F-35 Cancelled, then what ?
Ecce Homo! Loquitur...
F-35 Head: Delays Coming if Test Planes Grounded Through September
WASHINGTON — The head of the F-35 Joint Strike Fighter program is warning that there is a real danger of missing deadlines if his test fleet of aircraft are not flying regularly by the end of September. “I need all of [the test airplanes] back to full envelope by the end of this month,” Lt. Gen. Christopher Bogdan said at Wednesday’s ComDef conference in Washington. “Otherwise we will start seeing some delays in future milestones.”
However, any retrofit needed to the F135 engine at the root of the restrictions will be borne by contractor Pratt and & Whitney rather than taxpayers.
The entire F-35 fleet were placed under restrictions following a June 23 fire that heavily damaged an F-35A conventional takeoff-and-landing model at Eglin Air Force Base, Florida. Since then, the small test fleet has had some restrictions relieved, but is still not allowed to operate at full capacity. While insisting that the Marines remain on track to take the F-35B jump-jet variant operational next summer, Bogdan said there has been a “headwind” of about 30- to 45 days added to test points due to the restrictions. Testing the Navy’s F-35C model at sea is one of the tests affected by potential delays. “Can we make some of that [time] up? Yeah I think we can,” Bogdan said. “But we have to get all of those airplanes up and flying again.”
The cause of the fire was identified as “excessive” rubbing of a fan blade inside the F135 engine, designed and produced by Pratt. Bogdan went into further detail for the first time on what actually happened to cause the damage.
The issue began three weeks before the fire when a pilot took the aircraft up and executed a two-second maneuver involving adding Gs, roll rate and yaw to the plane at the same time. Although that move was ““well within the envelope of the airplane,” Bogdan said, those two-seconds led to the engine rubbing against a rubber piece at a much higher rate — and nearly double the temperature — than it was designed to do. In turn, that led to what Bogdan called “microcracks” that went unnoticed until the day of the fire. “Over the next three weeks of that airplane flying, those microcracks started growing in what we call ‘high cycle fatigue,’” Bogdan explained. “And eventually on the day this happened, that fan-blade system just cracked too much, the whole circular part of that engine — through centrifugal force — stretched out and became a spear; that spear went up through the left aft fuselage of the fuel tank and it was the fuel tank that caused the fire.”
An investigation is still ongoing into the root cause of the issue to discover whether it was a production or design flaw, Bogdan said his team has narrowed down the cause to four sources and should have the results by the end of the month. He also noted that while no microcracks were discovered in other jets, there were marks that indicate potentially similar, if lesser, issues.
That leaves the question of how to make sure this problem doesn’t crop up again. Bogdan laid out how his office is moving forward with potential retrofits to the engine.
The first step involves taking a new engine and slowly working it through its paces to get it through the “burn in” phase. Bogdan indicated that testing would begin in the next two weeks, and if that two-sortie process works, it can be replicated for the test fleet.
The second step is more dramatic, requiring a redesign of the F135 to include what Bogdan described as a “pre-dug-in trench” into the fan section to separate the rubber and the fan blade in that part of the engine.
Gen. Mark Welsh, the Air Force Chief of Staff, told Defense News in August that a redesign could be coming for the engine, but Bogdan revealed that they intend to develop a prototype engine for that potential solution. For fielded airplanes, the Air Force could replace the fan section with the new, pre-trenched fan section in the engines — a relatively painless procedure that could be done in depot.
Pratt & Whitney has agreed to cover the costs of the retrofit engines for the F-35 fleet, a move praised by Bogdan. “I will tell you that Pratt & Whitney’s reaction to this problem, from my opinion, has been very good. They clearly recognize this is a problem they need to solve,” Bogdan said. “Pratt has said whatever the cost of retrofitting that 156 airplanes is, ‘that will be ours to bear.’”
The general also indicated that the cost for retrofit will not be “very great,” but declined to offer a general cost estimate........
WASHINGTON — The head of the F-35 Joint Strike Fighter program is warning that there is a real danger of missing deadlines if his test fleet of aircraft are not flying regularly by the end of September. “I need all of [the test airplanes] back to full envelope by the end of this month,” Lt. Gen. Christopher Bogdan said at Wednesday’s ComDef conference in Washington. “Otherwise we will start seeing some delays in future milestones.”
However, any retrofit needed to the F135 engine at the root of the restrictions will be borne by contractor Pratt and & Whitney rather than taxpayers.
The entire F-35 fleet were placed under restrictions following a June 23 fire that heavily damaged an F-35A conventional takeoff-and-landing model at Eglin Air Force Base, Florida. Since then, the small test fleet has had some restrictions relieved, but is still not allowed to operate at full capacity. While insisting that the Marines remain on track to take the F-35B jump-jet variant operational next summer, Bogdan said there has been a “headwind” of about 30- to 45 days added to test points due to the restrictions. Testing the Navy’s F-35C model at sea is one of the tests affected by potential delays. “Can we make some of that [time] up? Yeah I think we can,” Bogdan said. “But we have to get all of those airplanes up and flying again.”
The cause of the fire was identified as “excessive” rubbing of a fan blade inside the F135 engine, designed and produced by Pratt. Bogdan went into further detail for the first time on what actually happened to cause the damage.
The issue began three weeks before the fire when a pilot took the aircraft up and executed a two-second maneuver involving adding Gs, roll rate and yaw to the plane at the same time. Although that move was ““well within the envelope of the airplane,” Bogdan said, those two-seconds led to the engine rubbing against a rubber piece at a much higher rate — and nearly double the temperature — than it was designed to do. In turn, that led to what Bogdan called “microcracks” that went unnoticed until the day of the fire. “Over the next three weeks of that airplane flying, those microcracks started growing in what we call ‘high cycle fatigue,’” Bogdan explained. “And eventually on the day this happened, that fan-blade system just cracked too much, the whole circular part of that engine — through centrifugal force — stretched out and became a spear; that spear went up through the left aft fuselage of the fuel tank and it was the fuel tank that caused the fire.”
An investigation is still ongoing into the root cause of the issue to discover whether it was a production or design flaw, Bogdan said his team has narrowed down the cause to four sources and should have the results by the end of the month. He also noted that while no microcracks were discovered in other jets, there were marks that indicate potentially similar, if lesser, issues.
That leaves the question of how to make sure this problem doesn’t crop up again. Bogdan laid out how his office is moving forward with potential retrofits to the engine.
The first step involves taking a new engine and slowly working it through its paces to get it through the “burn in” phase. Bogdan indicated that testing would begin in the next two weeks, and if that two-sortie process works, it can be replicated for the test fleet.
The second step is more dramatic, requiring a redesign of the F135 to include what Bogdan described as a “pre-dug-in trench” into the fan section to separate the rubber and the fan blade in that part of the engine.
Gen. Mark Welsh, the Air Force Chief of Staff, told Defense News in August that a redesign could be coming for the engine, but Bogdan revealed that they intend to develop a prototype engine for that potential solution. For fielded airplanes, the Air Force could replace the fan section with the new, pre-trenched fan section in the engines — a relatively painless procedure that could be done in depot.
Pratt & Whitney has agreed to cover the costs of the retrofit engines for the F-35 fleet, a move praised by Bogdan. “I will tell you that Pratt & Whitney’s reaction to this problem, from my opinion, has been very good. They clearly recognize this is a problem they need to solve,” Bogdan said. “Pratt has said whatever the cost of retrofitting that 156 airplanes is, ‘that will be ours to bear.’”
The general also indicated that the cost for retrofit will not be “very great,” but declined to offer a general cost estimate........
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Pratt & Whitney sues supplier of titanium used in F-35 engines - 9/3/2014 - Flight Global
The sole manufacturer of engines for the Lockheed F-35 Lightning II discovered in May 2013 that it had used substandard titanium alloy that might have been illegally purchased from Russia.
Pratt & Whitney halted delivery of F135 engines that contained the suspect titanium and has subsequently sued the supplier, A&P Alloys, of West Bridgewater, Massachusetts.
Titanium is popular in aircraft manufacturing for its strength and light weight. In May 2013, P&W learned a majority of an order of 900 pieces of the metal was originally melted in Russia, according to the lawsuit filed on 29 August in the US District Court of Massachusetts.
The discovery last year of conflicting documentation of the metal’s origin resulted in a “quality hold” on delivery of the F135 engine, the company says. The titanium was used to manufacture some parts used in engines made by Pratt & Whitney Canada.
Pratt & Whitney halted delivery of F135 engines that contained the suspect titanium and has subsequently sued the supplier, A&P Alloys, of West Bridgewater, Massachusetts.
Titanium is popular in aircraft manufacturing for its strength and light weight. In May 2013, P&W learned a majority of an order of 900 pieces of the metal was originally melted in Russia, according to the lawsuit filed on 29 August in the US District Court of Massachusetts.
The discovery last year of conflicting documentation of the metal’s origin resulted in a “quality hold” on delivery of the F135 engine, the company says. The titanium was used to manufacture some parts used in engines made by Pratt & Whitney Canada.
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The titanium issue has no direct connection to an engine fire that caused the F-35 fleet to be grounded this spring and miss a pair of major European aerospace shows. The fire, officials concluded, was caused by fan blades rubbing.
The part for which the titanium was used is called a fan-variable vane arm and had already been installed in more than 100 engines. The existing parts are to be replaced during regular maintenance at Pratt & Whitney's cost.
General Bogdan said the natural “flex” of the mishap engine under high-G conditions caused fan blades to “rub” and “dig too deep” in the rubber-like seal around the power plant.
Hmm, may take a little doing to stop the flexing of the engine inside the current flight envelope. Keep in mind the flight envelope has been reduced from what was originally expected and promised.
The part for which the titanium was used is called a fan-variable vane arm and had already been installed in more than 100 engines. The existing parts are to be replaced during regular maintenance at Pratt & Whitney's cost.
General Bogdan said the natural “flex” of the mishap engine under high-G conditions caused fan blades to “rub” and “dig too deep” in the rubber-like seal around the power plant.
Hmm, may take a little doing to stop the flexing of the engine inside the current flight envelope. Keep in mind the flight envelope has been reduced from what was originally expected and promised.
What really galls me is the lack of proper kit for the UK pilots, surely the MoD can do better to properly outfit their crews, just look, no gloves, non-fire resistant coveralls, and the much hyped sensory helmet looks rather austere.
So much for Lone Ranger's screed - ha ha.
And just so I have it correct, according to Lone Ranger standards, then everyone in the UK is also "arrogant arsewipe" with the Typhoon on display? Or maybe everyone in Germany, Spain and Italy and the UK, since it is a multi-national program? Just curious.
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Apparently the Typhoon is a replica, but to me it looks like the real deal with the ribbons of the safety pins for the weapon systems and landing gear clearly visible, especially from the news footage. Can anybody confirm if it is indeed a replica or a real aircraft?
Second question: How would they get a real fixed wing aircraft in there? At 12 tonnes, I would have thought it's a bit too heavy for the Chinooks? Even if it wasn't, at ~Ł80 million a piece I'm surprised the RAF would allow that.
Second question: How would they get a real fixed wing aircraft in there? At 12 tonnes, I would have thought it's a bit too heavy for the Chinooks? Even if it wasn't, at ~Ł80 million a piece I'm surprised the RAF would allow that.
Can anybody confirm if it is indeed a replica or a real aircraft?
Second question: How would they get a real fixed wing aircraft in there?
Interesting story on the titanium source and all that, but other than Pratt and Whitney doing the sort of thing that leads to why we require oversight of acquisition contracts, it doesn't seem to have moved the program any closer to being cancelled.
Perhaps its momentum has reached that critical value where nobody could stop it even if they tried.
it doesn't seem to have moved the program any closer to being cancelled.
Perhaps its momentum has reached that critical value where nobody could stop it even if they tried.
Perhaps its momentum has reached that critical value where nobody could stop it even if they tried.
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returning to the engine issue, won't any "pre-dug-in trench" reduce efficiency and so increase fuel burn?
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What does this do to timelines and in year costs?
As I think many of us feel a solution to the engine problem has yet to be engineered and tested, that is if the real cause of the problem is known. I have read that P&W are going to repair all of the engines that are in existence at the moment, as has been stated well over 100 of them, quite an operation when the solution has yet to be found and the kits to implement the fix designed, produced and distributed prior to installation.
I assume that the Fort Worth production line is at best just making engine less planes, what this does to the in year cost of these LRIP aircraft could be interesting.
With the Marines wanting to declare IOC next year I assume that for this to happen they will have to have their initial squadron aircraft updated, is this really possible?
The carrier trials that the USN have planned for the F35C I suppose could be interesting and slightly prolonged if the engines have to be checked every three hours.
There are of course many other test points that may not be achievable with an aircraft limited as to what it can do.
Another year or so's delay in realistic IOC in my view, it transpires that it was a good move to delay the UK Aircraft Carriers for financial reasons some years ago.
I assume that the Fort Worth production line is at best just making engine less planes, what this does to the in year cost of these LRIP aircraft could be interesting.
With the Marines wanting to declare IOC next year I assume that for this to happen they will have to have their initial squadron aircraft updated, is this really possible?
The carrier trials that the USN have planned for the F35C I suppose could be interesting and slightly prolonged if the engines have to be checked every three hours.
There are of course many other test points that may not be achievable with an aircraft limited as to what it can do.
Another year or so's delay in realistic IOC in my view, it transpires that it was a good move to delay the UK Aircraft Carriers for financial reasons some years ago.
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Agreed, delaying the entry to service of the QEC Aircraft Carriers due to cash flow considerations now with the benefit of some hindsight looks to have been fortuitous....
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What really galls me is the lack of proper kit for the UK pilots
This seems like a bit of deja vu, all over again 
.
On the JT9D on the 747 and 767, we had problems with engine bending and compressor case distortion causing excessive tip rub, efficiency loss, and engine surge.
Again on the 747 and 767, the PW4000/94" had problems with compressor case distortion causing excessive tip rub, efficiency loss, and engine surge (it got so bad on the PW4000 that the FAA issued an AD, forcing Pratt to redesign the compressor and retrofit over 2000 engines with new compressors at a cost of several billion dollars).
So, now, on the F135 we have a problem with engine bending and case distortion causing excessive tip rub. Hum, I wonder what the common thread might be
BTW, I like the implication that wasn't that bad because it wasn't the engine that caught fire, it was the ruptured fuel tank. Yea, that makes me feel much better...
.On the JT9D on the 747 and 767, we had problems with engine bending and compressor case distortion causing excessive tip rub, efficiency loss, and engine surge.
Again on the 747 and 767, the PW4000/94" had problems with compressor case distortion causing excessive tip rub, efficiency loss, and engine surge (it got so bad on the PW4000 that the FAA issued an AD, forcing Pratt to redesign the compressor and retrofit over 2000 engines with new compressors at a cost of several billion dollars).
So, now, on the F135 we have a problem with engine bending and case distortion causing excessive tip rub. Hum, I wonder what the common thread might be
BTW, I like the implication that wasn't that bad because it wasn't the engine that caught fire, it was the ruptured fuel tank. Yea, that makes me feel much better...
Had a scan but couldn't see this posted
F-35 Blade Microcracking Began Three Weeks Prior To Engine Fire | Defense content from Aviation Week
The microcracks in the third stage of the integrally bladed rotor that caused a catastrophic F135 engine fire in an F-35A on June 23 began forming three weeks earlier when a pilot conducted a fairly benign maneuver with a unique combination of yaw, roll and g stresses