PPRuNe Forums - View Single Post - Flying faster because of decreasing winds
Old 16th Nov 2008, 22:29
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Port Strobe
 
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If it's "Horlicks" to state that, for a given mass, inertia (kinetic energy) is a function of GS, perhaps you can tell us what else? IAS?
Although I was trying to avoid formulae, it is actually proportional to the GS (velocity) squared, which makes a shortage of it even more difficult to correct
Mass is a measure of inertia, not groundspeed, indicated airspeed or any other flavour of speed. To say a helicopter in the hover has no inertia is simply inaccurate, not pedantic as SR71 suggests. Momentum is a function of groundspeed (taking an Earth fixed frame of reference as absolute for our purposes) for a given mass, not to be confused with inertia. I don't require the Ladybird guide to kinetic energy either thanks.

On the subject of being accurate I was incorrect to suggest GS mini is controlled by autothrust, so let managed speed faff with the command speed until you're content then.

The postings this evening seem to be a sales pitch for the Airbus. It may be a clever machine but I'm not qualified to give backing nor counter arguement to your statements. I am qualified to say faffing with the command speed on the Boeing is not the way they nor the vast majority of operators propose to use the AFDS. To think you're smarter than them and the person three feet away by doing so is a shortcut to creating an incident in my own opinion. On the assumption we're talking about relatively modern passenger jets then the instant wind is going to be right under your nose so any drop in airspeed can be anticipated, it's basic situational awareness. Manipulating the thrust and flight controls is part of a pilot's job description so I don't object to having to do that. If the windshear is going to be really sudden then it calls into question whether or not you should be executing an approach in the first place, plus you'll probably get a predictive if not reactive windshear warning. Horses for courses, but transferring techniques between types simply doesn't seem sensible to me.

Last edited by Port Strobe; 16th Nov 2008 at 22:39.
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