HUSH, HUSH, SWEET 727, could become a popular song if one large cargo carrier succeeds in a new approach to muffling its planes.

The carrier, which wants anonymity for the time being, apparently found a way to reduce the sound level from its Boeing 727s that involves neither different power plants nor new engine nacelles a la traditional hush kits. As described to Inside Talk, this new-technology approach provides significant cost benefits compared with the more traditional approaches described above.And if the system functions as well as described, the carrier may share the advance with others. Of course, doing so should enhance the wealth of the carrier and establish it as a technology innovator in the area of airframe- engine combinations. Stay tuned.

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IF A NOISE LEGISLATION proposal falls in DOT, speaking of noise, does it make a sound?

The proposal for a national noise policy addressed here came to life in the mind of Federal Aviation Administration boss Allan McArtor. Shortly after he took office last summer, Administrator McArtor promised to submit such a proposal to Congress by April 15.

Apparently the idea died at DOT due to President Reagan's New Federalism policy. At a briefing with reporters last Wednesday, Secretary James Burnley said no proposal would be forthcoming.

Mr. Burnley concedes that the problem of local noise constraints is the classic confrontation of federalism and the Interstate Commerce Clause of the Constitution. Users disappointed with the secretary's position maintain his decision illustrates exactly who is in charge. But as long as rivers flow, grass grows and FAA remains a part of DOT, that will be the case, as it has been for 20 years.

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THE TIMES, THEY ARE a changin' and we failed to show that shift in our story last Tuesday on the departure of FAA's chief spokesman.

Air Force Lt. Col. James C. Jannette returned to his Pentagon post amid charges of a continuing policy feud between Mr. Burnley and Mr. McArtor. We quoted current and former FAA officials who complained about DOT's control of agency press releases, and the tendency to highlight the secretary's role at the expense of the administrator's.

While scores of examples exist from the term of former DOT Secretary Elizabeth Dole, the problem has all but vanished in Mr. Burnley's tenure. Of about 23 FAA press releases issued since early December, when Mr. Burnley became secretary, only seven mention the secretary at all, and those also mention the FAA administrator. The rest make no reference to the secretary.

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FAA ADMINISTRATOR ALLAN McARTOR answered a grave question during his press briefing announce the commuter airline safety audit last week.

A Detroit reporter asked about prospects of the agency approving plans to expand the runways at that city's Metro Airport, plans which if approved would require tearing down a cemetery. Mr. McArtor repeated a reporter's quip, I think it's a dead issue.

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COMPETING LEGISLATION introduced in the House would force the transportation secretary to study any large airport fee increase, or prohibit his intervention.

The bills were filed by Reps. Sherwood Boehlert, R-N.Y., and Charles E. Schumer, D-N.Y. Rep. Boehlert's bill, H.R. 4074, would require the secretary of transportation to review proposed airport fee hikes within 180 days of receiving requests from governors of two states. Rep. Schumer's proposal would limit the secretary's role regarding such fee hikes.

Conceding that the Massachusetts Port Authority's program for airport capacity enhancement for Logan International Airport provided the catalyst for his bill, Rep. Boehlert also acknowledged that the bill won't have any impact on Massport's timetable. the Boston authority wants to impose fee increases in an attempt to drive out smaller aircraft, including regional airliners and general aviation aircraft, opponents say. Massport claims it's trying to stave off a future capacity crisis at the airport.

Currently, according to the FAA, Logan operates well below maximum capacity.

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APPLAUSE, APPLAUSE, enough to bring down the Capitol.

During Rep. Boehlert's press conference touting the bill discussed above, representatives of user groups came to the podium to applaud the effort . . . every one of them.

Now if words were applause, all the work refurbishing the Capitol building would be for nought. The vibrations would have brought down the House side, at the least.

Can't someone find another word for support?