Hi,Read something on page 5-13 in PMDG's AOM that got me confused. It says:"When on localizer intercept heading, verify ILS tuned and identified, LOC and G/S pointer displayed, arm APP mode and engage second autopilot."Does that mean I should engage APP and the second autopilot (CMD :( prior to localizer 'alive'? I thought you should press the 'APP' button when localizer comes alive and then engage autopilot B when G/S is captured?Could someone please explain the correct procedure to me?TIA,

Hi TIA.>>>>Does that mean I should engage APP and the second autopilot (CMD :( prior to localizer 'alive'? I thought you should press the 'APP' button when localizer comes alive and then engage autopilot B when G/S is captured?<<<

As the APP mode, the dual mode is prearmed.You can pre arm the dual mode until (i think) 2000ft (or maybe 1500ft), after that if you haven't already done so, you can't activate it anymore.Technically teh flight computers put the modes on hold no matter what you do:if you are on course for the ILS (which is not still active) and you press APP, you'll see the LOC and G/S mode go in ARMED mode (white lights in the PFD), you can even pre arm the dual mode now, by pressing the second AP switch (providing you have tuned the NAV2 to the NAV1).The flight computers automatically manages all of this, activating the single modes when they are needed.Airlines may issue safety limitations to this, for example that you can't activate the APP mode before the loc is alive, or that you can't preactivate the dual mode until at 8nm from th....Whatever :)Technically although you can do what i said above as the system automatically manages it.

You are coming in and your current heading will cross the localizer (intercept), so by pushing the APP button you will ARM LOC and G/S (less workload) You should catch the LOC first. Once established on final and cleared to land engage the second A/P, make sure the second A/P is engaged prior to 800'. On some real Ngs there is an option to inhbit G/S over LOC for good reasons. Of course you could just push LOC and not APP. You would then need to push APP if you desire to capture the G/S for an autoland. So take the AOM as a suggested capture but certainly not the only way one can do it. That would take up many more pages ;-) [h4]Best Wishes,Randy J. Smithhttp://www.precisionmanuals.com/images/forum/betaimg.jpgAMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | WD SATA 80 GIG | 512 DDR 400 |

Thanks for all your replies guys!

As Randy says some NG's have a GS inhibit function to stop descent on the glide if the LOC isn't captured yet, this is to ensure you are within the protected cone of the ILS. Going down beofre being in this cone can be hazardous to your health and that of your passengers! The system we use on the 300 (classic) is as follows:Configured at Flap 5 speed 180 prior to loc intercept.when ATC put you on final vector to the LOC select LOC, ensure you have VOR/LOC in white on the flight mode annunciator at the top of the PFD.Once captured on the LOC and cleared for the ILS select APP, G/S will appear in white then go green on the FMA when it captures.The only hard and fast rule about engaging the 2nd autopilot is that you must have it engaged by 800ft Rad Alt. This means it has enough time to do the comparison check and arm the FLARE mode before the 500ft check.Our procedure is to put the sencond A/P in once established on the LOC. The computers will see the 2nd A/P is selected butwon't allow it to engage till the 1500ft ILS comparison check is done. until this time you should get SINGLE CH annunciated on the PFD.Hope that helpsKris

Just a small point.As Kris says, on the 300-500 series teh AFDS will capture teh GS regardless of whether you have a LOC capture. This has been corrected in the NG and the aircraft will ONLY capture the GS AFTER established on LOC and it is quite a normal procedure to arm APP as soon as you are cleared for it by ATC. Although some of us old farts still go through the old two step process. Always a good isea if you are flying both EFIS and NG.. saves embarrasing scrambles for the knobs :)Rgds,

:-) OK Brad, thanks for the info. And when you say "...as soon as you are cleared for it by ATC" - does that equal to when ATC says "You are cleared for ILS runway XX, call when established"?Cheers,

RandyI got your e-mail but I cannot reply, I just keep getting error messages from yahoo.com. can you send me another e-mail with another e-mail address so I can reply to you.CheersKris