For most aviation maintenance technicians, the first day on the job involved a wash bucket instead of a wrench, but the fact is that’s the first tool in aircraft care. After all, a clean aircraft is easier to inspect. Crud can hide cracks, working rivets, damage and many other potential problems. When you clean an aircraft, you get the opportunity to touch and see parts up close and personal, allowing you to catch problems when they are small and manageable. That bucket helps a tech learn about attention to detail. In addition, a clean aircraft is a reflection of a department’s dedication to its equipment and ensuring its aircraft are in good order.

While passengers expect company aircraft to be immaculate at all times, they have no idea the amount of work involved to accomplish that. Some probably think that the dirt is blown off while in flight or washes away in clouds and rain. But the sky is neither benign nor helpful. Air pollution, smoke, acid rain and the attack of ultraviolet radiation from the sun comprise constant attack on an airframe. Add to this assorted drips, leaks and goo from deicing operations, and even the most high-tech coating will suffer without corrective intervention.

For most passengers, the aircraft interior’s condition and appearance are more important than its exterior; after all, that’s where they spend many long hours on business trips. Cleanliness of the carpets, upholstery and hardware are very noticeable and become items that they tend to note, particularly if unsatisfactory. For your customers, cabin appearance and utility may be only second in importance to aircraft availability. A sloppy aircraft can be a one-way ticket to the unemployment line.

While keeping a clean aircraft is just one of your many important tasks, the issue for maintenance managers and senior technicians is resource management. How do you find the right balance of manpower, budget and aircraft availability to keep the aircraft clean and safe? Do you burn out your technicians with rubbing and buffing? You might need outside help, so how do you go about finding the right company? 

Aircraft Cleaning Basics

When it comes to washing an aircraft’s exterior, there are two basic types of methods — wet and dry. The wet wash is the most familiar: Spray on water and cleaning agent (soap), scrub the surface, rinse and dry. The biggest problem with wet wash is that the water needs to be clean and free of minerals. Yet most water has some mineral content, and this can actually capture the dirt and leave deposits on the surface, kind of like rings left by beverages on a coffee table.

You can add agents to the water to help break up the deposits or use demineralized water, but depending on the size of your aircraft, this can be burdensome. In addition, you need to capture the drain water and ensure you are not violating environmental regulations. Water also can seep and pool into the fuselage compartments, leading to corrosion problems down the road.

Be sure to avoid using pressure washers on aircraft, because this will force water into faying surfaces and seals that can damage the aircraft. It often takes an extraordinary amount of elbow grease to keep gear and wells clean, in order to inspect them properly. Always consult your maintenance manuals when working near the landing gear to ensure proper safety procedures such as installing pins, covers and blocks.

Take care when rinsing aircraft to prevent water from entering pitot or static ports, which will affect the instruments and air data computers. Pay particular attention to the landing gear area, which is often filthy from rubber, carbon and runway detritus. The frequency and intensity of your cleaning activities revolve around your flight schedule and environment.

“Every time the aircraft has been parked in a salt air environment it is washed and detailed upon arrival back at home base,” said pilot Mark Jones, who doubles as head of maintenance for a small, IS-BAO-registered flight department based in the Midwestern U.S. “We use the wet wash method, even though it takes more time. The cost of the dry wash chemicals is expensive, so the wet works best for our department. The aircraft is completely sealed and polished twice a year. We use chemicals that are only approved for our aircraft and we believe that the aircraft is a true reflection of the department and that gives us the incentive to make sure it looks good at all times.”

Meanwhile, the dry wash method, which cleans and shines in a single process, is becoming much more common and widespread. Much like waxing your car, you wipe the exterior with the wet cleaning compound applicator, then leave to dry or glaze over. Then you rub the surface with clean towels to remove the dirt and shine the paint. Although this process can take a lot of elbow grease, the end result is often less intrusive than a wet wash and wipe.

The key to this method is access. You will need to ensure your technicians have the correct safety gear and work platforms. The cost of cleaning/polishing compound is also a concern, especially if you must clean often.

Cockpit windows require special attention as they are often assaulted by insects, which are subsequently baked in place by the sun. The glass laminates can be easily scratched and ammonia-based cleaners can cause disbonding. Replacement windows are very expensive and, if installed, you will need to keep the aircraft grounded until the sealant cures and then perform a leak test. Always use approved window cleaners and never, ever use off-the-shelf ammonia-based cleaners unless explicitly called out by the OEM.

Cleaning aircraft components such as engines, reversers and actuators takes special care and caution. Carbon and soot from unburned fuel, oil and lubricants often stain the part and make cleaning a real chore. Industrial cleaners and solvents may seem to provide an attractive way to speed the cleaning process, but you need to check with the component manufacturer to determine which cleaners are acceptable because unapproved materials can cause corrosion pitting and lead to cracks. For beauty shields made from stainless or chrome, you need to use cleaners that will not leave residue that will discolor with heat, or roughly abrade the polished metal finish, leaving it dull and gray.

It’s All in the Details

Although the cleanliness of the aircraft’s interior is important to you and your customers, there are also important safety concerns that you need to address in the process. An aircraft’s interior materials all meet stringent flammability requirements and cleaners can degrade and sometimes remove that capability. So, it’s important that you follow your maintenance manual when choosing cleaning products.

When work is scheduled for the galley and lav, ensure that you take the necessary precautions to protect your technicians from germs with protective gear while cleaning. Pay particular attention when cleaning your fresh water system because your passengers and crew can become ill rather quickly while in flight if it’s compromised.

Interior cleaning comes in several levels — the quick and light, all the way to a complete detail with carpet and fabric extraction. You need to decide when and how much effort is required to meet your customer expectations.

“We do two types of cleaning, a light daily cleaning inside and out, and a deep, detailed cleaning every six months,” said Heath McDaniel, aircraft director of Maintenance for Michelin North America in Greer, South Carolina. “Our light cleaning is completed after every flight, which is basically clean the areas that a passenger would see with a dry cleaning product on the outside and the various cleaning wipes on the inside. We shampoo the carpet as needed. Our deep cleaning is a full detail cleaning on the outside, wheel wells, behind flaps, etc., and a paint protective product.”

Keeping your aircraft clean is labor intensive. And today, with increased concerns about safety, security and liability, you need to ensure that anyone who gets near your aircraft is properly trained, authorized and equipped. Depending on your standards, you need to consider the level of autonomy that you will allow your cleaning service provider. Do you need to remain on board or on the ramp while they do their work?

There are many reputable cleaning service providers, and if you are considering engaging one there are several key items to keep in mind. First and foremost, identify those that meet your standards of service and safety.

“You need to have a systematic approach to your selection process. Start with assessing your needs and expectations,” advised Stephen Clark, director of Marketing for Immaculate Flight LLC, a Grand Rapids, Michigan, aircraft cleaning and detailing company with multiple locations and traveling teams across the US. “What you are really looking for is a partner who matches your expectations. Do they have a safety management program? Do their training and qualification standards meet or exceed your own? And then, are they reasonably priced and flexible enough to meet your particular needs?”

Also, personally verify all references provided by the candidate service provider. Have the vendor’s proof of insurance sent to you directly from the insurance carrier since any certificate provided directly from the vendor may no longer be valid, or even worse — be fictitious. In addition to having trained and qualified individuals, you need to ensure that the service provider uses only approved materials. A good company will ask you about your aircraft and particular concerns before beginning work. And it will verify the acceptability of its materials by providing you with Material Safety Data Sheets (MSDS) and OEM approval data.

Depending on your needs, your service provider must be flexible in scheduling to accommodate your operation. Since most of the cleaning work happens at night, you may want a provider who has multiple bases, or teams that travel to meet your aircraft when it lands.

“As a DOM you want to have a shared culture with your vendors. Your relationship will be much better when they meet your requirements. Then it really just boils down to teamwork,” noted Clark.

Keeping your aircraft clean is a tough but important job. Your technicians need to be properly trained and equipped to address safe and efficient aircraft cleaning practices. Ensuring their safety while performing these tasks is your responsibility — from biohazards to fall protection. Only use approved cleaning materials and processes as specified in your maintenance manual. If you hire outside help, verify their credentials and provide enough oversight to ensure they are qualified and can perform according to your expectations.

There is no room for cutting corners, or easy solutions, just good old-fashioned elbow grease and attention to detail. And don’t forget that bucket.