Just a question for the A320 pilots... I notice sometimes when watching YouTube, that the pilots on landing approach, disconnect the auto-throttle and use the thrust levers manually...

I'm just wondering what the purpose of this actually is as thought managing the throttle on landing was one extra thing to do when it can be done with auto throttle?

Is there some advantage to this or is it pilot choice?

Thanks chaps for any insight - i haven't tried it as yet so wondering if i should!

Cheers

Doug

Edited January 3Jan 3 by vonduck

i cannot say i have seen it, but the only reason i can think of, are the throttles more responsive manually? Say in windy conditions or such, and the pilot flying prefers it. Probably totally wrong though.

Practice purposes mostly. Also, SOP varies by airline. DLH requires manual thrust with AP off, whereas BAW forbids it and so on.

my buddy flies A320/21's for a US based airline.   He said they basically very rarely fly it with manual throttle.  

All down to SOPS really most airlines land with it on. Only a select few turn it off. Airbus recommends to keep it on

Some great real world videos of flights here : (12) Approach and Departure Videos - YouTube

I believe this is Eurowings and they disconnect the auto throttle on most approaches.

This is most interesting guys! Thanks for the insight!

Adding a little to all the information that the other members have already provided you, when disconnecting the A/THR you lose the GROUND SPEED MINI function which is especially useful in approaches with mid/strong winds.

It's company SOP thing.

While Airbus themselves recommend to leave the Autothrottle on when disconnecting the AP, there are some airlines who ignore this and want their pilots to manually control thrust as well.

 

Lufthansa for example is one of those airlines.

18 minutes ago, Farlis said:

some airlines who ignore this and want their pilots to manually control thrust as well.

I wonder why? Not having flown the real thing, i would have thought that the less work or things to focus on in the landing phase would be better? Perhaps not! I wonder then if it makes for better piloting skills?

30 minutes ago, vonduck said:

I wonder why? Not having flown the real thing, i would have thought that the less work or things to focus on in the landing phase would be better? Perhaps not! I wonder then if it makes for better piloting skills?

I believe the idea is a carryover from non-FBW aircraft. On a jet with underslung engines, increasing thrust produces a pitch-up moment, and decreasing thrust produces a pitch-down moment. If you've got the autopilot off but autothrottle on, you won't necessarily be expecting the thrust changes that the autothrottle makes, and the pitch changes that go with them. The idea, therefore, is that it's better to control both pitch and throttle manually, so that you can anticipate any pitching moments that will be caused by throttle changes, rather than having to react to what the autothrottle is doing. "Manual flight, manual thrust" is the catchphrase that I've heard to describe this idea.

On the Airbus, this is less relevant, since the FBW will compensate more or less for any pitch moments caused by thrust changes. Hence the Airbus recommendation to simply keep autothrust engaged even if flying manually. Some airlines, however, have chosen to carry over the "manual flight, manual thrust" idea to the Airbus.

@martinboehme Thanks for that! Simming is quite a bit different in some ways from RL as im discovering everyday!

On the 747 it was always considered best practice to take the auto throttle out if you were taking the autopilot out, due to the huge pitch/ power coupling on that aircraft the auto pilot could get confused and lead to oscillating if you started changing power by much.

With the 787 we leave the A/T in for the landing, I don’t like doing that so much as we still have our hands on the thrust levers and so instinctively change power in response to gusts and speed changes, it can’t be doing the servo motors much good.

Incidentally , did you see the new throttle quadrant from the guys who used to be honeycomb will have the option of fitting servo motors to the throttles , it will be great for TOGA on Boeing aircraft.

6 hours ago, Ilari Kousa said:

Practice purposes mostly. Also, SOP varies by airline. DLH requires manual thrust with AP off, whereas BAW forbids it and so on.

Not sure what you said about Lufthansa. They usually fly A-Thrst on. Its different for Discover Airlines as it is Lufthansa Group too

What everyone else said is right and also, from memory (it's been 10 years since I flew the A32X) the autothrottle didn't always do what you expected.

I recall being on final and the autothrottle happily letting the speed drop a few knots low, then at about 100ft suddenly realising and stuffing on a fistful of power. As the thrust levers don't move, unless you were looking at the ECAM at the time you wouldn't really notice until the power came on.

Let's just say that it could 'destabilise' the approach.

It didn't always do it but when it did it caused a bit of sphincter exercise, especially if it was a challenging landing already.