Thanks, Miekleour.
Quote from Wizofoz:
I've kept out of the minimum GS debate entirely. I understand the concept and have no doubt it works.
[Unquote]
Why? It was central to the topic. It was the main element of Olendirk's original post, which was a thoughtful request for an explanation of how the technique works. His question was effectively ruled out as heresy by BOAC (post #3).
Referring to anyone who advocated the technique, he wrote:
"ignore them - they are mad."
Just to ram the point home, he wrote:
"IF you choose to do it, the info is on your EFIS, but I suspect any Captain with half a brain would then take control and have you sectioned - I would."
This paternalist scolding seemed to me to be less than helpful. The concept needed to be explained, which I attempted to do in common cockpit parlance. In Physics terminology, of course, my use of the word "inertia" was wrong – as Wizofoz (and others) pointed out, and I quickly accepted. Since then, the "debate", as he calls it, has consisted mainly of nit-picking.
As Wizofoz understands the concept – and can presumably explain it better than my feeble efforts, would it not be more helpful to do so? There's still time...
Quote from Wizofoz:
...you constantly allude to an aircrafts ground speed somehow effecting it's aerodynamic performance.
[Unquote]
Rubbish. Any quote?
Quote from Wizofoz:
...don't get snitty with someone for correcting you
[Unquote]
Examples?
Quote from Wizofoz:
I also note that you are a greater authority than Boeing on how to fly Boeings, and anyone who doesn't fly as you recommend is open to mockery and criticism
[Unquote]
No. I recommend that pilots remain within the limits of their companies' SOPs. galaxy flyer and framer have provided evidence that manual versions of the concept have been in use elsewhere, since the introduction of INS. Although I attempted to explain a possible procedure to Olendirk ("D.I.Y. GS-mini?", post #17), I included several caveats, and ended it with a strongly-worded warning not to deviate from SOPs. Since then, I have added:
"It's only fair to admit that most twins, including BOAC's and SR71's B737, have the luxury of a good thrust-to-mass ratio in the all-engine case. Maybe that is why they can stick to the old version of energy management on the approach..."
The difference between me and many of the pilots on PPRuNe is that I spent 17 years flying approaches on a variety of jet transports, including the underpowered B707, using IAS with SOP-increments, and ignoring any GS read-out. I later spent 14 years flying GS-mini-equipped twins.
The B707-320, with a MLW of 112T and only about 30T (spare us a lecture about Newtons, etc.) of rated thrust, could have benefited from the technique more than most. There is no doubt that automated GS-mini, used iaw SOPs, is a useful and protective system. It is particularly advantageous in the engine-out case.
But both pilots and the A/Thr need to avoid the mistake of using the "managed" IAS as a minimum speed, rather than a target.