With the surviving passengers of Korean Airlines Flight 902 safely at the end of their journey, the mysterious sequence of their calamity remains obscure.
Why the flight went astray somewhere east of Greenland Thursday and headed south into the Soviet Union to disaster is but partially known. Many questions have no answers so far and perhaps never will. They involve the intricacies of high-speed jet flight, the uncertainties of polar aeirial navigation, and inadequate communications and understanding that haunt international relations.
It is unknown whether the crew was in constant communication with ground stations during this crucial portion of its journey from Paris to Seoul via the North Pole.
It is also unknown if ground control stations who now say they saw the plane heading into restricted air space over the Soviet Union tried to communicate the danger to the plane and failed.
The veteran South Korean pilot, Capt. Kim Chang Kyu, who, with the plane's navigator is still detained by Soviet authorities, was quoted by passengers as saying that his "sixth sense" told him he was headed wrong, but that he trusted his instruments.
Several of the passengers said yesterday in Tokyo that they had become concerned when they noticed that the plane, which had been flying toward the setting sun, was suddenly flying away from it, Washington Post correspondent William Chapman reported.
In any case, those crew members who have been released by the Soviets said the planes navigational on its correct course.
Instruments indicated the flight was on its correct course.
"We will have to wait until the return of the captain and navigator to find out what reallyhappened, "Korean Air Lines President Cho Chung Moon said in Seoul yesterday, Reuter reported.
It seems unlikely, however, that Soviet military radar, keeping stern over the heavily defendedKola Peninsula, could not have spotted the plane, flying at a 35,000 feet, as it headed ever nearer toward Soviet airspace.
Norwegian military sources at the important listening post of Bodo, Norway, said yesterday, according to United Press International, that they tracked the plane for approximately 200 miles inside Soviet territory when it disappeared from their radar screens.
Passenger Seiko Shiozaki's precise diary account matched against an official Kremlin account of the plane's fatal flight path indicated that Flight 902 was inside Soviet airspace minutes when it was attacked by a machine gun firing interceptor
According to the Norwegian account, however, the plane was in Soviet airspace for about an hour before it disappeared from radar, apparently when it was hit by gunfire that killed two passengers, injured 10 and forced the plane to drop and eventually crash land.
The official Soviet version implied that the plane traveled two hours unmolested before landing.
The Boeing jetliner, recently purchased by Korean Air Lines, was understood to have had aboard a gyrocompass navigation system as well as a radio compass. The is a question about whether it had a so-called Inertial Navigation System , a device superior for precision tto the gyro-compass.
The plane, according to authorities in Washington, was probably one of two recently sold by Pan Am through an intermediary to Korean Air Lines.
At the time those two planes were sold, a Pan Am spokesman said, they did not contain an Inertial Navigation System. According to the flight plan received by the Federal Aviation Administration's air traffic control center serving Anchorage, however, the plane was equipped with the Inertial Navigation System, an FAA spokesman said. Anchorage was to have been a refueling stop for the flight.
The Inertial Navigation System requires no attention to point the way accurately along the flight route once it is properly set before takeoff.
The instrument is coming into common use among passenger planes and is especially valuable for polar flights where there are fewer navigational aides and bizarre geophysical effects that make direction finding difficul t.
At the North Pole, a rapidly turning earth moves about 15 degrees an hour on its axis, which can throw a navigation off course. A gyro-compass in that area must be corrected every 20 minutes or so by a visual navigation check with stars or the sun.
Copilot S. D. Cha said yesterday the crew became disoriented and did not know where they were flying. Pilot Kim and copilot Cha had been flying the polar route since 1973.
The passengers thought they had crash landed in Alaska. Anyone who has flown over the vast expanses of Soviet Russia at night can attest ot the erie disorientation that envelopes the traveler looking out at endless miles of darkened countryside, devoid of an ything so familiar or friendly as the precise geometry of a landing field's lights.
After the plane was machine-gunned by a Soviet interceptor, Kim descended to 3,000 feet and apparently continued southerly for another hour and 42 minutes.
It has been speculated that he was searching for an airfield. Even if he had been and even if the crew had known they were over the Kola Peninsula, it is certain that their charts of ground facilities would not show any Soviet airports in this heavily defended, sparsely settled and secrecy-shrouded part of the world. Such military airfields as are there are sure not to be illuminated at night.
One unanswered question is why Kim chose to fly to consume his fuel instead of jettisoning it. One can speculate that Kim, realizing his plane had been fired on and fearful of another attack or of damaged instruments that could not indicate whether he was losing fuel from ruptured tanks, was preoccupied with keeping the four-engined liner under control while searching for a safe landing place.
In the cockpit were two devices which could have answered some of these questions. These were a cockpit voice recorder, which keeps a four-hour record of all voice communications, and crew conversations, and a so-called "black-box", a device that keeps a complete record of the speed, compass direction, altitude, engine power, and aircraft attitude. These were not brought out of the Societ Union, and presumably are in Soviet custody.
The voice recorder could answer the crucial question of whether the South Koreans made any effective voice contact plane that suddenly appeared next to them. The copilot has told officials that the crew tried frantically but unsuccessfully to speak by radio with the threatening interceptor.
Commonly, commercial airline radio frequencies are different from military frequencies.
According to FAA officials, there is a standard international signal by which an intercepting aircraft can lead another aircraft to a landing site. However, that signal and its acknowledgement are part of an international convention that has no standing in military communities. Further adding the confusion is the fact that the Soviets are signatories to that convention, but the South Koreans are not.
It is also unknown whether the plane flashed a "May day" signal, an emergency message on radio frequencies shared worldwide.
In an age of jet travel, a complex radar and radio information system has developed around the world to safely direct high-speed craft that can easily cross sensitive national borders indiscernible from 35,000 feet.
To avoid calamity, airliners are required to file flight plans before departure specifying in great detail their experted direction, speed and altitude and when they expect to pass above radar radio stations on the ground. These plans are normally transmitted to all ground control points along the plane's route.
As the plane proceeds, the pilot normaly speaks regularly by radio with ground controllers indentifying his flight, his altitude and when he expects to arrive over the next ground control point. In this way the plane's intended track over the ground is plotted ahead an if it should fail to appear search operations can be launched. As the plane passes from one control point to another, it is "handded off" by successive controllers.