Boeing 777 Autothrottle
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Boeing 777 Autothrottle
After reading the Asiana 214 thread and doing some further research, I get the impression that most airlines that operate the B777 mandate the use of autothrottle in all phases of flight, even when handflying, and Boeing recommends so.
Now I'm wondering, why does the B777 need to be flown with autothrottle?
I understand that on the FBW Airbus use of autothrust makes sense because the artificial flightpath stability can lead to speed deviation (yet many airlines allow manual thrust in manual flight on the Airbus).
I understand that on conventional aircraft, use of autothrottle while handflying is not recommended because of thrust-pitch coupling, which does not happen on the B777 due to FBW control laws. So is autothrottle recommended for handflying on the B777 simply because there is no reason against it (as on other types), or is there a specific reason for it (on the B777)?
And another question: If autothrottle is used for a manual approach and landing, is it used until touchdown? If so, does the autothrottle automatically retard the thrust levers or is that done by the pilot?
Now I'm wondering, why does the B777 need to be flown with autothrottle?
I understand that on the FBW Airbus use of autothrust makes sense because the artificial flightpath stability can lead to speed deviation (yet many airlines allow manual thrust in manual flight on the Airbus).
I understand that on conventional aircraft, use of autothrottle while handflying is not recommended because of thrust-pitch coupling, which does not happen on the B777 due to FBW control laws. So is autothrottle recommended for handflying on the B777 simply because there is no reason against it (as on other types), or is there a specific reason for it (on the B777)?
And another question: If autothrottle is used for a manual approach and landing, is it used until touchdown? If so, does the autothrottle automatically retard the thrust levers or is that done by the pilot?
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the A/T on the 777 works well manual and in auto.with very quick response.
it will retard to idle at touchdown.
its protected by min maneuvering speed with some limitations in flight.
it will retard to idle at touchdown.
its protected by min maneuvering speed with some limitations in flight.
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"I understand that on conventional aircraft, use of autothrottle while handflying is not recommended because of thrust-pitch coupling, which does not happen on the B777 due to FBW control laws. So is autothrottle recommended for handflying on the B777 simply because there is no reason against it (as on other types), or is there a specific reason for it (on the B777)?"
That nails it. It's normally left on but there is no reason you can't turn it off if you wish. Yes it retards the TL in the flare.
That nails it. It's normally left on but there is no reason you can't turn it off if you wish. Yes it retards the TL in the flare.
The way I see it is that there's no good technical/piloting reason for insisting the A/t stays in on the 777 the aircraft is a beaut to hand fly compared with the likes of the 747 because of the FBW. However because Boeing say it can be used "full time" management insist that it must used full time because as long as it works it provides another "layer" of protection from the lawyers.......
Just sayin.......cynical, Moi?.
Just sayin.......cynical, Moi?.
Last edited by wiggy; 11th Jul 2013 at 18:41.
