Fire Suppression Crashes

[scoober78]

Anyone heard of this before now? Strange that there were two in such short succession...curious to hear the follow up.

http://www.cnn.com/2012/07/02/us/south-dakota-air-tanker-crash/index.html?hpt=hp_t1

On a side note...3000 gallons of retardant in 5 seconds? Damn!! Can't imagine what #24000 going out the door in 5 seconds feels like. I guess for air drops though...that's kinda standard. Any flying experience around here with that kinda GW change?

 

[Catmando]

Anyone heard of this before now? Strange that there were two in such short succession...curious to hear the follow up.

http://www.cnn.com/2012/07/02/us/south-dakota-air-tanker-crash/index.html?hpt=hp_t1

On a side note...3000 gallons of retardant in 5 seconds? Damn!! Can't imagine what #24000 going out the door in 5 seconds feels like. I guess for air drops though...that's kinda standard. Any flying experience around here with that kinda GW change?

B-52Gs dropped a bit more than that GW - over #25000 - with Mk-82s.
Having dropped #6000 from a fighter, I can tell you it gives a nice instant lift.

 

[Brett327]

I'm sure they've been generating plenty of sorties this season thus far. Law of averages & coincidence - it's bound to happen.

From the June 3 Neptune mishap. Pretty unsettling pic:

 

[scoober78]

Unsettling is one word for it. Damn.

 

[GroundPounder]

Same type occurrence from 2002, this time a C130.


Those guys are doing a lot, with equipment that is past it's prime.

 

[BusyBee604]

Any flying experience around here with that kinda GW change?

In A-4 combat bomb runs, I've rippled off 6-MK82 500#ers (20-100 ms release interval) from a centerline MER, just a big thump & a bump...no biggie, same for MK84 2000#ers C/L. Also, jettisoned a full 400 gl (3000#) drop tank, just a thump & bump in altitude.

Assymetric sudden GW weight reductions are more interesting in smaller jets, as the weapon release wing tends to rise rapidly and must be prepared for. On some missions in which we carried 2- 2000# AGM-12C "Bullpup" missiles (one on each wing) fired on separate runs, the stick had to be held against a predetermined cranked in aileron trim setting until release, or the bird would snap roll at release, causing you to lose sight of the weapon. Being controlled from the cockpit by a small joystick, lose sight of missile tracking flares...lose missile control!

It seems that most of the 'heavy' fire-fighting tankers drop their loads from close to a/c centerline (symetrically), probably just giving them a sudden healthy rise in altitude!
BzB

 

[Renegade One]

Anyone heard of this before now?

B-52Gs dropped a bit more than that GW

it's bound to happen.

Same type occurrence from 2002, this time a C130.

In A-4 combat bomb runs, I've rippled off 6-MK82 500#ers (20-100 ms release interval) from a centerline MER, just a big thump & a bump...no biggie,

I'm taken with the fact that all of these "heavy hauler aircraft" failures/mishaps seem to result in complete wing failure at the wing butt or wing box or whatever. I mean, NOTHING good ever comes out of that type of failure inflight.
With respect to TACAIR jets and heavy bombers that were specifically designed with that type of "near-instantaneous load change" due to mission requirements, I wonder if these aircraft aren't being flown outside of design parameters/safety margins. I ain't no structural engineer, mind you, but a near-instantaneous "delta minus" of what?...45K pounds by some of the estimates above?...would result in one heck of a "negative load heave" to the wing attachment structure. Not sure how you test for that...but I'm sure there are ways.
And these are "high-time" aircraft/wings, etc.
Dangerous business, that's for sure.

 

[jmcquate]

And that's got to be a rough ride down low with the updrafts from the heat. There's a company named Evergreen out west that uses (or used) 747s for fire drops. The firm I used to work for loaned them the monet to buy them.

 

[Brett327]

I presume that the maintenance and inspection requirements from the FAA are similar to our own. I also presume the engineers designing the maintenance requirements are aware of how the aircraft are being used, much like the Fatigue Life Expended (FLE) programs in NAVAIR are designed to manage these kinds of things for us. If that's not the case, this event will probably highlight the need for a deeper look at the structural airworthiness of these aircraft.

 

[jollygreen07]

I'm sure they've been generating plenty of sorties this season thus far. Law of averages & coincidence - it's bound to happen.

From the June 3 Neptune mishap. Pretty unsettling pic:

That right there is pretty much my worst nightmare. I seriously shuddered when I saw that...

 

[Brett327]

I know, man. I wasn't even looking for a pic of this mishap, but there it was. Pretty amazing that someone got this shot off.

 

[Catmando]

I'm sure they've been generating plenty of sorties this season thus far. Law of averages & coincidence - it's bound to happen.

[wrote this earlier but forgot to post]

I'm guessing firebomber crashes are more than coincidence and are well beyond the law of averages. There aren't all that many , they just don't fly that often, but they do crash a lot. Why?

I'm thinking very old and well used aircraft with many cycles and lots of originally unintended stresses put on them, combined with dangerous flying close to the ground and in heavy fire-bred turbulence. Fatigue - not pilot but airframe.


I know there was a lot of unpublished controversy after that C-130 crash that groundpounder posted, but I never heard the final determination.

Fortunately they have some great pilots who are willing to take on the risk, saving lots of homes if not lives. But although it looks like great fun flying and serving a great purpose, I would not want to do it.

 

[scoober78]

I'm taken with the fact that all of these "heavy hauler aircraft" failures/mishaps seem to result in complete wing failure at the wing butt or wing box or whatever. I mean, NOTHING good ever comes out of that type of failure inflight.
With respect to TACAIR jets and heavy bombers that were specifically designed with that type of "near-instantaneous load change" due to mission requirements, I wonder if these aircraft aren't being flown outside of design parameters/safety margins. I ain't no structural engineer, mind you, but a near-instantaneous "delta minus" of what?...45K pounds by some of the estimates above?...would result in one heck of a "negative load heave" to the wing attachment structure. Not sure how you test for that...but I'm sure there are ways.
And these are "high-time" aircraft/wings, etc.
Dangerous business, that's for sure.

Damn skippy...

One of the thoughts I'd had, since most of the wing box failures seem to happen right after release and at "pull up" initiation goes like this:

I wonder, if similar to G's, there's a sorta push/pull effect at work here? So, you pickle off 5000 pounds a second for 4 seconds, no doubt yielding a big unload, and subsequent downward flex of the wing structure....and then, probably before that effect has gone away, start a pretty healthy pull for the dive recovery which will cause the opposite...It seems like there would be some pretty healthy inertia within the structure itself after that unload, and then to add a pull, along with some updrafts from the fire...Could this be the path to exceeding these limits?

Somebody out there smarter than me shoot this full of holes....

 

[scoober78]

That right there is pretty much my worst nightmare. I seriously shuddered when I saw that...

Has to be a completely sick feeling...couple seconds where you know that you are no longer capable of changing anything on the airplane...because it has ceased to be an airplane...and that you are going to die...

I looked at some of the job listings for these guys on the USA jobs website...they aren't making tons of money either...Can't speak to the Aero-Union or Evergreen guys, but the USFS folks are making less than six figures...doesn't hardly seem like enough...

 

[jollygreen07]

The only way I'd fly with 'em is if they'd let me fly the OV-10. They have those, right?