Aircraft cleaning: Not just clean - pristine
Environmentally friendly aircraft washing
When a jumbo jet or an Airbus A380 is towed off to the maintenance hangar for external cleaning, there is plenty of dirt and grime on the fuselage skin. The plane has probably seen more than 3,000 hours of intercontinental flight in the six months since it was last washed. The dirt makes the aircraft less attractive, heavier, and less aerodynamic. Clean aircraft are therefore more economical and more environmentally friendly. Until just a few years ago, wide-bodied aircraft had to be washed four times a year with foam and up to 13,000 liters of water. Today, thanks to newer cleaning agents, a resource-friendly dry wash every six months is enough. To date, there are no suitable machines available, so that the entire dry was process has to be performed by hand.
The first thing to be done when the aircraft enters the hangar is for all the highly sensitive sensors and instruments such as speed, temperature, and altitude sensors to be masked and the wheels encased to protect the tires and brakes from chemical solvents. Then the dry wash can begin. The personnel apply a thin layer special cleaning paste to the surface. The paste bonds with dirt, and after polishing and drying it seals the surface. Unpainted parts of the engines are left so that the surface material is not corroded, which could make it porous. Special cleansing agents are also used for the hand-cleaning of the windows. These agents were first tested and certified in Lufthansa Technik's in-house laboratories. All the cleaning cloths used can be washed and reused.
A dry wash requires considerably more effort than a wet wash. Around 20 cleaning personnel work on a wide-bodied aircraft for an average of 24 hours, whereas a wet wash can be completed within eight hours. But the work - up to 450 hours in total - pays off, both for Lufthansa Technik and for the airline customers. During a wet wash, because of the sensitive on-board electronics, no other work can be carried out on the aircraft. With a dry wash, though, maintenance work and interior cleaning can be carried out at the same time. It is good for the environment, too, with kerosene savings of up to two percent, and the dry wash eliminates the need for complex and intensive filtering of the water contaminated with dirt and cleansing agents. The only part of the aircraft that Lufthansa still cleans with water and cleaning fluid is the undercarriage, which is always extremely dirty.