Saturday, April 02, 2005

Sam's Arch-Nemesis

Whoever designed the heating/cooling system on the MegaWhacker needs to be severely beaten with a blunt instrument (and I mean that in a very positive way, Sylv). It has two temp controls, one for the cabin and one for the flight deck - but in actuality only has one pack (heating/cooling unit). That'd be kinda okay because there are two sets of seperate expansion chambers, heat exchangers, etc - but then the air is all mixed together before being split for the various ducts. So basically, if we run the system in auto mode, we get the same temperature of air that the passenger cabin gets. If there are more than 40 people in back, we need to keep the duct temps pretty cool because of all the body heat. Of course, this means we freeze our butts off in the flight deck. It's worst on full flights. I've been cold to the point of uncontrollable shivering on full flights to Canada or Montana. We rest our feet on the instrument panel because the floor is often cold-soaked.

Sometimes we can get a mediocrum of heat going in the flight deck by using a bass-ackwards combination of manual pack controls, or turning the flight deck pack off, turning flow control to max, and turning the pax control way up. Each plane is different, though, and seems to change from week to week.

The situation is made worse by the touchiness of the temp controls. The slightest movement can drive the packs to full hot or full cold. Sometimes selecting the packs to manual improves things; sometimes it makes it worse. Also, I've had situations where the temp was set up perfect, but reducing power to start descent drove the pack to full cold or full hot. One time descending into Santa Barbara, it was essentially a race to get on the ground before the passengers passed out from the heat, because nothing we did could nudge the packs from full hot. On the return leg, they worked perfectly.

So needless to say, dealing with this A/C system requires a mastery of four-letter words. If any MegaWhacker pilot ever catches the Canadian engineer who designed it in a dark alley...well, it ain't gonna be pretty. One really wonders how it made it through flight testing and certification, in Canada of all places. If anybody can design a proper heating system, it should be them. I mean, heck, Bombardier puts hand-warmers on their snowmobiles - how about foot-warmers on their airplanes!?