F-35 fleet grounded after electrical subsystem failure

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by neptune » 03 Aug 2011, 20:48

Stand Away From The JSF, Please
Posted by Bill Sweetman at 8/3/2011 2:16 PM CDT

The last two JSF groundings (in October and March) were short, but the action taken in response to an incident at Edwards AFB on Tuesday morning has been more severe: not only are flight operations suspended, but there are no ground operations, such as engine runs or power-on tests.

Details are scant: A statement from the JSF program office reads that "aircraft AF-4's Integrated Power Package (IPP) experienced a failure... The engine was immediately shut down and the jet was secured. No injuries to the pilot or ground crew occurred."

The halt in operations "is the prudent action to take at this time until the F-35 engineering, technical and system safety teams fully understand the cause of the incident. Once the facts are understood, a determination will be made when to lift the suspension."

As discussed earlier on Ares, the Honeywell IPP (this is not Honeywell's year at all) is a unique system that combines the normal functions of a back-up generator, APU/starter, emergency power unit and the air cycle machine (ACM) that runs the environmental control system.

Since the incident took place in a ground engine run, the IPP was probably operating either as the starter or in ECS mode.

[...]

Source: http://www.aviationweek.com/aw/blogs/de ... d=blogDest


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by neptune » 03 Aug 2011, 21:19

F-35 fleet grounded after electrical subsystem failure
By Stephen Trimble - 03 Aug 2011

The Lockheed Martin F-35 fleet is grounded while the joint programme office (JPO) investigates the cause of a failure in the aircraft's electrical system during ground tests.

The failure occurred on an F-35A conventional take-off and landing (CTOL) test aircraft, numbered AF-4, but the precautionary grounding applies to all 20 F-35s that had reached flying status, according to a JPO statement.

"Once the facts are understood, a determination will be made when to lift the suspension and begin ground and flight operations," the JPO said.

The incident marks the third grounding order for the F-35 fleet since last October, and the second in five months involving the AF-4 test aircraft.

In this case, the Honeywell-built integrated power package (IPP) failed during a standard engine test following a maintenance check at 08:30 on 2 August, the JPO said.

The IPP is primarily used as both a starter for the engine and a back-up electrical system, supporting the two main generators. In March, the IPP proved its worth by activating after both generators shut-down with the AF-4 still in flight. The power generated by the IPP allowed the flight control system to keep operating until the pilot landed.

That incident also triggered a fleet-wide grounding in March until Lockheed fixed a flaw with a new generator system design introduced on AF-4. Some aircraft remained grounded for several weeks until the problem was fixed.

Last October, the fleet was also grounded after Lockheed discovered a software glitch that could have allowed the fuel pump to shut down above 10,000ft.

The electrical system has been the cause of three of four major incidents so far during the development phase. The first incident was recorded in May 2007, when the test aircraft numbered AA-1 experienced an electrical short that disabled flight controls on the horizontal stabliser.

The F-35 has the highest degree of electrical integration of any DOD a/c and is the only DOD a/c flying with electrical actuators of the control services without a common hydraulic system. The current design is the most advanced and will have challenges and improvements thru this SDD effort.....as they say "That's why we call it Testing!".

Source: Source: http://www.flightglobal.com/articles/20 ... ilure.html
Last edited by neptune on 04 Aug 2011, 04:11, edited 1 time in total.


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by alloycowboy » 03 Aug 2011, 22:17

This is just reasonable flight test safety, their is no need to pull the fire alarm just yet.


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by 1st503rdsgt » 04 Aug 2011, 06:50

All I can say is... http://www.youtube.com/watch?v=hP5KzBJ42r4

All 20 U.S. F-35 Lightning IIs have been grounded following a failure of the aircraft's integrated power package (IPP).

THE IPP ISSUE occurred in one of the U.S. Air Force's conventional takeoff and landing F-35As, similiar to the one seen here. (Angel DelCueto / Lockheed Martin)
The incident took place at about 8:30 a.m. Aug. 2 at Edwards Air Force Base, Calif., during a ground maintenance run of aircraft AF-4, the fourth conventional takeoff and landing version of the triservice Joint Strike Fighter. Following the failure of the IPP - which combines the functions performed by an auxiliary power unit, emergency power system and environmental controls - the crew shut down the aircraft as per standard operating procedures, according to a press release by the JSF program office. There were no injuries.

Government and contractor teams are reviewing the incident to find out what caused the IPP to fail. The program office suspended flight operations as "the prudent action to take at this time until the F-35 engineering, technical and system safety teams fully understand the cause of the incident," according to the statement.

This is the second time the F-35 has been grounded this year due to electrical problems. In March, the F-35 fleet was briefly grounded after the same aircraft experienced a dual generator failure that was traced to faulty maintenance procedures.

The Navy's F-35C was also grounded for six days in June due to a software problem with the wing-fold mechanism that might have caused the flight control surfaces to freeze in flight. The aircraft returned to flight June 23.


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by popcorn » 04 Aug 2011, 06:58

Didn't they attribute the previous failure to overfilling the engine with oil? Hopefully they find and resolve the cause of the problem quickly. I was getting spoiled with all the positive news the past several months though.


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by Happy_Gilmore » 04 Aug 2011, 08:00

but there are no ground operations, such as engine runs or power-on tests.

That's funny, I had electric power and 4000 psig hydro on one tonight here in F/W, it was freaking awesome as per the norm.


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by shep1978 » 04 Aug 2011, 08:14

Happy_Gilmore wrote:quote] but there are no ground operations, such as engine runs or power-on tests.

That's funny, I had electric power and 4000 psig hydro on one tonight here in F/W, it was freaking awesome as per the norm.


So Bills been caught out again. How shocking.


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by Happy_Gilmore » 04 Aug 2011, 08:51

Quote again: Since the incident took place in a ground engine run, the IPP was probably operating either as the starter or in ECS mode.

This guy Sweetman must be as stupid as he reads/writes, freaking unreal.


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by neptune » 04 Aug 2011, 12:45

F-35 Temporary Suspension of Ground and Flight test operations

August 3, 2011 - The F-35 Joint Program Office issued a fleet wide precautionary suspension of ground and flight operations earlier today. This action was taken as a result of an incident involving the F-35 conventional takeoff and landing (CTOL) variant AF-4 at Edwards AFB, Calif.

Yesterday, at approximately 8:30 a.m. PDT during a standard ground maintenance engine run, aircraft AF-4's Integrated Power Package (IPP) experienced a failure. Following standard operating procedures, the engine was immediately shut down and the jet was secured. No injuries to the pilot or ground crew occurred. The F-35's IPP is a turbo-machine that provides power to start the engine and generates cooling for the aircraft.

The government and contractor engineering teams are reviewing the data from the incident to determine the root cause of the failure. Implementing a precautionary suspension of operations is the prudent action to take at this time until the F-35 engineering, technical and system safety teams fully understand the cause of the incident. Once the facts are understood, a determination will be made when to lift the suspension and begin ground and flight operations of the 20 F-35s currently in flying status. These aircraft are part of the System Development and Demonstration (SDD) and Low Rate Initial Production (LRIP) fleet.

Determinations of root cause and potential mitigating actions have the highest priority of the F-35 Team. Impact to SDD execution and production operations is being assessed. The program has built schedule margin into the test schedule to accommodate these kinds of incidents that occur in a development effort. Periodic updates concerning this situation will be released as warranted.

Source: http://www.f35.com/news-events/


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by spazsinbad » 04 Aug 2011, 22:02

F-35 Grounding Could Last Weeks Aug 4, 2011 By Bill Sweetman | Washington

http://www.aviationweek.com/aw/generic/ ... dline=F-35 Grounding Could Last Weeks

"Flight and ground tests of the 20-strong F-35 Joint Strike Fighter force could be suspended “for a few weeks,” according to an industrial source close to the program, after the secondary power system of F-35A AF-4, a USAF-variant test aircraft, failed on Aug. 2 at Edwards AFB, Fla., during a ground maintenance engine run. However, another government source says that foreign object damage has not yet been ruled out, and notes that such a finding would allow a more rapid return to flight. A clearer picture is expected to emerge in the week of Aug. 8.

The failure occurred in the integrated power pack (IPP), which combines the functions of the engine starter, emergency and auxiliary power unit, environmental control system and back-up generator.

This is the third grounding inside a year for the Lockheed Martin program, but the first for which ground operations were also suspended. In October, a potential problem with software controlling the fuel pump was detected in ground tests and flights were suspended while the fix was installed. In March, AF-4 lost both engine-driven starter-generators in flight. That grounding was traced to a redesigned generator, allowing earlier aircraft to return to flight within days, and the problem was ascribed to a maintenance error.

F-35 flight-testing has been running ahead of the revised schedule that was adopted as part of the restructuring and stretch-out announced in January. At the Paris air show this year, deputy program office director USAF Maj Gen. C.D. Moore said the flight-test success would provide the program with margin, but not allow the schedule to be brought forward."


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by deadseal » 05 Aug 2011, 03:30

I didnt know they moved edwards to florida....wow


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by neptune » 05 Aug 2011, 04:44

spazsinbad wrote:..., during a ground maintenance engine run. However, another government source says that foreign object damage has not yet been ruled out, and notes that such a finding would allow a more rapid return to flight. ...


Where is the air intake for the IPP? , sidestream from the main air intake ducts? :?:


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by 1st503rdsgt » 05 Aug 2011, 06:01

neptune wrote:
spazsinbad wrote:..., during a ground maintenance engine run. However, another government source says that foreign object damage has not yet been ruled out, and notes that such a finding would allow a more rapid return to flight. ...

Where is the air intake for the IPP? , sidestream from the main air intake ducts? :?:


So drunk right now. I used to work as a fuel technician for an FOB (AMR Combs) at Denver International Airport. APUs can be finicky things. I once saw an APU shooting 50 ft flames out the side of a DC-10 as it taxied into the cargo ramp. Hope they fix it soon.

BTW, I didn't know the F-35 had an APU. Sounds like a good idea for reducing ground personnel demands (no need to hook up a GPU), but I wonder how much it adds to airframe costs.


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by spazsinbad » 05 Aug 2011, 06:26

There is another thread with graphic about IPP - probably the document thread. Anyway here is a link to the original PDF 2.5Mb about the IPP (amongst other innovations for the F-35): [perhaps an answer for 'neptune' below also ("Where is the air intake for the IPP?, sidestream from the main air intake ducts?")]

http://www.asetsdefense.org/documents/W ... r-F-35.pdf

• Integrated Power Package (IPP) Replaces Hydrazine System
• Small Turbine Engine Integrated with Other Vehicle Cooling/Heating Systems
• Basically a Small Jet Engine
• Easy to Start/Stop, No Hydrazine, No Leaks

No More Hydrazine Hazards
__________________

“At the heart of the IPP is a small gas-turbine engine “turbo-machine” that provides power to the engine-mounted starter/generator, bringing the engine to its threshold starting speed. The engine then increases to idle speed & the electrical system, which includes the engine-mounted starter / generator (ES/G) transitions from operating as a motor to operating as a generator. The IPP is also available for in-flight emergency power." In the F-35B (unlike the -A/C) the exhaust from the IPP points downward – which can damage the deck. If you operate the IPP in "bleed" mode, the amount of fuel consumed is decreased – resulting in cooler IPP exhaust temp. The disadvantage is operating in bleed mode does not allow the ECS to run efficiently at all – resulting in high cockpit temps – and another heat issue."
http://forum.keypublishing.com/showthread.php?p=1613080
____________________

IPP
From LM: “The aircraft’s integrated power package (IPP) combines into a single system the functions traditionally performed by the auxiliary power system, emergency power system, and environmental control.”
____________

& from: http://www.codeonemagazine.com/images/C ... 8_6299.pdf

"Environmental Control System Package
The X-35 used environmental control system, or ECS, packs from the F/A-18 with heat exchanger scoops on the lef t side of the fuselage and under the wing. An additional heat exchanger was mounted on the belly of the X-35B during the flight test phase to provide cooling for hydraulic system oil. The demonstrators had ram air scoops that fed cooling air through the heat exchangers in the roll post bays for the X-35 aircraft or centerline heat exchanger for X-35B. The F-35 integrated power package, or IPP, provides the legacy ECS functionality, providing conditioned air and liquid cooling to aircraft systems. A unique feature of the F-35 cooling system is the integration of the IPP with the engine using engine fan-duct heat exchangers as a cooling source to the hot air side of the IPP. The F-35 environmental control system uses both fuel and air as a cooling medium. The fuel/air heat exchanger, located on the right top of the wing-glove, features a scoop inlet and screened exhaust." [See attached extra graphic from F-35B STO + static photos] http://www.codeonemagazine.com/images/m ... 7_3717.jpg
&
http://www.navair.navy.mil/img/uploads/ ... _003_1.jpg

Auxiliary Power Unit
The X-35 carried a conventional auxiliary power unit on the forward right-hand side that provided power for engine starts. It also served as an emergency power source. The F-35 uses a unique integrated power package that provides emergency power and engine start capability as well as providing cooling air and cooling fluid."
Attachments
F-35IPPgraphic.gif
F-35BinletIPPstbdWingGloveZoomTEXT.jpg
F-35BinletIPPstbdWingGloveZoom2.jpg
Last edited by spazsinbad on 05 Aug 2011, 15:41, edited 10 times in total.


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by spazsinbad » 05 Aug 2011, 06:37

Just in case anyone thinks the IPP exhaust heat issue is not being addressed then there is this.

JSF Heat Woes Getting Fixed | Naval Open Source INTelligence July 19, 2010

http://nosint.blogspot.com/2010/07/jsf- ... fixed.html
-
“Changes are being made to the integrated power package (IPP) on the Marine’s F-35(B) that should limit heat damage to carrier decks and other surfaces, Lt. Gen. George Trautman, deputy commandant for aviation, told DoD Buzz in an exclusive interview one day before the start of the Farnborough Air Show.

In addition, the heat buildup from the STOVL drive shaft will be addressed in LRIP 4, although negotiations on that are still underway so costs for that are not set yet.

“We have made the decision to adjust the IPP,” he said Sun-day, reshaping the nozzle so that the enormous [?] thrust comes out in an oval shape instead of the more highly focused circle now used. It takes a “slight adjustment” to the IPP. The oval “will resolve that problem for almost all surfaces,” he said.”

I'm guessing 'the oval' is shown above in graphic OR it is being made 'more oval'?


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