localizer/glideslope blinks yellow?

[Guest tmetzinger]

Flying in to KMHT on a single-channel ILS approach, I noticed the LOC and GS scales blinking in yellow for a second, then going back to white.Can't find any reference to this behavior in the PMDG manual, and the closest I can find is in Bulfer, who states that a two second self-test is performed at 1500 RA ONLY IF DOING AN AUTOLAND.Since I only had one CMD button engaged, I wasn't expecting this.So, either a minor nit to pick, or something else was going on, and I'd like a clue what it was.

[Kosta 122]

I noticed this also, though can't remember if I've seen it when approaching manually.

[Guest wee_davie_2612]

I get it whenever I pass 1400ft Rad Alt. Doesn't matter if I 'm flying Dual, Single, or full manual.You also get it a number of times in the same approach if going over uneven ground!CheersDavid

[Guest zip]

It appears that this happens when the dual channel kicks in autoland as before the flash it displayed "SINGLE CH" and after that it went to regular "CMD", indicating duals.

[Guest Andrea]

Yes, during approach it blinks (yellow) when changes from "single channel" to "autoland". Before, with only 737 600/700, the behaviour was different. Andreahttp://www.precisionmanuals.com/images/forum/800driver.jpg

[744pilot 0]

It seems to me logical that at 1500FT RA the single CH will be replaced with CMD. and by that it also flash in yellow. (the LOC and GS scale)

[crvm 0]

I could be wrong but where exatly does it SAY that a single channel approach will NOT perform checks at G/S? Single CH should STAY if only one A/P is engaged when passing 1500 RA (NOT 1400 RA) and the ONLY differences in a single channel approach areNo automatic FLARE, flare manually**No automatic LANDING, disengage A/P at least be 50' RANo automatic GO-AROUND F/D only.**Our 700 NG pilot stated that the 700 NG will perform an AUTOLAND IN SINGLE CHANNEL! It is not CERTIFIED to do so (no cross checking) BUT regardless of what is written it CAN autoland and FLARE in SINGLE CHANNEL. This still does not mean that we should have SINGLE CH removed at 1500' RA. [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 |

[Guest wee_davie_2612]

Hey all,I should clarify what's happening to me. The deviation indicators blink yellow even if I'm hand flying the approach with guidance from only the FD. It doesn't only happen when changing from single to dual. Apart from the auto land in Tim's tute, I've only performed one full autoland so I'm pretty sure I'm not mistaken as to when it happens :).I found this in the AOM:http://forums.avsim.net/user_files/74124.jpgCheersDavid

[Guest tmetzinger]

>> I could be wrong but where exatly does it SAY that a single>channel approach will NOT perform checks at G/S? Single CH>should STAY if only one A/P is engaged when passing 1500 RA>(NOT 1400 RA) and the ONLY differences in a single channel>approach areBulfer 737 Cockpit Companion - 9/1/2003 - 38th printing. pic attached of page 127, the section on the EADI.http://forums.avsim.net/user_files/74159.jpgThe key reference is (test only if doing an "autoland", which requires both autopilot paddles to be engaged).As I parse that, it SHOULDN'T do the self test if in a single channel mode.But, maybe in later models, they changed the logic and Bill Bulfer hasn't caught up yet.Maybe Iz or one of the other drivers can shed some insight.Oh, and maybe this will help the backcourse problem too!Best wishes,

[crvm 0]

Well I will agree that it appears that is indeed the case for the yellow blinking, not sure about the fix, something Lefteris can comment on but I will agree that the flashing should not be there for the single channel since there is not any cross checking. But even if this is corrected does not mean that they will modify the ability of the single channel flare and landing. Simply do not ever take the A/P down that far because in real life you would no longer be flying a plane ;-)[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 |

[Guest tmetzinger]

>> Well I will agree that it appears that is indeed the case for>the yellow blinking, not sure about the fix, something>Lefteris can comment on but I will agree that the flashing>should not be there for the single channel since there is not>any cross checking.>> But even if this is corrected does not mean that they will>modify the ability of the single channel flare and landing.>Simply do not ever take the A/P down that far because in real>life you would no longer be flying a plane ;-)>>It's not a problem - I can live with the yellow flashing. I really just wanted to be sure that it was caused by the self-test sequence and not something else.

[zubart 5]

>> I could be wrong but where exatly does it SAY that a single>channel approach will NOT perform checks at G/S? Single CH>should STAY if only one A/P is engaged when passing 1500 RA>(NOT 1400 RA) and the ONLY differences in a single channel>approach are>>No automatic FLARE, flare manually**>>No automatic LANDING, disengage A/P at least be 50' RA>>No automatic GO-AROUND F/D only.>>>**Our 700 NG pilot stated that the 700 NG will perform an>AUTOLAND IN SINGLE CHANNEL! It is not CERTIFIED to do so (no>cross checking) BUT regardless of what is written it CAN>autoland and FLARE in SINGLE CHANNEL. >> This still does not mean that we should have SINGLE CH>removed at 1500' RA.>> > >>[h4]Best Wishes,>Randy J. Smith>http://www.precisionmanuals.com/images/forum/betaimg.jpg>>AMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA>@535/1000 | WD SATA 80 GIG | 512 DDR 400 |I'm pretty sure at 1500 feet RA, each pilots deviation alerting system self-tests in Single and of course Duel channel. I'm not totlally sure about FD mode, but I think it does.I don't think it's possible to autoland using Single Channel. You'll never get FLARE ARMED for one thing and without that how is the autopilot going to flare? The way the thing works in DUAL CHANNEL is the autopilot using the least force is in charge and when the other autopilot disaggrees with the one in charge they both disengage, giving controll back to the pilot. FloydFloyd

[crvm 0]

Ok guys this is now checked on the real bird today by one of our NG pilots, The confidence check (yellow flashing) in SINGLE CHANNEL is DONE! As for the no flare on the FMA, this is also true BUT was confirmed by another NG pilot and will indeed FLARE. Point about thew flare thing is that one would NEVER do it in real life, so any of you who are trying this are not backed up by any real world procedures! EDIT: One more note about the no FLARE on the FMA, to me this is simply Boeing not giving any false impressions or ideas to the pilots that they MUST land manually but this too is only because the single channel landing is not CERTIFIED but does not mean that it will not![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 |

[Qavion 19]

"You'll never get FLARE ARMED for one thing and without that how is the autopilot going to flare?"The Boeing Maintenance Manual confirms what Randy and the beta team are saying. It is part of the basic design of the A/P, but the aircraft is not certified to land using a single A/P... therefore, FLARE is not annunciated and the BMM recommends disconnecting the A/P at decision height.Hope this clarifies things.Regards.Ian.