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RAIN IN THE DESERT A SWEDISH OASIS ?

By

Kenneth A Cubbin

Some time ago I wrote an article titled Rain in the Desert in which I examined the problems associated with cabin air moisture in what most people would agree is an extremely dry environment. Moisture, created by passenger respiration, forms frost on the inside airframe behind insulation blankets during flight. On descent, as the aircraft enters warmer air, this frost layer melts and water drips onto passengers, collects in insulation blankets, causes corrosion problems, facilitates the growth of bacteria and fungi and threatens the integrity of various electrical components. Meanwhile, cabin humidity levels, ranging from less than 5% to around 20%, depending on seating configuration and airconditioning airflow, cause discomfort for passengers and exacerbates their upper respiratory ailments.

This has been the status quo for over forty years, but thanks to the resourcefulness of a Swedish company, these maladies may be a thing of the past.

CTT systems, has developed the Zonal Comfort System which incorporates a Zonal Drying System plus a humidifier. Some airlines have chosen to install only the Zonal Drying System to date, but the simplicity and synergy of both systems promise universal appeal in the near future. CTT has attracted a respectable list of customers that includes numerous European airlines. Like most clever innovations, the principles behind CTTs systems are deceptively simple. Heres how they work.

Zonal Drying System Overview

The Zonal Drying System includes one or more dryer units (depending on aircraft type) and a ducting system that is easily installed in approximately 100 man hours. The dryer units active component is a slowly turning rotor filled with silica gel. Cabin air is ingested into the dryer unit, dried and expelled into the crown area of the cabin above the ceiling panels. This dry air output lowers the dew point of cabin air in this region thereby

preventing condensation from forming on the aircraft skin inside the fuselage. A small portion of the ingested cabin air (20%) is heated by electrical elements inside the dryer unit, passed over the silica gel to reabsorb the moisture, and is directed back to the recirculation system (regeneration air). Dry air in the crown area and moist air in the cabin; just what the doctor ordered.

From an operational point of view, one of the most significant areas of concern of frost and water accumulation inside the cabin is the extra weight added and resultant increased fuel burn. According to Bob Tyler, Vice President of Operations of the now wound-up company, Flight Sciences Inc., the increased cost of carrying each additional pound of weight ranges from between $13 to $50 per year depending on aircraft type and airline cost-index.

Boeing studies revealed that water accumulation in insulation blankets alone can be as much as 800 lbs for a Boeing 737. Bob Tyler says that for a Boeing 747, unwanted weight due to water accumulation can reach 2,000 lbs.

As seen from the table on the right, other benefits of eliminating these water problems are: the ability to add more freight and reduced maintenance costs. Pay-back for the system is approximately one year.

So drying the crown area of the fuselage is obviously beneficial. But we are still left with a dry relatively dry atmosphere in the passenger cabin. Wouldnt it be nice if we could raise levels of passenger comfort by humidifying this air without exacerbating the historically proven problems associated with moisture accumulation inside the airframe? Maybe we can; CTT comes to the rescue once again.

Zonal Comfort System

Human beings feel most comfortable when the humidity level is approximately 50 percent, but unfortunately aircraft environments never reach this level. Because passenger respiration adds moisture to the aircraft cabin environment, humidity levels will vary according to seating density: For example, humidity levels will be highest in closely-packed, economy sections and lowest in first class compartments. However, even in the most densely-packed charter-flight configuration, humidity levels rarely exceed 15 percent. Typical complaints of dry atmosphere include dry throats, eye and skin irritations, respiratory-tract problems and general malaise.

After developing a system to dry the air in the crown area of the fuselage, the next problem for CTT to tackle was the low humidity inside the passenger environmental envelope. In typical fashion, CTT developed an exquisitely simple system that works on evaporative-cooling principles. In short, dry air is passed through a wet pad where moisture molecules are transferred to the air, thereby cooling it and making it more humid. Water is drawn from the spare capacity already loaded in the aircrafts potable water system, therefore, no extra water need be loaded.

The humidifier is presently designed to increase moisture levels in the most affected areas of the cabin; namely, business and first class. For this configuration, water consumption is approximately 6 to 7 liters per hour. A long-haul airplane, such as a MD-11 needs two humidifiers, with a resultant water consumption approximating 100 to 150 liters for a ten-hour flight. Because of the robustness and simplicity of the system, maintenance needs amount to regular changing of the pads.

CTT contends that benefits of the moister air in the cabin for passengers and crew include, better sleep, less risk of getting a cold, no more sore throat or eyes and an increase in food quality and sense of taste. Could this provide a competitive advantage for forward thinking airlines? SAS think so, because they are the launch customer of the Zonal Comfort System. The system has been installed on one of SASs Boeing 767s and its effectiveness will be gauged by numerous methods, including passenger surveys.

Whereas the Zonal Drying System has a proven track record, the incorporation of a humidifier into the total Zonal Comfort System has to date, not been proven in service. But initial feedback from SAS is proving that the humidifying aspect of the sytem is proving popular with passengers and crew.

Reality bites!

With such obvious, proven benefits of the Zonal Drying System, one would think that airlines would be beating down the door of CTT to purchase and install their systemright? Well, not really; the Zonal Drying System is yet to make an impact on U.S. airlines.

The function of Flight Sciences Inc. was to consult with airlines and determine what areas of operations could afford cost savings. Bob Tyler remarked that to his amazement many airlines senior management teams refused to acknowledge or ignored the fact that there were obvious areas where money could be saved. His company had lauded the operational benefits and cost savings that could be realized by installing CTTs Zonal Drying System; often to deaf ears. In large airlines, there are fiefdoms to protect, budgets to meet and rear-ends to cover; therefore, it is often easier for airline management teams to refuse to acknowledge that a problem exists than to admit that improvements can be made. Whatever the rationale, it is clear that airlines had better wake up and smell the coffee before its too late.

In my MBA studies, it was stated that companies have a distinct life cycle. Like humans, companies are born, grow, mature and die. Much of the cycle depends on the reticence of management to adapt and change to market forces and major trends. In the airline industry, the roadside is littered with the debris of companies that refused to acknowledge change and adapt accordingly: PanAm and Eastern come to mind. In todays hyper-competitive market, the ability of a management team to adapt to change is critical.

Modern business theory proffers that the new-age company must always have its ear to the ground, be constantly questioning its operations, be obsessively customer-oriented and be able to change direction dramatically with little disruption. Such an organization is called a learning organization; but it is doubtful as to whether any organization actually falls into this lofty ideal. Without question, the airline that comes closest to this category today is Southwest Airlines.

As a shareholder of an airline, you have the power to ask questions of management and demand sensible answers. If I were you, I would be asking why the airline in which you own stock has not chosen to install a system that will not only provide cost savings, but will prolong airplane service life and increase safety. What logical answer can be given?

For those of you who are wondering; no, I am not an employee of CTT, nor am I affiliated with them in any way. What I am is an airline professional with over thirty years of experience who is astounded by the inertia of management and blind adherence to age-old practices. An airline should last longer than its longest serving employee, but nothing is written in stone. Bad business decisions are made every day while many good ideas are stifled because of the hierarchy of decision making. We should all take a lesson from Mother Nature: Adapt or die.