CSI Aircraft Maintenance (Cue Theme Music!)

As an aircraft mechanic we encounter a lot of mysteries. Sometimes the mysteries are as simple as:

Why won't this light come on?

Where is this fluid coming from?

What kind of fluid is this?

Much like that TV show CSI we are trained to dissect the problem in order to solve it. It's one of the things that I think really makes the job enjoyable. When you can figure out what is wrong with a component it's very satisfying. Follow the clues and figure it out.

Most problems are not this obvious!

For this reason it is important to hone your skills by learning to read wiring diagrams, prints and such. Also, even though it is a huge pain in the ass, you will need to get your Run and Taxi license as well as your CAT ticket. These things help us to correctly troubleshoot!

Not as hard to read as it would seem.

Sometimes (and this is the dark side of it) the CSI reveals that some of your coworkers are lets say- working harder at trying to find an excuse to NOT fix something then it would take to simply fix it.

I'll give you an example. When I arrived at work in the morning one of the planes was broken. The fellow who was working on it is not one of the sharpest tools in the shed. You know the type, always troubleshoots down to the part which is "not in stock."He miraculously cannot get to the hard MEL because he is still "working his check."

Long story short we decided to start the troubleshooting process over from the beginning due to this guys rep. Sure enough within an hour we figured out that this guy lied about what was going on and all we had to do was change "the big part" to fix the issue. Another hour and we had the plane back in service.

So what do you do when you find out a fellow mechanic simply lied to get out of doing work? What can you do? If your leaders (management) already knows about the guy (and they do) there is little you can do. Complain? Sure. But nothing official. Just kind of keep it in the memory bank and watch your work when that guy is involved.

There are other times when we do the unexpected (at least to non-mechanics) to solve the mystery. A pilot will call us about a leak and we show up, first thing we do is touch it and rub it between our fingers, smell it, and sometimes to the horror of the pilot you taste it. He or she is in horror but I'll wager that an aircraft mechanic is one of few people who can tell the difference between oil and hydraulic fluid by taste! Admit it once you have tasted hydraulic fluid you can never forget the taste.

There are other times when your CSIing will figure out that the flight crew input some incorrect info into their FMC! Those are great times almost as satisfying as finding the CB popped while the crew is struggling to figure out why some system won't work.

So...keep sharp, never stop learning, be honest and hone those taste buds!!

Boise Road Trip

Last weekend we had only four guys working on day shift. As usual when there are only four mechanics working everything went to pot quickly. Amid the din of the radio calls for remoting, gate calls, and general upheaval, there was a phone call. The call was from Maint Control, and pertained a broken plane in Boise.

Those of us who have been to Boise know that once we get there (from Oakland) there is no way to get back until late in the day. The only return flight after like 9am is one at 6:45pm. This makes Boise road trips very desirable. A guy on day shift (me) could fly up to Boise, fix a plane and wait until 6:45pm to fly home, thereby getting a whole shift of OT.

Boise Terminal

Of course I agreed to go. I went on the trip with a guy I'll call Tang. Tang and I got all our tools and, with the help of the stores guy, all the parts needed. We were told there was a hydro leak and to take an electric pump with us.  Once we got on the plane and settled I sat back and tried to relax. When we pushed back from the gate I closed my eyes to sleep on the way up when Tang says "why are we turning around?" Sure enough we were turning back toward the terminal. The Captain comes on the PA and says that there is a light on in the cockpit that should be out. Tang and I went up front to talk to the crew and found out that the FO Pitot Static light was on.

Make a long story short we had to fix the plane that we took to fix the other plane. After changing the Pitot Tube the rest of the flight was uneventful.

Tang and I got to Boise and checked the plane out, sure enough there was a leak but luckily the pump itself was leaking so we just had to swap it out and go eat lunch and wait the 4 hours until we could make it back to Oakland. Boise sure is a premium road trip, when it comes up. These days road trips are getting scarce since LAX MX is the road trip station now.

One Of Those Days

As an aircraft mechanic we all know that it is coming. The it can be several different things. For some guys the it is having to work with a certain mechanic or foreman. For others the it maybe a road trip, still others may have their it in the form of a check plane with an MEL on it. The list goes on and on. For me that it changes from time to time and situation to situation.

Also as a profesional aircraft mechanic I realize that the it is going to come and I like to think that I am mature enough to accept it when it happens. We all know guys who whine about the work that they get assigned and know how frustrating it is to deal with those guys. As a person who has moonlighted in the foreman slot I know all too well that dealing with those people is not a pleasant experience. That said we as profesional mechanics have to realize that guys have good days and bad days, and some of us are not good at leaving all that home stuff at home. I personally try not to complain about the hand that is dealt me (although I know that I have before) and I can understand that if a guy has to change an HMU one night he may complain if he comes in on OT and gets assigned another HMU.

Unlike other jobs where if things are not going well we often cannot simply put something down or aside and work on another thing. There is not going to be any closing of the spreadsheet or going down the hall to visit a co-worker. Our job is a results based job and like it or not a time based one as well. So my main it, the thing that drives me the most crazy is working on a plane all day and leaving it broke, having made very little headway. So here is what happened:

Day shift, about 10am I head out to a gate call for Leading Edge Slats not retracting upon landing. As I roll up on the plane, sure enough the slats are out. When I talk to the crew they are in a good mood (which always helps) they inform me that this is a repeat write-up from yesterday and sure enough the leading edge B system pressure hydraulic fuse was replaced for the same problem just the night before. I tell the OPS guy not to board and go check out this fuse. I'm looking around, as you guys know there are a few hyd fuses in the wheel well and I have no idea which does what. Up on the ceiling there is one fuse that is clean (this is an old work dog 300) so I figure thats the one. The lead calls MX Control and gets no help from them really so I checked the Auto-Slat box on her advice to make sure the problem was not in that system, no joy.

As I start up the jetway the Captain stops me to ask if the plane is good to go-"nope". As I get into the jetway the FO asks me if the plane is good to go-"nope". As I turn into the cockpit the Flight Attendants ask me if the plane is good to go-"nope". As I leave the cockpit the OPS Sup asks me if the plane is good to go and thats when I had had enough and asked them all if they thought I would keep the status of the plane a secret from them. I mean why not let me work and get back to them when I was ready? I know, I know-thats a subject for another post.

Turns out I had the right fuse so I back off the B nut drain the one side of the thing, back off the B nut on the other side and get a face full of Hyd fluid. Luckily just moments before the Lead asked me why I was not wearing safety glasses so I threw them on. The glasses deflected the majority of the fluid but could not stop the stuff dripping off my forehead and right into my eye. I got a good bit in mouth as well and as it turned out that was only the first time of many that day in which the taste of hyd fluid would be in my mouth.

Once the fuse was reattached the slats worked fine except (you knew that was coming) one end of the fuse now had a leak. I tried to tighten the B nut but it did not help, I took it off again and cleaned the B nut out but that did not help so we ordered a new fuse. Well as it is a fuse does not typically shut unless there is a leak so I put everything back together, hung my bucket on the dripping line and we ran the Flaps/Slats a bunch of times to find the leak. Not too long into this I found #2 Slat actuator leaking. Cool, I'm thinking, at least now I'm getting some where. The Lead checks it out and of course we have neither the Actuator or the Fuse! Since the actuator had to come out I started to take off all the panels and such to gain access. Anyone who has done this before knows that there are about two hundred screws, four or five access panels a bunch of bolts and a few nuts to deal with. After that it was wit til 4pm for the parts.

Fast forward to 4pm I grabbed the fuse and installed it first. I figured it was the quickest. Another couple of drops of hyd fluid in the mouth/hair/eyes and it was time for a leak check. Guess what? That SOB was still leaking! I took off the line that the fuse connected to and the flair was cracked! Now I need a line! I can't use a temp line because this line snakes in between the Aileron mixer, two cables, and two rods. When I called AOG they told me that the line was NIS (Not In Stock) system wide and that they would have to call Boeing! Well now it's about 5 or 5:30. It's Saturday we only had four guys on shift and Terminators were in range so I had to stop and help with that. Actually I was not even supposed to be working that plane since we only had four guys covering the line but the guys were cool and let me break off here and there to work it.

When I left the plane to a guy working RON I had accomplished zero. As a matter of fact we were worse off than when we started since we needed a line that nobody had! Before I gave up completely I did put the old line back in, and hung my bucket from it again so the RON guy could change and leak check the #2 actuator. Kind of sucks but hey he was on OT.....