Monday, January 13, 2014

Accident Analysis II

"The National Transportation Safety Board determines that the probable cause of the accident was the flightcrew’s failure to use the taxi checklist to ensure that the flaps and slats were extended for takeoff. Contributing to the accident was the absence of electrical power to the airplane takeoff warning system which thus did not warn the flightcrew that the airplane was not configured properly for takeoff. The reason for the absence of electrical power could not be determined."

Keeping with my plane crash theme, some people watch true crime stories and murder mystery reenactments but I like to read Aircraft Accident Reports.

I think the reason I like to read these documents is because they are written for the layman with footnotes to define terms I might not understand like "Heading Bug" but the incidents/accidents are outside of my career path. However; the principles that are under the microscope are completely human and apply to any field, including oil field electrician. Reading one of these reports would benefit everyone.

It's a rare plane crash caused completely by weather or hijacking lunatics. Almost all of them are caused by human error and by that I mean a series of humans, dozens, involved in each accident. None of them technically "cause" the accident because that would mean they had designs to cause some event. The authors of these documents all use language like "contributing factors" or "failed to prevent" or "neglected to observe"...the authors admit no one wanted a plane to crash.

Maybe the best way to investigate why a plane crashes is to take a plane the doesn't crash and investigate every contributing factor to why it flew from Point A to Point B. This is why aviation won't be on Oggy's profession list because before going to work I would have to start from the very beginning and deconstruct a successful flight...and that would take a decade or two as it involves aerodynamics, welding, mechanics, electronics, and jet fuel refinery. Then include all the good decisions like mechanics double checking the torque on a nut, using correct wire nuts, solderings circuit boards cleanly, ground crew closing doors securely, captains navigating the ground etc etc. it's hundreds of thousands of good decisions and if you omit or overlook only a handful of these decisions then you will kill 50-200 people. It's easier to look at flying like a hundred accidents waiting to happen if you don't say the magic words; basically, you're already doing the wrong thing by trying to fly so you'd better be extra vigilant and careful.* These reports delve deep into those overlooked decisions.

In the sad story of Northwest Airlines Flight 255 we have an otherwise operational plane that crashes. Read the report to find out why. There is a brief summary that I pasted up top but it takes 146 more pages to really get into the details and the details are what I crave.

Here's a diagonally related anecdote:
A master electrician and I were way out on a ranch installing the wiring for a flare stack motor. The motor was a 240v/480V three phase motor running off a 240v/480V generator (Set to 480v) the company had rented and was sitting nearby running all day long. Someone's job is to drive around a gas tanker and fill up all these generators that run all day and night. So, the project was actually to combine 3 generators that powered a flare stack, and lights and a compressor motor into a single generator situated at the front of the site. We lay the raceway and wiring over the course of a hellish month and finally got around to wiring it all together and moving one generator to the main breaker box (where the future power grid will arrive in 2015) and the other two generators were moved off the site. Well, these big motors are designed to run off of 240V or 480v. There are two separate windings for the coil and depending on the 9 wires coming from motor and how you attach the line, then you can get it to run off whatever is available. Previously, the motor had been wired for low voltage, meaning you join a blue wire from the generator with line 1 and 7; a red wire from the generator with 2 and 8; and a black wire with 3 and 9 and join 4,5,6 of the motor together. These are color coded on the ID plate of the motor. You use a big old wire nut or these weather proof fancy hex head junctions and electrical tape. Since we were preparing the whole site for 480V we had to wire it for 480v which means line blue to 1, line red to 2, line black to 3...and join 4-7, 5-8,6-9.

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Careful: 480V+ 100 amp will blow your ass through your hat.
So, the electrician and I were trying to wire the motor to the ground wiring and we were not being casual because we actually had to drive 300 miles to another location for something that I've forgotten about because we never got there.

Contributing factors:
That morning it was about 105 degrees. About three miles from the job site on a particularly rocky section of road the axle u-bolts of the trailer had broken in half so between 7am and 11am Oggy and the the electrician became field mechanics as we drove about 200 miles round trip to get new axle bolt hardware and then using completely inadequate equipment, like a rock bar and Oggy's aching back and arthritic knees, we managed to replace the hardware...but that put us 3 hours behind schedule for the other part of our day which was about 200 miles away.

Oggy had never wired a motor before and was dreamily fantasizing about Atlixco and chicken mole and churros and hammocks etc etc. He had done no research into this procedure the night before because of an addiction to cheerleader porn. He figured he would learn as he went along.

The usual apprentice helper with lots of experience was not with us because it was a Saturday.

The electrician had done this procedure countless times before but was already thinking ahead to the next job of the day laying a few hundred miles east.

I stood next to the electrician as he wired the motor perfectly for 240V. I noted all the wires he joined. I asked no questions nor asked for clarification and he didn't give any. Really, I barely understood what was going on. We were in a hurry because of the delay caused by our axle and realistically, there was no way to do both jobs in one day but we were going to try as two days of rain storms had caused delays already. I figured it was a bad time to ask for an explanation or details.

It was very hot and humid because of the recent rain. Sweat poured from our faces.

Fatigue was a factor as the electrician and Oggy rarely got enough sleep. This was a saturday after a 60 hour week.

Results: Well, we hit the breaker and the motor sprang to life. No strange sounds. Good. A success. We moved onto the next motor and were about to finish the wiring when the first motor started clanking like my first Huffy bicycle with a loose chain. It clanked for about 5 seconds. Long enough for the electrician to say, "What's that about..." and then it stopped dead.

Actually, the electrician wired the second motor for 480v (there were 2 flare stacks) but it didn't click with either of us that he had just moments earlier wired the first motor for 240v. We were conversing but it was about the next project of the day because it was more involved than this simple wiring.

Of course, the first motor had burned out as it was running 480v off the 240v windings. It was a $2100 motor...that really cost much more because of the time and effort it took a few days later to replace (I was on that project too). They basically paid us Overtime wages to destroy a motor and then paid us regular wages to replace the motor.

If a report was written about this incident the author would say, "The apprentice Oggy's failure to double check the electrician's wiring, his dreamy and distracted attention, his inexperience and his lack of dedication and vigilance FAILED TO PREVENT the error."

See, I didn't cause the accident...but I failed to prevent it. And this is a fine detail that I think we can all learn from since I was technically in a position to prevent it. The electrician said this was the first motor he'd burned out in 22 years so I determined to start a mental category called "Critical Wiring Tasks During Which Oggy Does Not Daydream and Asks Mucho Questions." And I put "Wiring Motors" at the top of the list.

In another tragic airplane accident the pilot taxied to the wrong runway (too short for takeoff) and the first officer failed to notice the painted numbers on the asphalt indicating the width of the runway, which was different than the longer runway. (A funny joke: two (pick your ethnic group) pilots landed a plane. As soon as they hit the pavement the landing strip ended and the plane slides into a field. The first pilots says, "That was short landing strip." The copilot says, "Yeah, but it was very wide.") The Air Traffic Controller didn't visually see which runway the plane was entering. And one or two flight crew members who were also in the the cockpit also didn't notice...and the pilot had not briefed everyone with the longer and more detailed taxi protocol for this airport which included "We cross runway 26 on the way to runway 22" And both the first office and the captain said, "This is a short taxi" when in fact the short taxi was to the wrong runway and it was a little longer to the correct runway, like taking a left turn one block early, although both runway turns were almost identical. Neither the captain nor the first officer noticed the heading bug (A compass setting feature) was not matching the actual exact compass heading...and lights were out on the was dark...there was construction that made the charts different from the actual layout...the first officer and captain (on their first flight together) conversed about non-essential topics...etc...etc. It wasn't merely a brief lapse of attention that made everyone involved miss the cues but that lapse of attention had to happen in the critical window when all the cues were present...and all the others present and involved had to also be distracted or feel it was not their place to interject. Many factors contributed and it's a reminder that it's no accident planes don't crash regularly. If you've ever made a turn in a car down a wrong road that looked identical to the right one or missed an exit on a highway now imagine that mistake being fatal.

P.S. a few minutes after we figured out what had gone wrong with the first motor a storm rolled through and the rain caused us to quit for the day so we never went to the next project. And we moved the trailed to avoid it getting stuck in mud...and because we have a tradition of leaving the trailer keys in the lock so we don't lock them inside, we drove off with the keys in the lock and they fell into the mud...and thus began a ridiculous hunt in the mud and rain for the trailer keys...So, the company had paid us a few hundred dollars to break and fix a trailer and destroy a $2100 motor...and to make matters worse, because the flare stack had no motor, the H2S that was pouring out of the ground could not be ignited and blown into the air...and this is a problem that required immediate attention. Replacing this blown motor was actually the last project we did for that particular company as they said, "Don't call us, we'll call you." and then management restructured and we never heard from them again. The electrician was dispatched to the western desert and Oggy went to Louisiana where he got old and grey.

* I finally arrived back in Texas and as I'm doing laundry I get a call to drive 6 hours west almost to New Mexico and relocate I get back in the van with my clean laundry and head back to the ranch and at the right turn I usually make off the highway THE BRAKE PEDAL GOES TO THE FLOOR actually bringing to life a scenario I'd always wondered about...what happens when you are traveling at full speed and have no brakes with fracking trucks flying all around you? I pumped that brake like Bugs Bunny on crystal meth but it did no good. I'll say it was a close close call and I laughed a little knowing I had written this post only one day earlier and almost died. har har har. If it had happened at a hundred other moments there would be no more Oggy. But the one moment it happened I had a chance to go into complete emergency mode evasive tactics out of Top Gun and came to a halt in a cow pasture with no injuries to anyone.
Now, after the initial problem was diagnosed which was a blown out brake line/wheel cylinder that erupted without warning as punishment for being neglected for three months...I had to decide what to do...and I got back in the van and drove back to the ranch because I knew that I could use the emergency brake and also downshift...which is how I got the van back home at 5mph. The first problem was an accident but the following drive was purely irresponsible. I only have 8 lives left.
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Man in the Van by Oggy Bleacher is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License.