PMDG 744 autothrottle and AOA DVDs

[basa 0]

Well, I got the AOA's DVDs as a Christmas present (...from me to me :( ). Worth every single cent I must say.Now, whatever can be the procedure they are explaining, they keep the AutoThrottle engaged until 50 feet (which is the normal threshold crossing altitude), then they disengage the A/T and bring the levers to idle power for touchdown.Isn't is this more an Airbus-like procedure than a Boeing one ?I've read comments in this forum saying that (when flying Boeings) Autopilot and AutoThrottle should go off together.What do you experts think about this question ?. Thanks.

[downscc 1,327]

I think it is up to company policy. The autoland system will soon be closing the throttles at about 50AGL anyway.SWA policy is no A/T on approach (something I read a year or so ago). This keeps the pilot flying in the loop as far as thrust control is concerned. However, both PMDG Boeings will autoland, retard throttle and stay on center line (747) for you... no need to turn off Otto until you want to leave centerline. I always hit F1 before F2 for thrust reverse and wouldn't know if it works any different way.

[FlyChuck 3]

This is what I extracted from my FCOM I ( chapter 'Limitations'): "The autothrottle must be disengaged before descending below 50 feet HAA during a manual landing." It doesn't say why that is (because Boeing says so!), but I believe the autothrottle will not automatically move the throttles to idle when the autoland logic is not active, and will try to maintain the selected speed until touchdown (making it very difficult to idle the throttles and prevent you from floating forever). My company advises not to use the autopilot or autothrottle independently, except for the takeoff roll and climb. So the 50 feet is a Boeing limitation, while the independent use of AP/AT is a company restriction. For those who are interested: I just had a look in the 777 manuals, and with the 777 it is adviced (by our company) to use the autothrottle during all phases of manual flight, also when landing manually. Proving the point that you don't need to be a pilot to fly a 777 ;-)Tom

[Chris from Angle of Attack 7]

From the material I used for the videos, derived from UAL procedures (but not official by any means) this was what was to be done. With that said, there's no limit on how early you can do that. So, if you'd like, you can do it earlier. Many of these details are company specific, as has been shared.

[basa 0]

From the material I used for the videos, derived from UAL procedures (but not official by any means) this was what was to be done. With that said, there's no limit on how early you can do that. So, if you'd like, you can do it earlier. Many of these details are company specific, as has been shared.

Thanks Chris,Got your Christmas greeting with the magnificent DVDs pack. I've already given it the first round and looking forward to having time for a second go.Now, going to the procedure, doing as you do in the video is perfect for speed control when you have not a very precise joystick throttle wheel (which is my case), but, as I said, it seemed to me more Airbus than Boeing, (perhaps the 777 is an hybrid specimen).And talking about Southwest Airlines, I've read that their 737s don't have any autothrottle. Best regards.

[craig_read 43]

As I think was said before, if you're landing the aircraft manually, and not using any of the autolanding features, then SPD will maintain a specific set speed at ALL times. That will include your landing roll, if you do not disengage the autothrottle. This will result in landing, trying to brake, but the engines throttling up to maintain your set REF speed. As a result it is necessary to disengage the autothrottle system before the aircraft touches down. When you do this, is really entirely up to you, whether at 50 or 500 feet, it is your decision as pilot in command.Autolands are different, as part of the autoland functionality the aircraft will idle the throttles (but not engage reverse thrust) on touchdown. This means there is no need to disengage the autothrottle system at any point. The pilot in command will monitor the system and approach and engage the reversers when on the ground and keep an eye on the decelleration.FYI, I believe most landings are manual, although the majority of the approach may be using the autopilot, it is usually disengaged around 500 feet give or take a few, and the landing continued with manual control of the aircraft and throttle. It's good practice when you are landing to listen for the call outs...ONE HUNDRED... just continue approach..FIFTY... continue approach.. should be passing over the thresholdTHIRTY... flare.. and begin to bring throttles to idle.. you should aim to slowly reduce the thrust so the moment your main gear gently meets the ground (if you've done it right it should be gentle) your throttle is at idle. It's also no problem to engage reverse thrust without the nose gear in contact with the ground, so long as the aircraft is straight and under control there is no problem. I know that might upset some people who believe this isn't correct, but there are plenty of youtube videos or airliner photos in which crews are engaging reversers without the nose down and it's normal practice. This is because the nose gear is NOT steering the plane, the rudder is providing steering at high speed, so the nose gear is not required to begin reverse thrust braking.If you are not convinced, look up an Air Pacific 747-412 landing at Auckland International 23L on airliners net..... the caption reads "DQ-FJL (cn 24062/722) Everything extended and reverse thrust on - landing 23L " it's a good picture by Jonathan Rankin and it clearly shows the aircraft just after landing, reversers deployed and the nose gear still in the air.It's also normal practice even on autolands to disengage the autopilot and autothrottle not long before touchdown to manually control the final part of the landing, as far as I am aware, and have been told, complete autolands are not as common as you might think.Hope that helps you...Craig

[FlyChuck 3]

Craig, it is common practise to reverse as soon as you touch the ground, because reverse thrust has the most effect on high speeds. There is no need for the nosewheel to be on the ground, because the stabilizer has enough authority to prevent the nose from diving into the runway.Tom

[basa 0]

Craig, it is common practise to reverse as soon as you touch the ground, because reverse thrust has the most effect on high speeds. There is no need for the nosewheel to be on the ground, because the stabilizer has enough authority to prevent the nose from diving into the runway.Tom

Well, Tupolevs 154 deploy reversers BEFORE touching the ground !!See this:http://es.youtube.com/watch?v=VIGtAjjnQbs

[FlyChuck 3]

Well, Tupolevs 154 deploy reversers BEFORE touching the ground !!See this:http://es.youtube.com/watch?v=VIGtAjjnQbs

Wow! :D haha, very cool!