FAILURE!

"Can you hear it?"

"Yeah it's still clicking!"

"OK what should we try now?"

Last night I worked graveyard shift. My airplane was making a clicking noise in the aft cargo bin. I met the plane and talked to the Captain. The Captain tells me that the noise is coming from the area of the Flight Data Recorder in the Aft Bin.

At this point I bite my tongue and inform him that the box in the aft bin is the Voice Recorder and not the Flight Data Recorder. Of course he doesn't believe me and starts to ask me all kind of nomenclature questions which I expertly redirect back to the matter at hand. Something back there is clicking, that's the bottom line.

Once I get the plane out to Tango (remote parking area) I quickly finish up the MV-1 check, fix the few things I found broken, and get into the aft cargo bin. Sure enough you can hear a clicking noise, as a matter of fact you can hear it by just standing with your head in the door opening. "Click, click, click, click.....".

My first thought is the CVR is messed up so I open the access door and give it a tap, no help. I tap the APU temp. box next to the CVR, no help. On the side of the CVR enclosure is the J-11 Junction box and I can see a few relays in there through the holes cut in the side of the box. Pop that sucker open and sure enough it looks like the R353(?) relay is clicking. I call on the radio for someone to look up the relay part number and they tell me that Maintenance Control has already ordered it and it is on the way-be here at 10pm.

Now I'm thinking: If MX Control called and wanted to know which relay was making the noise (they were the ones who called about the plane originally), how could they have already ordered the relay that was busted? Even better why not let me know so I would not go beating up two other boxes, and possibly saving me some time. Whatever.

By the way all this time the worse storm of the year is roaring outside. Rain, wind, flooding at the airport, it's crazy outside. So I get my part and go back to the plane, put the new relay in, go up stairs to turn on power, go back down to the aft pit and CLICK, CLICK, CLICK...

Strike one.

I had doubts as to if that relay was the one clicking so with the power on I decided to disconnect the cannon plugs that go to the relay rack. The plugs are labeled 1 and 2, and the only other relay that could have been making that noise was labeled 2 while the relay I just changed was labeled 1. Sure as heck the noise stops when I pull of plug 2!

"Hey someone check to see if we have an R625 relay" I call on the radio.
A few moments later they tell me "We do not stock that relay". Before I can say for sure that the relay is the trouble I wanted to rob one from another plane and "slave" it in.

Now the wind is blowing at about 25mph, but the rain has stopped.

I get my "volunteer" relay and put it in, reconnect the cannon plug and CLICK, CLICK, CLICK...
The problem is not the relay.

Strike 2.

I drive my golf cart back to the shop which takes a while since it is old and the wind is blowing right at me. My normally slow cart is having to push through the wind and it going about 5 mph. At the shop I discuss the problem with the foreman and check out the wiring diagram. The relay gets a signal from two switches both of which are in the flap drum. For those of you who know the 737 the flap drum switches are one of the most loathed jobs in all of Line Maintenance. All the work is over head on the wheel well ceiling and the wires to the switches cannot be spliced they must be unclamped from the switch all the way up to the cannon plug, a run of about five feet or so with about 7-8 clamps to deal with.

I decide to see if I can adjust or clean the switches. While I am doing this I notice that one of the switches is loose in the drum and that the wires leading to the switch are spliced. I lower the flaps and check, no clicking. I raise the flaps up one setting, no clicking. I raise it one more setting, no clicking. I do this again and again, running up the stairs and down to see if the clicking is back. I figure if I can get these flaps all the way up and there is no clicking I'm going to sign this bad boy off. Sure enough at the last setting I go down stairs and CLICK, CLICK, CLICK...

Strike 3.

Now it's about 1am. I have a 50/50 chance on which switch to change but I have a pretty good idea that it is the loose and spliced switch that needs to go. Start digging! Off comes the switch, off come the clamps, I de-pin the cannon plug. I take the old switch to the shop and lay it out on the work table so I can put new pins on where they belong and new ground lugs and terminate the unused wires. It is now 2:45am. Since its not raining anymore I figure I'll take off my rain boots (they are killing my feet) and put my regular work boots back on.

Back at the plane I re-pin the plug. String the wire. Re-do the clamps. Put the switch in. It is now 4am. the moment of truth! By now the foreman and one other mechanic has come out to give me some moral support. We turn on power go to the cargo door and....

CLICK, CLICK, CLICK....

Damn! Strike 4!

We go through the adjustment on the switch to see if that is the problem but it is no help. Now it is raining again, the wind is blowing so hard that the plane is dancing around while I'm trying to adjust the switch and tie up all the loose wires. The final part of that adjustment calls for me to listen for the switch to click and then back it off and tighten it there. The wind is so loud that I cannot hear the tiny clicking of the switch. Time for the alternate method (I love this job). Any way it is starting to look like my 50/50 guess was incorrect and that the other switch is going to have to come out! Now it is 5:50am. I have been standing on my ladder the whole night. My back is killing me. My shoulders are burning from the overhead work. Remember when I took off my rain boots? Bad move, for the last 2 hours my feet have been soaking wet. My hands are black from the grease and muck in the wheel well and I cannot feel my fingers they are so cold.

I have the awkward experience of recounting my tale of woe to the day shift lead mechanic and informing him that one of his guys will have to change that second switch. I leave soaked, pissed off, dejected, and filthy. Part of being a Line Mechanic is that feeling of failing to fix the problem. Some people handle it better than others and some people just don't care. Not fixing a problem is a fact of life in our industry almost as much as fixing a problem is. The really talented mechanics will always learn something from each of their failures like - leave the rain boots on!