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A COVID-19 logistical puzzle: how airlines safely store their aircraft

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When the COVID-19 crisis hit Europe and North America in earnest in March, airlines faced an unprecedented drop in demand for flights and a growing list of countries where they could no longer land. As air traffic nosedived, many aircraft were parked without a clear idea as to when exactly they would fly again. The result was a logistical puzzle at many airlines as operations departments, fleet planners and engineers had to come up with a storage plan that would allow for safe parking of aircraft for as long as necessary and allow for an efficient return to service as and when demand picked up again.

This presented a number of challenges: finding space for dozens or even hundreds of aircraft; ensuring the right mix of aircraft for the flights that did continue to operate; deciding which aircraft were likely to be parked for just a few months and which might be mothballed for longer; and ensuring that those planes could be kept in tip-top shape for as long as it would take.

For most airlines that meant parking a number of planes at hubs and airports where they have maintenance facilities, while at the same time sending other aircraft to dedicated storage locations, ideally in cool, dry locations. And while airlines could handle some of the required ongoing maintenance of parked aircraft with in-house technicians and engineers, some of the work has been outsourced to firms dedicated to aircraft storage – a highly specialized field.

Nearly two dozen Lufthansa widebody Airbus aircraft stored on a deactivated runway in Frankfurt.

Preparing for storage

Aircraft storage looks a little different depending on how long the storage is expected to last. Since the coronavirus pandemic hit, the majority of airplane groundings have been more on the short-term side, with an expected parking of up to three months or so. But either way, planes need to be prepped extensively for parking and then regularly inspected and moved, with some systems started up and given a test run. For example, engines may need to be turned on and run for 15 minutes or so once every week or two depending on the type. Tires are a major concern, so aircraft generally need to be moved, also once every week or two. Electrical systems will likely need test runs and checks at regular intervals as well.

Just to get the aircraft ready for storage requires an extensive process. The cabin is deep cleaned before being sealed up, and all windows covered. Moisture is also a concern, especially if the aircraft is parked in a more humid environment. Qantas for example says that one A380 needs over 100 kilograms worth of silica moisture absorption sachets throughout the cabin and engines to keep things dry. Plugs and covers are applied to all external holes and sensors to keep not only dust and dirt but also insects and birds out. Anti-fungal agents are likely to be needed in fuel tanks, and certain cables and the landing gear will need lubricant applied. Everything is geared towards ensuring the plane stays frozen in time, as it was when it was parked, so that it can be put back into service as quickly and safely as possible.

Tarmac Aerosave is a specialty outfit based in France that offers tailor-made storage solutions as well as maintenance, heavy checks and if necessary also dismantling and scrapping of the plane. For them, the crisis has meant a boom in the storage side of the business, although they’ve seen a steep drop in customers getting regular maintenance done. The increase in storage business doesn’t quite make up for the loss in maintenance, they say, but the storage demand is helpful nonetheless.

Former Transaero 747s in Teruel
Former Transaero 747s stored in Teruel.

Tarmac Aerosave has a large aircraft parking site in Spain, at Teruel (TEV) in Aragon, which benefits from a desert climate and is at a 1000-meter elevation, so it’s not as hot in summer. They have space for around 225 aircraft there. That’s in addition to a 65 aircraft capacity in Tarbes, south of France, and space for another 25 or so at a third site in Toulouse.

“By the end of June we will be full for the first time in our existence,” says Grégory Beyneix, VP Programs & Operations, noting that they’ve been actively looking for more sites and plan to announce a new one this week. So far they’ve received 60 aircraft for parking in the past two months, already half the number they received in all of 2019. They have a number of aircraft from Lufthansa and Air France in storage, as well as planes from all the major lessors – both narrowbodies and larger models and from just about every major manufacturer.

Keeping the aircraft ready to fly

Airworthiness of aircraft after several months on the ground is a common concern for the traveling public. Luckily that’s a concern for manufacturers and aviation regulators too – aircraft are filled with finely tuned and sensitive machinery, so the standards for basic upkeep and maintenance are extensive and follow a very clear and detailed process even for aircraft stored short-term.

“Some people think after long term storage the aircraft won’t be in good condition, but we make sure they’re maintained so they can be returned to service quickly,” says Beyneix. “After active parking you can return the aircraft within a few days. Long-term, it takes a few weeks. These ‘bridging’ tasks are our specialty.”

Qantas has been especially good about giving its customers a glimpse into the extensive work that goes into this. When demand for air travel disappeared in March, the Australian carrier parked 94 aircraft out of a total fleet of 129, mostly at airports around Australia but also in the US. That includes six of its A380s and all of its 747s – the largest aircraft in most fleets were the first to be grounded due to the lower demand – but also a number of 737s and even 787s and A330s.

A Qantas A380 stored in Sydney.

Sydney (SYD) has 20 aircraft parked around the airfield, Melbourne (MEL) has 16, and Brisbane (BNE) has the most with 28, but smaller Australian airports like Adelaide (ADL) have received a few here and there as well. Because these are parked at active airports, odds are they’re expected to fly again. The three Qantas 747s that were recently sent to the Mojave Airport (MHV) in California’s desert, however, have reached the end of the line.

Qantas says there are plenty of considerations that go into deciding where to put aircraft. “It is about space but also access to maintenance engineers,” explains John Walker, Head of Line Maintenance at Qantas. “Aircraft require regular periodic checks and maintenance when parked and wherever possible Qantas utilizes our own engineers to carry out this work.”

There is also the matter of weather and atmospheric conditions in Australia, which can be intense. “The strength of the Australian sun and the effect of UV light on our cabin and cockpit interiors drives us to ensure that all of the cockpit and cabin windows are either covered by the installed window shades or by attaching additional material to shield the aircraft from the sun,” says Walker. Any parked aircraft would have their windows covered, especially in the flight deck, but in a place like Australia it’s especially important to get it right. And specific considerations will exist in any given place, as Walker explains. “As we head into winter, particularly in Melbourne, Adelaide and Avalon, as the strong winter southerly winds roll in off the ocean we need to ensure that our aircraft are safely chocked, have additional fuel onboard to help weigh them down and ensure a sufficient gap such that if the aircraft did move in the wind, also known as ‘weathervaning’, then we minimize the risk of damage.”

Qantas and Jetstar aircraft in Avalon
Jetstar and Qantas aircraft stored in Avalon

Qantas says its maintenance team, which includes over 700 engineers dedicated to both operational and parked aircraft, is up to the task of managing stored aircraft and keeping them in flying condition. They do that by following the guidelines set out by the aircraft and engine manufacturers to the letter.

Read the storage instructions

A spokesperson for United Airlines seconded the notion that it’s vitally important to make sure all steps are rigorously followed no matter where the plane is parked. “While aircraft are on the ground, we perform routine preventative maintenance tasks in accordance with the manufacturer’s specific storage instructions. United Tech Ops technicians, engineering, quality control personnel and others are responsible for performing and overseeing the storage of our aircraft at our in-house locations. At the off-site locations where work is being performed by our FAA approved essential maintenance providers, United has a vendor management team providing oversight of maintenance activity being performed.”

United Aircraft stored in Cleveland
United Airlines aircraft stored in Cleveland

United says the majority of its fleet are stored where United has maintenance facilities, though airplanes requiring more substantial maintenance prior to returning to service have been moved to offsite storage locations. For United’s in-house teams, the airline points out it’s a good thing technology is available to keep track of the status of each of hundreds of parked aircraft – something that would have been much more labor-intensive without an iPad and the right software. “Our teams use tools to electronically access critical information about the processes and procedures required to maintain a stored aircraft. In addition, we have developed web based solutions that illustrate the condition and status of every aircraft scheduled for, or currently in, an approved storage program,” United’s spokesperson explained.

Bringing aircraft back to life

What remains a question mark for everyone in the industry is whether many of these planes can be returned to service in coming weeks and keep flying for good, or whether some will end up returning to storage or even staying parked for years instead of months. At Tarmac Aerosave, Grégory Beyneix says the mix is around 50/50 between so-called active parking, for storage of just a few months, and long-term parking.

“In such a period because airlines hope to have them back in service as soon as possible, in most cases they put it in active parking,” says Beyneix. “And depending what happens they can switch it to long term storage if necessary. We have other aircraft that are waiting for new lessees, and it’s unclear how much time that will take.”

As would be expected, Beyneix points out that the longer you park an aircraft, the more you need to do with it to keep it in good shape and then to return it to flying condition. If storage lasts a long time, the plane has to actually be flown at the two year mark. Short of that, full landing gear tests need to be done every six months during long-term storage, as well as upon return to service. Though he notes that Airbus has given some approvals to deviate from that requirement because of the crisis. That’s because you need a hangar to do the tests and many aircraft have had to be parked in places without such facilities.

Beyneix says working with stored aircraft, they get to know the particular traits of each aircraft type well, and that it’s an ongoing process to refine and improve storage guidelines and processes. “Each aircraft type has some specificity,” says Beyneix. “There is always some specific attention to apply on some areas – for example with some aircraft you know the engine is leaking a lot. We’re always giving feedback to the manufacturers to update and improve the manual to follow and maintain the aircraft. The aircraft is living.”

For those who follow and work in the aviation industry, it’s nice to know aircraft aren’t simply parked and neglected for months, but continue to live and breathe, even if in a much-reduced capacity. With any luck many of these planes will be taking back to the sky before too long, but in the meantime it’s reassuring that at the very least, they’re all being kept in great flying shape.


Featured image © George Lau
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