Just to be sure to point out that it depends on the approach one is implementing. A CAT IIIc approach requires crews to let the A/T control the throttle until touchdown and the A/T will auto disconnect when two seconds have elapsed since landing touchdown. Section 4.20.9 of the FCOM manual 2 has all the information about auto throttle use and automation. So there is no one "correct" answer, because its based on the weather and/or how much manual control one wants to have during any phase of the flight. The 737 NG could be flown totally manually if you wish. Usually airlines will have their policies in place about all this, so maybe when/if real world pilots chime in they may indicate the airline policy.

I find for me atleast the auto throttle often has trouble maintaining correct speed (within 5 knots or so) in gusty winds, a few occasions on approach the aircraft started overspeeding the configuration and flap protection was about to kick in. Also on departure in gusty weather it tends to lose too much speed if I try cutback (so I don't unless weather is calm, which is more of a pitch issue anyway) and after that it can't keep the speed below 250 knots/10,000. So I am either disconnecting it and manually throttling or pulling the throttles back manually with A/T still connected,

 

So for me atleast in gusty weather I can do a much better job manually controlling the throttles than the A/T, I don't remember the A/T in the MD-11 having issues in gusty weather however.

I turn off the A/T and A/P at 4000 feets after LOC "captured".

I find for me atleast the auto throttle often has trouble maintaining correct speed (within 5 knots or so) in gusty winds, a few occasions on approach the aircraft started overspeeding the configuration and flap protection was about to kick in. Also on departure in gusty weather it tends to lose too much speed if I try cutback (so I don't unless weather is calm, which is more of a pitch issue anyway) and after that it can't keep the speed below 250 knots/10,000. So I am either disconnecting it and manually throttling or pulling the throttles back manually with A/T still connected,

 

So for me atleast in gusty weather I can do a much better job manually controlling the throttles than the A/T, I don't remember the A/T in the MD-11 having issues in gusty weather however.

 

Surely thats why the good book advises VREF +5, VREF +10, VREF +15 & in extremis VREF+20 in gusty conditions???

 

The A/T then has a larger margin of response & you're always on the better side of the drag curve...as would say the descision to use Flaps 15 for better gust penetration....the A/T is just not capable of response to within 5 kts or so under those conditions.

Surely thats why the good book advises VREF +5, VREF +10, VREF +15 & in extremis VREF+20 in gusty conditions???

 

The A/T then has a larger margin of response & you're always on the better side of the drag curve...as would say the descision to use Flaps 15 for better gust penetration....the A/T is just not capable of response to within 5 kts or so under those conditions.

 

Yeah I do VREF+ (whatever required) but it doesn't matter what I set the speed, A/T will just allow the slowly aircraft accelerate (albeit bumpy) away until flap overload protection, it really doesn't bother me as I do approaches manually anyway.

Matt-

 

The four-square method refers to the idea of the FD cross-pointers dividing the nose box into 4 little EQUAL squares. The idea is to maintain that- correcting BEFORE deviations are larger than outside the area within the box- forcing the pilot to learn/develop precise flight path control. All too often deviations are massive (compared to what the AFDS achieves). If you work towards keeping those 4 squares, square- you will be flying pretty well. For most, it takes some practice :)

I'm familiar with the technique, but I've never heard it called that before. Is that something the Brits teach? Maybe something that comes from the ab initio programs?

 

I'll lead or lag the F/D to keep things smooth if everything is copacetic - if not, then I'm tucked in nice and tight on the F/D. If only my company would switch to single-cue. . .

Yeah I do VREF+ (whatever required) but it doesn't matter what I set the speed, A/T will just allow the slowly aircraft accelerate (albeit bumpy) away until flap overload protection, it really doesn't bother me as I do approaches manually anyway.

 

When using the autothrottle, position command speed to VREF + 5 knots. Sufficient wind and gust protection is available with the autothrottle engaged because the autothrottle is designed to adjust thrust rapidly when the airspeed drops below command speed while reducing thrust slowly when the airspeed exceeds command speed. In turbulence, the result is that average thrust is higher than necessary to maintain command speed. This results in an average speed exceeding command speed.