Excessive secrecy may have doomed the attempt last April to rescue American hostages from Iran, a military review panel said yesterday in a report portraying a badly flawed operation.

Although panel Chairman James L. Holloway, a retired admiral and former chief of naval operations, told a Pentagon news conference that the rescue plan "probably represented the plan with the best chance of success," the report puts this assessment in question.

The Joint Chiefs of Staff were so obsessed with keeping the plan secret, for example, that they never wrote it down or subjected it to the traditional "murder boards" (panels of critics) for review.

Also, radio communications among the eight helicopters on the mission, and between the helicopters and the C130 transport planes carrying the mission commanders, were so restricted that the helicopter pilots did not receive vital information that might have save the mission.

The picture of a desperate night of mistakes and confusion emerges from the report as it describes the scene at Desert One, the mission's rendezvous point in the Iranian desert April 24-25. It was there that eight servicemen were killed when a helicopter collided with one of the C130s during the process of aborting the rescue attempt.

Long before the mission was close to being launched, the report says, the plans and rehersals were so fragmented to maintain secrecy that cohesion and coordination became early casualties.

Much of the nation's intelligence community was frozen out of the planning, again in the interest of secrecy, and weather experts seldom had a chance to educate the helicopter pilots about the dust clouds and other bad conditions they might run into in the back country of Iran.

With secrecy keeping so many people out of the know, the Joint Chiefs of Staff became judge and jury for the plan they designed, approved and recommended to President Carter for execution.

The mission was aborted because only five of the eight helicopters which flew from the aircraft carrier Nimitz to the first rendezvous point were capable of flying on to the mountain hideaway that same night. The plan called for at least six Rh53 choppers taking off from Desert One.

The military review panel, comprised of Holloway and five generals from the Army, Air Force and Marine Corps, said the rescue plan should have provided for an initial force of 10 helicopters. C130 planes should have flown ahead of them to guide them to the rendezvous spot and pass along weather information, the panel said.

Army Maj. Gen. James Vaught was the overall mission commander. Holloway at the news conference declined to pass judgment on Vaught's performance. Later the Pentagon issued a statement in Holloway's name saying that there was nobody more experienced and competent than Vaught to run the mission.

Holloway said his group's report addressed only the military issue of the first stage of the rescue operation.

"Quite frankly, we were apprehensive that the critical tone which this resulted in could be misinterpreted as an indictment of the able and brave men who planned and executed this operation. . . . We encountered not a shred of evidence of culpable neglect or incompetence."

The panel recommended, however, that the Joint Chiefs establish a standing counterterrorist joint task force, comprised of specialists from the four services, to provide a permanent source of expertise for planning such operations as the rescue mission.

Also, to provide a more critical look at future plans before they are implemented, the Holloway group recommended that the chiefs appoint a five-to seven-member advisory panel of experienced military officers, both active and retired.

Pentagon spokesman Thomas B. Ross announced yesterday that both recommendations have been approved. Defense Secretary Harold Brown, he said, will establish a counterterrorist task force under a single command, and the chiefs will submit their plans to an oversight group.

Key findings of the Holloway group:

Lack of review. A recommendation to establish a special review group for the rescue plan was rejected early on in the interests of secrecy. "As a consequence, planners, in effect, reviewed and critiqued their own product for feasibility and soundness as they went along . . .

"On the three occasions when the Joint Chiefs of Staff were briefed on the status and content of the plan, there had been no intervening scrub-down or murder board of the planning product.

"Further," to keep the plan secret, "the Joint Chiefs of Staff were acting in essence as their own action officers and were denying themselves the staffing support they normally enjoy when reviewing plans of a less sensitive nature.

"In sum, this meant that the hostage rescue plan was never subjected to rigorous testing and evaluation by qualified, independent observers and monitors short of the Joint Chiefs of Staff themselves. . . .

"No final plan for the rescue operations was ever published prior to the mission execution. A written plan to supplement oral briefings to the Joint Chiefs of Staff would have provided them a document to study and review in the privacy of their own offices, which might have sharpened their understanding of details and led to more incisive questions . . ."

Intelligence community input. "The group believes that intelligence community assets could have been pulled together more quickly and effectively. . . . Some of these officers felt their initial effectiveness may have been impaired somewhat by not being told more about the true nature of the operation from the beginning. . . ."

Uncoordinated training. "Through integrated training exercises of the joint task force for the final plan were not conducted." The joint task force commander, as part of the super-secrecy, imposed "decentralized command supervision of training and evaluation. . . .Thorough, integrated rehearsals would have developed precision and speed in execution, increased inter-unit coordination, suggested necessary changes and resolved problem areas," although this would have increased the chance of leaks.

The crews of the C130 transports which were to meet at Desert One on April 24 did not critique each other face to face after training together, but were largely dependent on less -- effective communications. The Holloway group said there should have been an overall commander to coordinate the training better.

"Operational readiness of the force would have benefited from a full-dress rehearsal, and command and control weaknesses would probably have surfaced and been ironed out. . . ."

Flawed command and control. "Command and control was excellent at the upper echelons, but became more tenous and fragile at intermediate levels. . . ."

Number of helicopters. The plan kept changing as it was tailored to new information about the hostage situation in Iran. One change was the need to provide more airlift at Desert One than had been contemplated when eight RH53 helicopters were deemed enough.

"The review group concluded that additional helicopters and crews would have reduced the risk of abort due to mechanical failure, were operationally feasible and could have been made available until quite late in the planning evolution . . . . An unconstrained planner would more than likely have initially required at least 10 helicopters under joint task force control rule, 11 under the most likely case and up to 12 using peacetime historical data.

Aside from secrecy considerations, "no operational or logistic factor prohibited launching 11 from Nimitz and continuing beyond the halfway point to Desert One with 10 helicopters . . . . In retrospect, it appears that on balance an increase in the helicopter force was warranted. However, such an increase would not itself guarantee success."

Weather predictions. The joint task force planning the rescue mission had been given a table, showing "by location and month, the frequency of suspended-dust occurrences" over Iran. "Helicopter pilots, however, were surprised when they encountered the dust, were unprepared to accurately assess its impact on their flight and stated that they were not advised of the phenomenon. C130 pilots were also unaware of the possibility of encountering suspended dust. . . .

The traditional relationship between pilots and weather forecasters was severed. This was done to enhance" secrecy of the operation.

As it turned out, the two dust clouds the eight helicopters flew into after leaving the Nimitz at twilight proved disastrous. One helicopter, caught in a dust storm of unknown size to the pilot, turned back to the Nimitz. He said later he would have kept going if he knew his helicopter was the crucial sixth one for continuing the mission and that there was clear flying beyond the dust cloud.

Excessive secrecy on communications. "The pilot of helicopter number five" -- lacked certain knowledge vital to reaching an informed decision to proceed or abort. . . . Failure to pass this vital information back to the carrier and support bases and rebroadcast it via secure high frequency was the result of a very restrictive communications doctrine related to the overriding concern for operations security. However, there were ways to pass the information to C130s and helicopters enroute that would have small likelihood of compromising the mission. . . .

"The group concludes that restricted communications flow within the task force denied information essential to reach informed decisions. The additional information might have prompted helicopter number five to continue on to Desert One. One more flyable helicopter would have enabled the mission to proceed."

Night at Desert One. "Perhaps because the scope and complexity of Desert One was not replicated in a full-dress rehearsal, the plan for this desert rendezvous was soft. There was no identifiable command post for the on-scene commander; a staff and runners were not anticipated; backup rescue radios were not available until the third C130 arrived; and, lastly, key personnel and those with critical functions were not identified on the scene for ease of recognition . . ." Pilots told the Holloway group afterward that "in some cases, they did not know or recognize the authority of those giving orders at Desert One . . . .

"Instructions to evacuate the helicopters and board the C130s had to be questioned to determine the identify of those giving the orders to establish their proper authority. . . ."

Failure to destroy secret information. After all the emphasis on secrecy in planning the rescue, the helicopters abandoned on the desert floor when the mission was aborted contained top-secret information about the operation which the Iranians captured and exploited for propaganda purposes.

The Holloway group said the failure to destroy the secret material "reflects unfavorably on the performance of the personnel involved." The group also decried the lack of destruct capability" at Desert One, meaning explosives to blow up secret maps, codes and sensitive equipment.

Serving with Holloway on the review group, which convened in May, were Army Lt. Gen. Samuel V. Wilson (ret.), former head of the Defense Intelligence Agency Air Force Lt. Gen. Leory J. Manor (ret.), who planned the attempt to rescue American prisoners from North Vietnam's Sontay prison camp in 1970; Maj. Gen. James C. Smith, Army training director; Maj. Gen. John L. Piotrowski, deputy commander for air defense at the Tactical Air Command, and Maj. Gen. Alfred M. Gray Jr., director of the Marines' development center at Quantico, Va.