APP light

[cz4hkr]

Hi,
Does somebody know why APP light is still on?

it should be off after LOC and G/S is captured.

I hope I am right and there is another bug in PM MCP

regards, Jan

[Trevor Hale]

APP Light? After LOC Mode is intercepted and APP mode is engaged, the APP mode, and Light will continue until Autopilot is disengaged.

I guess I don't understand your question.

Trev

[cz4hkr]

in attachement is screenshot of 737-800 manual.

Pilots of czech airlines claim that this behaviour of PM MCP is incorrect.

[tomenglish2000]

Hi Jan.

I fly the 767 in the sim and on that aircraft you ARM the LOC mode, when localiser is captured you then ARM the APP mode. When APP mode captures the glide slope it engages and it takes over from the LOC mode. The LOC mode light then goes out and you are left with the APP mode light.

I expect the 737 autopilot to behave the same.

I would suggest that the manual has a mistake and that it actually means the LOC mode light and not the APP mode light.

Tom.

[Trevor Hale]

I agree,

Also the fact that the NOT FOR OPERATIONAL USE is written across that perhaps is an indication this was for a simulated aircraft too, and not the real thing.

Either way, After Loc Mode, the LOC LED does disengage in PM and only the APP light remains illuminated.

Perhaps you should ask a real 737 pilot, I am sure there are some around here.

Trev

[JonathanRichardson]

Hi

the 737 APP mode light is different to other Boeing types, the theory being that as it is not possible to deselect the mode or change once the GS and LOC are in full capture, the APP mode light on the MCP goes out. The only way to deselect is AP off / cycle FD / TOGA or re-tune a nav. *But* it might be that Boeing are changing/standardising the 737 in this regard towards the later Boeing types, it is listed as an option and that is the reason we are hesitant to jump to change it right now and consider it low priority given that the primary indication is the FMA anyway. It is on the list to look at again...

Regards
Jonathan Richardson
Project Magenta

[cz4hkr]

thanks for info.

I will create SIOC script to correct this behaviour, is anybody interested in this?

[dvincent]

Hi guys,

both app status are possible.
Illuminated when engaged is the standard but there is another configuration possible as an option. I've done a copy/paste from the AOM.

********************
APP Mode
The approach mode arms AFDS to capture and track localizer and glideslope and
can be engaged for dual or single autopilot operation.
One VHF NAV receiver must be tuned to an ILS frequency before approach mode
can be engaged. With one VHF NAV receiver tuned, onside AFDS is enabled for
guidance and operation.
For dual autopilot operation, both VHF NAV receivers must be tuned to the ILS
frequency and both autopilots must be selected in CMD prior to 800 feet RA.
APP mode operation:
[Option - G/S capture inhibited before LOC capture]
• localizer must be captured prior to glideslope
• localizer can be intercepted in HDG SEL, LNAV, or CWS R
[Option - EFIS/MAP]
• 1 CH annunciates in A/P Status Display after localizer capture
• for single autopilot approach, 1 CH remains annunciated for entire
approach
• for dual autopilot approach, 1 CH annunciation extinguishes when
second autopilot engages and FLARE armed is annunciated

[Option - PFD/ND]

• SINGLE CH annunciates in A/P Status Display after localizer capture
• for single autopilot approach, SINGLE CH remains annunciated for
entire approach
• for dual autopilot approach, SINGLE CH annunciation extinguishes
when second autopilot engages and FLARE armed is annunciated
• glideslope capture occurs at 2/5 dot below glideslope
• APP switch light extinguishes after localizer and glideslope capture.
After localizer and glideslope capture, APP mode can be disengaged by:
• pushing a TO/GA switch
• disengaging autopilot(s) and turning off both F/D switches
• retuning the VHF NAV receiver.

[JonathanRichardson]

>I will create SIOC script to correct this behaviour, is anybody interested in this?[/QUOTE]

Hi

Just for clarification, it is correct as is, it is a Boeing Option - there are *hundreds* of Boeing options! So, it would be incorrect to state you are writing a script to 'correct' this behaviour..... don't get too mixed up / caught up with all the various options, they are endless.

Regards
Jonathan Richardson
Project Magenta

[dvincent]

Hello Jonathan,

your statement is 100 % correct.

Greetz from Holland,

Dirk