SARS-CoV-2. It's hard to believe that something so tiny has managed to bring so many economies and industries to their knees. With closed borders and blocked tourist destinations, commercial aviation has been one of the hardest hit, and major airlines only have two options: retire the oldest aircraft and store the rest. Placing an obsolete model in a graveyard doesn't sound that complicated, but what about those aircraft that must return to the sky?
The COVID-19 pandemic has trapped us in a perverse dance. Countries open, close, relax, and adjust based on the number of detected cases. As expected, these maneuvers conflict with activities that rely on mass transportation of people... and that's how we arrive at commercial aviation.
Airlines are in crisis, no doubt about it. Some try to restart their structures with offers and future ticket purchases, but today they are basically a shadow... and they also have thousands of aircraft grounded. That raises several questions: Where do you store them? What kind of care do they need? How long can you keep them out of service? Questions that seem basic on the surface, but require a more detailed exploration.
The Ideal Storage Location
The first step is finding a good location. Most traditional airports were not designed for long-term storage, and there are climate requirements that must be considered. The 'ideal place' for an aircraft is dry and relatively cold. There are two reasons: on one hand, humidity accelerates corrosion, stimulates microbial growth, and promotes the appearance of fungi both inside the aircraft and in specific elements (e.g., fuel tanks). On the other hand, excessive heat damages anything based on rubber and adhesives, and ultraviolet light can cause additional damage.
If that 'cold and dry' combination is not available, airlines are willing to accept regions with higher temperatures, as long as maintenance personnel are nearby to work on the aircraft if necessary. For example, Qantas decided to let its Boeing 787s rest at Victorville airport, since humidity in California is lower than in Australia, and the company has a team of engineers stationed in Los Angeles.
Active Parking vs. Deep Storage
Another important distinction is between 'active parking' and 'deep storage'. Aircraft under active parking are essentially ready to fly, stored at airports or very close to their routes. Under this configuration, an aircraft would take no more than 48 hours to return to service. Landing gear is lubricated, and all openings are covered, with special attention to engines. They are also 'taken for a walk' to prevent deformation of tires, and periodic reactivations of electronics and hydraulic systems are performed.
https://old.neoteo.com/que-hacen-los-pilotos-cuando-el-avion-esta-en-piloto-automatico/Deep storage demands another kind of work. Engine lubricants are replaced with anti-corrosion agents, and in more extreme cases, they are completely removed for return to the manufacturer. If a pause is too long, some airlines will probably prefer to retire or recycle the aircraft rather than keep paying for storage. That is one of the reasons they are retiring 747s around the world.
Source: Hackaday
