sorry, obviously got the wrong bloke. You're quite clearly Doug NeidaLessonInAircraftPerformance.

And, now your comments are just getting downright rude, in fact your behaviour reflects that of many previous reincarnations of SSG.

So I think that we have flogged this horse to death........

Mutt

Last point first, I've had people put me up for a Darwin award, say I haven't got a clue what I'm doing, say I am guilty of making up procedures which are not in the AFM, accuse me of being a bar room pilot, and send me messages in private which are not pleasant. Paul (Doug) is someone I have known for a long time - I worked with him at a previous company and he knows that when he pokes at stick at me I'll poke back because its fun.

[1]You still haven't published a speed chart.
I will as soon as possible.
[2]You haven't come back with examples at the higher elevations or higher temperatures. I'll work through any example you like. Send me a scenario.
[3]You have clearly forgotten that some aircraft need to accelerate before they climb, look at the figures you were given by His Dudeness and someone else posted figures for the B737.
[4] No I haven't. You take the flaps at V2+x wherever that may be. For many bigger aircraft (A340 for instance) that may well take quite a while but once at the speed, you raise the flap.

You are fixated that there are only two heights involved in this process, 400 and 1500 feet.
There are no heights in relation to raising the flap. There are only speeds. If you need a level platform to attain the speed in the event of an engine failure for instance then you can use any platform for which you can calculate the resultant climbs.

[5]Your haven't mentioned obstacle clearance anywhere in your comments.
[6] Because its a total red herring. If you have a particularly close in obstacle which affected your climb predicated on an engine failure at V1 you will be above it very quickly. Any obstacle which you will clear with an engine failure at V1 and take off flap you will clear if you are all engines operating to V2+20 then climb clean. Thats exactly what the chart I posted shows you.

[7]
You haven't received any response from FSI, who you have accused of teaching people incorrectly.
Verbally they have told me that it is a Flight Safety SOP, nothing more. They are very unlikely to say anything more than that to me as I am a CAE customer.

I've had someone accept the bet which is great, and posted the climb charts.
I will put the speed chart up as soon as I can - probably when my kid is asleep.

There are heights when the manufacturer specifies them in the AFM. You don't mess with this stuff. Both types of commercial jet I have flown specify it for the reasons given in my first two replies. Not for reasons of pure numbers on a chart.

Scares me.

http://myaccount.dropsend.com/file/3e0e7c7fcf8cbc20

Final segment climb speed.

Thats all the data posted which proves your net climb gradients clean when you take flaps up at V2+20.

Would you like any more data?

Send me any scenarios you wish run that you think change the manufacturers AFM.

Fact is, what most people do is not in the AFM and what I have suggested to you is exactly what the people that make the planes want us to do. There is a clear divide here - somewhere along the line the message has become confused and we no longer deal with any engine failure case other than the one that is most critical. It is correct that we plan for that but it is not correct to then degrade the flight path performance of the aircraft by not doing what the manufacturers say.

Almost all of us - me included until recently - have been doing it wrong because we have been taught badly.

Cough..

Its great that its in the commercial type you previously flew - which type was it?

An all engines flap retraction height is not in the Challenger manual, its not in the XLS manual, its not in the Lineage manual, its not in the Phenom manual, its not in the Citationjet manual, its not in the Hawker 125 series manual, and I don't understand what scares you. I've never seen an all engines flap retraction height in any flight manual ever. I've never seen a flap retraction height at all - only acceleration altitudes. If you don't need the level platform then no platform exists.

The obstacle clearance is irrelevent to the arguement because the take off performance calculation is exactly the same - the obstacle clearance and net take off flight path calculation is based on OEI at V1 so nothing has changed. What I think is misunderstood is the effect of retracting the flaps as per the manufacturers AFM and performance data. In fact, I'll go further. If you don't do it the way the manufacturer says, you are on unknown ground. What type do you fly and what departure profile do you use for a noise abatement and non noise departure? Lets see how compliant it is.

Explain exactly what scares you. I do the same perf calcs as anyone else - almost certainly a lot more as I cross check the FGP data. I then fly the aircraft as the flight manual states. Does it scare you that I don't simply copy what I learned on an airliner and apply it to a business jet? Does it scare you that I'm doing exactly what it says in the manual?

I've kind of had enough of tribal knowledge ruling this thread. Post the legislation that imposes a flap retraction height in the case of an all engines operating take off. Post the data which shows a flap retraction height as opposed to an acceleration altitude exists at all. Post any AFM procedure which states that exceeding V2 by 30, 40, 50 knots is acceptable practice and has no effect on aircraft performance. You need 1.25 V2 to have the flaps retracted on a challenger - thats what the speed to fly table gives you. Thats not even V2+20 so at V2+20 you have plenty of handling margin and thats probably why the speed was chosen. What you definitely dont have is any idea how much you have degraded the flight path by if you dont raise the flap.

bizarre that you all think this is sensible but don't have any data or any statements in the AFM that show it!

Cough.

Post the section of your AFM that discusses an all engines operating flap retraction height. I've had a bet accepted for a thousand pounds that data did not exist for a clean climb below 400 feet and I've posted it. From the AFM. I'll directly issue a double or quits to you if you like that what you do on a normal departure does not come from your AFM. I'm going to suggest it comes from Flight Safety.

Are you up for the double or quits? Are you sure what you are doing is what the people who built the plane think you're doing and that I'm nuts?

If so, bets on.

by the way, saying I'm up for a Darwin award and I make stuff up when it comes straight out of the manual is offensive.

The bets still open to anyone else who wants to take it.

On the 737 and with the way our performance is set up any obstacle and engine failure between V1 and passing MSA is considered. To be safe during that time we have to stick to the calculated flap schedule which is based on heights. V2 + 20 can be up to 50kts below minimum clean speed, so pitching down to accelerate those 50kts upon reaching V2 +20 will immediately invalidate any obstacle clearance (not to mention any required NADP). The furthest obstacle considered I've seen was around 30NM from the departure end of he runway, our EFB tells us something like that just for information. Acceleration heights are usually different for all engines operating and one engine out, both have to be filled into the Take Off Ref page 2 during preflight, same as the thrust reduction height.

Tom, you're getting increasingly strident on here and all you're doing is proving the old adage that a little knowledge is a dangerous thing.

You keep banging on about one graph in the AFM as if that were the only factor, when I and others have pointed out to you that several other things, not least EU-OPS, are the driving factors.

To give a couple of similar examples:
1. According to the AFM I can join the visual circuit at Oxford at 300 knots; you know perfectly well, though, that the Rules of the Air limit us to 250 below 10k and that for practical reasons of preparing for the final approach and fitting in with other traffic we want to be back nearer 150knots and configured appropriately. By your logic I should go for the higher speed clean and damn the rules and other airspace users.
2. Where in the AFM does it say that I can't land in 100m RVR? By your logic because it doesn't say it in the AFM I can go ahead and do that if I want.

The reason why EU-OPS and every equivalent regulation round the world says you must follow your Part B procedures is precisely to stop people who've read one bit of information in isolation coming up with their own hare-brained procedures. And once again, you must follow your Part B; it's not a case of " maybe if I feel like agreeeing with it I'll do it". If you think your Part B isn't correct, then raise a fuss with your company until they either explain why it's written the way it is or change it if in fact your point is correct.

And finally, again this has been written before but you choose to ignore it because it doesn't fit your little theory, the heights mentioned in some AFM's and many SOP's are not retraction heights; they are acceleration heights, except that normally on two engines in high performance bizjets you are already above the minimum retraction speed when you get there. Just because many people refer to them incorrectly due to poor training does not invalidate the procedure.

Tom,
I think that BizJetJock has highlighted an important issue. We, as commercial pilots, are bound by several parameters: firstly, what the AFM says that the aircraft is capable of, secondly what the Regulating Authority says is legal, and thirdly what the AOC of your particular company has decided to do (potentially more restrictive than the other two).
Rightly or wrongly, we are bound by the AOC, which is an evolving document and should, with time, address any anomalies that might occur. On the Hawker in my operation, the Authority, the AFM and the AOC allow either flap 0 or flap15 take-offs. The AFM publishes second segment climb profiles for both and under certain circumstances we get a better rate and gradient using flap 0. However, the AFM doesn't publish a profile for a combination of flap 0 and flap 15 to 1500', therefore we have to use one or the other.
The practical advantage of flying flap 15 to 1500' with both engines operating is that the aircraft is already configured such that it will give a known climb gradient if one engine fails at any point between V1 and 1500' agl provided that climb power is set on the operating engine and the aircraft is pitched to climb at V2. Of course, with two engines operating we will follow the SID which, unless stated otherwise, has a Terps climb gradient requirement of 300' per nm or so to clear obstacles (or 900'pm at 180 kts).
Therefore, all you need to do with a fully functioning aircraft is to climb at a sensible speed and adjust rate of climb with power such that you at least achieve the required SID climb gradient. If an engine fails before 1500', apply climb power and pitch for V2. However, if your AOC says that you must leave climb power set until 1500' regardless of how many engines are operating just in case one fails and you forget to apply climb power to the live one then you have another set of problems to contend with, particularly on a cold day out of Farnborough with an initial level-off at 2200 agl !
Of course, without an AOC, operators are only bound by the law and the AFM. It is often the ambiguous wording of AOCs that causes pilots to fly illogical procedures and these anomalies should be highlighted to the Operator for possible amendment.

AP

Tom,

We have the same profile for both my types, the 737 and 320. In both types the profile is the same, around v2-v2+20 until minimum 400' (Though our thrust reduction alt is higher) then select climb thrust and accelerate. If we are using full thrust on departure, or given a positive windshear then I will pitch to maintain a stable climb speed within those values. Gin and tonic isn't served on take off.

The 400' reference is found the the QRH for the all engines running, normal takeoff profile for both airbus and Boeing.

As for the noise profiles, we comply with them as written.

evening Cough

Thats exactly in accordance with what I've been trying to raise as you are flying to the speeds suggested in the AFM. What I'm trying to raise is the fact that the majority of business jet pilots will routinely exceed the flap up speed by 30, 40, 50 knots, sometimes even more, because they believe there is a mandated flap retraction height. If a particular manufacturer has imposed one (I've seen it in the Boeing training guide for the 737 and 757 and many 737 operators impose an MFRA of 1000 feet) then thats fine and you have to comply with it but nobody should make the mistake of believing that its in EU-OPS or EASA (my knowledge of EU-OPS is pretty good, my knowledge of EASA is not so good) until a reference is found. I cannot find one, I have asked many times if any pilots can quote one.

thanks for your input - haven't flown airliners and its interesting that this difference exists.

400 feet is not mentioned in the AFM of any type flown by my company. I'm not at all sure that it is best practice - I think its tribal knowledge and promulgated by training organisations on types for which its not appropriate. Its a bad place for to use as a trigger for retracting the flaps precisely because its a common place for things to start happening - turning on a SID for instance, or getting told on the radio to contact another frequency. A height check is just not logical for moving flaps - the wing configuration is only dependent on speed so what is the logic? Its utter rubbish to say "you might move the wrong lever" otherwise it would be mandated that you leave the gear down and you can't go around under 400 feet. You degrade the climb performance of the aircraft in both the all engines operating and one engine inoperative conditions if you fail to retract the flaps once you are through the retraction speed (otherwise what is the logic in retracting them at all?).

The chap with the Hawker has the data - compare a typical take off with flap and without. Look at the OEI net take off climb chart for the same conditions. Which has the better gradient? If its clean, take off clean. If you cant take off clean because of runway limitations, why don't you raise the flap at V2+10 and benefit from the improved climb gradient at that point? What is the logic of climbing against drag? As soon as the flaps start to travel the aircraft is trending from the net gradient flapped to the net gradient clean so what stops you doing it? I'm getting a Hawker manual from a colleague today so I can see if its true that Hawker mandate that you can't do this in the AFM.

The argument about needing "maneuvering margin" when clean is also bogus. The minimum clean wing speed on a Challenger is 1.25Vs. At low weights this is V2+4, at high weights its V2+7. However, the manufacturer says flaps up at V2+20 - the margin is already there which is why they set that speed.

So far nobody has posted a regulation and nobody has posted an AFM reference which states this (I take Cough's comments on the Boeing and the Airbus because I have seen 400 feet and 1000 feet referred to in training notes but I very much doubt any operator of an airliner would exceed the minimum flap retraction speeds by 20 to 50 knots in the way that business jets routinely do).

Please, somebody, post the rule which prevents the flap retraction before 400 feet and, failing that, the section of the AFM which prevents the flap retraction during an all engines operating take off when passing V2+X. If that bit is hard to find, please explain why we bother to take the flaps up at 1500 feet if the climb is better with flap?

ta

Several people have posted references to regulations, but since you don't want to listen to anything that doesn't fit your idea, you just ignore them. Not so much confirmation bias as confirmation bigotry.:ugh:

they quoted a section of FAR25 without quoting the conditions one of which is a failure of the critical powerplant at V1. How is this relevant if you have planned for that failure but actually achieved V2+X and are climbing with all engines operating to that point?

Let me stress again because some people seem to be concerned that the planning changes. The planning remains performance group A - nothing has changed. In the event of a failure of a powerplant at any stage the actual flight path exceeds that of the net take off path calculated (as shown by the two charts I posted).

What I've been suggesting is that we follow the AFM. What most pilots are doing is making up procedures which rely on falling back to the most degraded flight path possible and I have no idea why they are not following the manufacturers guidelines. I'm being accused of making up procedures - the opposite is true. I'm suggesting that we read the AFM properly and do exactly what it says rather than come up with utter rubbish like climbing against drag to control the speed, delaying flap retraction so that theres "handling margin" and all these other bogus arguments which would be in the flight manual if they were true.

If you are going to quote regulations you have to understand them. FAR25 is for certification and nothing I've said changes what you do if an engine fails at V1. But the lack of aerodynamic understanding and made up rules that people are applying simply because they have never even considered failures at other points in the climb is astonishing. Where have you got your procedures for an engine failure at 500 feet with V2+50 and take off flap set? It simply doesn't exist! Its nowhere and you made it up! More likely, someone else made it up and you and others follow it blindly without thinking about it. What is the problem with following the AFM? I simply don't understand what the argument is against doing this.

If its in the AFM then fine (cough and his 737 and 320, its very good that he's read it and knows its in there) but is isnt in the AFM for the types I have flown or written manuals for. Is it actually in the AFM for your aircraft or do you just think it is?

ballyeck 297 posts including mine - on flap retraction, Im with poster number 10 of referring to handling the big jets from a bygone era but still very relevant . Im pragmatic anything less than 400ft its a bit early (which is all the fuss is about I think?) and unless your doing the NAPD 1 or 2 then if there not up by 1500ft tell me otherwise I may think you've forgotten them anyway I don't loose too much sleep I'll stick with the phrase 'height and speed good' before I my hand on the lever. 400,500, 1000, 1300 1500, 3000ft. Whatever I dont loose to much sleep ; I follow whatever SOP provided has its been said many many times so long as its in the AFM

1st prize if this makes 300 posts:E

What do you fly? Is it in the AFM? Where? Can you post it?

If you cant move the correct lever below 400 feet you can't go around at any height below that so you have to modify your part B. You have to move flap at 200 feet and the gear shortly afterwards on positive rate. How can you do that below 400 feet?

just doesn't add up