Take That Extra Step (It's Harder To Do Than It Sounds)

Well I'm back from vacation. Back to work time. Time to push tin, it's what we do.

I had the opportunity to go on a road trip to Boise to fix a 300 with one of the other Oakland mechs, let's call him TwoTurns. So we get to Boise and it's raining and cold. The ONLY plane there besides the one we flew in was an old work horse of a -300. Before we left Oakland we got the low down on the issue with the plane. The number two engine "START VALVE OPEN" light came on after engine start and remained on. So with us we brought: Rain gear, rain boots, tools, a start valve, an N2 indicator, starter, a korry light, a bunch of other stuff that was already in the downline box. I also brought my MagLite, and an extra bag of open end wrenches where I keep my trusty Ford Wrench.

We let OPS know we were there and went over to the plane. Once up in the flight deck we turned the plane on and what do ya know? The number two "START VALVE OPEN" light is on. TwoTurns checks the log book and we hit our first snag of the trip. Not only is the start valve written up but on the next log page the crew wrote up "Over weight langing at 155k". Great! we had no idea that the plane actually took off and landed again, heavy. We called Oakland and got the Foreman to look up the Over Weight Inspection for us so that we could concentrate on the start valve issue.

I suggested to TwoTurns that we start up the APU, put the bleed air on and see if the engine starts to spin. I figured that if the valve was really open, once the bleed air was turned on the engine would spin up. The APU comes up we turn on the bleed and nothing happens, but the "START VALVE OPEN" light remains on. We motor the engine to see if the light would go out but that did nothing. TwoTurns goes down and manually opens the valve but that did not help either. When he took the canon plug off the valve the "START VALVE OPEN" light went out! TwoTurns put the canon plug back on and the light remained extinguished. Cool, looks like the valve was messed up or at least we knew we could change the valve and that would most likely fix the problem.

I went downstairs to the engine and told TwoTurns that I was going to get the valve and my tools so that we could get this pig back in the air and making money. When I got back TwoTurns says one of the things that no mechanic wants to hear-"we have bigger problems than the valve". Second snag of the trip! While aiting for me TwoTurns took the extra step to look at the wire bundle which fed the canon plug for the start valve and he found that the N2 Alternator wires had chaffed against the start valve wires causing the indication in the cockpit. There were seven wires in the bundle and five of them would have to be repaired. The question came up about splicing wires under the fan cowl and what type of splice to use if we could do it. A quick call to MX Control confirmed that the wires could be spliced with environmental splices but then a Planning Item would have to placed on the engine to have the engine wiring harness replaced within 500 flight hours.

The third snag.TwoTurns searched his line bag, I searched my line bag, we both searched the downline box that goes on all road trips-no environmental splices anywhere. We figured that someone on the field must have them so we asked OPS and they had the number to Horizon Air MX. After describing what I needed they said they would drive it over for us. After a short wait the Horizon Air guys brought us the correct splices and sleeves and told us to keep the extras! (thats how we roll in the Line Maint. world, one company generally is willing to help the other!) With the wires spliced we ran the engine to make sure all was good, did the paper work and closed her up. Of coure being SWA they were boarding the plane while this was going on but hey it worked so I figured that if the pax wanted to wait while I was sure that my paper work was correct than they would just have to wait.

The main thing is that if TwoTurns had not taken the extra step of checking those wires, we would have changed the valve, which may have had the false effect of working for us while potentially failing on the next revenue flight! Taking that extra step is not the haredest thing to do and I think that most mechanics know that it should be done. The problem is that outside pressure (OPS, Mx Control, Foremen) often creates the byproduct of skipping that extra step. Once we find something that we believe has fixed our problem, we go with it and often times omit that extra step. As with any real skill, troubleshooting takes time to develope into an artform. If we practise taking that extra step, looking over our paperwork, ignoring those outside pressures (OPS, Mx Control, Foremen, etc) we become better mechanics and that should be the main goal in our professional lives.