Issue with the AP APPR bouton

[Guest JUJU78]

I have a small issue with the autopilot appr bouton on the PMDG 737-800. I made some flight with this plane since two month and at each time and at any airport when I engage the appr bouton the bouton light turned on, the plane intercept the localizer and the glide and the appr bouton light turned off.The plane follow correctly the ILS but the light is just off.I have set the ILS Frequency on the two NAV, the CRS is set following the MCDU information.It's not a big issue but it's not realistic to make a CAT3 approach with the APPR bouton light off...If somebody could help me on this issue... Thanks in advance. Julien MOREAU

[JAT 185]

Cant help you but i have the same problem sometimes.Nebojsa

[basa 0]

>It's not a big issue but it's not realistic to make a CAT3>approach with the APPR bouton light off...>Julien, that is the way it works. After LOC intercept and GS capture the lights in the buttons turn off (as to say the have already done their mission).Better take a look at your PFD and see if you have a CMD (dual channel) annunciation over the artificial horizon, and in the FLIGHT MODE ANNUNCIATOR (upper block of the PFD) you have the following:MCP SPD VOR/LOC G/S FLAREIf you have that, you are in a perfect CAT III autoland configuration, and forget now about the lights in the buttons.Also, when passing 1500 ft radio alt, the ILS deviation indicators will autocheck and flash yellow.Jose Luis

[Guest JUJU78]

Jose,Thanks for your answer,I have the good indicatopn on the PFD. I did not know that is the way it works.Thank you very much for your help.Julien MOREAU

[falcon999 24]

The documentation can be a great reference tool. :-)From the documentation included with the product "Section 9, Automatic Flight Management Systems" (09_AFDS_SYSTEM_737_678900_V14.pdf), Page 9-8, "Approach Modes" section, 7th paragraph:"When 2/5 dots below the Glideslope, the APP switch on the MCP will extinguishes after localizer and Glideslope are captured."