Cessna crashed off Latvia – pressure drop possible cause

(dpa)/jse. After the crash of a small plane over the Baltic Sea, many questions remain unanswered. The private plane had flown over the Baltic Sea on its way from Spain to Cologne and crashed into the sea off the coast of Latvia. The Latvian Air Force confirmed the plane’s crash on Twitter on Sunday evening. Previously, all contact with the plane was broken off. According to “Image” information, a pilot, a man, a woman and her daughter were on board.

The newspaper “El País” reported, citing Spanish sources familiar with the incident, from a German family who is said to have heard the machine – an elderly man, his wife, a daughter of the couple and a man their age. According to information from the Austrian news agency APA, the jet was registered in Austria and licensed to a German company.

German and Danish fighter planes sent out to investigate were unable to make contact with the crew of the Cessna. The pilots did not see anyone in the cockpit either, it said.

Pilot unconscious?

It sounds improbable: A Cessna Citation II business jet that took off from Jerez in Spain, a proven machine with around six to eight seats on board and usually steered by one or two pilots, apparently flies over the planned destination of Cologne without a driver.

The crew no longer reacts to radio contacts relatively soon after take-off. The jet crashed far behind its original destination Cologne after a five-hour flight in the Baltic Sea near Latvia. But that’s what happened on Sunday. According to media reports, the pilot reported problems with the pressurized cabin during the flight.

According to initial findings, the pilot may have become unconscious. Aviation safety expert Hans Kjäll told Swedish news agency TT pressure problems could have caused passengers to lose consciousness. This can happen quickly, especially at altitudes where small aircraft are used.

The plane was a Cessna 551. The machine flew over the island of Rügen, entered Swedish airspace, flew south of Gotland and continued its ghost flight towards the Gulf of Riga. Then she fell into the sea. Actually, the plane should have landed at Cologne-Bonn Airport in the early evening.

Since there were only four people on board the Austrian-registered plane, which is owned by a German company from Bergisch-Gladbach, according to a Spanish newspaper, it is likely that one of the four passengers was the pilot himself. Because the Cessna Citation 2 built in 1979 has a so-called single-pilot approval. This means that two pilots are not required to fly, but only one.

For example, entrepreneurs with the right pilot’s license and instrument rating are often happy to steer a Cessna jet from the Citation series themselves. The 72-year-old father, his 68-year-old wife, their 26-year-old daughter and another 27-year-old passenger were probably on board. According to German media reports, it can be assumed that the well-known Cologne entrepreneur had the appropriate pilot licenses and piloted the Cessna jet himself.

Printing problems already after the start

“Bild” reported that the machine reported pressure problems in the cabin after taking off from Jerez in southern Spain. Accordingly, contact with the ground broke off just behind the Iberian Peninsula. In the airspace over France, a squad from the French army took over, before a squad from Neuburg an der Donau and later from Rostock-Laage took off in German airspace.

Something like this has happened several times. Experts therefore immediately suspect a sudden drop in pressure at high altitude. Because this twin-engine jet has a so-called pressurized cabin, which regulates the internal pressure in the cabin. So if the machine flies at an altitude of around ten kilometers, the pressure in the cabin and in the cockpit would only correspond to an altitude of around 2500 meters. This means that the oxygen supply and breathing is possible without an oxygen mask.

If there is a sudden loss of pressure, the pilots only have a few tens of seconds, depending on the altitude, to react and reach for an oxygen mask. If they don’t, they’ll be unconscious in no time. At cruising altitudes from about 3000 meters or above so-called flight level 100, the aircraft is almost always controlled according to instrument flight rules and thus usually by the autopilot and not manually. It flies along the entered course or various programmed so-called waypoints and continues to maintain the set altitude.

The pilot and passengers on board are now probably unconscious and, if the flight altitude is maintained by the autopilot, as in the case of the crashed Citation at 10,900 meters, will probably die from a lack of oxygen. However, the plane flies undeterred until the fuel runs out. If both engines stop, the jet stalls due to lack of lift and spins in a spin until it hits the ground or the sea. This scenario could well have been possible in the Cessna Citation crash, because the machine is likely to have run out of kerosene after almost five hours.

In the assumed case of a rapid drop in pressure, the fact that nobody was apparently to be seen in the cockpit could be due to the fact that the unconscious pilot slumped in his seat and was therefore no longer visible to an escort aircraft. The same applies to the three passengers in the cabin.

Such crashes are not uncommon

Such accidents caused by sudden decompression have already occurred several times: The well-known US professional golfer Payne Stewart crashed on board a business jet. The Learjet 35 with Stewart, three other passengers and two pilots on board was supposed to fly on October 25, 1999 from Orlando in the US state of Florida to Dallas in Texas. Soon after take-off there was a sudden drop in pressure, which the crew probably didn’t react to quickly enough. All on board fell unconscious due to lack of oxygen. The Learjet flew over 2400 kilometers on autopilot for more than four hours and then only crashed in the state of South Dakota due to a lack of kerosene. All six on board died.

In September 2000, a Beech King Air turboprop in Australia could also no longer be reached by radio due to a sudden loss of pressure. On board were the pilot and seven miners. Controlled by autopilot, the machine flew more than 3000 kilometers through Australia for seven hours before it crashed in rough terrain due to a turbine failure due to lack of fuel.

Another pressurized Beech King Air turboprop crashed over the English Channel more than 40 years ago after a sudden depressurization. The machine flew in large circles for three hours before it ran out of fuel. At the time, crews of military aircraft that had taken off had noticed that both pilots were slumped over the control stick in the cockpit. It can be assumed that all persons on board had already died before the crash due to lack of oxygen.