Simviation Forums

...Use your speed hold on final and even when touching down?

[smiley=dankk2.gif]
Jimmy

I don't think it's a good idea. But what do I know!

Sounding like a total newbie, What is speed hold?

I presume it literally holds your speed, but how and why do you do it?

To engage speed holder you hit the auto throttle button set your speed on the Auto Pilot then hit the speed hold button.  Its normally used during cruise on long flights. Rarely ever used on landing but it can be done. I do however suggest you do it manually.

Why would it be better to do it manually?

1.  good practice
2.  in case of emergency
3.  and because in real life, speed hold isn't really used on landings

Imagine the situation, approaching the runway.  Flaps are correct, altitude/glide slope are correct, speed is on auto but not over the top, about 190 is ok and manageable.  Undercarriage is down, cleared to land.  You hit the Speed Brake set to activate as you press on the brakes.  Touchdown, perfect line up!  You hit the brakes, Speed Brake engages, you put on reverse thrust and know that you are going to stop soon.  As you approach the end of the runway quite quickly and this big bird is still moving you realise your mistake.  No matter what brakes you utilise the speed hold is still pushing that bird at 190knots against the brakes.......

Not a good idea!  I forgot once or twice and had to take off again.

Reider

In real life autoland will close the throttles automatically at screen height. In pratice the autothrottle is not used in cruise more for landing and approach.  If you are using autothrottle during the landing phase add it to your check list to dissengage at screen height having set the manual throttle to idle beforehand!!!
Vololiberista

In real planes (Boeings atleast), when doing autolandings autothrottle with automatically "RETARD" the throttles when you cross the runway threshold, this does not work with manual landings. In Flightsim, 95% of planes will only hold the speed, but won't "RETARD" the throttles, and then you'll have a high landing speed and long rollout. So, no, don't use speedhold for landings, it is dangerous, and it will make you float down the runway.

"RETARD" teh throttles when you're 10-20feet high. The correct way to flare most airliners is to flare till you're at level flight attitude for your approach speed. Obviously retarding the throttles at 20 feet will cause airspeed to go down from approach speed, lowering lift, hence a smoooooooth touchdown.

about 190 is ok and manageable.

190knots for a conventional airliner is WAY WAY WAY to fast. The highest regular approach speed for a conventional airliner is under 160knots.

Alright, thanks for the help guys!  

[quote]To engage speed holder you hit the auto throttle button set your speed on the Auto Pilot then hit the speed hold button.

Why would it be better to do it manually?

One good reason is in case of a go around. Another is that you really don't want the airplane trying to maintain 200 kts when you are landing on a short runway. That might get interesting (in a bad way that is).    :o