The Russian plane that crashed in Egypt was not struck from the outside and the pilot did not make a distress call before it disappeared from the radar, according to a source in the committee analysing the flight recorders.

The comments to Reuters were based on the preliminary examination of the black boxes recovered from the Airbus A321 which crashed in the Sinai peninsula on Saturday, killing all 224 people on board.

There could have been a catastrophic failure such as a fuselage split, or an on-board bomb

Captain Mark Micallef Eynaud, former head of flight operations at Air Malta, told this newspaper the positioning of the wreckage was a clear indication that the plane had split apart in mid-air.

“There are a number of possibilities for why this might have happened. There could have been a catastrophic failure such as a fuselage split, or an on-board bomb, missile strike or an on-board explosion from the systems,” he said. “The other possibility is a mid-air collision, although no other aircraft were reported in the area.”

‘Plane split apart in mid-air’

Meanwhile, Captain Joe Farrugia, head of operations at Medavia, said that in principle, the possibility of either a missile strike or collision with a drone could have led to the disaster.

“The flight data recorder and cockpit voice recorder will be crucial in determining what happened,” he said. “What was said in the cockpit, any noises that can be heard, whether the issue was known to the crew or something immediate – everything could point to the problem.”

An Egyptian militant group affiliated with Islamic State (also known as IS) said on Saturday it had brought down the plane in response to Russian air strikes, but Egyptian and Russian officials have dismissed the claims.

Militants in the area are not believed to have missiles capable of hitting a plane at 30,000 feet.

Alexander Smirnov, deputy general director of airline Kogalymavia, which operated the plane under the brand name Metrojet, said yesterday that only a “technical or physical action” could have led to the crash.

“The plane was in excellent condition,” he said. “We rule out a technical fault and any mistake by the crew.”

The A321 is a medium-haul jet in service since 1994, with more than 1,100 in operation worldwide and a good safety record.

Airbus said the plane was built in 1997, had been operated by Metrojet since 2012 and had flown 56,000 hours in nearly 21,000 flights.

According to the airline, both engines were inspected in Moscow on October 26 and no problems were found. Initial concerns over a previous tail strike were also played down, as the damage had been fully repaired and would not have affected safety.

The aircraft disappeared from radar screens 23 minutes after take-off from Sharm el-Sheikh en route to St Petersburg at an altitude of 31,000 feet (9,400 metres), Egypt’s Civil Aviation ministry said.

Those on board the flight included 214 Russians, at least three Ukrainians and one Belarusian, most returning from the Red Sea, a popular holiday destination.

*Additional reporting by Reuters