The exhausted but relieved passengers and crew of a Korean Air Lines plane forced down in the Soviet Union left here yesterday for home and what is certain to be an emotional arrival.

The relief plane carrying 105 surviving passengers and crew members and bodies of two dead passengers refueled in Anchorage, Alaska, late yesterday and was to arrive in Tokyo and Seoul today.

During their 11-hour stay here after their dramatic release from the Soviet Union, the people of Flight 902 painted a story of an air crew that lost its way through faulty instruments and then tried frantically but unsuccessfully to signal its distress to a Soviet interceptor that suddenly appeared near them in the clear, pale light of Arctic night and opened fire.

Passengers and the plane's copilot, interviewed separately, told basically the same story. Details of the plane's two hours of horror came from a diary, kept by a Japanese passenger, that provides a remarkable running account of her observation of incidents and emotions in the cabin as the crippled plane sought refuge and finally crash landed at a frozen lake in the Soviet far north.

The diary indicates that rather than being allowed to fly unmolested over Soviet territory for two hours while Soviet jets tried to turn it back or make it land, as Soviet authorities described the incident, Flight 902 was attacked by lethal gunfire only 18 minutes after its strayed into Soviet airspace.

By late yesterday, Soviet officials had not released the plane's pilot or chief navigator. The plane's black box, the inflight recorder that possibly could answer questions about the bizarre voyage, was apparently in Soviet custody.

The U.S. Embassy in Moscow, acting on behalf of South Korea, which has no diplomatic relations with the Soviet Union, asked authorities for an explanation of the detention of the two crew members. A State Department spokesman said in Washington that a senior Soviet diplomat had been told there that the United States was concerned about the situation.

The strange flight of the Korean Air Lines plane began Thursday when it left Paris on a scheduled flight across the North Pole to Japan and South Korea. North of Canada it veered off course and, unknown to the crew and passengers, flew toward the Soviet Union, entering the country in one of its most sensitive military regions.

From that moment until a Pan American rescue plane brought the survivors here early yesterday, the plane's occupants - mostly South Koreans and Japanese with a few Europeans - were at the mercy of the Soviet Union.

The diary of Seiko Shiozaki, 28, indicates that an hour and 42 minutes of desperate flying by the stricken plane occurred between the time it was attacked and the time it landed. The Kremlin has asserted that the South Korean plane stay airborne two hours in restricted space. This would mean that only 18 minutes passed between the time the four-engine Boeing 707 entered Soviet air space and the moment it was attacked.

The woman's version is supported by other passengers and copilot S.D. Cha.

Cha was quoted by reliable sources as saying that the crew somehow became disoriented while flying north of the Karelia Peninsula. Their instruments seemed to be indicating they were in a safe flight path outside Soviet air space, but they began seeing an unfamiliar land mass beneath them. Within minutes Cha saw a Soviet fighter, psssibly a Mig 19 or 21, suddenly slide close along the right side of the 707's nose.

The crew began frantically signalling with their radios on every frequency available to them, but to Cha's horror, the Soviet fighter seemed not to hear and made a threatening sign of some sort which was not explained here yesterday.

Elaborate international codes, such as wagging wings and turning on landing lights, are used between planes of foreign countries to signal airspace violations. The Kremlin version asserts that the Soviet fighters did these maneuvers but whatever Cha saw, the vetern South Korean crew did not understand.

In the passenger cabin, the Soviet jet was seen to cruse very close along the right side of the airliner which was painted in the red, blue and white of KAL and carried large Peman letters and Korean characters identifying it on the fuselage.

The interceptor flicked out of sight and moments later Shiozaki recorded. She saw "many lights" suddenly winking close to her out the left side window of row 19 where she was sitting.

There were at least three blasts punching a hole the size of a melon into the left side of the fuselage four row behind her. Jean-Charels Fory, a Parisian businessman sitting nearby noticed that his jacket draped over an adjacent seatback suddenly was riddled by three holes about the size of a quarter.

Bahng Tais Hwang, 36, sitting in the middle seat of Row 23 on the right side, died instantly of a wound to head. He was a salesman from Seoul.

Yoshitako Sugano, 31, sitting in 24A, the left side window seat, collapsed in a gush of blood, his right arm and shoulder mangled. The coffee shop owner from Yokohama, Japan, later died.

His brother, Yasuo, 33, sitting inboard, took sharpnel in his right leg. Brother-in-law Takamasa Fukui, 25, in the aisle seat, Row 24, was hit with 20 small pieces of shrapel in his left foot.

There were cries of agony and fear in the cockpit, pilot Kim Chang Kyu and the crew saw their instruments register a sudden decompression in the passenger cabin, a catastrophe spelling potential death for the passengers as the cabin's pressurized air rushed out through the hole. Releasing the emergency oxygen masks in the ceiling over the passengers, Kim nose-dived to get down the denser air and enough oxygen.

"It was sudden, like a lift," or elevator, recalled Karlheinz Schwaken, a young Duesseldorf steel equipment salesman who was on his way to a Far Eastern sales trip.

"We turned around and saw wind rushing" past the shell hole, wrote Shiozaki. The plane dived for five minutes, her diary shows.

"We felt . . . we are going to be dead," she wrote a moment later. She checked her watch, set to Paris time. It read 8.43 p.m. "We are falling down, down, down," her notes read.

Kim reached 3,000 feet and leveled off. The interceptor had disappeared, never to be seen again by anyone on the plane. The bewildered passengers made no connection between the jet they had seen flying on the right side and the unseen attack from the left.

Kim ordered the passengers to don inflatable life jackets from under their seats. He steered south, expending fuel, a standard procedure to reduce fire hazard for a plance headed to an emergency landing. The passengers thought they were over Alaska, more than 1,000 miles to the east.

The terrifying dive ended and the passengers were strangely calm. One passenger, a physician, began treating the wounded, but Yoshitako Sugano's life ebbed. They were unable to staunch the massive bleeding.

Shiozaki recalled an immense sense of life rising uncontrollably through her.

"We floated for about an hour and 40 minutes," she wrote.

Kim, searching for a suitable landing area, spotted a flat, open snowy expanse and landed the stricken plane without lowering the wheels. The left wing was broken.

"Along the back it looked as if King Kong had grabbed it," Schwaken said.

"I've had many worse landings at international airports," leather designer William Howard of London recalled here later, an immense grin on his face. He and his partner, Benson Cohen, 55, had been headed for a business deal in Seoul.

Dim light filtered through the cabin. Seiko checked her watch. It said 10:25 p.m. Elapsed time from gunfire to landing: one hour 42 minutes.

Unknown to Shiozaki, the Kremlin would declare misleadingly 12 hours later that Flight 902 "landed . . . two hours after entering Soviet air space."

The Kremlin statement did not mention that its armed jet fighter had machine gunned Flight 902. It did not mention - although the leadership must have known by the time their statement was issued - that people had died from Soviet bullets.

Kim came back to the passenger called Schwaken. "It was a question broke out.

"It was not a question of words," recalled Schwaken. "It was a question of the feeling of everybody for the crew."

But Kim told the people he had made a terrible mistake, ignoring a "six sense" that told him his course was in error even though the navigation equipment said it was right.

Later, here, copilot Cha, his face working with effort to get the words out, murmured, "I am very, very, sorry for the dead."

After two hours of bewildered waiting in the darkened cabin, the people saw soldiers with weapons tromping in the deep snow outside.

"We saw people, maybe soldiers," seiko wrote. "They have guns and long coats and we are afraid they are American . . . But afterwards I understand they are Russians, and people are very scared.

If she was frightened, her diary does not show it. At that point in the little notebook she sketched a simple drawing of the sun coming up surrounded by rays hanging on the page like a child's delicate fantasy.

Soviet soldiers clambered aboard, passports were taken, and the people of Flight 902 were sent into the frigid air down the Boeing's forward escape chute. Three largfe military helicopters came and they were finally taken to Kem, a small town 320 miles south of Murmansk.

Women, children and the wounded were helicoptered out first, but by then Sugano had died.

They were billeted in a community center, fed well if monotonously on hamburger patties with rice, groats (coarse grain) or potatoes and separated by sex in two large rooms where they slept part of Friday afternoon and Friday night.

The two most seriously injured persons were taken to Leningrad for medical care.

Soldiers guarded the community center and children peeked in the windows with curiosity at the confined foreigners of Flight 902. No calls were allowed, and no information was offered, a although they were told by officials that an international effort was being made to extricate them.

Early Saturday they were flown by two small Aeroflot airliners to Murmansk and some hours later headed to Helsinki aboard the Pan American evacuation plane, the "West Berlin," which also carried coffins bearing Sugano and Hwang.

Pilot Kim and his unidentified navigator were not permitted to leave. Soviet officials said the two were under investigation for violating Soviet airspace.

Exhausted passengers were given rooms in the Intercontinental Hotel, where they rested and spoke to reporters.

This afternoon the passengers boarded Finnair buses to go to the airport and board a special flight heading for Seoul. As the relieved passengers crowded out through the hotel doors they unknowingly rubbed elbows with the groups of Soviet officials drifting in for the First International Socialist Disarmament Conference.