Moving one throttle lever forward of the others...why?..

[UALdave]

I was watching a cockpit DVD of the 747-200, and the flight engineer moved the #1 engine throttle lever "ahead" or forward of the other 3-why would he do this? There was no mention of anything being wrong with the other 3 engines, or with the #1 engine. EDIT-this was during cruise.

[MCM]

It depends how far forward he moved it.

On older types (and some newer types, but it is less frequent) it was common to need to move the thrust levers to slightly different postions to produce equal amounts of thrust from each engine. The difference wasn't a large one, but just made the aircraft fly straighter.

These days FADEC has largely eliminated the problem, and the computers do this thrust trim for you.

[Gabriel]

Dave,
Was that during a right turn, by chance?

[TeeVee]

Dave,
Was that during a right turn, by chance?

so, and yes, i'm assuming, is it normal to turn an aircraft like a twin screw boat?

[Peter Kesternich]

I think MCM pretty much covered it On the older 747s the thrust levers could look quite staggered. The important thing is not the position of the thrust lever but the read-out of the engine instruments.

[UALdave]

It depends how far forward he moved it.

On older types (and some newer types, but it is less frequent) it was common to need to move the thrust levers to slightly different postions to produce equal amounts of thrust from each engine. The difference wasn't a large one, but just made the aircraft fly straighter.

These days FADEC has largely eliminated the problem, and the computers do this thrust trim for you.

Gotcha, and no, it wasn't during a turn. It was on the excellent Air Atlanta Icelandic 747-200 DVD, by World Air Routes/Just Planes. I own more of their DVDs then I do actual movies!

[Gabriel]

so, and yes, i'm assuming, is it normal to turn an aircraft like a twin screw boat?

Come on, TeeVee, you know I know better than that.

Of course you don't turn a plane like a tank.

To turn a plane you bank it and USE THE RUDDER PEDDAL (or differencial thrust) to keep the ball centerd.

[groundpounder]

Come on, TeeVee, you know I know better than that.

Of course you don't turn a plane like a tank.

To turn a plane you bank it and USE THE RUDDER PEDDAL (or differencial thrust) to keep the ball centerd.

No you don't.

[UALdave]

So, what was the first commercial aircraft to use FADEC? The First Officer on board one of the flights was an older guy who was either German or Dutch, and he said that he had flown Airbus aircraft, and the Fokker 100, and that the 747-200 was very easy to land! That's amazing to me, because I would think that it would be more difficult to land then more technologically advanced aircraft.

[Gabriel]

No you don't.

I've heard that due to some combination of very big fin (to deal with highly asymmetric thrust) and huge dihedral effect (due to both geometric dihedral and lot of sweep), and due to the yaw damper too IIRC, the 747 has a tendency to slip a bit and slowly level the wings if left alone in a turn, and that ir requires either a constant pro-turn aileron input (which will keep the plane turning but a bit uncoordinated) or a constant pro-turn rudder input whichcan be replaced by adding a little thrust in the outside engine (the one farther from the center of the turn).