We pay a $20 lab fee each quarter at the A&P school to cover supplies used in the classes. These are typically things like rivets, sheet metal, electrical components and the like. As I've spent the last few class sessions outside in the frigid cold (quite forcibly reminding myself of why I got out of the airplane maintenance gig 20 years ago) working on the Boeing 727 donated by FedEx last year, I have determined that $20 ain't gonna get anywhere near what we've spent this week alone.
The topic we're working on is 100 hour 'A' check inspections on the big bird. In order to facilitate the inspection of the under-bits of the flaps, slats, and spoilers, it was deemed necessary to light up the Auxillary Power Unit (APU), which is a tiny little jet engine buried deep in the bowels of the machine. Monday night, all of the ice and snow that had accumulated in the APU exhaust had finally melted away and we could crank up the noisy little bugger. That went fine, but the reponse to the commandments to move ancillary flight controls like the flaps, slats, and spoilers were met with the same kind of "go pound sand" grumbling that I get from Hogarth when insisting that he stir his dirty old self from an illicit nap on a piece of high quality furniture. The problem was quickly determined to be a complete and total lack of the life-giving blood of hydraulic systems: the Skydrol hydraulic fluid. This determination was quickly followed by the quite natural question of "well, where did eight gallons of Skydrol disappear to??"
Now, I may or may not have previously shared the sordid details of my continually degenerating relationship with the instructor, but suffice it to say that it's not the most congenial of working relationships. This manifested itself quite apparently when it came to determining where the leak was. We started back in the tail cone of the airplane where the hydraulic fluid tanks are located, visually inspecting lines, valves, and surrounding floors for evidence of leakage. None was to be found. As the goal of Monday's efforts was more or less just to prove that the APU could be started, it was decided that we would defer the search for the leak until Wednesday. As we were walking back to the hangar, we walked past a puddle under the belly of the plane, near the leading edge of the wing. I pointed out the fact that there were no water puddles anywhere to be seen, so the mysterious puddle might very likely be the clue we were looking for. This idea was summarily discarded by the instructor as unlikely. Fine, thought I, for I would rather be in the nice, warm hangar than outside on that frigid, windy, bone cillingly cold night hunting for a fluid leak.
Come Wednesday, eight gallons of Skydrol had been procured at the exhorbitant cost of $103 per gallon. The first gallon was pumped in (by me) and was soon gone missing. The second gallon met the same fate. The third gallon was pumped in, and I went back to the tail cone to find the same thing as Monday night: a determined search to find a 55 gallon drum in a haystack. In other words, the tail cone was still bone dry, but the single-minded search in the proximity of the tanks continued apace, with the same distressing lack of results. My query of "why does the leak have to be here, given the miles of hydraulic lines coursing through the entirety of the aircraft" was again summarily dismissed. Being of the easily peeved type, I removed myself from the vicinity and began my own search. At this point in the tale, you will not be shocked to learn that I quickly discovered that the mysterious puddle from Monday not only still existed, but was something on the order of three gallons larger. Against my better judgement (which is a polite way of saying "going against my long ingrained passive/aggressive style of conflict avoidance") I went back to the tailcone to report my findings. That, of course, was futile. Ego was in full force on both sides at this point, so my discovery was met with no more than a shrug of the shoulders and yet another brush off.
Well, by this time I was cold, tired, and pissed off, so I adopted the petulant strategy of just removing myself from the problem. As I stood off to the side, I was eventually joined by the rest of the students, who themselves were also apparently starting to feel somewhat redundant to the entire process. I showed them my theoretical leak, and we soon agreed that there was definitely a problem somewhere in the right wing. It soon became apparent to the one lone remaining tailcone resident that his entire class had abandoned the pointless inspection of the tailcone, and that it might be beneficial to actually look at the stream of purple Skydrol dripping down the side of the airplane.
Long story short (heh, too late!!), the right inboard leading edge slat actuator was leaking like a sieve. We capped the hydraulic lines (managing in the process to soak my gloves with Skydrol, which would later lead to a stupid incident involving me rubbing my left eye with a finger covered in a film of Skydrol - a burning sensation I hope never to repeat!) and re-started the APU.
Problem solved. But I doubt if my $20 is going to make much of a dent in the invoice for eight gallons of Skydrol!