FOR the group of more than 50 Russian schoolchildren, the trip to the Mediterranean coast of Spain promised to be the holiday of a lifetime.
But a series of delays and flight alterations conspired to send them to their deaths in a freak mid-air collision 35,000 feet over Germany.
The children, all under the age of 18 and students at an international school, had missed their original flight connection to Barcelona on Saturday evening and waited in Moscow for an alternative to be arranged.
It was more than 48 hours before a charter jet was laid on and the school party took off bound for a holiday at the Spanish resort of Salou.
The plane, a Tupolev 154, was due to take off from Moscow’s Domodedovo airport at 7:30 pm (BST) on Monday, but there was a further delay - of 18 minutes - before it left the runway.
Less than three hours later the path of the charter jet crossed catastrophically with that of a DHL cargo plane flying from Bergamo in Italy to Brussels.
"If only they had flown on time, nothing would have happened," the mother of one 11-year-old victim said as she prepared to travel to Germany. "If only we had known, if we had only known."
Last night, the cause of the collision appeared to be shifting away from pilot error and towards the actions of Swiss air traffic controllers who had just taken over responsibility for the two aircraft when they collided.
The children on board the Tupolev 154 were all from the Russian republic of Bashkorstotan, in the southern Urals, and members of a United Nations sponsored club in the republic’s capital Ufa.
They were the sons and daughters of the oil-rich republic’s ruling elite and were travelling to Spain for a two-week holiday in a four-star hotel complex.
Din Uzhin, an adult chaperone for the students, was supposed to have gone with them but was among five adult members of the party who were refused a Spanish visa and had to stay behind in Moscow.
"The parents of the children are calling non-stop asking whether I know anything about the fate of their children," he said yesterday.
"And I have to say time and again: Your children were on that plane."
Relatives of those who travelled on the aircraft were yesterday leaving Ufa to travel to southern Germany.
On the ground near Lake Constance, rescue workers had found 26 bodies by yesterday afternoon, many of them still strapped into their seats in broken sections of the Russian plane.
Wolfgang Steiner, a gardener at a children’s home close to where the tail section of the airliner crashed to the ground said: "We came across five bodies just lying in the field next to each other.
"One had his neck broken, one was missing a foot but there was no blood. I kept saying to myself, ‘Why is there no blood?’ They looked so small lying in that field." Large sections of the aircraft fell among houses at Owingen, just north of Ueberlingen on the banks of Lake Constance but no-one was injured.
The British pilot of the Boeing 757 cargo plane was described by his employer DHL as "extremely experienced". Paul Phillips, 47, originally from Liverpool, was killed along with his Canadian co-pilot, Brent Campioni.
Mr Phillips lived with his wife, two daughters and a son in Bahrain, and he had 10,000 hours of flying experience with DHL since joining the company in April 1989.
His aircraft took off from Bahrain at 2:16 pm BST on Monday and arrived at Bergamo in Italy seven hours later.
There was only a short break at Bergamo before leaving at 10:05 pm bound for Brussels, departing less than half an hour before the collision with the Russian jet travelling across his path.
The crash comes less than six months after aviation authorities in Europe relaxed flight rules to allow aircraft to pass closer to each other in the skies.
Eurocontrol, the Brussels-based pan-European air traffic control agency, introduced the rule change, called RVSM, on 24 January this year in an attempt to increase airspace capacity for the busy holiday routes across the continent.
It means that aircraft flying between 29,000 feet and 41,000 feet have to be separated by a vertical distance of only 1,000 feet, instead of the 2,000 feet previously required.
Eurocontrol, and other regional air regulators, are expected to conduct a review of the regulation change, but it is not thought to be to blame for the collision over Germany. Eurocontrol said both aircraft involved in the collision were well within the limits set by the new system.
"Based on the available information, there is currently nothing to indicate that the introduction of RVSM was in any way a factor in this accident", a spokesman for Eurocontrol said.
"Both aircraft complied with technical and operational RVSM requirements.
"The height-keeping performance of both aircraft had been recently verified and shown to be well within limits," the spokesman added.
The collision took place in German airspace but in an area controlled by Skyguide, the Swiss air traffic control body, because it lies on an approach to Zurich airport.
Skyguide took over responsibility for the Noing 757 cargo plane at about 10:23 pm BST and for the Russian plane at about 10:30 pm.
The accident occurred at 10:35 pm - at a time when just one air traffic controller was on duty in Zurich because his colleague was on a break.
The controller, who was described as an experienced member of staff, was being treated for shock yesterday and had not been questioned.
It was Skyguide which offered the first explanation of the accident yesterday, claiming that the Russian pilot was told three times to decrease altitude before he began to go into a dive.
A spokesman for the body initially claimed that the warning had been between 90 seconds and two minutes before the collision.
"It was cutting it close but absolutely acceptable", the spokesman said.
But Skyguide later admitted that the Russian pilot was warned to decrease altitude only 50 seconds before the collision and that he had responded on the second warning, with only 25 seconds to spare.
By that stage, an automatic proximity alarm had sounded on board the DHL Boeing 757, sending Mr Phillips into an identical dive.
The head of the Bashkirian Airlines, which owns the charter jet involved in the collision, dismissed suggestions that it was the Russian pilot who was at fault, and he raised questions over Europe’s fragmented system of air traffic control.
"My version is that the [air] traffic controllers are to blame," Nikolai Odegov, the Bashkirian Airlines general director, said at Domodedovo airport.
He stressed that the pilots on board the Russian aircraft were experienced at international flight and that they spoke English well.
The chief pilot, Alexander Gross, 52, had amassed 12,000 flying hours and navigator Sergei Kharlov, 50, had 13,000 hours. Both had flown on Unesco humanitarian aid flights to Brazil and Pakistan.
Sergei Rudakov, the head of Moscow’s Domodedovo airport, said: "All the sources of the accident are to be found in the skies over Europe. I am 100 per cent certain of this."