Thread: Another Anti- F-22 blog?

F-22 design problems force expensive fixes

By Bruce Rolfsen - Staff writer
Posted : Wednesday Nov 14, 2007 9:21:20 EST

The F-22A Raptor can shoot down another jet before the bad guys even know they are in trouble. It can fly circles around any other military fighter plane on the planet.

But with a price tag of $130 million per plane — $330 million if you take into account research and development costs — critics wonder why millions more will have to be spent to fix corrosion problems and design flaws on some of the 104 stealth fighters delivered so far by the plane’s manufacturer, Lockheed Martin.

Leaky fuselage access panels at the top of the jet are leading to corrosion issues in many of the planes. Also, problems with the plane’s core structure — particularly the forward boom, which supports the plane’s weight and must endure the stresses of high-G maneuvers — must be fixed.

These are among the latest in a series of problems for the Raptor as it continues the transition from developmental test jet to operational fighter. Over the past year, another problem — overheating avionics — has been fixed.

An additional 79 F-22As will be added to the Air Force fleet over the next few years, bringing the total number of Raptors to 183. The latest milestone came Oct. 31, when the Air Force stood up a second operational F-22 squadron at Elmendorf Air Force Base, Alaska, the fourth overall. None of the latest structural or avionics issues has grounded the fleet, said Brig. Gen. C.D. Moore, who oversees F-22 upgrade and sustainment issues across the Air Force as commander of the 478th Aeronautical Systems Wing at Wright-Patterson Air Force Base, Ohio. He logged about 100 hours as a Raptor test pilot before taking the Materiel Command desk assignment.

Despite the problems, Moore boasted that the most recent F-22 appraisal by the Air Force Operational Test and Evaluation Center rated the jet as “suitable” for maintenance in real-world situations. In other words, most problems that arise can, as a matter of course, be fixed by maintenance squadrons at local bases, and the fighter is not breaking down on a regular basis.

The center also determined that the Raptor is “effective” in the role of destroying anti-aircraft missile, gun and radar systems.

Moore expects that as Raptors get more flight hours and are flown day to day on a wider range of missions, unexpected problems will arise — what he calls “known unknowns.” But he continues to think the service made the right calculation in having the Raptor ready for combat, rather than waiting for the jet to be perfected.

Philip Coyle, a former director of the Defense Department’s Operational Test and Evaluation Office, points out that the Air Force has spent two decades trying to get the F-22A right and meet the high expectations set for the fighter.

The dilemma is not a lack of time to find and fix problems.

“What you see now is poor design and reliability,” Coyle said.

Quality assurance is also an issue. A potential metal fatigue problem in the front of the jet’s fuselage should have been caught before 91 aircraft were built, he said.

One of the high expectations for the F-22A is that its onboard computers and avionics will do work that was left to the pilots of earlier jets. In the Raptor, electronics must not only tell the pilot what the sensors are detecting but also advise the pilot what to do, Coyle said.

Achieving that goal requires flawless integration of software and plenty of heat-generating electronics. Those facts created reliability problems with the fighter’s avionics that were a concern when Coyle was with the Pentagon’s test office.

“The computer would crash and then it would have to reboot and crash again. ... You wouldn’t accept that with your home and office computer,” said Coyle, now a senior adviser at the Center for Defense Information, a Washington, D.C.-based think tank that is often critical of how defense projects are managed.

Coyle worries that the F-22A problems are being repeated with the F-35 Lightning II, the warplane intended to replace the F-16 and A-10, as well as Navy and Marine Corps fighters.

Even though a test version of the F-35, also called the Joint Strike Fighter, has been grounded for several months, the jet’s builder, Lockheed Martin, is seeking Defense Department permission to fly fewer test hours.

“That is always a sign that the aircraft is in trouble,” Coyle said of cutting test flights.

Fixing the problems

The leaking water resulted in corrosion on the aluminum panels that cover 21 access points on top of the jet. The essential problem was that the original seals and panels were not watertight. The presence of moisture set off galvanic corrosion where different metals touched.

Because corrosion is a common problem for aircraft, coming up with a solution was not difficult. “Once we understood it, it was easy to clean up,” Moore said.

The four largest aluminum access panels will be replaced with titanium panels much less susceptible to corrosion, Moore said. Each set of new panels cost about $50,000.

All of the leaky hatches will get a new coat of paint primer and a seal between the fuselage and covering, Moore said.

In addition to the leaking access panels, there have been concerns about the aircraft’s core structure.

A year ago, Air Force Times reported that F-22A structural problems could cost $1 billion to fix. But after further tests, the Air Force now estimates the fixes will be in the millions of dollars, although a final estimate for labor and parts has not yet been calculated, Moore said.

The biggest concern is the jet’s “forward boom,” which Moore compared to a backbone, supporting the weight of the plane. The Air Force learned that the titanium used in the forward boom of 91 jets had not been heat treated and strengthened to Air Force specifications.

That mistake prompted the Air Force to inspect the jets and determine the real strength of the titanium. The tests concluded that the titanium in the forward boom is strong enough for the jet to meet its life-span requirement of 8,000 flying hours, Moore said. Sections of the forward boom would not have to be replaced, but the service did target the boom for a handful of additional inspections.

Moore added that engineers are looking at how to keep the F-22A flying beyond its specified 8,000 hours.

The Raptor had a different problem with the aft boom. Engineers were worried the rear section of the jet, as designed, could not meet the 8,000-hour requirement, so they designed an aluminum reinforcement, called a “doubler.” That fix was added to the production line, but 41 jets were turned out before the production-line change. The repairs to these F-22As will have to be made at either the Ogden Air Logistics Center at Hill Air Force Base, Utah, or at Lockheed’s Palmdale, Calif., plant. Moore could not estimate the repair bill other than to say labor costs would be higher than parts costs.

The repair depots also are replacing on 60 jets some lugs that help attach the Raptor’s wings to the fuselage. Again, the concern was that the original lugs could not withstand the strain over the Raptor’s life span.

Depending on how much overall work is needed, including upgrades not related to maintenance problems, the Raptors will spend three to six weeks at the depots.

Fortunately, the overheating issue has been resolved. A year ago, engineers were concerned that the F-22A’s avionics overheated and shut down if the planes sat outside in 120-degree temperatures for more than 44 minutes with the engines running.

The root of the problem was the jet’s stealth requirements and that the Raptor uses jet fuel to help cool the avionics; the fuel wasn’t able to handle the heat, Moore said.

Through software and procedural changes, the time the jet can now sit in extreme heat with engines running has been doubled, alleviating concerns about avionics shutting down, Moore said.

http://www.airforcetimes.com/news/20..._rust_071112w/


Kinda old, but ever since Gates has released his plans a few days ago, many people I know have been bashing the F-22 and saying the F-35 can do up to 95% of what the 22 can do any thousands of other anti- F-22 phrases.

I debate with them on why the F-22 and F-35 are different jets and meant for different roles, but they keep on persisting be quoting Gates that the F-35 is better in certain aspects than the 22, cheaper while having a better quality jet, etc. etc.

How do I respond to these guys lol?