Four Army paratroopers were killed and at least 71 injured today in a chilly dawn airdrop, the opening operation in a month-long training exercise for the newly created Rapid Deployment Joint Task Force.

The airdrop, the largest during peacetime since the Korean War, was the first phase of Gallant Eagle 82, a $45 million military exercise being conducted in the Mojave Desert here. More than 2,200 paratroopers of the 82nd Airborne Division had flown during the night from Fort Bragg, N.C., to take part in the exercise, which is expected to involve 40,000 personnel from all four branches of the military.

Lt. Gen. Robert C. Kingston, commander of the deployment force, said that two paratroopers died as a result of parachute malfunction, one landed on a piece of heavy equipment and a fourth apparently was dragged along on the ground by the wind. Kingston said four other soldiers suffered serious injuries in the airdrop. Eleven paratroopers, including three in critical condition with head injuries, were hospitalized.

According to military regulations, no peacetime airdrop is supposed to take place if winds are above 13 knots. As observers assembled in pre-dawn hours, winds were estimated at more than 30 knots, but the winds died down shortly after dawn when the drop took place.

Kingston told reporters that the winds were calculated at 6 and 10 knots at the time of the airdrop in the two drop zones where the men were killed. But some of the C130 and C141 transport planes had to circle the area waiting for the winds to die down before going ahead with the drop.

Military officials here say that the average casualty rate during such exercises is about 1 percent. "This was a simulated combat drop," said Kingston. "It is an inherently hazardous job, which is why the men receive hazard pay."

Several paratroopers said winds were reported above the 13-knot level before they jumped, but military officials claimed that at drop time the winds were below the danger level. Military officials have not revealed the names of those killed and Kingston said that the deaths are under investigation. Such investigations usually take about 30 days.

The purpose of the military exercise, according to Kingston, is "to test and evaluate the development and coordination" of the deployment force, and he seemed to deem the operation a success.

The Rapid Deployment Force was created after a 1977 presidential directive called for a four-service force that could be quickly deployed outside of North Atlantic Treaty Organization areas, particularly in the Middle East and Persian Gulf.

In April, 1981, Defense Secretary Caspar W. Weinberger announced that the RDJTF would evolve into a separate unified command beginning next January. In its 1983 posture statement, the Pentagon calls the new force the Southwest Asia Command, and the Pentagon has asked for more than $4.5 billion to support the RDF in its fiscal 1983 budget.