T O K Y O, Sept 29 - Aviation experts discount the theory that
 zero visibility in dense smog could have caused the crash of an
 Indonesian Garuda airliner, but they have not ruled out another
 theory: engine failure caused by smog intake.
      The Garuda aircraft, an Airbus A300-B4, crashed into a hillside
 plantation 45 km from the west Indonesian city of Medan last Friday,
 killing all 234 people aboard.
     The flight from Jakarta flew most of its way through a dense
 smog that has blanketed much of Indonesia and Malaysia in recent
 weeks due to forest and brush fires.
                     Smog's Role Unclear
     Many experts and pilots said it was unlikely that a loss of
 visibility could have caused the accident, because pilots are
 trained to fly "blind" on instruments and modern airliners are
 well-equipped for instrument flying.
     But Japanese aviation experts say smog could have affected the
 airplane in a different manner.
     "It is a well-known fact that jet and turboprop engines can fail
 when they fly through volcanic smoke," said Yasutomo Aoki, an avia-
 tion commentator and former editor of the magazine Aviation Journal.
      "We must study the effect of engines flying through smog,
 especially on long flights. We are focusing on the residue of
 particles of smog on the engine blades," Aoki told Reuters.
      Another expert, former Tokai University aeronautics professor
 Haruro Terao, said he, too, could not rule out the effects of smog
 on the airplane itself, rather than on the pilot.
     "The massive smoke could have affected the atmosphere and it is
 not impossible that this had some effect on the airplane," Terao
 wrote in the daily Asahi Shimbun.
      Aoki said sand-like grains of volcanic debris in the air have
 been known to cause engine failure.
      The particles block small coolant holes on the surface of
 engine blades, which causes overheating. Blades can break off after
 heat expansion and these bits can damage the engine's interior.
      But one Singapore-based airline pilot with 20 years of exper-
 ience, who declined to be identified, said smoke particles from
 forest fires are too small to pose any problem to the engines and
 wings of modern airplanes.
      Volcanic ash is the worst kind and if planes can survive that,
 the smoke is no big deal, he said.
                Particles Shown to be Dangerous
     In 1991, an expert told an international conference on the dan-
 gers of flying through volcanic clouds that many planes have risked
 disaster by doing so against the expressed advice of airplane
 manufacturers.
      Captain Ernest Campbell, then the manager of airline support
 and flight training at Boeing Co, said his company replaced 10
 engines on different planes that flew through ash from the plume
 of Mount Pinatubo in the previous year.
      "This kind of trouble has also been seen among warplanes during
 the 1991 Gulf War (from the sand in the air)," Aoki said.
      While the smog that has descended on Indonesia and Malaysia is
 different from volcanic smoke, no one has carefully analysed the
 minute particles in the fumes and their possible effects on airplane
 engines, Aoki said.
      "This is the first crash of an airplane that flew for a long
 time through this dense fog. We are awaiting word about this possible
 factor after investigators study the engine blades and black boxes
 from the wreckage," he said.
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           Russian air traffic controllers abort strike
     MOSCOW - September 29, 1997 06:39 a.m. EDT - Less than an hour
 after going on strike Monday, Russian air traffic controllers called
 off their strike when state aviation officials promised to pay up to
 six months of back wages, trade unionists said.
     "The strike has been called off. The head of the Federal Aviation
 Service signed an agreement with the head of the union, meeting all
 our demands," union official Viktor Budich said.
      A copy of the agreement, provided to Reuters, said the aviation
 service promised to pay all overdue wages, scrap a plan to cut the
 controllers' vacations and index pay to the government-set minimum
 wage.
      Controllers complained that pay in some regions had not risen in
 line with the latest increase in the minimum wage.
      The strike involved controllers in 56 cities, including one of
 Moscow's four airports, Domodedovo, as well as the capital's air
 traffic control centre, Budich said, adding that it froze traffic in
 the regions for at least an hour.
      Aviation officials played down the impact of the strike, saying
 controllers did handle aircraft already in the air. A duty officer
 at Domodedovo said that no flights had been delayed, and that the
 strike had not actually started before it was called off.
      The unions have announced many strikes in the past that never
 took place.
     Union officials accused the aviation service of hiring non-union
 labour and not telling airlines about the planned strike, leaving
 some planes in the air as the strike was due to start.
     The union said the strike had no political aims.
--- DB 1.39/004487
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