Ask Captain Lim - Why the plane often pitches up or down during the ILS approach?

When on approach hold flying the glide slope and disconnecting autopilot for manual land, the aircraft often pitches up or down - usually down, sometimes significantly, sometimes just slightly. Obviously I need to correct the pitch manually to keep on the glide slope. Strangely, sometimes, after disconnecting AP, the aircraft stays exactly on the glide slope, without pitching. Is there any trick to this, perhaps the way the autopilot is connected initially?

The sequence I usually use:

After TO at approx 2000 ft (approx 1500 fpm rate of climb) engage AP master and then engage the preset altitude and heading holds.
Change heading after ATC instruction (knob).
Change altitude after ATC instruction (knob).
Usually lower the rate of climb to approx 1000 fpm (knob).
After reaching altitude, fly with the AP engaged and prescribed heading and altitude.
After instruction to land ILS usually use AP to get below the glide slope and head to it under approx 20 deg angle.
Level at 20 deg angle to GS and disconnect heading hold only, AP still connected.
Manually line up heading with the runway direction. (Still on AP for altitude).
When established on both glide slope and direction, engage Approach Hold.
Aircraft usually swivels a bit and starts descending. Eventually holds the glide slope and direction pretty well.
Until the AP disconnect ....when experiencing the pitch change, see my question above.

Many thanks

Best regards,

Peter (With BA for 38 years)

Hi Peter,

I hardly fly the FS2002/2004 anymore but I still think it is the best software around for amateurs who want to get a feel of flying the airplanes at home.

I had add-ons for the PSS Boeing 777 and the Airbus A320 PIC installed onto the MSFS2002 Professional Edition and found them fun to play with.

In the past, you would have read that I complained about the PSS Boeing 777 having some glitches in my software and tend to pitch down below the glideslope during the autoland in the final approach. I had to use VS to control the descent rate. (In a real plane, it does not behave as such) So, it was not perfect and I have not gone to find out what had caused it to do so.

Perhaps some MSFS experts can enlighten you further...