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Up close of a stored SpiceJet 737 MAX at Paine Field following the global grounding of the aircraft earlier this year. (Photo: AirlineGeeks | Katie Bailey)

The Process of Preparing Aircraft for Long-Term Storage

With COVID-19 decimating the travel industry, demand has dropped to almost nothing. Planes have been sent to storage for who knows how long. Many aircraft will be brought into service as demand picks up but some will be kept in storage longer since it will likely take some time before demand returns to normal. However, there is a whole process to maintaining planes in storage and it isn’t as easy as parking in a corner and leaving some reflectors in the windshield.

The first thing that goes into parking an airplane long-term is the weather. Continuous exposure to freezing temperatures can damage tires. In addition, the moisture in the air can cause corrosion. This is why many aircraft are sent to aircraft storage locations in dry climates with little precipitation.

In some cases, where aircraft are put into a deeper state of storage the engines are preserved and sensitive parts such as batteries are removed. While this makes it cheaper to store the plane it limits how quickly the plane can be brought back into active service again. It can often take 120 hours of work to get a plane in airworthy condition after storage.

Protecting the Engines

One of the biggest threats to aircraft in storage is rust on the engines. Aircraft engines are built with the idea that they will be used regularly so any length of grounding requires proper maintenance. Engines that aren’t operated long enough will rust due to water condensation that often comes from storage.

For long time storage preservative oils must be put on various parts of engines to prevent corrosion. These special oils work better than the regular oil used in aircraft engines at preserving engine parts

In addition, the engines are ‘pickled.’ The oil is replaced with a corrosion prevention solution and desiccant bags are placed in the inlets before they’re covered. This whole process prevents corrosion and damage to the engines. Any openings in the fuselage are also either covered with special tape or screen that will prevent insects or small animals from calling those areas their new homes. It’s actually quite important to check aircraft for things like nests before operating an airplane. For shorter-term storage it is necessary to spool up engines weekly. Engines should be idled for 15 to 20 minutes to vaporize any moisture that may have collected in the oil and fuel systems. Engine parts should be covered in a new coating of oil to prevent corrosion.

Auxiliary power units are generally powered up weekly along with flight computers

Other Aircraft Checks

Every week, airplanes are generally checked for corrosion; every two weeks electrical systems are powered up and checked. About once a month, planes are moved a third of a wheel’s turn to prevent flat spots in on the tires. Carpets and seats are also checked for mildew and fuel checks and checked and drained if needed to prevent water build-up which can cause the growth of bacteria and fungi. Every three months the rudder and other control mechanisms are powered up and moved.

On hot summer days, doors are opened to provide ventilation so cabins aren’t damaged by the heat. Though this can create problems before the aircraft is entered into service due to dust and sand ending up inside the aircraft which then either have to be vacuumed out by hand or wiped down which can end up being a time consuming and expensive process.

Whether it’s long-term or short-term storage of aircraft there is a lot that goes into making sure airline assets stay in a condition where they don’t sustain expensive damage and can be brought back into service relatively quickly. A good rule of thumb is to always assume an aircraft will be in storage longer than expected. This way an aircraft can be prepared appropriately for storage from the onset instead of labor-intensive preservation techniques being implemented down the line


  • Hemal took his first flight at four years old and has been an avgeek since then. When he isn't working as an analyst he's frequently found outside watching planes fly overhead or flying in them. His favorite plane is the 747-8i which Lufthansa thankfully flies to EWR allowing for some great spotting. He firmly believes that the best way to fly between JFK and BOS is via DFW and is always willing to go for that extra elite qualifying mile.

Hemal Gosai
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