B737NG F/D's on Initial Climb Out.
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Secondly, the received wisdom is that the pitch attitude is not to exceed 20 degrees NU. The reason for this is to give you a decent opportunity to get the nose down without rapid speed loss if an engine fails and also to allow for wind sheer - it has nothing to do with comfort levels. Going beyond 20 degrees is needless and most companies' OFDM systems would be pinging off. I certainly wouldn't be happy with a colleague who did it without very good reason. Pitching higher sounds like show boating to me.
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Quote: "Fourth, any pilot that blindly follows the FD without "looking through" it to verify against the performance data that suitable attitudes are being commanded is a fool. FDs are very useful but not infallible and they are reactive, not pre-emptive." Unquote.
We are talking about subtle differences hopefully, a few degrees at most. Now, if you want to compare them with the available performance data in Vol.1 during your take off, I wish you and the airline good luck.
We are talking about subtle differences hopefully, a few degrees at most. Now, if you want to compare them with the available performance data in Vol.1 during your take off, I wish you and the airline good luck.
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Originally Posted by centaurus
"Looking through" the flight director presentation is quite difficult...
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Flyboyike:
Trust you apply a QNH correction as well.
After all, putting the correct pitch and getting the targeted lift, to obtain the required climb gradient, is WAT related.
Me, I take the liberty not to do that. And it works fine since many years.
Trust you apply a QNH correction as well.
After all, putting the correct pitch and getting the targeted lift, to obtain the required climb gradient, is WAT related.
Me, I take the liberty not to do that. And it works fine since many years.
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Secondly, the received wisdom is that the pitch attitude is not to exceed 20 degrees NU. The reason for this is to give you a decent opportunity to get the nose down without rapid speed loss if an engine fails and also to allow for wind sheer - it has nothing to do with comfort levels. Going beyond 20 degrees is needless and most companies' OFDM systems would be pinging off. I certainly wouldn't be happy with a colleague who did it without very good reason. Pitching higher sounds like show boating to me.
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You can recover from that far nose up, but the recovery will be bigger and need more time and potentially more altitude, commodities you may not have just after take off. Granted, the margins between stalling attitude and commanded attitude may be similar for a FD command of 18o when heavy and 25o when light, but you don't need to be pushing the aircraft close to its performance capability when light, and you're increasing the chance of triggering TCAS, so why do it when 20o will give all the performance and more than you need?
Centaurus, I both agree and disagree (mildly) with you.
I agree that FDs are not infallible, and that they have led, along with FMCs and other automation, to a loss of basic SA and flying skills. I only disagree that they're hard to look through - as long as the rest of the instrument scan is maintained to corroborate and anticipate the FD commands, then I think it's not a difficult thing to do. Shame so many blindly follow them, failing in the rest of their scan.
Centaurus, I both agree and disagree (mildly) with you.
I agree that FDs are not infallible, and that they have led, along with FMCs and other automation, to a loss of basic SA and flying skills. I only disagree that they're hard to look through - as long as the rest of the instrument scan is maintained to corroborate and anticipate the FD commands, then I think it's not a difficult thing to do. Shame so many blindly follow them, failing in the rest of their scan.
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Aluminium Shuffler:
There is no such thing as a stalling attitude. A stall is only related to AOA.
How you guess your rate of climb is adequate, with a lower pitch, ignoring now all your take off data?
You are really worried about a TCAS warning during TO due excess closer rate with a target above?
There is no such thing as a stalling attitude. A stall is only related to AOA.
How you guess your rate of climb is adequate, with a lower pitch, ignoring now all your take off data?
You are really worried about a TCAS warning during TO due excess closer rate with a target above?
Originally Posted by Latetonite
How you guess your rate of climb is adequate, with a lower pitch, ignoring now all your take off data?
My FCOM limits pitch to 20°; speed is to be allowed to increase if 20° is reached while (trying to) maintaining V2+20.
Call me a Luddite, but I treat the flight director the same way I treat most computing devices. If they don't give me what I want - as in 'right bloody now' - I turn the poxy things off, give them a bit of time to review the error of their ways, and then - being the forgiving type that I am - allow them another chance to satisfy my desires.
Somewhere in the recesses of my training I recall reading, or being told, that when the flight director or any other automatic goodie is not giving you what you want, deselect it. It is actually easier to fly attitude and heading than to mentally filter out unwanted information such as excessive pitch up demands or bank angles greater or less than needed to do the job.
As for whether pitch attitude being flown is producing the required climb gradient, surely the old rate of climb over groundspeed formula can be computed mentally by most. All the info you need is right in front of you on the panel (unless you are flying a DC3 with no GPS, and how likely is that?). Or don't pilots do this basic stuff nowadays?
Like Greed, Easy is Good.
Somewhere in the recesses of my training I recall reading, or being told, that when the flight director or any other automatic goodie is not giving you what you want, deselect it. It is actually easier to fly attitude and heading than to mentally filter out unwanted information such as excessive pitch up demands or bank angles greater or less than needed to do the job.
As for whether pitch attitude being flown is producing the required climb gradient, surely the old rate of climb over groundspeed formula can be computed mentally by most. All the info you need is right in front of you on the panel (unless you are flying a DC3 with no GPS, and how likely is that?). Or don't pilots do this basic stuff nowadays?
Like Greed, Easy is Good.
Last edited by Mach E Avelli; 4th Jan 2014 at 02:16.
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C'mon Masher, do you actually know what performance you need to achieve on your departures and how that relates to the actual performance during your greater-than-20° pitch attitude takeoff?
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Probably not practical with a low leveling off altitude, but in that case one use CLB 2 anyway, which gives a low climb rate. However in many areas of the world unrestricted climbs are possible and there is nothing wrong with a 5000+fpm climbout. In fact it saves a lot of fuel without any negative sideeffect.