mikem wrote:

Yes, that works, but you will have a hard time hearing the 2" speaker
in the handheld, especially if you are wearing aircraft headphones.

The observer operates the HT, via an earphone under his flight headset.
As the pilot I would remain on the air radios. From what I
understand, any direction from the ground would be relayed to me via the
intercom.

Unfortunately, we don't have an aux or available open position on our
comm panel.