Well done, that man.
why you should run a turbine engine at low power before shutdown
Without the exam answer options, it is only practicable to observe that most SOPs for turbines require a period of low power operations prior to shutdown to stabilise temperatures, especially in the turbine blades and disc.
Similar requirements exist for motor vehicles with turbo supercharged engines, especially on higher power engines such as truck diesels.
So far as oil considerations, the following report makes interesting reading
www.tsb.gc.ca/eng/rapports-reports/aviat...14Q0068/A14Q0068.asp
.. taking a sample and getting green
This is a curly one as the resulting colour is going to be heavily dependent on quantities. The following CASA AWB makes useful reading
www.casa.gov.au/sites/g/files/net351/f/_...worth/awb/28/003.pdf. The following Shell information may also be useful
www.shell.com/business-customers/aviatio...tion-fuel/avgas.html.
There used to be a multiplicity of fuel grades and colour was a useful marker for correct fuel grade. Nowadays, Australia only supplies 100/130 (green) and 100LL (blue). A good read for those interested
en.wikipedia.org/wiki/Avgas
Maybe "100/130 AVGAS or AVTUR".
100/130 green, AVTUR varies from pretty well colourless through to a straw colour. Having said that I can't ever recall seeing any colour in AVTUR.
Doesn't AVTUR dissolve into AVGAS
That's something I've never given a thought to. I would be interested in the answer as well ..
Although way beyond a civil pilot's routine needs, the following paper provides a lot of information for anyone who might be interested
www.dtic.mil/dtic/tr/fulltext/u2/a132106.pdf