The recent visit to Tivat of a delegation from the Pardubice Region of the Czech Republic, led by the Governor Martin Netolicki, besides opening up space for further cooperation between that city and the most economically developed Czech region in various areas, it also had a sad aspect.
Namely, the delegation from the Czech Republic and their hosts from Tivat, during their tour of Tivat Airport, recalled the only major aviation accident that has occurred at the local airport in the almost 70 years of Tivat Airport's history - the tragedy of Inex Adria Aviopromet Flight 450, which occurred exactly half a century ago.
On October 30, 1975, a McDonnell-Douglas DC9-32 aircraft of the Slovenian company Inex Adria took off from Tivat Airport towards Prague on a charter flight with Czechoslovak tourists returning home after a stay on the Adriatic. While approaching to land at Prague Airport, the aircraft crashed, killing 79 of the 120 people on board.
In the mid-1970s, the then Socialist Federal Republic of Yugoslavia, which was ruled by a fairly liberal communist regime by Eastern European standards, was for the inhabitants of the Czechoslovakian Republic, but also for the inhabitants of other socialist states on the Soviet side of the “Iron Curtain”, a real window to the much-desired West. Czechs and Slovaks – at least those among them lucky enough to receive permission from the local authorities and political police to travel abroad – looked with longing to the Yugoslav Adriatic.
They enjoyed the rare opportunities that presented themselves with the frequency of winning the lottery, to spend a few days in one of the, in their terms, ultra-luxury hotels on the Yugoslav coast, and to swim in the Adriatic, even if it was in October when the sea water was already too cold for the hosts.
Experienced crew
Such was the case with a group of 115 Czechoslovak tourists who, after a stay on the Montenegrin coast, boarded an Inex Adria DC9-32, registration YU-AJO, at Tivat airport on October 30, 1975. The modern American-made aircraft, only four years old, was an attraction in itself for Czechoslovak tourists, because they were used to traveling by train, bus, and only occasionally, the outdated, uncomfortable, and noisy Soviet “Tupolevs” that then made up the fleet of the Czechoslovak national airline, ČSA.
Unlike that and other airlines from Eastern Europe, Yugoslav airlines were already flying almost exclusively on much more modern, safer and more comfortable aircraft from Western manufacturers: McDonnell-Douglas, Boeing, SUD Aviation or Lockheed.
At the helm of the "nine" that shone in the jagged morning sun on that clear autumn day in Tivat was an experienced captain. Miodrag Marovic (40) who already had over 5.000 hours of flight time. In the right seat in the cockpit of the aircraft YU-AJO was the copilot, the first officer Jovan Popov, who had about 6.500 flight hours. In addition to them, the crew of Flight 450 also consisted of three cabin crew members - one purser and two flight attendants. In total, there were 120 people on board the Inex Adria DC9 that morning when the plane took off at 7:55 a.m. above Tivat.
The takeoff and climb to cruising altitude were successful: the Czechoslovak tourists watched the Adriatic Sea disappearing somewhere in the depths for the last time through the plane windows, the Yugoslav mountains slowly shrinking and receding, and the dream vacation began to turn into memories. In Yugoslavia at that moment, it was clear, the surrounding slopes were illuminated by the sun's rays. In Prague, however, the situation was completely different. The weather there was gloomy and damp - a typical October. However, here too the sun was starting to break through the clouds. The differences between day and night temperatures were great, which in the morning hours led to the creation of an almost continuous mass of fog, which during the day, as the temperature rose, relatively quickly retreated towards watercourses, primarily towards the Vltava River, which passes near Prague's Ružinje Airport, where the Yugoslav plane with the Czechoslovak tourists was expected.
YU-AJO enters the airspace of the Czechoslovak Socialist Republic after 65 minutes of flight, at exactly 9 a.m. It is then at a flight altitude of 22.000 feet, which corresponds to approximately 6.700 meters. The air traffic controller in Prague establishes contact with the Inex Adria crew and approves its descent to an altitude of 10.000 feet, or slightly more than 3.000 meters.
What followed was something the pilots of the Yugoslav plane did not want to hear, especially in challenging weather conditions of reduced visibility that required the plane to land at Prague airport according to the principles of instrument, not visual, flight. At exactly 9:02:40, the pilots received the necessary information in their headsets about temporary problems at Ružinje airport. The air traffic controller informed them: “I repeat, runway 31 in Prague is closed, and neither ILS nor PAR are working on runway 25.”
ILS is an instrument landing system, and PAR is a precision approach radar — both of these systems are extremely important in the final stages of an aircraft's landing in instrument flight conditions.
The confused Inex Adria crew asks for advice on what to do in such unfavorable conditions, to which the controller replies that they have the option of diverting to another airport, only to inform them a little later that conditions are partially improving and that visibility on runway 25 of Ružinje Airport, where they originally planned to land, is 1.100 meters.
After another thirty seconds, new information arrives from Ružinje:
“Runway 25, approach lights and NDB are OK.”
Panicked calls from Czech controllers
NDBs are non-directional radio beacons that can make the situation easier for pilots during the landing maneuver itself. This is the moment when the hesitant crew of the Yugoslav plane finally decides to stick to the original plan and try to land at Ružinja. Beneš's plane reports the radio beacon flight to air traffic control at 9:09, and at that moment the crew receives permission to descend to a flight altitude of 6.000 feet, or about 1.800 meters.
The controller requested and received confirmation from the crew that they had also flown over two other beacons, after which he approved a descent to an altitude of 550 meters and an immediate approach to landing. This, however, was the last communication confirmed by the Yugoslav flight crew. After that, Flight 450 Inex Adria no longer responded to the increasingly panicked calls of the Czech controllers, who assumed with horror that something terrible had happened in the meantime, because at 9:20 a.m. the Yugoslav DC9 disappeared from their radar, about 8,5 kilometers northeast of the airport where it was supposed to land.
Meanwhile, as a later investigation showed, the Inex Adria plane had strayed, meaning its pilots had lost a reliable sense of where they were on the approach to Prague airport. The plane had completed a prescribed right turn that was supposed to take it to runway 24, but the crew made a mistake because the turn was wider than it should have been, which put the plane outside the prescribed landing path, about 0,7 miles south of where it should have been.
In conditions of reduced visibility, the plane, whose landing gear was already lowered because it was expected to land at the airport soon, went into the Vltava River gorge in a way that the crew did not immediately notice. When they could finally see the hills and rocks directly ahead through the wisps of fog, the pilots tried to save the plane by giving the engines maximum power and climbing urgently. However, it was too late: the fuselage of the plane managed to fly over the cliffs of the Sedlec Rocks, or Suhodol as this locality is called where there was a small weekend village. One of the legs of the landing gear, however, caught trees on the ground and a nearby small weekend house. This threw the plane off balance and the DC9 tore the ground with its left wing and crashed. The fuselage bounced off the ground several more times, but with each impact it broke into pieces. Each part went in a different direction and slid along the ground, destroying everything in its path. Some parts of the wreckage left a 350-meter-long furrow in the ground. The torn-off airplane engines moved with the most destructive power. The largest part of the body slid all the way to the vicinity of the large family house, which still stands today on the edge of the Sedlečki stijene. The burning wreckage stops only nine and a half meters from the house in which several residents were at the time. More than five tons of kerosene remained in the tanks of the DC-9, which spilled on the ground and fueled the fires. The characteristic smell of jet fuel was still felt at the accident site 14 days after the accident. The plane flattened ten cottages and damaged another five houses at the crash site. Fortunately, there were no people in those buildings, except for one woman who miraculously survived with serious injuries.
Of the people on board, 75 died on the spot, while four later succumbed to their injuries in hospital. The response of the Czech rescuers was exceptional and within 35 minutes of the plane crash, all the injured were evacuated from the scene of the accident and given medical care. Among them was the only surviving member of the Yugoslav crew - a stewardess Tatjana Rijavec.
The plane deviated from the route.
Czechoslovak investigators sealed off the apocalyptic-looking crash site and began searching the wreckage and the rubble of houses for the Yugoslav DC9's black boxes and other clues that might help them determine the cause of the crash. Later analysis of the cockpit voice recorder was of no use, as it turned out that the CVR, due to the shortness of the tape it contained, had stopped recording cockpit events 15 minutes before the crash, while the flight was still in a completely normal phase and under normal circumstances.
Data from the instrument data recorder showed that the plane had deviated slightly from the route it was supposed to follow, but also that the crew descended significantly lower than the minimum flight altitude of 550 meters that air traffic control had set for it on the approach to the airport. Namely, the plane hit the ground in the Vltava Gorge at an altitude that was as much as 91 meters lower than the altitude at which the Ružinje airport itself is located, i.e. it descended as much as 600 meters higher than the minimum permitted flight altitude at that moment. Precisely because of the lack of cockpit voice recording in the last 15 minutes of the flight, it has never been determined with certainty how and why the Inex Adria pilots allowed the plane to descend so low, which, along with other contributing factors (fog and poor visibility and the malfunctioning ILS and PAR systems at Prague airport), was the main cause of the accident.
After thirteen months of investigation, the final report of the Czechoslovak investigation commission was published. However, it also did not provide a clear explanation. The final conclusion was: “The aircraft crew did not respect the established altitude profile of the flight in the middle part of the approach. The cause of the non-observance of this trajectory could not be determined.”
At that time, most aircraft in Europe did not yet have the so-called Ground Proximity Warning System (an automatic system that warns pilots that there is an imminent danger of the aircraft hitting the surrounding terrain or other obstacles on the ground). After a series of aviation accidents in the late 1960s and early 1970s in which aircraft, due to the spatial disorientation of the crew, hit the terrain in controlled flight and crashed, the US Federal Aviation Administration (FAA) ordered all manufacturers of large passenger aircraft to regularly equip them with the GPWS system. However, the International Civil Aviation Organization (ICAO) only recommended the installation of GPWS in all commercial aircraft in 1979. Inex Adria's "nine" YU-AJO, produced four years before this system became mandatory in the USA, and which crashed in Prague half a century ago, did not have such a system that, if it had existed in that aircraft, would almost certainly have prevented this accident, which to this day remains the worst aviation accident on the territory of the Czech Republic.
Vladimir sensed disaster
Among the passengers returning from a vacation in Yugoslavia on an Inex Adria plane on October 30, 1975, was an aviation technician at Ružinje Airport, Vladimír Vedlih, with his wife.
His wife said during the hearing after the disaster:
"Vlado was very restless during the landing approach, he kept looking out the windows. I could see that something was wrong, but he didn't say anything. Suddenly he unbuckled his seat belt and ran to the cockpit, he wanted to warn the pilots. He didn't make it."
Vladimír Vedlih died on the slope of Suchdol, his wife survived.
Bonus video:
