An airworthiness bulletin published three years ago is worth a read if you are considering laying up your aircraft in response to the Covid-19 pandemic.
First, it’s important to state that CASA has imposed no restrictions on general aviation activity in response to Covid-19; indeed, we have extended certificates and licences to allow you to fly. You are free to fly your aircraft so long as you comply with public health directives.
But if you decide to give your aircraft a holiday for the duration of the current situation, Airworthiness Bulletin 85-021 Issue 1 – 29 March 2017 has useful information on preservation of unused piston engines, that you can use in conjunction with the manufacturer’s recommendations. Information from aircraft and engine makers should be your first reference but you may find useful tips in AWB 85-021.
Airworthiness bulletin 85-121 says aircraft piston engines last longest with regular use and maintenance. Corrosion and contamination can begin within a few days for aircraft stored in humid coastal locations, but engines stored in more favourable conditions can go several weeks between flights with out ill effects. AWB 85-121 concurs with the manufacturer’s recommendation that engines which won’t be flown for 30 days or more, should have a preservation regime.
The bulletin goes into detail about moisture formation in unused engines, analyses some widely used but ineffective preservation measures, and discusses the correct type and freshness of engine oil for preserving unused engines.