use of autothrottle

[Guest gooper]

Hi to all felow PMDG pilots, I would like some help in knowing what the proper procedure is when using the autothrottle during a manually flown approach. is it left on until moments before the flare or is it at the pilots discretion when they want to disconnect it?

[Guest wee_davie_2612]

Hey Gooper,You can do any way you want to. You can leave it running all the way to the ground (including touchdown), it will automatically disconnect when the reversers are activated. You can also take it out just before the flare, this allows you to concentrate on flying the approach all the way down not having to worry about the speed and also allows any wind correction to bled off during the flare which will reduce floating along the runway due to a slightly higher speed.You can also take it out at any time you want, be that a mile away or ten miles, anytime.I normally fly approaches using option two as my throttle isn't too accurate (jumps about like a yo-yo :)).In the real world, most pilots use option three, it's about the only time you actually get to fly the aircraft :)Hope this helpsCheersDavidP.s. You need to sign with your real name in this forum, 'tis the rules :)

[Guest tmetzinger]

>Hi to all felow PMDG pilots, I would like some help in>knowing what the proper procedure is when using the>autothrottle during a manually flown approach. is it left on>until moments before the flare or is it at the pilots>discretion when they want to disconnect it?If you look for some posts by Iz (he's a real-world driver) in this forum, I believe he mentions that on all approaches except the autolands, the autothrottles are disconnected no later than the 50 foot callout.

[Guest Zapper]

Boeing recommend that when Autopilot is disengaged that you also disengage autothrottle. Some companies prefer to have the SPD mode disarmed (just press SPD button on MCP when it is illuminated) only at say 400' which leaves the A/T ARMED (in FMA) and so will automatically advance thrust levers should speed get down near the red bars (ie stick shaker)The Limitations on the AP is that is be disconnected not later than 50' on any sngle AP approach and may not be engaged less than 400' after T/O. It may of course remain engaged as does teh A/T for all Dual Autopilot autolands.A little extra info:For Takeoff the A/T is ONLY armed when entering the runway and is part of the Captains scan at that time.Rgds,Brad

[Mats_J 2]

HiI checked the www.pprune.org forum a couple of days ago. (It's a forum for real world pilots and other aviation related folks.) And I stumbeled onto a thread discussing just this question. And it seemed there are as many options as there are pilots, or at least air lines. Some flew manually with having A/T on. SOme were laughing hard at that and stated that real flying is A/P off AND A/T off. And some were refering to their company's SOP for acurate procedures.So it all depends...Hope it helps, ;-)

[Guest wee_davie_2612]

Hey all,Sorry for the confusion, I should have mentioned the first 'procedure' in the earlier post is for FS only (you can still do it this way if you want, after all it's just a game :)).Mats,I would have defined the different 'modes' of flying as:Hand Flying - a much more concise way of describing manual flying. I'd consider this to be any time you're using your hands on the yoke or throttles to directly control the aircraft. I'd also consider it hand flying if you are only using the yoke while leaving the A/T to control speed. Manual Flying - A blurred definition. I'd probably consider someone to be manually flying the aircraft if they are not hand flying it and not being automatically flown around. For example, I'd consider it manual flying if you were in CMD, LVL CHG and HDG mode in the 737. In these modes you are manually telling the aircraft where to head/climb/descend etc. The fact that you are not actually moving the control surfaces yourself doesn't mean that your not controlling it.Auto Flight - The FMC does the work and you get the job of sitting and watching, making sure it's doing it right.What are your thoughts on this guys? Also which way(s) do you fly each segment of the flight?CheersDavid

[jjeffreys 12]

My personal preferences are to let VNAV and LNAV take over at about 1000AGL (unless the SID dictates otherwise) and fly with autopilot until TOD. On the decent if ATC starts to vector, then I will manually control till 400AGL and then hand fly. If ATC leaves me alone then I will Auto until 400AGL and then hand fly it in. I fly this way for almost all flights except for CATIII when I let the plane do all the work. I am by no means a IRL pilot but I have been flying VA's for a while.

[Guest wee_davie_2612]

Hey Jeremy,Thanks for the reply :)I do it quite a different way to you. I'll normally hand fly it all the way up to cruise level following the FD bars with the A/T controlling the speed. I'll put the FD on in LNAV and VNAV modes, this way I control pitch and roll, following the FD bars to stay on the correct path, and let the auto thrust control the speed. If I'm vectored in the climb I'll change the mode to what's needed but I'll normally leave the CMD off. Once up to cruise I'll hand over to the autopilot. For the descent - I'll normally begin the descent in full auto mode and then change to manually altering the autopilot once I start getting vectored. I'll usually leave the autopilot on until established on approach. I normally kick the AP off after intercepting the LOC and capture the GS myself all the time letting the Auto Thrust system handle the speed. Once down to about flare height I'll take out the A/T to reduce down to Vref at touch down.What about any of you real world NG pilots, how do you guys go about it in each stage of flight?CheersDavid

[Guest boxjockey99]

I can only speak for how my company operates the 300 series (Classic) but here's what we do, apparently it is the same on the NG but I'm prepared to be wrong!If flying with A/P engaged it is the norm to have A/THR engaged also.If hand flying you CAN leave the A/THR engaged BUT be aware that the A/THR will constantly make adjustments to maintain the set parameters depending on its mode ie if in MCP SPEED it will attempt to maintain the speed in responce to any pitch changes you make. The problem with this is that there is a big pitch/thrust couple due to the engines being below the C of G. In laymans terms this means that if you put power on the nose pitches up and vice versa if power is removed. If you are handling the throttles manually you know when you move the power levers and so can predict the movement of the nose but if the A/THR is engaged then you find the nose bobs around like there's no tomorrow!So my company, and I stress that this is MY company, say we should use A/THR only when A/P is in use. On landing the company line is that the A/THR should remain ARMED but the modes should be deselected ie SPEED or N1 should be off and just ARM should show on the Flight Mode Annunciator (FMA). By leaving A/THR armed it means we can use the TOGA button to apply Go-Around power should we need to go around and therefore not have to set the power manually. ie the A/THR will move the power levers and all you need to do is follow the Flight director. ie you have one less thing to worry about!I think that explains it but if it is still foggy please do post more queries as I love a challenge!Happy TrailsKris

[crvm 0]

"it will automatically disconnect when the reversers are activated" David you loose the prize buddy ;-) On an Autoland with A/T *ON* it will disengage (the A/T switch is spring loaded) 2 seconds after TD with or without REV engaged. This is a pilot (company SOP) thing guys. The most important thing about leaving the A/T on is for stall protection, this works even IF you have speed de-selected. ' [h4]Best Wishes,Randy J. Smithhttp://www.precisionmanuals.com/images/forum/betaimg.jpg

[Guest wee_davie_2612]

Hey all,Thanks for the info Kris, very interesting :). As Mats pointed out some airlines allow you to hand fly with auto thrust. I guess it's all down to airline SOP. Randy, You at least got to give me that one - I've only had the airplane a couple of weeks :). Besides how many landings have you or I done without reversers or even rolled out longer than a couple of seconds before deploying the reversers? ;)That's the whole first line of my first reply been blown out the water, should have just kept quiet :-doh :)CheersDavid

[PilotGav 0]

Thats it!! I'm buying a CO PILOT. I can't handle flying the aircraft AND flipping all these dang switches! :)Flaps up on taxi landing my eye ;)Gavinhttp://www.interprom.com/gavhttp://www.precisionmanuals.com/images/forum/ng_driver.jpgSpellink doesn't count!!