First with a turbine APU maybe, but nothing says an APU has to be a turbine of course. The name "Auxiliary Power Unit" contains no implication of power source.
What's a "true turbine APU"? Putt-putts (and they didn't, they made a very healthy clamour) provided power for engine starts and what's more powered all electrical systems, not just "a lot of them"(!). They were therefore "true"APUs.
Last edited by Agaricus bisporus; 30th May 2012 at 10:13.