Flap retraction
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I didn't read it, but would bet my last dollar that one is gonna make less noise for less time climbing with less flap. For the purpose of this argument though, who gives a fcuk about the noise when you are climbing out on one engine? Noise will be the last thing on my mind, so could we get back to the topic in hand?
Seems to me that nobody has come up with a good argument to disprove Tommie's theory.... yet. It's all very well stating that it's not possible to define precisely the gradient he might make using early flap retraction, but if it is the case that the gradient will be better is that not enough to make his case?
Seems to me that nobody has come up with a good argument to disprove Tommie's theory.... yet. It's all very well stating that it's not possible to define precisely the gradient he might make using early flap retraction, but if it is the case that the gradient will be better is that not enough to make his case?
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I didn't read it, but would bet my last dollar that one is gonna make less noise for less time climbing with less flap.
For the purpose of this argument though, who gives a fcuk about the noise when you are climbing out on one engine?
but if it is the case that the gradient will be better is that not enough to make his case?
But all this also begs the question of what is the rush? Why are you so keen to have hands flashing around the cockpit close to the ground?
Personally I think the most immediate action is making sure the coffee maker is on..
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Tom,Why don't you explain to me what I am missing?V2 gives you a better climb gradient then V2+20V2 with flaps take off gives you an even better climb gradient.Retracting flaps means you started the third segmenet...pushing the nose over for a faster speed, a level off...something you might not want to do whilst trying to get over the hills...get it?I will assume that you fly in the real world with real hills to smash into...so explain to me why on a climb gradient restricted SID in the soup you would retract the flaps and push the nose OVER if the whole point of the exercise is to get over the obstacles?That makes sense right? I am all ears.
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BizJetJock;
If that's what it states, then okay, I'll eat the humble pie and accept it. I don't have the time or inclination to read about noise abatement, and as non CAT, I don't give a fcuk about it either; I've never been busted for noise, but that is not the topic in hand.
Guys, I am prepared to learn here if that's what's needed, but so far nobody here is doing the teaching. Most are happy to quote "it aint in the AFM, so therefore it can't be right," but the fact remains that in the Hawker (which many of you have been quoting), the 900 does, under ALL conditions, provide a better OEI climb gradient with flaps retracted than it does with flap 15. All day long, and day, any WAT.
Unless one is runway length limited, any Hawker driver will, as a matter of course, choose to take off with zero flap. Why? Does it have anything to do with second segment? Er ...yes it does!!
Taking this just one step further. If you are runway length limited, what reason is there for NOT getting shot of the flaps at the earliest possible opportunity (provided all engines are operating) when by doing so you know know that your climb gradient is suddenly improved should an engine quit?
Now, on the other hand let's consider the engine failure, with take off flap selected, just after V1. This is an entirely different scenario, and in such a circumstance there is a very good reason why one should NOT retract the flaps too soon. It's not to do with the fact that you won't better the gradient with flaps retracted, but rather the reason is to do with the reduction in climb gradient while you accelerate to a speed that provides the margin for flap retraction.
As stated at the beginning I am prepared to learn if I have got it all wrong, but please if you want to teach please add some meat and gravy to your argument rather than amplifying the " it anit in the AFM, so therefore it can't be right."
If I hit V2 +20 with all engines operating, and it arrives before VFTO, please tell me why I should NOT retract the flaps in the knowledge that, in my aircraft, under any conditions, doing so will improve my climb gradient should en engine quit? Please teach me.
Enjoy your life of destitution... it concludes that climbing at a lower speed with flap is quieter than a higher speed clean.
Guys, I am prepared to learn here if that's what's needed, but so far nobody here is doing the teaching. Most are happy to quote "it aint in the AFM, so therefore it can't be right," but the fact remains that in the Hawker (which many of you have been quoting), the 900 does, under ALL conditions, provide a better OEI climb gradient with flaps retracted than it does with flap 15. All day long, and day, any WAT.
Unless one is runway length limited, any Hawker driver will, as a matter of course, choose to take off with zero flap. Why? Does it have anything to do with second segment? Er ...yes it does!!
Taking this just one step further. If you are runway length limited, what reason is there for NOT getting shot of the flaps at the earliest possible opportunity (provided all engines are operating) when by doing so you know know that your climb gradient is suddenly improved should an engine quit?
Now, on the other hand let's consider the engine failure, with take off flap selected, just after V1. This is an entirely different scenario, and in such a circumstance there is a very good reason why one should NOT retract the flaps too soon. It's not to do with the fact that you won't better the gradient with flaps retracted, but rather the reason is to do with the reduction in climb gradient while you accelerate to a speed that provides the margin for flap retraction.
As stated at the beginning I am prepared to learn if I have got it all wrong, but please if you want to teach please add some meat and gravy to your argument rather than amplifying the " it anit in the AFM, so therefore it can't be right."
If I hit V2 +20 with all engines operating, and it arrives before VFTO, please tell me why I should NOT retract the flaps in the knowledge that, in my aircraft, under any conditions, doing so will improve my climb gradient should en engine quit? Please teach me.
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V2 gives you a better climb gradient then V2+20
Retracting flaps means you started the third segmenet...pushing the nose over for a faster speed, a level off...something you might not want to do whilst trying to get over the hills...get it?I
As the Hawker appears to have 0 flap performance tables, is there any reason why he can't do what he wants in THAT aircraft.
For me, the lack of 0 flap performance information limits what we can do, we have no data to back up the theory that we will get a better gradient with 0 flaps and the appropriate speed and can guarantee obstacle clearance. We also have an issue with the higher speed increasing the takeoff path and possibly encompassing more limiting obstacles.
Noise, not rushing the configuration change, standard sop's across fleets, liability, are all external issues.
Mutt
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when you retract the flaps and level off
Mutt
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Tom, you came into this saying that you wanted to use Speed as the trigger for Flap Retraction rather than Height, we argued that you couldnt due to the acceleration portion of the takeoff and the height to initiate this acceleration. You are fixated on 400 feet an 1500 feet, but in reality we can use any altitude with the thrust limits.
Gross
Gross Track Gross X Lateral Gross
Distance Distance Offset Height
FEET FEET FEET FEET
-------- -------- -------- --------
Screen Height 7443 7443 0 35
Gear-Up 11320 11320 0 173
Level-Off 100000 100000 0 3175
Start Final Climb 136643 136643 0 3175
Or
Screen Height 6551 6551 0 35
Gear-Up 10565 10565 0 245
Level-Off 59064 59064 0 2855
Start Final Climb 82945 82945 0 2855
Both of these are clearing the same distant obstacle. So for aircraft like these, the only way that you can ensure that you will clear obstacles is by following the specifed flight path, you must use an altitude for flap retraction/acceleration and not a speed.
So to end, you have 0 flap performance data in the Hawker, so you can accelerate in the climb and retract the flaps. But for a lot of other aircraft that need to accelerate more than the Hawker does, then you cannot use a speed reference for Flap Retraction/Acceleration.
Mutt
Gross
Gross Track Gross X Lateral Gross
Distance Distance Offset Height
FEET FEET FEET FEET
-------- -------- -------- --------
Screen Height 7443 7443 0 35
Gear-Up 11320 11320 0 173
Level-Off 100000 100000 0 3175
Start Final Climb 136643 136643 0 3175
Or
Screen Height 6551 6551 0 35
Gear-Up 10565 10565 0 245
Level-Off 59064 59064 0 2855
Start Final Climb 82945 82945 0 2855
Both of these are clearing the same distant obstacle. So for aircraft like these, the only way that you can ensure that you will clear obstacles is by following the specifed flight path, you must use an altitude for flap retraction/acceleration and not a speed.
So to end, you have 0 flap performance data in the Hawker, so you can accelerate in the climb and retract the flaps. But for a lot of other aircraft that need to accelerate more than the Hawker does, then you cannot use a speed reference for Flap Retraction/Acceleration.
Mutt
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I've never been busted for noise,
What a stupid attitude..
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Noise, not rushing the configuration change, standard sop's across fleets, liability, are all external issues.
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Hello again all
Make yourself a coffee and read this properly - have a biscuit on me..
The reason you will clear obstacles is that you are always above the gradient required to clear them. (before you stop reading and just bang out another post, just hear me out).
I will ignore all the benefits which you can't account for because either you don't have the data or we do but currently don't account for it.
I am not suggesting for a moment that anything at all changes in terms of planning. We have to plan for a failure at any stage, obviously, so lets all be absolutely clear that in the event of a failure from V1 up to flap retraction, nothing changes. So lets just think a little more about that case? What is the reason we don't retract the flaps at a lower height in the event of a failure at V1? The reason is we don't have the performance to climb at the calculated gradient AND accelerate at the same time. So we plan to accelerate at a known height and accelerate there. The only point of this acceleration is to raise the flaps. What is the point of raising the flaps? If we can achieve a better gradient with the flap at the take off setting, what would be the point in raising the flap? Why would we not continue climbing at V2 with the flaps set at take off? If the aircraft does not produce much drag, why is it so important to remain in that rather narrow band (V2 to approx V2+10 or maybe a bit more) with the flap at the take off setting in order to achieve the stated gradient?
The reason we accelerate raise the flap at 1500 feet in the event of an engine failure at V1 is to improve the climb rate and for many aircraft 1500 feet is the certified platform at which we do this. It is desirable to raise the flap not only because it improves the gradient and also the rate of climb but the aircraft is also easier to fly.
So here's the thing. If you don't agree that the aircraft climbs better and is easier to fly, what is your justification for raising the flap at 1500 feet? Do you do it only because thats what the manufacturer says or because thats what the bloke that taught you perf A says you should do? If so, noddy pilot, need to think more. Consider how much easier the aircraft is to trim, how much less rudder you need because you've moved the centre of lift, how much more effective the fin is, and how (because its easier to fly) the auto-pilot will now manipulate the controls effectively enough for you to deal with the screaming captain who's just wet himself and can start working the problem.
Does everyone agree that raising the flap at 1500 feet in the event of a failure at V1 has benefits? Or does anyone think the aircraft performs better with the flap down? If anyone thinks the aircraft will continue to climb better with the flap down then you need to lobby the manufacturer and your company to change your OEI V1 procedures to leave the flap down.
Right..
Now lets think about what the 1500 feet is for. It is absolutely not a flap retraction height. It is a level platform which you can use and plan for which will allow you to accelerate and ONLY IF YOU ACHIEVE THE SPEED raise the flap. I'm just going to reiterate that point for sillypeople. You don't raise the flap because you achieve a height. You only retract the flap because you achieve a speed.
Does anyone disagree with that?
So hopefully we have all got to three agreed points so far.
1 - the aircraft climbs and performs better if you retract the flap otherwise you are certifiably insane for raising the flap at 1500 feet.
2 - the 1500 foot platform is for accelerating not for retracting the flap.
3 - we only retract the flaps because we have achieved the correct speed.
The gradient clean is normally called the final segment gradient and should be in all AFM's because you use it to complete a climb to 1500 feet in the event that you run out of time with the remaining engine at max thrust and have to reduce to max continuous. You also can use it to determine reduced acceleration altitude procedures which will enable you to clear distant obstacles which you may otherwise hit. This is all basic perf A and there was always a question in the PerfA exam which was to do with the maximum take off weight you could go with and it was a sneaky trick question because you could take slightly more if you reduced the AA. Nobody ever bothered to work out the answer to this question - it was the slightly higher of the two close weights...
Lets get back to the original question - am I nuts to suggest that we can do what the men that build the plane say and raise the flaps at V2+x. Once we have accelerated to V2+x we have achieved part of the purpose of the level (third) segment and we have attained the speed at which we can retract the flaps. Tremendous! Now, as agreed above, we can trend the aircraft from the slightly poorer gradient that we have with the take off flap to the better gradient achieved clean. You cannot disagree with that statement because if you do you have to leave the flap down at 1500 feet and come up with a good reason to raise them at all.
What happens if the engine fails just as we flick the switch, move the lever, that makes the flaps travel? It doesn't matter - we are already at the speed we need to make the thing climb at the better gradient so all the time the flaps are travelling the gradient is actually getting slightly better. There is a feeling that we are sinking because we have to change the angle of attack but in reality, as long as the speed remains at V2+20, the gradient will remain as good or better than we had with the flaps at take off. Again, if you don't agree with this, don't raise the flaps at 1500 feet as you will obviously not climb so well.
Ok so now we have all agreed, without using any of the extra factors like shorter take off roll than a failure at V1 or take off climb increment because we need the gradient from the end of the runway not our take off point, or the improved climb to wherever the failure actually occured at V2+20, that we have achieved at the very least the same gradient that we would have had in the event of a failure at V1.
By the way, I haven't forgotten what the rest of the job of the 1500 foot acceleration altitude is for - to accelerate to Venr. At the enroute climb speed you will definitely get a better rate of climb than at V2+20 but now your forward speed is greater so the gradient may be less. If you need the gradient for distant obstacle clearance you can continue the climb at V2+20 clean (extended final segment) at max continuous rather than max thrust. This is why final segment climbs are quoted at max continuous (OEI). This is also why we will always exceed the final segment climbs when we use them at low level (ie when we look at the gradient following a failure at V2+20 we will exceed the quoted gradient because we can still have the engine at max thrust rather than max continuous). This is another bonus that we can't quantify but is good to have in your back pocket.
So now we can be sure that at the very worst we will achieve the same climb gradient that we would have achieved if the engine failed at V1. Not a guess - absolutely certain because its in the manuals as I posted. If you don't think its in your manual I'm happy to have a look at the manual but bear in mind that the manufacturer would not certify the aircraft to have the flaps retracted at V2+x unless it were true. There would be big bold letters saying "you have to achieve this height, you have to reduce speed in the event of a failure to V2" blah blah blah and we've already seen from lots of other posts that no manual says that (except perhaps Coughs in his airliner and I completely agree that if it says it in the manual then that's what you do).
(dammit, lost my thread, had to read Hairy Maclary to my daughter)
oh yes. The AFM - the one published which was written by the people that certified the aircraft - doesn't say that. I think its a good plan to do what it actually says. All the benefits are on our side should the worst happen if we do what it says.
Tom
ps.. not facilitation learning because the audience is far too hostile and unwilling to consider an alternative idea. This is called primacy, and its the reason this subject needs to be taught better at an early stage.
pps.. call me odd but that paper Mutt posted is very interesting indeed. The footprint reduction calculation far exceeds what I expected. Its especially interesting that modelling techinques have advanced so much since I left uni as it wasn't possible to model turbulent flow that accurately when I was an undergraduate. This may mean we can develop a more appropriate noise technique for business jets that we can actually fly!
Make yourself a coffee and read this properly - have a biscuit on me..
The reason you will clear obstacles is that you are always above the gradient required to clear them. (before you stop reading and just bang out another post, just hear me out).
I will ignore all the benefits which you can't account for because either you don't have the data or we do but currently don't account for it.
I am not suggesting for a moment that anything at all changes in terms of planning. We have to plan for a failure at any stage, obviously, so lets all be absolutely clear that in the event of a failure from V1 up to flap retraction, nothing changes. So lets just think a little more about that case? What is the reason we don't retract the flaps at a lower height in the event of a failure at V1? The reason is we don't have the performance to climb at the calculated gradient AND accelerate at the same time. So we plan to accelerate at a known height and accelerate there. The only point of this acceleration is to raise the flaps. What is the point of raising the flaps? If we can achieve a better gradient with the flap at the take off setting, what would be the point in raising the flap? Why would we not continue climbing at V2 with the flaps set at take off? If the aircraft does not produce much drag, why is it so important to remain in that rather narrow band (V2 to approx V2+10 or maybe a bit more) with the flap at the take off setting in order to achieve the stated gradient?
The reason we accelerate raise the flap at 1500 feet in the event of an engine failure at V1 is to improve the climb rate and for many aircraft 1500 feet is the certified platform at which we do this. It is desirable to raise the flap not only because it improves the gradient and also the rate of climb but the aircraft is also easier to fly.
So here's the thing. If you don't agree that the aircraft climbs better and is easier to fly, what is your justification for raising the flap at 1500 feet? Do you do it only because thats what the manufacturer says or because thats what the bloke that taught you perf A says you should do? If so, noddy pilot, need to think more. Consider how much easier the aircraft is to trim, how much less rudder you need because you've moved the centre of lift, how much more effective the fin is, and how (because its easier to fly) the auto-pilot will now manipulate the controls effectively enough for you to deal with the screaming captain who's just wet himself and can start working the problem.
Does everyone agree that raising the flap at 1500 feet in the event of a failure at V1 has benefits? Or does anyone think the aircraft performs better with the flap down? If anyone thinks the aircraft will continue to climb better with the flap down then you need to lobby the manufacturer and your company to change your OEI V1 procedures to leave the flap down.
Right..
Now lets think about what the 1500 feet is for. It is absolutely not a flap retraction height. It is a level platform which you can use and plan for which will allow you to accelerate and ONLY IF YOU ACHIEVE THE SPEED raise the flap. I'm just going to reiterate that point for sillypeople. You don't raise the flap because you achieve a height. You only retract the flap because you achieve a speed.
Does anyone disagree with that?
So hopefully we have all got to three agreed points so far.
1 - the aircraft climbs and performs better if you retract the flap otherwise you are certifiably insane for raising the flap at 1500 feet.
2 - the 1500 foot platform is for accelerating not for retracting the flap.
3 - we only retract the flaps because we have achieved the correct speed.
The gradient clean is normally called the final segment gradient and should be in all AFM's because you use it to complete a climb to 1500 feet in the event that you run out of time with the remaining engine at max thrust and have to reduce to max continuous. You also can use it to determine reduced acceleration altitude procedures which will enable you to clear distant obstacles which you may otherwise hit. This is all basic perf A and there was always a question in the PerfA exam which was to do with the maximum take off weight you could go with and it was a sneaky trick question because you could take slightly more if you reduced the AA. Nobody ever bothered to work out the answer to this question - it was the slightly higher of the two close weights...
Lets get back to the original question - am I nuts to suggest that we can do what the men that build the plane say and raise the flaps at V2+x. Once we have accelerated to V2+x we have achieved part of the purpose of the level (third) segment and we have attained the speed at which we can retract the flaps. Tremendous! Now, as agreed above, we can trend the aircraft from the slightly poorer gradient that we have with the take off flap to the better gradient achieved clean. You cannot disagree with that statement because if you do you have to leave the flap down at 1500 feet and come up with a good reason to raise them at all.
What happens if the engine fails just as we flick the switch, move the lever, that makes the flaps travel? It doesn't matter - we are already at the speed we need to make the thing climb at the better gradient so all the time the flaps are travelling the gradient is actually getting slightly better. There is a feeling that we are sinking because we have to change the angle of attack but in reality, as long as the speed remains at V2+20, the gradient will remain as good or better than we had with the flaps at take off. Again, if you don't agree with this, don't raise the flaps at 1500 feet as you will obviously not climb so well.
Ok so now we have all agreed, without using any of the extra factors like shorter take off roll than a failure at V1 or take off climb increment because we need the gradient from the end of the runway not our take off point, or the improved climb to wherever the failure actually occured at V2+20, that we have achieved at the very least the same gradient that we would have had in the event of a failure at V1.
By the way, I haven't forgotten what the rest of the job of the 1500 foot acceleration altitude is for - to accelerate to Venr. At the enroute climb speed you will definitely get a better rate of climb than at V2+20 but now your forward speed is greater so the gradient may be less. If you need the gradient for distant obstacle clearance you can continue the climb at V2+20 clean (extended final segment) at max continuous rather than max thrust. This is why final segment climbs are quoted at max continuous (OEI). This is also why we will always exceed the final segment climbs when we use them at low level (ie when we look at the gradient following a failure at V2+20 we will exceed the quoted gradient because we can still have the engine at max thrust rather than max continuous). This is another bonus that we can't quantify but is good to have in your back pocket.
So now we can be sure that at the very worst we will achieve the same climb gradient that we would have achieved if the engine failed at V1. Not a guess - absolutely certain because its in the manuals as I posted. If you don't think its in your manual I'm happy to have a look at the manual but bear in mind that the manufacturer would not certify the aircraft to have the flaps retracted at V2+x unless it were true. There would be big bold letters saying "you have to achieve this height, you have to reduce speed in the event of a failure to V2" blah blah blah and we've already seen from lots of other posts that no manual says that (except perhaps Coughs in his airliner and I completely agree that if it says it in the manual then that's what you do).
(dammit, lost my thread, had to read Hairy Maclary to my daughter)
oh yes. The AFM - the one published which was written by the people that certified the aircraft - doesn't say that. I think its a good plan to do what it actually says. All the benefits are on our side should the worst happen if we do what it says.
Tom
ps.. not facilitation learning because the audience is far too hostile and unwilling to consider an alternative idea. This is called primacy, and its the reason this subject needs to be taught better at an early stage.
pps.. call me odd but that paper Mutt posted is very interesting indeed. The footprint reduction calculation far exceeds what I expected. Its especially interesting that modelling techinques have advanced so much since I left uni as it wasn't possible to model turbulent flow that accurately when I was an undergraduate. This may mean we can develop a more appropriate noise technique for business jets that we can actually fly!
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For me, the lack of 0 flap performance information limits what we can do.
BizJet, the point I meant to make (but didn't type) was that if I was struggling to clear an obstacle I wouldn't give a fcuk about noise.
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I read it Tommie, but have two questions before I go out.
What actual gradient will you make with the flaps up, and what speed will you aim for depending on the WAT? And what gradient do you lose during the acceleration?
If you have the data to provide an answer, and it exceeds the numbers for climbing out on one engine with take off flap selected, I see no reason to disagree.
What actual gradient will you make with the flaps up, and what speed will you aim for depending on the WAT? And what gradient do you lose during the acceleration?
If you have the data to provide an answer, and it exceeds the numbers for climbing out on one engine with take off flap selected, I see no reason to disagree.
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I posted both of the required tables in post 274 and 285. In all cases that I've checked the final segment climb gradient meets or exceeds the 2nd segment gradient. As mentioned before, the final segment gradient is with the engine at max cont rather than max thrust which is the case for 2nd segment. So where we are only able to match the 2nd segment climb (which would be good enough anyway) we will actually substantially exceed it because for the remainer of the time available we will remain at max thrust.
There is no acceleration (in the event of an engine failure at V2+20) - we are already at V2+20 so don't need any acceleration. All we need to do is keep that speed - while the flaps travel the gradient will change from the flapped to the clean gradient. We do not accelerate. We still have the 1500 foot level acceleration platform available to accelerate from V2+20 to Venr so that we can establish in the enroute climb when necessary.
That acceleration phase in the level segment will be shorter than in the calculate scenario where the engine failed at V1. So our obstacle clearance calculations are still valid.
In all cases we outperform the critical failure at V1 case. Thats without counting all the other factors which are actually in our favour.
There is no acceleration (in the event of an engine failure at V2+20) - we are already at V2+20 so don't need any acceleration. All we need to do is keep that speed - while the flaps travel the gradient will change from the flapped to the clean gradient. We do not accelerate. We still have the 1500 foot level acceleration platform available to accelerate from V2+20 to Venr so that we can establish in the enroute climb when necessary.
That acceleration phase in the level segment will be shorter than in the calculate scenario where the engine failed at V1. So our obstacle clearance calculations are still valid.
In all cases we outperform the critical failure at V1 case. Thats without counting all the other factors which are actually in our favour.
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Wrong wrong wrong wrong, what does it say in the top left of the chart that you posted, did it say this chart includes loss of climb gradient from V2 to flap retract to final Single Engine climb speed? Keep it short man. X factor starts soon.
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right right right... we don't even commence the flap retraction until we achieve V2+20. So no acceleration, no loss of gradient.
X-factor? have some self respect man..
X-factor? have some self respect man..
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Tom, I have never flown an aircraft where flap retract and single engine climb speed have been the same, hand on heart I have not flown the 601 so that's where my confusion must of come from.
I am out of time, really sorry, maybe we can continue later, I don't know why this is getting me so involved as since I left the airlines I have turned into a proper cowboy with regard to stuff like this!
Have a good weekend.
I am out of time, really sorry, maybe we can continue later, I don't know why this is getting me so involved as since I left the airlines I have turned into a proper cowboy with regard to stuff like this!
Have a good weekend.
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as per the posts before, V2+20 is the speed for the final segment climbs. At acceleration altitude I would accelerate to Venr (190 kts) and climb away at that unless a distant obstacle calculation prevented it.
So in the event of a failure at V2+20, yes I would hold that speed. If they both keep going I would keep accelerating to cruise climb, 250 kts and climb away at that. Actually, thats not quite true, I've been doing a load of maths and would climb away at my most fuel efficient speed but thats another story that I'm messing about with. And I don't fly enough to prove if thats right so I'm not going to mention it..
DOH!
So in the event of a failure at V2+20, yes I would hold that speed. If they both keep going I would keep accelerating to cruise climb, 250 kts and climb away at that. Actually, thats not quite true, I've been doing a load of maths and would climb away at my most fuel efficient speed but thats another story that I'm messing about with. And I don't fly enough to prove if thats right so I'm not going to mention it..
DOH!