"Costly Flaws Found In Navy's Top Jet: Wing mechanism wear could halve flight hours"

http://www.boston.com/news/nation/wa...navys_top_jet/

Boston Globe
May 17, 2007
Costly Flaws Found In Navy's Top Jet: Wing mechanism wear could halve
flight hours
By Bryan Bender, Globe Staff

WASHINGTON -- Engineers have uncovered a flaw in the Navy's top
fighter jet that could reduce by half the aircraft's advertised
service life and potentially cost taxpayers hundreds of millions of
dollars in repairs, according to Pentagon documents and military and
industry officials. A mechanism inside the wings of the F/A-18 Super
Hornet, manufactured by Boeing Co., is wearing out prematurely,
prompting the Navy to order the company to make changes in the plane's
production as well as retrofit several hundred planes already
operating off the decks of Navy aircraft carriers, according to a Navy
official. Officials stressed that they are not considering whether to
ground the workhorse jet, because the problem does not affect its
operation. Still, the "fatigue life issue," if uncorrected, would
drastically shorten the $50 million aircraft's life span from 6,000
flight hours to 3,000 hours, the documents warn. "Through testing of
Super Hornets they discovered there is a fatigue issue on part of the
inside of one of the wings," a Navy official confirmed in a statement
yesterday. "From here on out every aircraft will be made so they don't
have the problem." The official said at least 193 planes now in
service will be retrofitted beginning in 2010. The plane was
introduced in 1999. But the wing is apparently not the only thing that
needs to be retrofitted, according to the Navy official, who asked not
to be named because he is not authorized to speak for the program. The
Navy did not comment officially about the problem despite numerous
requests. The current fleet of Super Hornets is slated to receive a
total of 40 modifications, both major and minor; additionally, a
separate problem with the aircraft's wing flaps could limit even
further the plane's ability to fly safely, the documents show. Special
fatigue tests now underway to identify a fix for the second wing
problem are set to be completed in July. Navy officials said they will
not know the price tag for retrofitting the wings until an
"engineering change proposal" outlining solutions is completed in the
coming months. Loren Thompson, a defense analyst at the Lexington
Institute, a defense and public policy think tank, said any structural
problem in the jet's wing "is a much bigger problem" that will require
expensive, time-consuming repairs. "It would be very costly to go back
and refit" the jets, Thompson said. "Usually, if there is fatigue or
corrosion problems [on aircraft wings], it is [on] the outside part
that is exposed to the elements. When you develop a fatigue problem
inside the wing, the challenge of fixing it grows. "The cost, the man
hours, the time the aircraft are out of service: No matter how you
want to measure it, it is not minor." The Navy plans to build 210
Super Hornets over the next five years. Ninety of the planes will be
outfitted with advanced radar and high-tech sensors to jam enemy
electronics. That version, known as the Growler, is awaiting approval
to begin initial production next year. Australia recently signed a
$2.4 billion deal to purchase 24 Super Hornets, the first sale in what
Boeing hopes will be a growing foreign market for the aircraft. The
structural problem in the wings has emerged at a time when Boeing has
proposed selling the Navy at least 100 more Super Hornets in case the
F-35 Joint Strike Fighter -- the Pentagon's next-generation attack jet
now under development -- is delayed further, according to news
reports. The F-35, produced by Boeing rival Lockheed Martin, is not
expected to enter service for eight years. The Super Hornet is 25
percent larger than its predecessor, which was first widely introduced
in the 1980s. Considered one of the Pentagon's most complex aircraft,
the Super Hornet became the Navy's mainstay jet after the infamous
A-12 stealth aircraft project -- launched to replace the aging,
earlier-model Hornets -- collapsed. Some critics argue that the design
changes and upgrades in the latest generation Hornets were so
significant that the Super Hornet project should have been scrutinized
as though it were an entirely new aircraft line -- rather than the
more cursory look reserved for modifications of earlier-model
aircraft. "They never built a prototype," said James P. Stevenson, a
military aircraft specialist and author of "The Pentagon Paradox,"
which reserves a chapter for the F/A-18 program. "After 25 years of
development they still haven't got it right." Indeed, the F/A-18
program has had a series of aerodynamic and structural problems over
the years. As far back as the early 1980s, the first versions of the
Hornets also had problems with premature wear and tear on the
airframe, requiring significant retrofitting. Those structural issues
have been more pronounced with the Super Hornet. For example, testing
of the Super Hornet in the late 1990s revealed that the plane would
"flutter" during certain maneuvers -- a flaw that nearly brought the
program to a standstill. It required the Navy and Boeing to make
substantial changes to the wings and pylons. Yet while those
adjustments made the flutter "manageable," according to the new
documents, it produced a new problem: accelerated wear on some of the
missiles carried under the wings, according to the documents. Now, the
Navy and Boeing are scrambling to come up with a solution for the
Super Hornet's wing fatigue, which first showed up in tests in 2005,
the Navy official said. The prediction that the flaw could drastically
cut the jet's anticipated life pan amazed some defense analysts .
"That would be a significant decrease," said Richard Aboulafia, a
defense analyst at the Teal Group in Fairfax, Va. Still, the documents
indicate the Navy and Boeing are confident they know how to fix the
problem. A proposal "that will address the inter-wing retro fit" is
expected within a few months, according to a document prepared by
Naval Air Systems Command and provided to the Globe. "Not until 2008
will aircraft roll off the line with full life" if Boeing makes the
necessary adjustments to its production, according to the document.