Can you use the glideslope in a localizer backcourse approach if the glideslope indication is moving on your PFD?

Using the glideslope in a localizer backcourse approach when its indication is moving on your Primary Flight Display (PFD) is not advisable because it indicates a false glideslope. In a backcourse approach, the glideslope is not aligned correctly with the localizer antenna, leading to unreliable vertical guidance. The glideslope signal is intended for use with a forward course, and when flying a backcourse, the aircraft is actually experiencing signals that may mislead the pilot regarding the proper descent angle.

In this scenario, the movement of the glideslope indicator signifies that the pilot could be misinterpreting the information, as the equipment is designed to function optimally when the aircraft is on the correct approach course. Therefore, reliance on the glideslope under these circumstances poses a risk, making it essential to disregard that indication and focus instead on the localizer for lateral guidance and any applicable minimums for the approach.