That One Key Piece Of Info

The other day while at work I got to go on a road trip with Maybe-Maybe down to San Jose. The information given to us was that the HDG flag was showing on both the Capt and FO HSI. We gassed up the truck, J-Bird (one of our stores guys) loaded up the parts, we got our tools and were off. For this problem we brought with us an IRU (inertial reference unit), a DAA (digital analog adapter), and both of the overhead panels that talk to the IRU.

This is an IRU from Northrop Grumman. We use a Honeywell system but  no pics avail.

The plane had been taxiing out for departure when the instruments flagged. The flight crew returned to the gate, then contract MX came out, performed a re-align of the IRUs. The flags went away and they signed it off. On push back, this time, the instruments flagged again so they returned to the gate again and called us to go check it out.

Road trips are a perk of being a Line Mechanic. There is a certain amount of pride in knowing that the company trusts us enough to go out and fix planes away from station. There is also satisfaction in the figuring out of what is wrong and using knowledge, and available tools to get a plane that is stuck at an away station back into service. Most guys enjoy road trips and I have written about them before.

Maybe-Maybe and I are of the same mind in that we like to go, fix the plane and come back as quickly as possible. We figured that this would be a quick fix and back to OAK.

Once we got to SJC and read the logbook we found out that the problem only existed on the FOs side instruments. All the instruments: ADI, HSI, RMI, and even the PWS INOP light came on. We began by aligning the plane and checking for any faults in the system. Of course we found no faults and everything worked as it was supposed to. We decide to put the new IRU and DAA in as we were sure the #2 IRU was acting up. When we put the new IRU in we found out that it was "Bad From Stock". There was a fault code that would not reset or go away. So much for a quick trip! We called MX CTRL and they got one headed our way through LAX MX. We could expect it in a little over an hour.

While we waited we kept busy by cleaning the plane (the flight crew left in a hurry and had no time to do it). We also changed some seat belts on another plane that had an issue.

When our IRU arrived we threw it in and got everything working correctly. I called MX CTRL to tell them I was signing off the plane and let them know that it had in fact been working when we arrived hours ago. We did the deed and soon enough a new crew arrived. Maybe-Maybe and I decided that since the plane had returned to the gate twice before, we would wait until it took off to make sure everything was ok. (I think you all know where this is going) The plane boards, pushes back and sits there for like 6-7 minutes. Maybe-Maybe and I are saying "That's it he's broke.....he'll be coming back". We went to OPS and asked the OPS guy to call them. Sure enough he said he was working on the same problem the plane had before.

DAMN! The freaking plane is POSSESSED!!!

They came back to the gate and said that the instruments on the FO side flagged out, but as soon as he put the APU bus back on line the flags went away!! That was it!! that was our piece of info that we were missing!! When the pilots put the plane on the #2 generator the FOs instruments flagged. The #2 generator was not powering the #2 IRU bus!!!

We called MX CTRL and I suggested we MEL the #2 engine driven generator. That was all we had to do all those hours ago when we got there and we could have been done!!

It's amazing how one little piece of info can throw off a whole troubleshooting plan. We had been chasing the wrong problem the whole time! In hind sight we figured the #2 generator must have stopped powering that bus when they first were taxiing out the first time the problem manifested itself. Of course the re-align worked because they were most likely on GRD power or APU power at the time.

We did wait until the plane pushed out to ensure they left. We got to SJC at 12:30pm and finally left at 7pm. A long day of waiting and chasing phantom problems. Oh well, we did figure out what was happening. The plane did finally go make some money.

The COAX Connector From Hell

Today at work I got to do a few "firsts" for me. I worked on a plane that had a VHF problem which was traced down to a VHF COAX connector attached to the #1 VHF antenna. I have changed the VHF antennas before and I have monkeyed around with the connectors before. My prior experience with these fun little connectors has been realizing that one was bad and MELing the system since we do not carry the right parts or equipment to fix the thing in OAK.

Since this was a #1 VHF problem it was not MELable, and since the previous shift had traced the problem and ordered the parts I had the relative easy task of putting the thing back together. A first for me, although I did do some COAX crimping at my house for TV cabling.

A little description. COAX  (Coaxial Cable) is a shielded electrical wire. The wire has an inner conductor surrounded by a flexible insulator surrounded by the tubular shielding.

The theory is that the electromagnetic field produced by radios etc. is contained within the space between the insulator and the shielding allowing COAX to be run along other wire bundles without fear of much interference. The thing about COAX on aircraft is that the length of the wire is pretty critical and you are not allowed much slack as far as simply cutting it shorter to allow crimping, stripping, etc.

The connector crimps onto the wire but you have to strip the shielded part of the wire back some so that the wire fits into the end of the connector. Looking at the picture on the right the wire feeds into the narrow hole on the left of the connector. First the barrel is placed over the wire, you push the wire into the connector, making sure it contacts the pin inside, push the shielding down over the narrow thing on the left, slide the barrel down over the whole thing and crimp it. The shielding must contact the connector to ground it out.

Not only was it my first aircraft COAX crimp but they also sent a complete Daniels Strip and Crimp set. Most of you know that Daniels makes all kinds of crimpers that we use on airplanes. They also make pin pushers and pin pullers, hex crimpers, strippers, etc. For this fix the company sent me two Daniels sets! It was pretty cool seeing just one complete set but they sent two. I tried to find out how much they cost but could only find one set on Ebay for $3000.

Any way, we used the hex crimper for COAX, we found the right die block to put into the crimper and squeezed away. When we were done we had a perfect crimp and what do you know the #1 VHF was transmitting again!

One of the things that threw me off for a little was that the wire we were working on had a wire tag on it that said #2 VHF. Apparently Boeing changed the locations of the #1 and #2 VHF antennas on the 737-700s somewhere mid production so the wire tags are all jacked up. Watch out for this one as I can see it really messing people up. I'm not sure why they did not change the tag but, whatever. That was the final first, incorrectly marked wires from the factory.

I have to wonder, this is the second COAX that I have been involved in and I know there have been others, why in such a relatively young aircraft series (the -700s) are we having so many COAX issues? Mines is not to reason why, mines is just to push tin!

Work Gloves

Big Time Products 20103 Grease Monkey Large General Purpose Work Glove
So a while back I said I was going to try out some of those mechanic style work gloves. I was at Home Depot the other day and found a pair from a company called Big Time Products. These are called Grease Monkey general purpose gloves "made especially for mechanics." I really liked that tag line since I'm a mechanic and I figured these things would work for me.

The gloves are pretty comfortable and have a velcro shaft on the back of the wrist to tighten the glove. They are made out of a synthetic suede material on the fingers and palm and a spandex type of stretchable material on the back of the hand. There are padded areas on the palm and knuckle and they seemed reasonably breathable. They cost me $10 at the store.

I was working a triple the next day so I was excited to give the gloves a try. That night I was working midnight shift first so I got my assignment and went to it. The gloves worked really well and were very comfortable. I changed some tires and did some engine work and hydraulics, etc. The next shift was days and I used the gloves for nearly every call I went on. Day shift is primarily oil and hydraulics with a little engine work.

Around the end of day shift I noticed a problem with the left hand glove. The index finger on that side was developing a hole in it. Try as I might to "favor" that hand or finger I could not and soon enough the hole got bigger and bigger. The material that makes up the fingers of the glove is getting very thin on all the finger tips. I'm not sure if its the oil or hydraulic fluid, or just maybe the type of work we do as Aircraft mechanics but these "general purpose" gloves just won't hold up. In 24 hours the glove failed (in my opinion).

The gloves are comfortable enough but not durable enough for airplane work. To be fair I went to the Big Time Products website and they do say specifically "for auto mechanics". There are other gloves with reinforced finger tips but I bought these for the tactile touch I though they would provide.

I still like the gloves and I still and going to use them. As a matter of fact I cut the finger tip off the left glove and continue to use them.

Plus I'm a broke, cheap aircraft mechanic and as you guys know we always adapt. The next time I'll be sure to get some better gloves but I must say that I really like using them.

My New Mag-Lite LED XL100 Dayshift and Swing Shift Friendly

A long time ago I did a post on my trusty 3D cell LED Mag-Lite. Anyone who remembers that post can recall how much I endorse the Mag-Lite line of tools. Tough as nails, reliable and of course able to be used as a whacker (hammer). I still use my 3D Mag-Lite almost every day I'm at work and certainly every time I work midnight shift. The light works great but recently I have been looking for something smaller to carry when I'm on day shift or swings and certainly when I'm on a road trip. Ideally something that I could place in my pocket but still throw out some good light.

I started looking at all those little LED lights that you can find at the gas station or Wal-mart etc. As a matter of fact my buddy, Maybe-Maybe< carries one of those little lights and it works fine for him. I could not bring myself to using one of those cheapies at work. I own one that I keep in my car and another as a back-up light, but as a primary light I just can't do it. Maybe-Maybe has told me that he is at a point in his career in that he does not wish to buy any new tools. He claims to be about five years from retirement (yeah right). I am no spring chicken but I also have about another twenty years before retirement so I still want to buy some quality tools.

I like most Aircraft Mechanics am broke!!! So when I got a Home Depot gift card a while back I knew I would waste it all on tools and such. Today while picking up a hose for my refrigerator (it was on MEL), I looked around and saw the Mag-Lite LED XL100. Small, compact, water and drop resistant (hey it is a Mag-Lite!) and its an LED.

The XL100 is 4 3/4" long with a diameter of a quarter. Once I got it unpacked and loaded with the batteries (they came with the thing) I tried it out. To say it is bright is an understatement. The XL100 puts out a nice focused beam which is fully adjustable like any larger Mag-Lite. The light is turned on by a thumb switch on the butt end, sealed of course.

One of the kind of gimmicky things that I don't really approve of is the way the light swithces between "modes". Yes Mag-Lite has jumped on the different modes band wagon, which is kind of sad but I know they have to appeal to more folks than just Old School Aircraft Mechanics. There are 5 modes: DIM (normal), STROBE, NITELIGHT, SIGNAL, and SOS. That would be ok but to switch between the modes you don't turn the little knob/button/switchy/red thing in the photo above like I thought. That thing may look like it is movable but it is not. I had to break open the included written directions to figure this thing out. Basically it is a motion sensitive switch, you hold the light so that the mode you want is at the twelve o'clock position, press the on/off switch and hold it down, in the DIM mode you can adjust the brightness by then twisting your wrist in a counter clock wise or clock wise direction. Ridiculous!!

I'm pretty sure I will never use any mode besides the normal one (DIM??).  Anyway the thing is pretty bright and for that it is doing it's job. I hope to never have to test it's drop test toughability but I'm sure it will happen sooner or later.

I will let you guys know how well it holds up. I hope to never have to read an instruction manual to figure out how to use what is supposed to be a simple tool but I fear the days of simple tools are over. Ahh another post subject....

Happy fixing!!

Golden Age Pics from SkyWalker

The plane above is a CV-340. I don't know any thing about the CV-340 yet but I am an airliner nut so I will be looking it up to learn some more. This is an incredible picture, it looks like a Untied Airlines plane that either had a gear down or got stuck in the mud or something. Check out the mechanics and the cranes! This was a day all those guys who worked on the plane would have remembered for their whole career. Thanks for the pic SkyWalker and anyone with info on the CV-340 drop us a line!

**UPDATE**

here is a link to Wikipedia for more info on the Convair 340:

Convair 340

"Did you really ask me that, Mr. Captain?"

I love working Line Maintenance and one of the things that really keeps me interested is seeing how other guys I work with deal with the situations that come up versus how I would react to them. For the most part we all have about the same reactions to Flight Crews, airplanes, the FAA, etc. There are those guys who have a really negative view toward all of the above and those guys generally hate their jobs/life. These are the types who are always negative. Most of the guys at SWA have positive out looks and really try to help the company by getting the planes back into service.

This week when I was at work something happened that put into words a philosophy that I have come to accept as a reasonable way to deal with Flight Crews who ask stupid questions or complain about systems that work fine.

We had a Captain who had just pushed off the gate and was taxiing to the runway when his APU shutdown on him uncommanded. Instead of calling Dispatch he called MX Control and they could not decipher his mumbo jumbo explanation so they told him to return to the gate. As we know if he had called Dispatch they would have helped him to Crew Deffer the APU and he would have been on his way. They mechanic (let's call him NiceNice) got the low down from the Captain and started to work the problem. Surprise, surprise the APU worked normally, there were on Faults on the thing and it would not break for NiceNice.

I was out working on another plane when the call came in so I was listening to all this on the radio. After a while NiceNice came back into the shop and I asked him what that was all about. NiceNice explained to me why the Captain returned to the Gate (MX Control) and what he was doing to check out the APU. When he was done and said the thing worked great I asked him if he signed it off as "Ops checks good, no faults found". NiceNice said "Nope. The APU was fine but I MEL'd it anyway because the Captain didn't deserve to have an APU". It turns out that when crews call him to fix things that are not broken or things that don't work because of something that the crews did, NiceNice always MELs it. He says that if they can't figure out or don't know how it works-they don't deserve to enjoy the use of it!

I really like that way of operating and until now I was torn when I came upon crews who are the ultimate reason for problems that I was trying to fix. Next time I come across the HUD problem and I look into the Fault History coming across the old ALTITUDE Warn, or INCORRECT NAV faults, I am going to MEL the HUD. Better to take it away from those dummies than to let them use it incorrectly.

I figure this will also work well for the crews that refuse to "take the plane" until their little problems are fixed or who are really demanding or obstinate about the work being done etc. One of my buddies here is MEL King. This is very close to what he does. He is known for MELing items because the Crew got on his nerves or couldn't explain things fully. Maybe if we all did such the Crews would bother to learn more about their systems....

Old Aircraft Spotlight- Lockheed L1011 Tri-Star

The Lockheed L1011 Tri-Star was the third wide body airliner to enter commercial operations. In the 60's American Airlines approached Lockheed about making a competitor for the Boeing 747. Ultimately American chose the DC-10 and the Lockheed L-1011 was launched by TWA and Eastern Airlines. The L1011 was very similar to the DC-10 in appearance and they both had three engines with the L-1011's number two engine is integrated into the tail by an "S" duct for improved quietness and stability. The plane had a bunch of production delays, mostly due to the selection of the Rolls Royce RB211 as the powerplant. The DC-10 was able to get into service before the L-1011 and consequently only 250 L-1011s were produced by Lockheed versus a production run of 446 for the DC-10.

The L1011 entered revenue service in 1972. Delta Airlines eventually became the largest customer for the L-1011 and that is where I first met her. We all remember the first real airliner that we work on and mine was a Delta Airline L1011 tail number 789.

Being pretty much straight out of school I was amazed by the sheer size of the plane. The largest plane I had been around before that was an Aero Commander. I did overhaul work at Delta and the L-1011 was not exactly an easy plane to do that sort of work on. The plane was built like a tank, everything was heavy, and none of it really wanted to be taken apart. We would strip everything out of one, fix the discrepancies and put it back together again. My time spent there gave me a huge appreciation for the airplane. I did not get to do a lot of different jobs on her but I tried to learn as much as I could about her while I was there.

I do recall that the flight deck on the L-1011 was huge! The picture above does not even show the observer seat and that was as big as a business class seat. Those of you who have squeezed into the observer seat in a 737 can appreciate that. I also recall that the windshields were very heavy. I had the chance to change one and we used an overhead crane in order to lift it. The doors, the Galleys, the elevator they were all very heavy and required four guys to lift them. The largest repairs I was involved in were gigantic door doublers for the entry doors and Beam Caps in the cabin floor area. This beast was all metal and way ahead of it's time. I know she had RCCBs (remotely controlled circuit breakers) and that she was the first wide body aircraft to achieve a CATIIIc rating. Apparently the autopilot system was way ahead of its time as well and one of the reasons pilots really liked to fly her. I wish I had the chance to do some Line Maintenance on the L-1011 but like I mentioned earlier they went into service in 1972 (when I was two years old) and I got to Delta in 1991, the L-1011 was pulled from service by it's last US operator (Delta Airlines) in 2001 so unless I move to Africa or South America I'm not likely to see one.

I know that I will never forget the BOOM and following cloud of dark exhaust that followed the starting of those RB211s or the BANG and shaking following a test deploy of the RAT (ram air turbine). I will also never forget the amount of work involved in overhauling the Eastern Airlines L-1011s we got from out of the desert. "S" ducts, Lower Galleys, RCCBs, CATIIIc, RB211s, corrosion all a major part of me and those of us lucky enough to work one of the true Queens of the Air.