC then you would be very unpopular if you sat on the runway without rolling. I seem to remember that an airline was in trouble at Heathrow a few years ago because their Airbus A340’s I believe, needed 30 - 40 seconds of power on the runway before they could roll. That’s how tight the separation standards had become at a busy airport.
Obviously all the pre departure checks should be carried out, including checking the cabin security, before take off is requested and you enter the runway.