Hello, No I don't think it's a bug or something, but most likely it's because of me.I have done some flight so far, and I'm having some problems with the HGS. For example today, I did a flight from LFBE to EHRD. When I was in my descent, I programmed the HGS for approach. I set the airport elevation of 49 feet, so it said "EL>49", then I clicked RWY again to programm the runway length. I set 7218 ft, and pressed ENTER. I left the mode on default just like in the tutorial flight. MODE set to PRI, and STBY set to IMC A III. I set the ILS frequencies of 111.90 in both the left and right radio, I set a course of 238 degrees in both course windows, I armed APP at about 3000 ft. Then my aircraft was capturing LOC and G/S. I put the gear down at about 2000 and set the FAS of 142 kts, and set flaps to 30 degrees. I opened the HGS, all the info was displayed correctly. I disconnected the A/P for a manual landing. Then at about 1500 something strange happened. A lot of info on the HGS dissappeared, the speed, altitude, compass, G/S. Only V/S, F/D and turn indicator was still being displayed. Then I took a look at the HGS mode window at the center pedestal, it had suddenly changed mode without any command! I can't remember correctly which mode, but it wasn't in PRI / IMC A III anymore. Can anyone help me? Thanks in advance, Arjen Vandervelde

Sounds like AIII mode, especially as you mentioned having AIII in STBY. Check out page 583 of FCOM2 to see if that looks like what you saw.

That's AIII mode indeed, but I want it to stay in PRI mode, any idea why it's jumping to another mode?

I've found the cause of this "problem". Infact, it's not a problem, but just my own stupidity. I had the option "Auto A III Mode", inside PMDG/Aircraft/Equipment in the FMC to "ON", that's why it's automaticly jumping into A III mode at 1500 ft. Right now it's only jumping into another when I command it myself, so problem solved.