Sunday, March 30, 2008

Parts Exchange Dance

Ok, now back to my life, and the uncooperative autopilot. If that US Airways A319 had had a bullet through the autopilot, it might start looking deliberate rather than accidental, but there would likely be grounds to consider it to be justifiable gizmocide.

Airplane repairs ought to be a lot like automobile repairs, and I suppose they mostly are, but the process seems different. I'm going to characterize airplane repair as more honest. Everyone admits from the outset that they have no clue what is wrong. The automotive shop pays a slight amount of attention to what the customer says, then tests it for themselves and says "You need a new X." Then when the new X doesn't fix it, they say, "you also need a new Y, and a Z, too." The aircraft maintenance engineer listens to the pilot's description of the symptoms and says, "You might need a new X, or maybe a Y. Could be the Z." So they get an X, and the airplane still doesn't work, so then they try with a Y. Because the stuff is so expensive, the customer gets to be more involved in the process. You'll probably all tell me I just have had bad experience with auto mechanics.

Rarely are airplane parts just available at the location the airplane is being repaired, and you can't get generic parts at Canadian Tire, so you have to order them from the manufacturer. Sometimes there is a loaner X available or another airplane in the fleet that can be cannibalized for parts, so you don't have to wait for everything to arrive. We spent the day alternating between watching the tech tweak things and then getting in the plane to test the tweak. Sometimes the malfunction was evident with the electrics on but the engines off. Sometimes it worked with the engines off, but malfunctioned after start

One of the possibilities is just to fly the whole thing down to some fabled Autopilots R Us facility in Oklahoma or Kansas or somewhere where they actually know how these things work. No one here seems to really know.

We never got as far as another test flight before my part in the exercise ended so I could go back to work.


John Schlosser said...

At my work they will often take serviceable parts of planes in the hanger for long inspections to get other planes out on time since part supply can be very poor.

Lord Hutton said...

So reassuring!

dpierce said...

I'm curious as to the capabilities of your autopilot. I know there's often tremendous variation in the sophistication of autopilots in twins. If this has been blogged on in the past, I apologize.

Aviatrix said...

According to the documentation, this one can turn to an assigned heading at a given max bank angle, hold an altitude, capture and fly an ILS, localizer or back course, track a radial or follow the GPS.

As far as I am concerned it can't fly its way out of its own anatomy. I don't even think it would make a good paperweight.

dpierce said...

Cool beans! Thanks for that.

Anonymous said...

Gizmocide? was the pilot a union member?
oh, poor "Iron Mike"...shoot him again, the ailerons are still twitching.