Timely bulletin has advice for engine preservation

Australian Lightwing GR 912 light sport aircraft

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.



  1. Pity they didn’t mention WD40 or similar and what to do with it. One shouldn’t have to go to specific engine manuals (if the have storage information at all) or special directives. You can simple spray it into the air inlet as the engine spools down.

  2. ” WTF”is right . I have not heard anything about shutting down the GA industry in Australia,I know that NZ has gone down that path.I am going down the same path as Walter, If I decide to commit aviation any time I choose to .I reckon that flying is the best form of social distancing I know of.If I was to decide to give my aircraft a bit of a long holiday I will be following best practice in long time storage and following the aircraft manufacturing instuctions,or my LAME’s past experience as a guide.

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