Every day, roughly six small airplanes falter and crash somewhere in the United States. On Thursday and Friday, air crashes left two prominent politicians dead - heightening awareness of the more than 2,000 small-plane accidents each year.

In addition to Sen. John Heinz III of Pennsylvania and former Sen. John Tower of Texas, 28 other people died in the back-to-back, highly publicized crashes.But even though hundreds of people are killed in such accidents each year, federal safety officials say the numbers of general aviation accidents have decreased dramatically over the past two decades.

The peak year for general aviation accidents was 1967, when 6,115 such crashes were recorded.

The National Transportation Safety Board, which seeks to identify the probable cause of such crashes, says the 2,138 accidents in general aviation last year were the fewest since it began compiling records in the 1960s.

And an industry group said the accident rate in that category was the lowest ever recorded with about seven accidents for every 100,000 flying hours.

In 1989 there were 2,201 accidents and 757 fatalities. Fatalities numbered 777 in 1988, 807 in 1987, and 965 in 1986.

Shortly after the 1990 figures were released in January, Donald Engen, president of the Air Safety Foundation of the Airplane Owners and Pilots Association, attributed the decline in accidents to improved aviation education and pilot training.

"Larger numbers of active pilots are participating in more professional initial and recurrent training; that's the key," he said.

"If pilots will continue their trend of more frequent training and upgrading of skills, the accident rate could be cut in half," he said.

Fatal commuter airline accidents have fluctuated sharply over the last five years with fatalities numbering as few as four and as many as 59.

Last year there were 14 accidents involving commuter air carriers. Two of them were fatal accidents and the number of people killed was four.

In 1989 there were 17 commuter accidents, five of them involving fatalities. The total number of people killed was 31.

Twenty one people died in commuter accidents in 1988, 59 in 1987, and 4 in 1986.