All about balance

Peter Landquist, VP Sales and Marketing at CTT Systems, on the importance of getting the humidity versus condensation balance right in aircraft

AH: Peter, you are in a very niche part of the market, providing humidifiers and dehumidifiers to both the commercial markets and the VIP space. How did the company get started in the aviation space?

PL: The company began in 1993 with the three engineers: Christer, Tom, and Thomas, whose initials form the company’s name. There was a problem with a small airliner which had some corrosion caused by condensation. They used a ground-based dehumidifier to clear up the condensation, but the problem quickly returned when the aircraft went back into service.

The condensation problem arises because when the aircraft is full of passengers, as they breathe out the humidity in the cabin rises. When the warm, humid air works its way to the inner metal skin of the aircraft, which is probably experiencing temperatures of minus 52 Centigrade on the outer skin, the water vapour condenses out as frost on the inner skin.

When the aircraft is back on the ground, that frosting on the inner surface melts and the puddles of water accumulate and cause erosion and damage. Water is also heavy, as anyone who has lifted a bucket of water will know. So, the additional weight that accumulates will have a negative impact on the aircraft’s range and its fuel burn.

Paradoxically, you have exactly the opposite problem in a business jet and in the First/Business-Class section of an airliner. There, where you have very few passengers, the air gets progressively dryer through the course of the flight. By the mid-point in the flight, the air in the cabin can be as dry as you would find in the desert.

There are plenty of medical studies which show that being exposed to dry air adds significantly to a passenger’s sense of discomfort during the flight. It also has a negative impact on your health. The mucous membranes in the nose and chest are a good defense against cold germs and other viruses. When these membranes dry out, there is nothing to prevent the virus from gaining a grip on the body, which is probably why so many people catch a cold either on the flight or when they walk through the airport after a flight. It takes time for the mucous membranes to get rehydrated and an individual remains vulnerable for some time after a flight.

We see an increased interest from the airlines to select humidifiers for the First and Business Class cabin due to dry environment. When actively humidifying First and Business Class, the Economy Class will also enjoy a humidity increase due to the aircraft re-circulation system.

This realisation has resulted in very good business for CTT from the commercial airline sector. We supply a balanced solution to them of humidifiers and dehumidifiers, to create the right conditions in the cabin while preventing the problems associated with condensation and corrosion on the inner skin of the fuselage.

By the end of the 1990s, a lot of VIP completions houses dealing with BBJs and ACJs asked if CTT could design balanced solutions for them to present to their high net worth and Head of State customers.

AH: So, the point is that in an airliner, or a converted airliner in the case of a BBJ or an ACJ, the multiple zones in the cabin each pose a separate problem when it comes to dry versus moist air?

PL: Exactly so. An aircraft cabin is divided into zones, and the fewer the passengers in a particular zone, the less humidity you will find there. In the First-Class zone, which may have only six to eight passengers, the humidity level rapidly drops to about 5 percent. Again, that means that the people who are paying the most, experience the worst humidity conditions unless you take steps to balance the humidity level.

The problem is even more exacerbated in a business jet, where it might just be the principal, or the principal and one other, that is in the cabin for the duration of a long flight. The air there will become desert-like over the course of the journey.

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