Another Problem with the USAF's New Baby

[Pooky 3,812]

DATE: 07/09/11

SOURCE: Flight International

Lockheed finds new structural weakness on two F-35 variants

By Stephen Trimble

Lockheed Martin will retrofit the first 64 production models of the F-35A and F-35B, after discovering a second aluminium part supplied by US-based producer Alcoa failed in durability tests.

The redesigned wing forward root rib forgings will be installed on new aircraft ordered by the US Air Force and US Marine Corps in the fifth yearly lot of low-rate initial production, according to the F-35 joint programme office (JPO).

The new structural problem was revealed even as the test fleet was cleared to resume un-monitored flying on 26 August, after Lockheed fixed a problem with the F-35's power system.

On 2 August, the Honeywell integrated power package failed, after a valve malfunctioned during a routine ground test on the AF-4 test aircraft.

© Lockheed Martin

All test aircraft were cleared to resume monitored flights on 18 August, with un-monitored tests cleared eight days later.

Early production aircraft remain effectively grounded, however, until a software modification can be installed in late September or October, the JPO said.

The production models have been cleared to complete one ferry flight from Fort Worth, Texas, to Eglin AFB, Florida, as they are delivered.

The structural problem is the second design change to be discovered in the 16,000h regimen of durability tests started last year.

The first problem was revealed when the Alcoa-supplied 496 bulkhead in the rear fuselage of the F-35B cracked unexpectedly only 10% through the durability test cycle.

Lockheed designed a patch to ensure the test fleet could survive long enough to complete the flight test programme.

According to the JPO, Lockheed's engineers were aware of the weakness problem in the root rib forgings as the aircraft entered durability tests.

The only surprise was that cracks appeared slightly later than expected, at 2,800h - about 17.5% through durability tests, the JPO said.

Alcoa is working with Lockheed Martin to address the issue. “It is not unusual to identify improvement opportunities during testing,” the company said. “At no time was flight safety compromised.”

Despite the 16-day flight test hiatus in August, the flight test programme has not fallen far behind schedule.

The F-35A variant for the USAF is 20 flights ahead of schedule, and the F-35C variant for the US Navy is lagging by five flights. Furthest behind schedule is the F-35B, which is 30 flights behind the scheduled pace.

Flightglobal link

How long is this problem programme going to continue drawing breath? If the deficit reduction super-committee doesn't reach a viable and agreed conclusion, the defence budget is going to see a very big axe fall on it.

Will this be the major casualty? Or will the vested interest of the super-committee members, a large number of whom represent constituencies with close ties to the defence industry, ensure that something happens on the deficit?

[slim 1,530]

How long is this problem programme going to continue drawing breath? If the deficit reduction super-committee doesn't reach a viable and agreed conclusion, the defence budget is going to see a very big axe fall on it.

Will this be the major casualty? Or will the vested interest of the super-committee members, a large number of whom represent constituencies with close ties to the defence industry, ensure that something happens on the deficit?

I wouldn't hold my breath on that.

[mawilson 2,133]

Will this be the major casualty? Or will the vested interest of the super-committee members, a large number of whom represent constituencies with close ties to the defence industry, ensure that something happens on the deficit?

I hope not. The DoD is not responsible for the deficit - the entitlement programs are.

[Azzudiin 26]

I hope not. The DoD is not responsible for the deficit - the entitlement programs are.

Spending more then 1 Trillion $ a year on Offense, and thats not contributing to the deficit?

I agree entitlement programs are out of control, but saying the DoD is not contributing to the problem is pure stupidity.

[Pooky 3,812]

I hope not. The DoD is not responsible for the deficit - the entitlement programs are.

The DoD may not be wholly responsible, but this programme in particular is seriously over-budget and has been subject to governmental review twice already, IIRC, for these budget overruns.

In addition, it doesn't meet the USAF operational requirements, and it's in-service date will lead to a significant capability gap, when the USAF and US ANG legacy assets reach the end of their structural life faster than LockMart can build Thunderpigs to replace them.

This programme and the CV-22 Osprey are both prime candidates when serious budget cuts rear their head.

[mawilson 2,133]

Spending more then 1 Trillion $ a year on Offense, and thats not contributing to the deficit?

It's not. We would be spending 2 trillion dollars today if the military budget was the same size as it was in the '50's as a percentage of our economy.

Military spending as a percentage of GDP by year:

2011: 6.40 percent of GDP <----- today

2010: 5.84 percent of GDP

2009: 5.62 percent of GDP

2008: 5.05 percent of GDP

2007: 4.64 percent of GDP

2006: 4.64 percent of GDP

2005: 4.75 percent of GDP

2004: 4.57 percent of GDP

2003: 4.34 percent of GDP

2002: 3.96 percent of GDP

2001: 3.56 percent of GDP

2000: 3.60 percent of GDP

1999: 3.56 percent of GDP

1998: 3.67 percent of GDP

1997: 3.90 percent of GDP

1996: 4.03 percent of GDP

1995: 4.40 percent of GDP

1994: 4.75 percent of GDP

1993: 5.16 percent of GDP

1992: 5.50 percent of GDP

1991: 5.35 percent of GDP

1990: 5.90 percent of GDP

1989: 6.26 percent of GDP

1987: 6.47 percent of GDP

1988: 6.76 percent of GDP

1986: 7.04 percent of GDP

1985: 7.00 percent of GDP

1984: 6.84 percent of GDP

1983: 6.98 percent of GDP

1982: 6.81 percent of GDP

1981: 6.19 percent of GDP

1980: 6.02 percent of GDP

1979: 5.61 percent of GDP

1978: 5.71 percent of GDP

1977: 5.99 percent of GDP

1976: 6.27 percent of GDP

1975: 6.73 percent of GDP

1974: 6.56 percent of GDP

1973: 6.72 percent of GDP

1972: 7.65 percent of GDP

1971: 8.24 percent of GDP

1970: 9.12 percent of GDP

1969: 9.62 percent of GDP

1968: 10.36 percent of GDP

1967: 10.06 percent of GDP

1966: 8.84 percent of GDP

1965: 8.57 percent of GDP

1964: 9.85 percent of GDP

1963: 10.40 percent of GDP

1962: 10.86 percent of GDP

1961: 10.46 percent of GDP

1960: 10.12 percent of GDP

1959: 10.66 percent of GDP

1958: 11.08 percent of GDP

1957: 11.13 percent of GDP

1956: 10.77 percent of GDP

1955: 11.37 percent of GDP

1954: 13.89 percent of GDP

1953: 15.01 percent of GDP

1952: 14.43 percent of GDP

1951: 8.61 percent of GDP

1950: 8.25 percent of GDP

[slim 1,530]

In addition, it doesn't meet the USAF operational requirements, and it's in-service date will lead to a significant capability gap, when the USAF and US ANG legacy assets reach the end of their structural life faster than LockMart can build Thunderpigs to replace them.

If only we would've had a stealth fighter...

[Pooky 3,812]

If only we would've had a stealth fighter...

The F-35 is supposed to be kind of stealthy, but only if you don't want it carrying any external weapons.

The F-22 is stealthy, but LockMart has just started assembly on the last one, and Robert Gates made sure the programme got buried after 187 units. Oh, and the onboard oxygen system doesn't work right, so the whole USAF fleet is grounded.

The F-117 Nighthawk was stealthy for its day, but it has already been retired.

What the USAF needs is something it can use. The Thunderpig, in my opinion, is not it.

[slim 1,530]

The F-22 is stealthy, but LockMart has just started assembly on the last one, and Robert Gates made sure the programme got buried after 187 units.

Had that programme been able to run it's course there would be no gap in capability. And, they'll sort out the sensors before too long.

What the USAF needs is something it can use.

You mean something like a budget that allows them to develop what they want instead of what the SECDEF tells them to?

[Pooky 3,812]

Had that programme been able to run it's course there would be no gap in capability. And, they'll sort out the sensors before too long.

At the 750 aircraft originally planned, it would have ended up with a lower unit cost than the Thunderpig, too. All this for a better platform, with greater adaptability and, given enough time and refinement, less of the maintenance issues it's currently suffering from.

You mean something like a budget that allows them to develop what they want instead of what the SECDEF tells them to?

Do you know what the last aircraft the USAF didn't really want, but ended up buying anyway?

This one ...

[slim 1,530]

Yeah, that one is currently sucking it up all around the world. It's horrible.

That's why everyone wants one.

[Pooky 3,812]

Yeah, that one is currently sucking it up all around the world. It's horrible.

That's why everyone wants one.

After 33 years in USAF service, it will still hold its own close-in with most anything else out there. Add to that the multi-role adaptability of a platform that was originally intended solely as a Lightweight Fighter and you have the best value-for-money package out there.

Ask most Viper pilots and they will tell you they wouldn't trade it for anything. Not bad for a plane the USAF top brass didn't want.

[slim 1,530]

Not bad for a plane the USAF top brass didn't want.

Amazing the disconnect between top brass and men in the field. (Or air, in this case!)

[spookyturtle 9,466]

They never should have killed the F-22, it would kick the snot out of the F-35 along with any other plane on the planet.

[Ban Hammer 13,415]

They never should have killed the F-22, it would kick the snot out of the F-35 along with any other plane on the planet.

personally i think the f-15 shoulda been upgraded and production restarted - really, what plane can compete with the f-15?