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slope and longerons.


t56jeff
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I'm no structures engineer, I'm just a pointy-head old RADAR tech.

But, given the sloping longerons are the primary structure on the aft fuselage, and there aren't any beefy pieces up on the top section of the fuselage that come close to the longeron, I would have to utilize very few Risk Assessment principles and say not only no, but...

There is nothing in the 130A-3 as a caution, but I seriously doubt an engineer would suggest that both can be done at the same time.

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Would not sloping longeron replacement be considered depot level maintenance?

This longeron, primarily the left one, has been problematic as long as I can remember. Many years ago it was a special emphasis item in the PDM work package. If units discovered a defective longeron on an acft. not going to PDM they submitted a depot maintenance assist. I believe the authority for this was contained in TO 00-25-107. Once the schedule was agreed the acft. would be flown to WR-ALC or one of the contractor depot facilities.

I would be very reluctant to tackle this task at the I level primarly for lack of special tools, shoring, tech data, experience level and large MMHs required. While don't have access to applicable TOs, it appears from prevous threads tech data is still sketchy. Shoring, a great deal of it, required is by itself as major issue and requires precise placement. And, as the troops at WR have stated the last thing you want to do is attempt to replace both at the same time. Further, my guess it no one in the org. has experience at the task. On the other hand the troops at WR have been doing this for 35+ years.

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I seem to remember having sloping longerons changed at home station a few times over the years.

Dont remember if it was local guys or a WR team that did the repairs or not tho.

Dan

Dan,

There are indeed situations where accomplishing depot level maintenance at home station does happen. For example, a Hays International depot repair team replaced the left wing on an AC-130A at Hurlbert damaged during fueling after fuel cell repair. It's very possible a similiar situation required longeron replacement at home station, especially if the longeron was damaged to the point the acft. was not flyable. Keeping in mind my perspective is TAC only acft., to the best of my feeble memory, although we replaced numerous left side longerons, don't recall doing any at home station. Acft. were repaired at one of three facilities; WR, Hayes International or Aero Corp.

What surprises me is this structure is still a problem after almost 40 years. In my day replacement was driven primarily by corrosion. Caused in part by troops/crew dawgs with short stacks and low manifold pressure failing to taxi up close to the aft urinal. Is corrosion beneath the urinal the problem today?

Regards,

Myers

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YES, the urinal is still a big part of the problem in the ones without encapsulated latrines. They even put in one with a bigger opening in hopes they would not miss. I suggested the take the system out and make them sit down and pee. I guess it is not to MANLY. Also the jumpers may have issue, but the zipper suits are just to good to do it!!

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It is still an issue but no where near the extent that it was in the day. Now the depot removes that skin panel FS 737-800 completely, removes all the paint, inspects, and then reassembles everything liberally using sprayable sealant and a gloss topcoat of paint (btoh as additional barriers to mitigate the corrosion). I kno wit doesn't sound like much but I can tell you that the normal corrosion issues I saw in the mid-late 80s are now rare to see as a result of new materials and processes. Given the circumstances surrounding this (directly below the urinal and mis-directed urine etc), I'm not sure that you will ever see an aircraft that has the gravitational drain type urinals without some corrosion...chalk it up as piss-poor design flaw.

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Just had brain dump realizing Dan and I are talking about two different time frames. My frame of reference is late 60s to late 70s. Believe Dan's to be later. My experience is the longer an acft. is in the field the more capability wing maintenance acquires. Some previous depot maint. tasks become I level tasks. Process usually driven by shop chiefs who believe task is within their capability. ALCs usually not receptive to giving up such work and raise all kinds of stupid objections. When necessary we would play the money card. The difference between depot repair costs and I level costs was usually the winner.

Edited by larry myers
Wrote Dave. Meant to write Dan.
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