Hi, G-SPOTs Lost,
Quote:
Nobodys suggesting an "uncontrolled burst of thrust" just enough to keep the desired speed whilst arresting the ROD a tad.....forgive me this is what we get paid for no?
I agree with most of your interpretation of my previous post, but am not entirely convinced that you understand why I’ve used the phrase: “uncontrolled burst of thrust”. If in any doubt, refer to the last paragraph of my post #69, and CONF_iture’s post #70.
As you know, on a conventional (driven) auto-throttle, a controlled, short-term thrust increase − for example, to add the right amount of energy (by increased GS) to recover from a sustained loss of headwind − is a simple matter of pushing the throttles forward, as much as you judge necessary, against the clutch mechanism. Once you’ve recovered airspeed, you allow the throttles to do their own thing again.
With the current Airbus system (unlike the A300 and A310), how much energy you add depends on how quickly the engines spool up towards the very high thrust setting you have commanded − something over which you’ve no control − and how long you dare to keep the levers forward of the CLB detent. If you overdo it, not only will you find yourself with too much energy, but the big fans will take another couple of seconds to slow down. This may result in the A/THR selecting idle, to correct an excessive IAS. Not something you want at 100ft.
As I said in an earlier post, the battle some of us putative A320 pilots waged − to persuade Bernard Ziegler that we needed conventional (driven) thrust levers, when in A/THR mode − was lost circa-1986. Our concerns included the issue of A/THR cancellation, but concentrated mainly on the loss of tactile information in A/THR with the non-driven thrust lever. The latter criticism was ruled out of order on the spurious, but undeniable, pretext that no pilot should assume that thrust is changing − without reference to the gauges − just because the throttles are moving. (I guess the B777 accident at LHR might appear to lend credence to that argument.)
Having said all that, the A320 throttle levers provide the smoothest thrust changes when operated in Manual Thrust: the best of the six jet types I flew. Left to its own devices, helped by the excellent GS-MINI system, the A/THR is also pretty good.
Chris