Author Topic: C-130 crash in CA video (Read 544 times)

Durr · « **Reply #15 on:** June 18, 2002, 10:08:17 PM »

C-130 is normally limited to 3.5 Gs. If they were pulling up from a drop, they were probably pulling in the neighborhood of 2 or more Gs already. Pilot induced loads and gust loads are cumalative. Thus a strong updraft could easily have momentarily put more than 5 or 6 Gs on the aircraft, possibly even more.

A vertical gust of 30 fps (often encountered during moderate turbulence) would produce approx. 2 G of acceleration on the airplane. The ultimate load factor of an airplane is the max load factor that an airplane can withstand without structural failure. There will be some permenant deformation at the ultimate load factor, but no actual failure of the major loadcarrying components should occur. If you exceed the ultimate load factor, structural failure of the aircraft is imminent, meaning something major on the airplane WILL break. The ultimate load factor of an airplane is 150% of limit load factor (limit load factor being 3.5 Gs for the C-130). That would make the C-130 ultimate load factor 5.25 G. So you can see that if the pilot was pulling 2.5 Gs coming off his drop, and he took a 60 fps updraft as he crossed the ridgeline, his G load could easily be in excess of 6.5 G, or well beyond the ultimate load factor for the aircraft. If he still had a lot of fire retardant on board adding weight, it would be even worse, as this would reduce the planes limit load factor as well.

Sclew · « **Reply #16 on:** June 19, 2002, 01:09:04 AM »

Looking at the rueters foorage on Yahoo makes it clear his left wing did NOT shear first. It is still attached until the pplane starts to roll whereupon it breaks off. You can see the wingtip is straight until the wing breaks (about a 1/4 roll) then it abruptly deforms and moves.

Something not touched on here is that the plane was obviously on fire when the wings seperated. My guess would be a possibility of fuel leaks allowing vapour buildup. Fly over a huge fire and you get detonation.

Durr has a good point too- overloading G from wind gusts is what was suspected in one of the Afghan crashes as well.

Kanth · « **Reply #17 on:** June 19, 2002, 02:22:21 AM »

News reported that the plane had been worked on for "wing cracks" prior to the accident.

http://apnews.excite.com/article/20020619/D7K80TAO0.html

The news footage was also alot clearer for me and it simply shows the wings ripping off almost at the same time..

DmdKanth

Fishu · « **Reply #18 on:** June 19, 2002, 05:31:44 AM »

The video footage was very saddening sight

Moose1 · « **Reply #19 on:** June 19, 2002, 07:20:23 PM »

This tanker was a C-130A, delivered to the USAF in 1956. 46 years old, and God knows how many hours on the airframe. I would imagine that the owners did regular maintenance on it, but how long can you keep an airframe going before something major fails?

I lost the link, but I found something interesting--there was another C-130A tanker crash in 1994 in the West, under somewhat similar circumstances. The NTSB originally cited the cause of the crash as a vapor buildup in a right-wing fuel tank that was set off by a spark (a la TWA 800), but an independent examination of the wreckage three years later showed that it was almost certainly a failure of the right side of the wing box from excessive loading. Like in this case, the "explosion" that people saw was fuel igniting after the wing snapped.

J_A_B · « **Reply #20 on:** June 19, 2002, 07:33:37 PM »

"I would imagine that the owners did regular maintenance on it, but how long can you keep an airframe going before something major fails? "

There's a pair of Martin Mars flying boats that serve as firebombers up near Vancouver (sp?). Those date from the late 40's and they're still going strong (at least they were a couple years ago). Perhaps, in a way, a flying boat is actually better suited to being a fire bomber because of the stronger structure a flying boat requires?

Airplanes are almost like humans.....relatively few parts of a 50-year-old airplane was actually on said plane when it was built, much as humans are constantly growing new cells.

J_A_B

Hangtime · « **Reply #21 on:** June 19, 2002, 08:45:46 PM »

unless i'm confused, one of those Mars flying boats went in while fighting a fire back in the 60's.

I think only two remain, and they are not agressively used.. drop heights are very low; pilot skill needs to be very very high, and they are pretty demanding with regards to operational parameters.. water landing/scoop sites, small spotter a/c support, etc.

Nothing else remains flyable with the 'douse' capacity the old MARS boats have.. except the C130's... which are a lot more rugged, more parts are available, they are less demanding in operation and can and have been used far more agressively than the MARS could be in the firefighting role..

Dinger · « **Reply #22 on:** June 19, 2002, 09:07:23 PM »

It's tough.
The forestry folks (or Hawkins and Powers) are pretty much stuck using old airframes for a very very demanding and dangerous job. I imagine for some of the stuff they pull converted CAS a/c would be more appropriate, but as far as I know, it's illegal to do that.

Anyway, the actual cause of this crash might come out later. It's just sad to see.

Sclew · « **Reply #23 on:** June 19, 2002, 09:13:53 PM »

Actually those mars boats are still heavily used.

They used to be supported by macBlo % forest tender owners and the provincial goverment, but when Weyrhauser stepped in they had to reformat it so they were "freelanced" more often (most notably they served in Alberta 2 years ago).

They undergo much more strenuous lifts than any "c" series plane- but they were designed for it since the airframes were for bombers in WWII originally. They do most of thier work as low altitude drops in mountain and valley ranges where their drop time consists of a 3000 foot spiral dive to get into a short ridgelines and valley areas and drop 500 feet over the trees followed by a heavy pullup to get out of the valley. I have been in the interior of BC and seen them at work- it's breathtaking and no other planes would even dream of trying it. Usually only helicopters are available.

You can tour them at Sproat Lake in Port Alberni Vancouver Island during the "wet" season when they see less use.

Marianis would be the one that was destroyed in 1960, but to be fair the plane was on it's trial flights and the pilot ignored ground control at the flame and hit the trees on a ridgeline.

Caroline was lost in a storm not long after while at moor in Sproat lake.

Hawaii II is currently out of service due to engine repolacement but should be back by next year.

Amazing flying boats.....

Hangtime · « **Reply #24 on:** June 19, 2002, 09:22:46 PM »

Quote

Actually those mars boats are still heavily used.

Propoganda.

I agree, they are spectacular. But C130's don't go outta service for entire seasons for engines. They also don't cost anywhere near as much to operate as the MARS. If the C130's could operate from water they'd retire those MARS boats in a heartbeat.

J_A_B · « **Reply #25 on:** June 19, 2002, 09:39:12 PM »

SPeaking of which, we need some flying boats in AH.

J_A_B

Durr · « **Reply #26 on:** June 20, 2002, 11:58:14 AM »

They still use some old WW2 bombers for firefighting too. I have seen fairly recent pictures of A-26s, and PB-4Ys being used in this role. There is also a proposal afoot to convert some surplus A-10 aircraft to the firebomber role. I personally think the A-10 would make an awesome addition to the firefighting fleet.

Sparks · « **Reply #27 on:** June 20, 2002, 07:44:39 PM »

Hmmmm - worrying if the aircraft had been in for repairs shortly before. Where I work we do a lot of C130 work (I'm not persoannly on them - another hangar) but I know we've replaced the main wing attachment plates for cracks - its like a machined rib just outbaord of the fuselage that the wing bolts on to - REALLY big job.

The FDR should tell a lot ......

All my sympathies go to the families of the crew

Sparks

Sclew · « **Reply #28 on:** June 21, 2002, 01:33:34 AM »

Actually hang- 1 season down for 35 years of continous service is something most C-130's could only have wet dreams of.

And even then Hawaii is back up- fought a fire yesterday at Ladysmith. The shutdown was more money related than anything else.

Money is a big factor- the Mars boats were a steal at 100,000 for all 4. Plus they got all the engines and die & toolings from the navy for another measly 20k. That means those planes were the cheapest airborne firefighters ever built! I am not really sure what their overhead to operate is- But I gaurantee it's less than the 3 C-130's it would take to do the same job. Some time ago they tried to have another 10 of these planes built. Unfortunatly the powerplants are just to rare and the rights & blueprits too impossible to find. New engines and a completely designed form the ground up plane cancelled the project.

C-130's have been available for some time but the Mars is still in service because no-one else can do what it can. Those two boats can operate for 6 hours and reload on the fly (the planes have a scoop that loads water off of a lake by skimming over top). Their record was 11 years ago? it was 37 passes for each boat in one day over a fire- a 265,000 gallon deluge per plane.... it turned a 250 hectare forest fire into a marsh.

The year came from the lack of funds when Weyrhauser refused to take over M&B's share of the load. All parts were available but no-one could pay for the overhauls.

http://www.martinmars.com/

In fact- considering that they are freelance anywhere in the world- and undeniably the best waterbombers ever made... I am disturbed they are not in the US working right now?

hehe

http://www.martinmars.com/video/vid3.mov

Look at the apples....
Further from the website: working in tandem, they are able to deliver 14,000 US gallons (54,500 litres) of suppressant for the initial attack and continue delivering as much as 7,200 US gallons (27,276 litres) every seven minutes thereafter in sustained operations if needed.

How long would that nasty blowup last under that? Change crews and refuel every 6 hours as needed.... Few fires in BC last longer than 3 days when they swing into action.