[aetherspawn]

Dumping the I part instead of just tuning it properly is kind of an insane thing to do … speaking as an actual controls engineer

[gbgarbeb]

"Actual controls engineers" use PD loops (no I) all the time.

[rcxdude]

In some circumstances, yes (usually when the system itself acts as an integrator somehow). Aircraft controls do not strike me as a system where this is sensible (trimming an aircraft is basically an integral control process).

(d'oh, should have read the specific context: in the case mentioned, it is where the system acts as an integrator (pitch -> altitude), and so pure P control is pretty reasonable)