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Welcome to Brooks Margolien's “As the Hangar Doors Shut” Blog

Welcome pilot, mechanic, aviation buff!

Stay aboard for the travails of a real, live airplane mechanic that's been at it for over three decades who finally decided to sit down and, well, blog about it.

An avionics tech I know, one of the best, forwarded some sage advice he received from an old aviation pro that has made a good living in the aviation business: “The further from the cockpit you are, the better off you will be in this business.”

Do I have to tell you how infuriated that statement makes me?

I AM THE GUY IN THE COCKPIT!!! UPSIDE DOWN BEHIND THE PANEL. DECIDING WHEN THE PLANE IS SAFE!!

I thought it was my time to let everyone hear about aircraft maintenance from the guy in the cockpit with the tools, the heated and air conditioned hangar, the prop balancer, the borescope, the TCM orifice, the calibrated tools, the pilot's ratings and the million dollar liability policy. The guy that forgot to get his MBA. The guy that has been breathing chromates and benzene since 1978 when my Dad handed me a can of zinc chromate primer for my 1971 Pinto (2.0Lw/4 speed) and said “This stuff is the best.”

Hope you'll stay with me for a while - I think you'll have a new found respect for the art, after all, we are industrial artisans.

Many pilots have never spent a day in a hangar with a box of tools next to their plane. It's a privilege. I can assure you, just as I tell my wife, it's not all fun and games. Well, once you get past the sticker on the hangar door that says “Caution: Objects in this hangar are more expensive than they look”, things get serious, well after we check out the mini bike collection, Dad's racing car photos and swap some pilot stories.

Before we even get the hangar doors shut there is a whole laundry list to work through. Ever try and move a Maule MX7 with full tanks and soft, oversize tires up a slope with a 25 kt wind howling? Simple tasks for a pilot or line crew take on new levels of importance when mechanics are charged with taking care of someone's baby. When you pull your plane out of your tee hangar, you know from experience where you stand, as well as the wing tip, although if you have a SR22 in a 39 ft. tee hangar, you better be standing right in the middle! When a plane gets rolled out of a maintenance hangar, it's never the same twice in a row, so multiple trips around the plane are needed. Add in a bystander who is not sure of his duty at the tail and the do-gooder pushing with his head down, you can run into some trouble. And since everything in the hangar costs more than it looks like, easy to see why the absolute worst time to waltz into a shop is when the planes are rolling in and out.

Today a customer came over with a seemingly innocuous issue with his plane, the parking brake on his Cherokee Warrior was dripping a bit of brake fluid, just enough to notice. Well that job seems easy enough at first thought, replace the o-rings in a master cylinder, ahh, but after heading under that panel with a flashlight, I am reminded that Piper built these Cherokees around the brake system. 5 master cylinders, one for each brake pedal plus a parking brake make 5 master cylinders, along with all the connecting rubber hoses, each due for replacement now. Of course, replacing the hoses is not so easy either, as they trap air and make bleeding the brakes on a Cherokee a bit of a challenge. Every mechanic has thought about a way to invert the plane in the hangar to get the air out of those hoses, so I guess you could say more than a bit of a challenge. I will mention, the service manual technique of bleeding from the reservoir down with pressure applied may just be the best way.

Well, I will say that job went ok, the parking brake master was in good enough shape to use over, good news as the new one is over $400 and the used ones will have the same nicks on the shaft that they all have. I needed a new spring for the thumb latch on the brake handle; found one in the “magic distance of 1 day UPS ground range”. Interestingly enough it had a 1988 parts tag. For 25 yrs that spring sat in a bin in a parts room waiting for my call. I will say this, the price of parts rises faster than inflation as specified by the US Gov't. The biggest surprise came at the very end. When I totaled the bill I made a multiplication error on the labor; I realized it later and just had to ask for it. Talk about awkward emails. Dear Sir, I know the bill to change three o-rings seemed very large, but actually, I left off two hours. As I said, not all fun and games.

Even the brake bleeding went ok, decent pedals, good parking brake. I can't tell you how many tools it took to change the o-rings in that master, but I can tell you it was a lot, and they travel a lot of miles from my toolbox, into the cockpit and back.

There are 100 reasons why fixing airplanes is nothing like fixing cars, but one of the biggies is that the tools travel 50 ft at a time when you are working on a plane, maybe 200 ft if you are in a big hangar and need a shop tool. When your skinny little 7 ft wide car is nestled in its mechanics bay, the tools travel hardly more than an arm span from toolbox to engine to do their job. If you think airplane maintenance is expensive, slap a set of 18 ft by 4ft “wings” on your Chevy, or garden tractor for that manner, take it down to your favorite wrench and see how much it will cost and how many times he hits his head. It's pretty universal, the more your mechanic hits his head, the more it will cost. Why it took me 29 yrs to put Cessna 150s up on casters for their annual inspection, I just don't know.

Anyhoo, it's back to the shop tomorrow to get a 182Q back together, find out if a fuel pump on a Beech has a tiny fuel stain in the casting and determine how lucky or unlucky was a pilot when he connected his jumper cables backwards. My second peek at the plane says the stars were aligned with his jumper cables, too bad not the battery posts, but it may just be a wire and diode. Of course it's never over until you get airborne and checked all the instruments. Sometimes you even need a few heat cycles to find out if you've really licked a problem.

For now,
Brooks Margolien
Aero Care, Inc.
Orange, MA 01364

Brooks Margolien is president and chief technician of Aero Care, Inc., a state-of-the-art piston engine aircraft (13’6” H by 50’ W door opening) maintenance shop in Orange, MA. Brooks has been an aircraft mechanic for over 23 years.