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View Full Version : What does "Cleared for Immediate Take Off" mean?


Dan Dare
26th Jan 2001, 15:23
There seems to be some confusion over this (especially frustrating when pilot is asked whether ready for immediate).

From MATS Part 1:-

When given the instruction "cleared for immediate take off" it is expected that the pilot will act as follows:
a) At the holding point, taxi immediately on to the runway and commence take-off without stopping the aircraft
b) If already on the runway, take off without delay.

What do you understand by the phrase, and more importantly, why do pilots seem to stop on the runway when given such a clearance?

Squawk 8888
26th Jan 2001, 19:08
It means exactly what it says- IOW "Get up & go now!" Such clearances are usually given when the runway is busy, such as a lineup to take off or an incoming aircraft. It can be quite dangerous to rev the engines first before starting the roll in these conditions, so if you need full static thrust to take off on the available runway then you shouldn't accept the clearance.

AYLGR
26th Jan 2001, 20:00
You guys are implying there should be a rushed departure, not so, it's just ATC want you to line up and take off "without delay". That means just make sure you're pre take off checks are done before you line up on the runway.

Bob

CallYouBack
26th Jan 2001, 20:08
While holding short of the runway awaiting the "Taxi to Position" or "Take-Off Clearance", there are often about 5 or 6 items left to clear up on the "Before take-off" checklist. When cleared to position, the first officer usually actions the items as the captain taxis the airplane. One of the final items is to "P.A." the flight attendants that take-off is imminent, and to be seated. If the demo video is still playing, the announcement shouldn't be made, and take-off will be delayed until it is.

Another item on the final part of the checklist is to check the video position of the airplane against the computer generated map on the HSI or ND. Since the aircraft I currently fly does not have automatic runway updating, there may be a slight position error built up from the time that the FMS was initiated which will necessitate having to fly the initial part of the departure using raw data until radio up-dating is available once airborne.

This can only be accurately determined once on, or very close to the runway. So there's a few things to check at that point, and if the controller wants an immediate take-off, probably because he's trying to get rid of you before the next airplane lands, then he's basically telling you to finish up your checks and be ready to roll as soon as cleared. LHR and other busy places are good examples of this. When you get to the runway, to keep things flowing, be ready to go without delay.

(Edited for typo).

[This message has been edited by CallYouBack (edited 26 January 2001).]

expedite_climb
27th Jan 2001, 00:50
..... ass .... in gear ....

3 putt
27th Jan 2001, 19:45
For ATCO's,
Immediate t/o obviously means 'ass in gear' and ready to go once lined up.However,for a normal departure,what is the max' acceptable time delay between giving t/o clearance and a/c moving?(all other things being equal)

Dan Dare
29th Jan 2001, 20:15
Keep the replies coming...
To clarify, I would not issue such a clearance unless assured by the pilot that he is willing/able to go, but I'm particularly interested to know why some pilots do not see fit to depart without delay. Obviously there are factors such as spool up time (I squeeze old jets off in smaller gaps than modern ones), but I feel that some airlines are more guilty than others. Are differing SOPs a factor?

Luftwaffle
29th Jan 2001, 22:29
I would say "unable" to a "ready immediate?" if ...

* a slow student pilot was doing the takeoff
* pretakeoff checks were not complete
* SOPs called for a static check on the runway before releasing the brakes
* I had just dropped my flashlight/SID plate/lunch in the rudder pedals
* I could see the traffic on final and judged the gap too narrow for my safe departure
* wake turbulence was a concern (but then I would say so)

cossack
30th Jan 2001, 00:24
Luftwaffle
I agree with all your points except this one:
"I could see the traffic on final and judged the gap too narrow for my safe departure"
That's ATC's job; if we think the gap is big enough, then its big enough. But if you have any of the other reasons for refusing the "immediate" just say "no". That'll be just fine.

Luftwaffle
30th Jan 2001, 03:39
I disagree, cossack. I acknowledge that you have experience and training in fitting multiple aircraft onto runways, but I'm the one flying the airplane. As pilot in command the final responsibility for the safety of my flight rests with me. It's my right to say "unable" if you ask me to do anything I judge unsafe. If you don't agree with my judgement, it's your right to mutter "stupid pilot" and let five departures from the other taxiway off ahead of me.

411A
30th Jan 2001, 07:31
Generally, when you are number one, you should be ready to go. If not, say so without delay. Have noted that some seem to "dauddle" on the runway like a rubber-necking tourist. I wonder why?

What_does_this_button_do?
30th Jan 2001, 17:59
I have a question: Wake Tubulence.

I thought this only applied to landing aircraft. At Heathrow last week (SLF) I was on an A320 and a 767 took off before us - PA said although we were next to hurl ourselves down the runway we had to wait 2 minutes due to wake turbulance.

Is that right?

cossack
30th Jan 2001, 20:38
Luftwaffle,
I agree that you are responsible for your flight, but we're trying to do a job in partnership and we wouldn't put you into a position that would be unsafe.
If, under normal circumstances, you are given a line-up clearance, we think there is enough room for you to depart otherwise we'd be mad to give it!. What we are talking about here are not normal circumstances. If an "immediate" take off is required, the gap may be less than ideal, but still safe, assuming you can accept the "immediate" condition. If you can't accept it then no worries.
As far as normal circumstances go, the gap will always be big enough for departure without the "immediate" and we would expect you to be ready on reaching the holding point (light aircraft power checks excepted).

What_does_this_button_do?
Yes that's right. Any non-heavy departing from the same departure point behind a heavy requires 2 minutes separation. This is also true for all lighter types following heavier types from the same point. If you are in the same situation but the second aircraft will depart from a point further along the runway, then 3 minutes is needed.

Luftwaffle
30th Jan 2001, 23:03
cossack, we've circled back to the beginning of the thread again: pilots and controllers not knowing how long each other's "immediate" is.

Don't you think it's fair to say that if a pilot doesn't think that he can be off quickly enough not to make that guy on final go around, that he should say so? I would think it more hassle for you to have someone in a go around than to have others waiting in an orderly queue at the hold short line.

I can't actually remember refusing an immediate take-off clearance because of traffic on final. Usually it's the other way around, me thinking "why didn't they let me out in that gap?" It's just something in my mind when I answer that question.

I don't know if the folloing is a true story, but it makes the point:

Seems that Tom was working local with a nervous FPL watching over his shoulder. He had one air carrier jet just touching down and another on a mile final, with a commuter holding short for departure release. "I'm going to get that commuter out between those two jets," said Tom aloud. The FPL could see that there might just *barely* enough time to make it work if nobody screwed up. But like any good instructor, the FPL wanted to let Tom make his own mistakes since that's the only way for a guy to learn. Still, the FPL couldn't help but mumble in Tom's ear "if this works, Tom, it'll be a miracle!" Tom keys his transmitter. He intends to say "Commuter 123, taxi into position and hold, be ready for immediate." What actually comes out of his mouth is: "Commuter 123, taxi into position and hold, be ready for a miracle." There's a pregnant pause on frequency, and the then commuter pilot says "Tower, I think under the circumstances we better just hold short. I don't feel quite that lucky."

CallYouBack
30th Jan 2001, 23:35
Getting back to the original question, I think that most professional pilots who regularly fly into and out of busy terminals know 'how the game is played'. At LHR, ORD, LAX, LGA and many other places, the traffic is run tight, because it has to be. Most pilots I've worked with over the years know from experience that you have to be ready when you are next to go near the runway. And for the most part, we are.

That said, I've also worked with the odd individual from time to time who taxied the airplane and followed ATC instructions as though he was the only airplane moving, by dragging the thing into position and being overly methodical when expedience was required. I even worked with one pilot who claimed that one should never taxi an airplane faster than a man can walk! Very frustrating to be a member of his crew.

On the other side of the coin, I can attest to the fact that pilots are often frustrated at some of the things we hear from ATC. For instance, calling for push and start clearance and being told to "standby", with no indication of how long a wait is to be expected. Or being number one at the runway hold point, anticipating a 'taxi to position' clearance when the arriving airplane is abeam us over the runway end, having everything done, and then either not hearing anything or being told to wait until the next airplane (who is 6 or 7 miles final) has landed.

In summation, I would ask every controller who issues a "Standby" response to a push or taxi or descent request to at least give us an idea when further clearance or instructions can be anticipated. It sure helps out at the pilot end.

As far as "being ready immediate take-off", to me it means just that. The checks are done, I'll get the thing promptly into position (runway conditions permitting) and the engines are ready to be spooled.

cossack
31st Jan 2001, 19:33
Luftwaffle
Our ATC manual states:
When given the instruction "cleared for immediate take off" it is expected that the pilot will act as follows:
(a) At the holding point, taxi immediately onto the runway and commence take off without stopping the aircraft. (Not to be given to Heavy aircraft.)
(b) If already lined up on the runway, take off without delay.

Immediate means immediate. There shouldn't be any question of how long you can take to depart immediately.

Often a normal departure turns into an immediate one because the guy lining up takes so long to get onto the runway. An average landing roll, from the time the arrival passes you to when he vacates, I would say, is about 45 seconds. It shouldn't be too much to ask that you are lined up when take off clearance is issued, rather than just crawling across the holding bar as the preceding is vacating, should it?.

I had a guy today who was raring to go. He was cleared to line up after the landing at full length with a lighter type lining up further down to depart ahead of him. Before the arrival had passed him he says "Can we have the stop bar down?" I'm all for a bit of expedition but this was going a bit far!

To answer the question you posed: Yes I would prefer you to say no if unable to accept an immediate, but would qualify it by saying don't turn every departure into an immediate by dawdling onto the runway.

When operating in mixed-mode (arrivals and departures on the same runway) I judge the arrival gap to give a time interval between the arrivals to allow a departure and permit landing clearance usually by about 200 feet.

In segregated mode (departure and arrival only runways) you should be ready to go as soon as the one ahead is airborne.

You find that at "quieter" airports pilots take longer than if they were at one of the busy airports because they don't see the need to get on with it.

I'll stop now, I'm turning into cossackwaffle!!!

(typos)



[This message has been edited by cossack (edited 31 January 2001).]