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Second grounding of the F-35 fleet in one month comes to an end

The entire Lockheed Martin F-35 Lightning II fleet spent six days grounded after a crack was discovered in an engine component of one aircraft. Flights resumed on Friday afternoon, following the conclusion of an investigation into the problem according to officials for the F-35 program.

"Following engineering analysis of the turbine blade which developed a crack, F-35 flight operations have been cleared to resume," the Joint Program Office and Pratt & Whitney said in a joint statement.

"This decision concludes a cautionary flight suspension that began on Feb. 21 after a 0.6 inch crack was found on a 3rd stage turbine blade of a test aircraft at the Edwards Air Force Base F-35 Integrated Test Facility during a routine inspection.

"The engine in question is part of the F-35 test aircraft fleet, and had been operated at extreme parameters in its mission to expand the F-35 flight envelope. Prolonged exposure to high levels of heat and other operational stressors on this specific engine were determined to be the cause of the crack."
 
The statement also noted that no signs of similar engine stress or other cracks were found during inspections of the remaining F135 engine inventory for the F-35 fleet. The investigation also determined that no engine redesign was required because the crack was only found in a single aircraft turbine blade.

 
The Pentagon also announced a new deal clearing a path to eventually lead to the purchase of Lot 8 in the LRIP plan for the F-35. The deal is worth $333,786,000.

Source: Defense News



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What about combat operations?
By cjc1103 on 3/4/2013 10:15:45 AM , Rating: 2
quote:
"The engine in question is part of the F-35 test aircraft fleet, and had been operated at extreme parameters in its mission to expand the F-35 flight envelope. Prolonged exposure to high levels of heat and other operational stressors on this specific engine were determined to be the cause of the crack."

You might need to operate your jet fighter at its limits during combat.. like using max afterburner to dogfight/evade SAMs..
I think they are saying they probably used max afterburner during testing a lot more than would be expected in normal operation. But still, makes you wonder if the Pentagon should have continued the second engine contract from GE, in case a design problem was found with the P&W engine.




RE: What about combat operations?
By FaaR on 3/4/2013 11:23:20 AM , Rating: 3
You're probably not going to be able to just plain evade a SAM. They are much faster and more agile than any fighter jet could ever hope to be. The pilot's hope lies in befuddling the missile with countermeasures, or possibly stealth passive defenses.

Anyhow, even if you afterburn and whatnot during combat, you probably won't experience any engine difficulties as the engine is designed to run using afterburner. This was apparantly a stress-tested aircraft and even if combat conditions are similar, cracks would typically not be threatening until well after the moments of combat are already over. ...Unless there's a manufacturing flaw that evaded detection, but hey, nothing can guard against that.


By Spookster on 3/4/2013 12:35:02 PM , Rating: 5
But the F-35s in Battlefield 3 can out run them so it must be true.


By Jeffk464 on 3/4/2013 4:47:25 PM , Rating: 2
I thought SAM's would have a hard time locking on to stealth figh-err attack planes.


RE: What about combat operations?
By Reclaimer77 on 3/4/2013 6:00:19 PM , Rating: 1
quote:
You're probably not going to be able to just plain evade a SAM. They are much faster and more agile than any fighter jet could ever hope to be.


Not exactly. SAM's, being launched from the ground, spend a lot of fuel just gaining altitude and speed. And they aren't as maneuverable while in this phase. Our pilots are very good at SAM evasion.

I saw a video of a Falcon driver evading no less than six SAM's over Iraq. After he landed, he discovered his entire chaff/flare modules were full. Malfunctioned. I'll try to find that, so awesome.


RE: What about combat operations?
By PadaV4 on 3/5/2013 4:50:14 AM , Rating: 2
By Reclaimer77 on 3/5/2013 9:49:53 AM , Rating: 2
That's the one! I remember the call sign now, Stroke 3. The full vid is on the sidebar too.

http://www.youtube.com/watch?v=2uh4yMAx2UA

Too bad about the low quality, but still, I'm on the edge of my seat watching it.


RE: What about combat operations?
By gamerk2 on 3/4/2013 11:47:27 AM , Rating: 2
Its a life expectancy equation. Under normal operation, the equipment on the plane will last for "x" hours. Under adverse conditions, that equipment will wear exponentially faster. As in, within a matter of hours in some cases. Thats why the aircraft now all have limiters built in to keep the pilots from wearing out the components.

Given its a test aircraft that was being used specifically test the aircrafts limits, I don't see a problem. If you see it again on a production model though, then there might be a problem.


RE: What about combat operations?
By Jeffk464 on 3/4/2013 4:48:52 PM , Rating: 2
Mig 25 was kind of famous for that if they really maxed out the speed it burnt up the engines.


By Dorkyman on 3/4/2013 8:26:15 PM , Rating: 2
I seem to recall some article about the remarkable P-51 WWII fighter plane. There was max power, max "military" power, and then "let it all hang out" power, after which an engine teardown was mandatory.


Drug trafficking causes planes to be grounded
By Creig on 3/4/2013 10:31:01 AM , Rating: 5
quote:
The entire Lockheed Martin F-35 Lightning II fleet spent six days grounded after crack was discovered in an engine component of one aircraft.


Couldn't they just have had the drugs removed from the one plane instead of grounding the entire fleet?




By Brandon Hill (blog) on 3/4/2013 10:40:34 AM , Rating: 2
HAHAHA, Tyrone Biggums got a military contract! :)


By Samus on 3/4/2013 11:47:53 AM , Rating: 2
That explains why Dave has been out of the news since the F35 program...


By Omega215D on 3/4/2013 11:01:44 AM , Rating: 2
Engine components made of crack... no wonder the planes cost so damn much to make.


By sorry dog on 3/4/2013 12:27:14 PM , Rating: 2
...and what's a single single ??


By Jeffk464 on 3/4/2013 4:44:57 PM , Rating: 2
The crack was just in the one that was flying around Chicago to long.


Good to see the F-35 back in the air
By Beenthere on 3/4/2013 10:14:51 AM , Rating: 1
Durability stress testing serves a valuable purpose. One crack does not make for a problem considering the extensive, extreme testing that these engines go through. You can bet that there will continue to be extensive component inspections to insure no further issue exist even though the issue was only in one test engine.




RE: Good to see the F-35 back in the air
By Jeffk464 on 3/4/2013 4:51:47 PM , Rating: 2
A crack in a turbine or compressor can result in a catastrophic engine failure, its not that minor. If your remember a crack in a DC10 turbine wheel ended up bringing down the whole aircraft.


RE: Good to see the F-35 back in the air
By Nfarce on 3/4/2013 5:36:09 PM , Rating: 2
Only because the genius McDonnell-Douglas engineers decided to route all three hydraulic lines through the tail.


By Jeffk464 on 3/4/2013 9:14:14 PM , Rating: 2
wow, you know your stuff


By Amiga500 on 3/5/2013 2:05:44 PM , Rating: 2
More importantly, they didn't think it necessary to have shut-off valves that would close up the lines in the event of a leak.


By Skywalker123 on 3/6/2013 5:45:28 AM , Rating: 1
Nope, the f35 is a plane that should be junked.Its nothing but shit.http://www.counterpunch.org/2013/03/04/when-money-...


We knew this was coming
By johnsmith9875 on 3/4/2013 11:41:11 AM , Rating: 2
A new engine design with a long driveshaft is going to be problematic since it digresses from traditional designs.
Just wait until the first STOVL F-35 vibrates itself apart when the driveshaft bearings fail.




RE: We knew this was coming
By Jeffk464 on 3/4/2013 4:52:41 PM , Rating: 2
? turboshaft is nothing new.


RE: We knew this was coming
By sorry dog on 3/4/2013 7:49:29 PM , Rating: 2
It was the A model jet that had the crack in the turbine blade.

You are referring to the F135-400 motor. I suspect that since the -400 motor has more cycles used per flight hour, it and accessories will be inspected more often. That is part of the reason the B is more expensive to operate.


What about combat operations?
By cjc1103 on 3/4/2013 10:17:49 AM , Rating: 2
quote:
"The engine in question is part of the F-35 test aircraft fleet, and had been operated at extreme parameters in its mission to expand the F-35 flight envelope. Prolonged exposure to high levels of heat and other operational stressors on this specific engine were determined to be the cause of the crack."

You might need to operate your jet fighter at its limits during combat.. like using max afterburner to dogfight/evade SAMs..
I think they are saying they probably used max afterburner during testing a lot more than would be expected in normal operation. But still, makes you wonder if the Pentagon should have continued the second engine contract from GE, in case a design problem was found with the P&W engine.




By siliconvideo on 3/4/2013 11:32:39 AM , Rating: 2
Does sequestration mandate 2% less stress? If so then we won't be pushing the planes to the boundaries as much causing cracks.




By johnsmith9875 on 3/6/2013 11:44:48 PM , Rating: 2
The ones that lose the rock-paper-scissors battle in the hangar, that's who.




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