Air Tas had a Chieftain some time between May 75 and May 77. No idea of rego, but fortunate enough to be given a drive from the right seat, and even a landing at Launy. Trusting soul who ever he was.
Edited to add, this web site suggests VH-TAS
Air Tasmania / Airlines of Tasmania
Terry Burns (ex Ansett Viscounts I think) was chief pilot, but he only flew the DC-3 I think (memory being what it is).