Sunday, May 20, 2007
Eating your way out of a fuel tank.
| So yesterday I introduced you to the concept of a "Confined Space." While many of the aircraft that are maintained where I work are HUGE, there are still many many confined spaces inside. The most notorious confined space is: The Fuel Tank. Now when I first thought about fuel tanks on big planes I started with the idea of a car fuel tank and multiplied the size by about a million. In reality that large of a concentration of fuel would be impossible to control during flight. Imagine trying to run down stairs with a very full cup of soda. Once you get a little momentum going, there's no stopping it. In most planes the fuel is carried in "bladders" scattered around the aircraft body and out into the wings. In fact we have one photo we use at work of an airplane that appears to be sitting up and "begging." The problem was as they were draining fuel (AKA "Defueling") they didn't properly transfer the fuel between the tanks and eventually the plane tipped backwards causing an astronimical amount of damage to the tail end. You can get a taste of in tank fuel repair in an episode of Dirty Jobs that quite coincidentally is being rerun this Wednesday 5/23 at 11pm and then Saturday 5/26 at 1pm on Discovery Channel. For the record thos are not the planes where I work and that show was not filmed anywhere near me. If you would like to have your own confined space fun at home try this: go to your kitchen and open the cabinet doors under your sink. Crawl in. Close the cabinet doors. Now do the New York Times crossword puzzle followed by some heavy duty knitting, wrapping up with some creative welding. Did I forget to mention the fumes? You see aircraft fuel fumes can concentrate in fuel tanks and suffocate you. Plus you are often laying down sealants that suck oxygen out of the air leaving you with nothing. So just before you crawl under your sink, open all of the household chemicals you store under you sink (that you know you probably shouldn't). Now dump them all over the place under your sink before you crawl in. If you are having trouble breathing you can hook together 4 or 5 straws end to end to make a snorkel to outside air. How's that crossword puzzle coming along now? In an effort to avoid death, a nifty gadget called a PID meter or PGM-50 is used to detect gas and oxygen concentrations in work areas. I prefer to call it a Canary, party due to the color, but also in vague reference to the birds used to detect deadly gases in coal mines. With all of this going on, I suppose it might not be a big shock that crawling into a fuel tank is not a favorite job where I work. In fact it is so hated there are various methods of getting out of that sort of work. The most famous of which is called "eating your way out of a fuel tank." Essentially, if you eat a lot, you get fat, and you can't get into the tank. Problem solved. You would be amazed at the number of LARGE individuals where I work. While I am sure some can reason that the long term health effects of being extremely overweight is somehow outweighed (pun intended) by avoiding the dreaded fuel tank. I am not 100% convinced. But then as you recall, my confined space is simple a scorching hot classroom on the 3rd floor of a 60 year old airplane hangar. About 2 weeks ago, I got to thinking about my confined space, as I was already sweating buckets at 7am. I walked down the hall and picked up a PGM-50 and placed it on my desk in the classroom. I wasn't especially concerned about harmful gas concentrations. And though I feel like I am suffocating some days I knew there would technically be enough oxygen to survive. I recalled that the PGM-50 also monitors ambient temperature. Sure enough, there it was: 84 degrees at 7am. Studies have shown that effective learning stops at about 78 degrees. The mind is just overwhlemed with signals to "get out of the heat" and new information doesn't "stick." At this point I haven't yet figured out how to eat my way out of my fuel tank. I suspect if I blew out my knee I couldn't climb the 3 flights of stairs to work, but again the cost-benefit ratio doesn't really get me excited. Teaching my class in my boxer shorts would probably solve the heat problem but would very likely create a whole lot of new problems. Somehow I doubt they'd invest the money to buy PID meters for all of the students and instructors since they tend to be a bit pricey even with out the typical DOD markup of about 500%. I suppose I will have to take comfort in knowing that I am the human equivalent of a Krystal. I am hot and steamy (but not in the "sexy" way). I have been assured on many occasions that I am quite square and very cheesy at times.  |
