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SW 737 with a hole in fuselage lands at MCAS Yuma

Fog

Fog

Old RIOs never die: They just can't fast-erect
None
Contributor
Jim123 said:
Holy crap that seems like a LOT! No matter which way you cut it, that is a lot, right? (Right?)


(Somebody mentioned the DH Comet disasters of the 1950s earlier. Apples vs oranges comparison, but both of those happened at about 1,000 cycles.)
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Jeem: I can't tell if you're making fun of me - but it really doesn't matter, it still seems like a lot to me. My point, if I have one, is that another pax a/c that stayed in service an incredibly long time was the DC-3. But it wasn't pressurized. No other high-usage, pressurized jet a/c is still around like the 737. Early DC-9s are long gone, and all but the -80s are also pretty much retired. I don't think the "metal balloon" analogy is a bad one, and there might just be some number certain of pressurization cycles an airframe can withstand before the damn rivets just start popping.
 
A4sForever

A4sForever

BTDT OLD GUY
pilot
Contributor
Fog said:
.... the SW 737-300 involved had over 39,000 pressurization cycles in its 15 years of use...
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THAT is yet ANOTHER reason to like this ol' girl:

b7472nw.jpg


PLUS ... she pays better and gives you more 'free time', overall ... :)
 
Jim123

Jim123

DD-214 in hand and I'm gonna party like it's 1998
pilot
Fog said:
Jeem: I can't tell if you're making fun of me
Click to expand...

No mockery (and none intended); the number really did make my eyes pop out when I read it. So did HAL's math.

I can relate to running the training helicopters up to maybe 5-10 flights a day- but usually much closer to the lower number. Granted, that's not the same thing but there is still a certain amount of overhead time on servicing/refueling, changing out crews, taxiing, etc. for each hop and then maintenance at the end of the day. So 12-15 flights each day, day in and day out (and night), really impresses me.

I thought about it from flight hours but that left me scratching my head too... never mind :)

I guess it goes to show that airlines stay in business by being good at their stuff... just like any business.

The metal balloon analogy works for me. It makes just as much sense to a layman as to an engineer or anyone in between.
 
wink

wink

War Hoover NFO.
None
Super Moderator
Contributor
Jim123 said:
Holy crap that seems like a LOT! No matter which way you cut it, that is a lot, right? (Right?)


(Somebody mentioned the DH Comet disasters of the 1950s earlier. Apples vs oranges comparison, but both of those happened at about 1,000 cycles.)
Click to expand...
The reference was to what caused airlines to focus on metal fatigue, not the number of cycles. The Comets went down from metal fatigue due to both a design feature and the fatigue caused by the high differential pressures the new jets were operating at. Even though some airliners were pressurized in the '50s, those recips did not operate at altitudes that required high differential pressures.

Fog said:
Jeem: I can't tell if you're making fun of me - but it really doesn't matter, it still seems like a lot to me. My point, if I have one, is that another pax a/c that stayed in service an incredibly long time was the DC-3. But it wasn't pressurized. No other high-usage, pressurized jet a/c is still around like the 737. Early DC-9s are long gone, and all but the -80s are also pretty much retired. I don't think the "metal balloon" analogy is a bad one, and there might just be some number certain of pressurization cycles an airframe can withstand before the damn rivets just start popping.
Click to expand...
Unless Delta parked all the NWA DC-9s, there should be a fair number of the old shorties still out there. In any case, I wouldn't say they are "long gone".
 
Fog

Fog

Old RIOs never die: They just can't fast-erect
None
Contributor
wink said:
The reference was to what caused airlines to focus on metal fatigue, not the number of cycles. The Comets went down from metal fatigue due to both a design feature and the fatigue caused by the high differential pressures the new jets were operating at. Even though some airliners were pressurized in the '50s, those recips did not operate at altitudes that required high differential pressures.

Unless Delta parked all the NWA DC-9s, there should be a fair number of the old shorties still out there. In any case, I wouldn't say they are "long gone".
Click to expand...

Maybe A4s can clarify this, but about 8-9 years ago, NWA performed a complete overhaul of their DC-9-40 fleet - including re-engining them. Whether that involved re-doing the inner airframes, I don't know.
 
K

KBayDog

Well-Known Member
Fog said:
Maybe A4s clarify this, but about 8-9 years ago, NWA performed a complete overhaul of their DC-9-40 fleet - including re-engining them. Whether that involved re-doing the inner airframes, I don't know.
Click to expand...

That's un-possible.

NWA broke up (more or less) in 1991.

nwa1.gif
 
wink

wink

War Hoover NFO.
None
Super Moderator
Contributor
Fog said:
Maybe A4s clarify this, but about 8-9 years ago, NWA performed a complete overhaul of their DC-9-40 fleet - including re-engining them. Whether that involved re-doing the inner airframes, I don't know.
Click to expand...
This is what I had in mind. I don't think they did anything to the airframe but inspect and repair as necessary, but not sure. I could have sworn I saw one just a couple weeks ago, but am fuzzy now.
 
A4sForever

A4sForever

BTDT OLD GUY
pilot
Contributor
From the horse's mouth: DELTA AIRCRAFT FLEET as of 12/31/2010

Nobody asked me ... but many aircraft MX "problems" (for example -- the aircraft that gave birth to this thread) began appearing w/ more frequency @ 15-20 years ago when the airlines started "outsourcing" (read: using overseas Gomer-MX for heavy checks) in the continuing, post-deregulation corporate zeal to "cut costs" ...

The problem is -- it "cut" reliability and MX oversight as well -- which has continued to be a system-wide airline problem, in my opinion.

"Overseas" MX, however, was never a problem in and of itself, for example: our JAP-anese and CHINEE-se mechanics were some of the best and most dedicated wrench-turners I've ever seen, military or civie-street -- but -- WE trained 'em and WE provided the heavy-duty QA oversight focus to make sure the fisheads & rice breaks didn't get so long that they interfered with turning out a quality product. Unfortunately, even these fine fellows eventually got "outsourced" (retired & fired) and the work moved to even more cost-effective (read: cheaper) venues ...

In the "good ol' days", getting a position as a Pacific system Line Mechanic or Shift Supervisor was maximum "face" for most of our Orient MX guys ... and it showed in their attitude(s) and production.

That's not happening now -- so what might be the message for the traveling public ???

Answer: You get what you pay for ... always have, always will ...
 
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