
DATE: Wednesday, November 26, 1997          TAG: 9711260679

SECTION: FRONT                   PAGE: A1   EDITION: FINAL 

SOURCE: BY DALE EISMAN, STAFF WRITER 

DATELINE: WASHINGTON                        LENGTH:  111 lines

NAVY FINDS FLAW IN FUTURE WORKHORSE SUPER HORNET MIGHT REQUIRE COSTLY REDESIGN TO FIX ITS WINGS

The Navy has encountered a potentially crippling problem in flight tests of its F/A-18 Super Hornet attack jet and may have to redesign the plane's wings to solve it, service sources and memoranda suggested Tuesday.

The trouble is a sudden and unexpected drop in one of the plane's wings during some banking maneuvers. The ``wing drop anomaly'' has occurred ``in the heart of the (flight) envelope,'' according to a memo prepared for Navy Secretary John H. Dalton, and efforts to attack it have been only partially successful.

Pilots flying the seven test-model Super Hornets at Patuxent River Naval Air Station in Maryland have had no trouble keeping the planes under control when the wing drop occurs, one source said, but there is no question that the problem must be solved before the planes become operational.

A redesign of the wings, if one is required, could take years. Navy officials said they remain hopeful that less drastic remedies will be successful and that a better picture of the problem and possible solutions will emerge by mid-December.

Oceana Naval Air Station in Virginia Beach is expected to be the Super Hornet's East Coast center of operations when the first of the new jets go into service around 2001. Hundreds of earlier-model Hornets now stationed at Cecil Field, near Jacksonville, Fla., are to be relocated to Oceana beginning next year.

The single-seat E-model Super Hornets and the two-seater F's being tested at Patuxent River are to replace those early Hornets and F-14 Tomcats, also based at Oceana, in the Navy's arsenal. The service hopes to buy 785 of the Super Hornets, which are about 25 percent larger and carry more weapons and fuel than today's models.

The wing drop problem in the Super Hornets is said to be so subtle that in some of the seven test jets it occurs during banking to the left and in others it is experienced only when banking to the right.

Efforts to understand the problem have focused thus far on a notch, or ``snag,'' on the outer portion of leading edge of each wing, sources suggested. A kind of flap, the snag is extended and retracted during various maneuvers.

The Navy has conducted a series of wind tunnel tests to understand how movement in the snag changes the air flow over other portions of the wing. It first tried to solve the problem by changing the computer software that adjusts the snag in response to the pilot's movement of the plane's stick.

The service also has experimented with some modifications of the wing surfaces but so far the ``low-cost, quick fixes, though improving the performance, have not completely resolved the issue,'' Capt. James Godwin, the program manager, reported in the memo to Dalton.

Though it has had a controversial history, the Super Hornet is touted by the Navy as a dramatic improvement over today's Hornets. To date, the service has managed to keep the program on schedule and under budget, features that have helped sell it to a sometimes skeptical Congress.

Lawmakers provided more than $2 billion for the Super Hornet in the fiscal year that began Oct. 1, agreeing to the purchase of 20 aircraft. It was unclear Tuesday whether any of that money has been released to the contractor, Boeing Inc.

In a series of reports over the past two years, the General Accounting Office, Congress' fiscal watchdog agency, has argued that the Super Hornet's improved performance is not enough to justify its $70 million pricetag. Current C- and D-model Hornets cost about $58 million each, according to the agency's figures.

The Navy says both planes actually are far cheaper and critics are inflating the cost by including development expenses in their computations.

Franklin C. Spinney, a Defense Department analyst for fighter aircraft programs, suggested Tuesday that part of the Navy's difficulty in finding a solution for the wing drop problem may be traced to the Super Hornet's history as a derivative design of the original F/A-18.

Initial Hornet models had aerodynamic problems that the Navy solved by adjusting computer software that controls the flaps, ailerons and other wing surfaces, Spinney said. The enlarged and redesigned wing and fuselage of the Super Hornet would be expected to generate a different set of airflows, which would then require new software adjustments, he added.

``It's a Band-Aid on top of a Band-Aid,'' Spinney said, rather than the more costly but straightforward solution that would come from a completely new design.

In the early 1990s, as the Navy prepared to gear up the Super Hornet program, Spinney lobbied for the construction of prototypical aircraft that could then ``fly off'' against the Hornet model now in service, the F/A-18C. The side-by-side comparison of the two planes was intended to test contentions that the Super Hornet will not deliver an improvement in performance over the Hornet C significant enough to justify its increased cost.

Spinney joked Tuesday that he has taken to referring to the Super Hornet as the ``whack-a-mole,'' likening the fighter's recurring problems to the carnival game in which a toy mole pops up out of a new hole every time the player whacks it down into its old one. ILLUSTRATION: Color Photo

[Airplane]

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THE POTENTIAL PROBLEM

What happens: A sudden drop in one of the F/A-18 Super Hornet's

wings has occurred during banking maneuvers. Test pilots have had

no trouble keeping the planes under control, but the problem must be

fixed before the planes become operational.

What is being investigated: Efforts have focused on a notch, or

``snag,'' on the outer portion of the leading edge of each wing. The

snag - a kind of flap, the snag is extended and retracted during

maneuvers.

THE AIRCRAFT