The Metropolitan Washington Council of Governments yesterday made a disclosure about as revealing as saying that night follows day or standing in the rain makes one wet. It announced the findings of two year-long studies that show that the Federal Aviation Administration's airplane "scatter plan" test made people upset.

The scatter plan, which diverted planes taking off and landing at National Airport from their normal Potomac River route and dispersed them throughout the Washington area from October 1983 to January of this year, brought loud protests and thousands of angry telephone calls from neighborhoods newly exposed to jet noise.

Elected officials on the COG board, which came under withering criticism from many area residents for recommending the scatter test last year at the urging of anti-noise activists who live along the river, said yesterday they will not resurrect the scatter plan.

Although the board voted to delay taking any action pending examination of the lengthy consultants' reports, its members clearly hoped the reports put the controversy behind them once and for all.

"We don't want to go through this again," Fairfax Supervisor Martha Pennino said at the meeting. "Ever," piped in H.R. Crawford, a District of Columbia City Council member and COG chairman.

"This has been one of the hottest issues to ever come before this body," Crawford added. Colleagues on the D.C. council attacked Crawford last year for voting as a COG member in July 1983 to hold the scatter test, one day after the council voted to oppose the test.

Anti-scatter plan activists welcomed the consultants' studies, which showed that the number of area residents who suffered from loud jet noise increased from 606,000 before the scatter plan to 883,000 during the experiment.

"I'm certainly happy the report seems to suggest elected officials want an end to the scatter plan," said Sandra Elligers, a McLean lawyer who said that jet noise became unbearable during the three-month scatter plan.

One report, performed for the FAA by the Howard Needle Tammen & Bergendoff consulting firm, centered on technical noise data gathered by 48 noise-monitoring devices in the area. FAA officials said they were unable to say how much the report cost. The other study, performed for COG by the firm of Bolt Beranek and Newman Inc. at a cost of $78,500, measured residents' response to the test.

There were 13,454 calls to the FAA opposing the test and 4,506 favoring it, according to COG, for a ratio of three to one against.

More than 7,000 interviews showed that residents of Northwest Arlington and McLean were most annoyed about the scatter plan, while there was less annoyance in some neighborhoods near the river such as Glen Echo, in Maryland, and Langley and Fort Hunt, in Virginia. The scatter plan cut down on air traffic over those areas.

The neighborhoods that experienced the greatest increase in jet noise during the scatter plan were in the District of Columbia and Arlington, Fairfax and Prince George's counties, the studies said. No change was reported for Alexandria.

Some anti-noise activists insisted yesterday that the studies should not stop future scatter plans.

William Moran, vice president of the Coalition on Airport Problems, a group largely made up of people who live near the river, said that while he and his neighbors in the Accokeek area of Prince George's endure an average of 22 airplanes an hour 15 hours a day, the approximately 277,000 people newly exposed to jet noise during the scatter plan heard at most three planes an hour.

"When you spread the noise, except for a very small number of people, you won't even notice it," Moran said. "We've got to do something that's going to regain the Potomac River for the people of Washington."

Moran acknowledged that chances that the FAA will resume the test are slim.