737 NG EEC alternate
Thread Starter
Join Date: Sep 2008
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737 NG EEC alternate
Hi,
The QRH states:
In my mind the thrust levers are already in a 'mid position' when cruising with 88% N1 set. I imagine it provides sufficient buffer to limits and would consider that step satisfied.
Your thoughts?
The QRH states:
2 Thrust levers (both) . . . . . Retard to mid position
This prevents exceeding thrust limits when switching to the EEC alternate mode.
This prevents exceeding thrust limits when switching to the EEC alternate mode.
Your thoughts?
Join Date: Jul 2013
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2 Thrust levers (both) . . . . . Retard to mid position
Obviously, if the throttles are already 'mid' position or lower, there would be no need to retard them.
Thread Starter
Join Date: Sep 2008
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Thanks td.
I understand that. To be more specific with my question, do you think that 88%N1 ( ie a standard cruise setting) is 'mid' enough to prevent any excedance being possible.
Personally I do, but I know of others who would retard the levers further in order to achieve a 'mid' position.
Cheers
I understand that. To be more specific with my question, do you think that 88%N1 ( ie a standard cruise setting) is 'mid' enough to prevent any excedance being possible.
Personally I do, but I know of others who would retard the levers further in order to achieve a 'mid' position.
Cheers
Join Date: Feb 2014
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By the way, how can you notice EEC Altn light during routine operations? As far as I remember it doesn't trigger master caution, so if there's no DEU failure with DSPLY SOURCE annunciation you'll hardly ever see it.
Join Date: Jul 2013
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Framer, I don't work 737 (I'm a wide body sort of guy 
), so I can't really comment on the specifics of the 737 installations. Your answer would probably have to do with the exact cruise conditions and how close you already were to max climb/con power set. But I suspect it is a least possible to exceed the max climb/con rating by selecting alternate mode with the throttle at a 'normal' cruise setting.
), so I can't really comment on the specifics of the 737 installations. Your answer would probably have to do with the exact cruise conditions and how close you already were to max climb/con power set. But I suspect it is a least possible to exceed the max climb/con rating by selecting alternate mode with the throttle at a 'normal' cruise setting.
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Join Date: Sep 2008
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Thanks again.
That really is the crux of the matter in that some people do suspect that, and others ( like myself )don't think it's likely there will be a 11 or 12% increase in N1. Unless I get more info I will be conservative and assume that it is possible as there is nothing to lose by retarding the levers a bit more.
Don't feel bad. I used to have the same problem until I entered a workplace 'Biggest Loser' competition. I now have so much energy it's amazing.
You do get ENG on the master caution panel.
But I suspect it is a least possible to exceed the max climb/con rating by selecting alternate mode with the throttle at a 'normal' cruise setting.
I'm a wide body sort of guy
By the way, how can you notice EEC Altn light during routine operations?
Thread Starter
Join Date: Sep 2008
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I think you are right Rat 5 but obviously the reason behind the physical mid point is to reduce the actual engine parameters in case the new data base sourced N1 is significantly higher. ( unless I'm completely missing something......it wouldn't be the first time 
)
)
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Yes, 'mid position' is geometric, but those instructions are common across the current production Boeing fleet - which encompasses a number of both N1 and EPR engines.
So 'mid position' keeps it simple and common.
So 'mid position' keeps it simple and common.
Join Date: Jul 2013
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Could you be more specific - which speed(s) are you speaking of? And are we still talking 737NG?
I know the EPR engine aircraft typically have a weight penalty associated with Alternate Mode dispatch (due to increased uncertainty in thrust) but I don't recall that being extended to engines with N1 thrust settings (GE/CFM).
I know the EPR engine aircraft typically have a weight penalty associated with Alternate Mode dispatch (due to increased uncertainty in thrust) but I don't recall that being extended to engines with N1 thrust settings (GE/CFM).
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Originally Posted by Emel.OW
By the way, how can you notice EEC Altn light during routine operations? As far as I remember it doesn't trigger master caution, so if there's no DEU failure with DSPLY SOURCE annunciation you'll hardly ever see it.
EEC alternate light triggers master caution and ENG on the system annunciator panel.
