PPRuNe Forums - View Single Post - windshear/TOGA
Thread: windshear/TOGA
View Single Post
Old 31st Dec 2013, 22:16
  #27 (permalink)  
AirRabbit
 
Join Date: Apr 2005
Location: Southeast USA
Posts: 801
Likes: 0
Received 0 Likes on 0 Posts
I'm just not sure what Maximum Available Thrust is with THR REF indicated … Max takeoff, max continuous, full climb thrust, CLB 1, CLB 2.
All “thrust references” are calculated values … where the result is dependent only on the parameters chosen … and they are always (at least more so than less so) based on efficiency and effectiveness of the “relationships” of those parameters at the anticipated normal ranges for the flight conditions expected.

…there is an automatic windshear recovery system for the aircraft allowing the FD to command appropriate pitch and can be followed by the autopilot
…so, are we to believe that you would be perfectly confident in the airplane systems to the degree that you would allow the airplane to safely fly itself out of a windshear encounter? I think that doing so is very likely a result of either “over confidence” in the airplane systems or “under confidence” in the pilot flying … who do you know better … YOU … or the guy(s) who designed, developed, constructed, and installed that system … and how come he isn’t there with you when you have to make that decision?

Maybe I'll just try a second TO/GA push in the sim.
Before you make any potentially life-altering decision on how to operate your AIRPLANE based on what you see, hear, and/or feel in a SIMULATOR, I would strongly suggest that you find out what kind of information was used to program that particular simulator for the specific conditions you desire to examine. The fact is that the simulator will do what it is programmed to do … and ONLY what it is programmed to do. Good input = good output … Bad input = bad output … and No input = potentially deadly output.

In that case you will overthrust the engine.(if you go more than the N 1 limit)
I think you meant to say “over speed” the engine. Unless they’ve made some remarkable advancements in jet engine technology that has escaped general notice, there is no such thing as a “thrust-limit” on a jet engine. As an example, I used to fly one that had a planned and used TO EPR of 2.83 – with water injection. There are limitations on "engine boost" that are applicable to internal combustion engines ... where additional pressure can be pumped into a cylinder to increase the power generated when ignition occurs ... and, in those cases, one can, indeed, "over-boost" an engine (pump too much air under pressure) into that pressure chamber - because of the structural integrity of that chamber. Additionally, as you probably know, 100% is not necessarily the real maximum rotation speed for any jet engine (you see maximum values all the time of 104%, 106%, and sometimes even higher); over-temp is a much more serious problem than over-speed; and if it is equipped with the necessary sensors and indicators, an increase in engine vibration above whatever is considered “normal” is also something that should be avoided. I’m relatively sure that if engine manufacturers could generate more “pressure” at the exhaust end of the engine in relationship to the “pressure” at the intake of that engine – without having to resort to dumping raw fuel into the burner sections (i.e., “after-burner”) - they would probably jump for joy. I’m not saying that one doesn’t need to know or respect engine limitations, but when it comes to IF or how hard I may have to hit the ground … I’m not at all worried about maintaining the integrity of that hunk of spinning metal.

And ... I, too, hope that each of you and each of your families' enjoy a peaceful, prosperous, and SAFE New Year!!

Last edited by AirRabbit; 31st Dec 2013 at 22:39.
AirRabbit is offline