Some aircraft, particularly gliders, have unreliable airspeed indicators when slipping
.. interesting comment .. can you cite any aircraft for which the ASI is much good in a slip situation ? PECs are pretty sensitive to such abuses ..
Good point, John. Sloppy writing on my part. I should have said "some aircraft have MORE unreliable airspeed indicators when slipping". I have flown some gliders with "pot pitots" in the nose, where the needle goes almost to the stop during a slip.