Wednesday, October 14, 2009

Pilots and Maintenance

John, aka Aviation Mentor, tweeted this morning about some major fines the FAA is proposing for United Air Lines and US Airways for maintenance lapses. Some were egregious, either for the shoddy maintenance practices involved (UAL) or for the fact that the continued to fly a deficient airplane even after the FAA pointed it out to them. Links to the FAA press releases are here.

I don't think that you can put too much blame on the pilots, especially in the 14CFR121 world. Pilot interest in maintenance is as variable as pilot interest in anything else. I have known some who were maintenance aces, and others who refused to do a walk-around.

Once when jumpseating home on SkyWest I sat next to one of my regional airline buddies. Somehow we got to talking about a 1997 incident in which a SkyWest Brasilia had an engine fire followed by a complete loss of hydraulics. The crew made a nice emergency landing at Miramar NAS. I used to use this to illustrate how to behave in a crisis when I was a 14CFR135 (charter) instructor. (The NTSB report is here.)

Todd looked around for a second and got all excited. "Dude!" he exclaimed, "it was this airplane." Todd makes it his business to know the fleet inside out.

But I used to fly gliders with a guy who was a mechanic for SkyWest. "So," I asked him, "do you get a lot of pilots
hanging around in maintenance, poking around the airplanes?"

"No," he replied, "almost never."

That seems like a lost opportunity to me. When I bought my Taylorcraft, I did the first annual (under supervision, of course); after that, I felt like I knew every bolt.

When I was flying King Airs, I looked forward to the major maintenance checks, not because it meant time off, but because it meant I would be able to learn more about the airplanes. I took a digital camera to record what I found.

Here we have the battery, which sits in the right wing near the root. Batteries are crucial for starting turbine engines: a weak battery could lead to low starter RPMs which could lead to a hot start which could lead to bankruptcy. While there is an overwhelming amount of cockpit instrumentation for the electrical system, the battery itself is hidden out of the pilot's view.

Here are the outflow valves from the pressurization system. One is the control valve, the other is the emergency valve. Again, they are hidden behind a big inspection panel with lots of screws, out of sight of even the most meticulous preflight inspection.

And here is the inspection plate for the nacelle tank. This was taken at a remote airport, after a passenger asked about the clear liquid running down the wing.

Maintenance sometimes need to get in there, which is probably obvious given the amount of plumbing on top. To get to the nacelle tank, you remove a large inspection panel; it's been removed in the picture. So, again, no preflight inspection.

Now notice the bits of orange at about 8 o'clock in the picture. When the tank is reassembled, maintenance puts a spot of paint on the bolts. If the bolts are removed, the paint tears away. What you see here is evidence that someone serviced the tank but did not put it back together.

I didn't - couldn't - catch it during the preflight. I have no idea when the maintenance was done, since this was my first flight after a long vacation. For all I know, the airplane had been leaking fuel for the past three weeks, but the first one to notice was my passenger.

The dozens of United pilots who flew around with shop rags in the engine couldn't have noticed, either.



At October 15, 2009 at 12:43 PM , Blogger Frank Van Haste said...

Dear Doc:

Didn't somebody say, "The most dangerous thing in aviation is a pilot with a screwdriver."

(Hope you're feelin' good.)



Post a Comment

Subscribe to Post Comments [Atom]

Links to this post:

Create a Link

<< Home