|Aircraft preservation during lockdown - Some guidance from the AOPA Maintenance Working Group|
As the pandemic proceeds and we are asked to stay indoors, our aircraft remain grounded, not an ideal situation. Aircraft, and in particular the engines, survive best if used regularly. So what can we do?
If you have a traditional older design engine and your maintenance organisation has access to your aircraft then consider “winterising”. They will probably change oil and spray a preservation fluid mist into the cylinders. They will also seal up the engine to isolate the internals from damp air. Ideally, they will move aircraft to a dry hangar or storage facility. Once done, the engine should survive for several months without degradation and not require any further intervention until you want to fly again. At this point, ask the maintenance organisation to return the engine to service.
If you cannot reach your aircraft due to the lockdown, then little can be done. However, we do suggest you discuss this with your maintenance organisation during the lockdown so that a plan can be formulated for getting the aircraft ready for flight after several months of inactivity. They may remove plugs and rocker covers to spray in some oil before the first start, for example.
If you have a Rotax, these seem to better survive longer periods of inactivity without significant consequences although even these would still benefit from winterising if possible. When finally back with the aircraft in a few months time, try pulling the engine through and if it feels quite normal then you are probably okay to proceed. However, if it feels rough and/or makes unusual noises as you start turning the engine over, stop and talk to your maintenance organisation!
If you are able to access your aircraft without infringing the government edict, then consider plugging the exhaust with newspaper and then a plastic bag, and cover the intake with a plastic bag. This should help keep moisture out. A dehumidifying device will help, perhaps a low wattage cabinet heater in the engine compartment. Also, a box of desiccant for the cockpit can help reduce damp and protect upholstery, avionics and instruments to some degree. It is now generally advised that you do NOT turn the engine over with the prop by hand periodically as this will wipe any residual oil film off the cylinder walls, camshaft lobes and tappets, thereby aiding corrosion onset. Also, do not be tempted to start and run the engine on the ground as you will not achieve normal operating temperatures, as in flight, and the oil can get increasingly contaminated which also aids corrosion. It can however, be a good idea to leave the fuel tanks full to help avoid condensation build up. We will come back to thinking about fuel when this lockdown is over as fuel does have a shelf life.
For those who want to know more, try: