Probe is still on into the recent EgyptAir plane crash that killed all 66 on board with all theories, including a terrorist bomb and a severe technical failure, are on the table yet without a strong clue for any. 

EgyptAir Flight MS804, an Airbus A320, went missing from radar screens early Thursday en route from Paris to Cairo with 66 people on board, including 30 Egyptians and 15 French, until the Egyptian military announced Friday the finding of some personal belongings of the victims and small pieces of the plane wreckage in the Mediterranean Sea 290 km north of the coastal city of Alexandria. 

The Egyptian investigation committee and the country's forensic authority are currently examining the found belongings, debris and the small body parts. 

"DNA samples were taken from the families of the victims to be used for identifying the bodies of the victims that were moved to Zeinhom morgue in Cairo over the past two days," the civil aviation ministry said in its latest statement Tuesday. 

TECHNICAL FALIURE 

Aviation experts say that there are four scenarios for the fall or crash of airplanes: a human error, bad climate conditions, a technical failure or a terrorist attack. 

"In the case of the EgyptAir Flight MS804, we rule out the first two possibilities, because the plane crew was highly professional and there were no signs of climate changes that might force to alter the flight course," said Gadel-Karim Nasr, former chairman of Egyptian Airports Company. 

Flying at 37,000 feet high and before vanishing in the Mediterranean, the doomed flight, led by a professional pilot of over 6,000 hours of flying experience including more than 2,000 hours on the same model of Airbus A320, made "sudden swerves" that made jet drop to 15,000 feet according to the Greek defense minister. 

He added that it first made a 90-degree turn to the east after the plane passed over the Greek island of Karpathos then made a full circular 360-degree loop before it disappeared. 

The Greek authorities said Tuesday that they will provide Cairo with all relevant radar data on Wednesday, as the European country was the last airspace where the doomed flight was spotted on its way to Cairo. 

Until this moment, no bulk wreckage of the plane was found to explain what exactly had happened before the crash, yet experts believe if it was a technical failure it must have been a severe and unusual one to force the pilot to make such sudden turns. 

As the pilot did not send a distress message according to official reports, Nasr stressed that the plane must have encountered "a rare malfunction" that made him unable to report, because an ordinary technical failure would give the pilot enough time to send distress signals. 

"Finding the wreckage takes much time and requires cooperation of other countries, because the debris might have fallen in deep water, which requires satellites, remote sensors and other devices to detect," Nasr continued, referring the reason for the crash to either a terror attack or a rare technical failure. 

"Although a rare malfunction is possible, it is still unlikely to happen," the aviation expert told Xinhua. 

He added that when found, the two black boxes could verify the reasons as one box includes data on the plane general conditions and the other contains the records between the plane pilot and the crew members, noting EgyptAir accidents are relatively few compared to other companies. 

A BOMB? 

Most Egyptian officials, topped by President Abdel-Fattah al-Sisi, said that all theories are possible behind the plane crash, yet some experts say a terror activity is the most likely. 

In October 2015, a Russian plane crashed over Egypt's Sinai Peninsula and all 224 people on board were killed, which Moscow said later it was a bomb attack and Cairo did not reject the theory. A Sinai-based terrorist group loyal to the regional Islamic State (IS) claimed responsibility for the plane crash. 

"What do those who brought down the Russian plane want? They want to ruin tourism as well as our relations with Russia," Sisi said in a speech in late February, indicating a terror activity was behind the Russian plane accident. 

The accident then led Russia and some Western countries to ban flights to Egypt over security concerns and caused the Arab country real losses in the tourism industry, one of the main sources of its national income and foreign currency reserves. 

"If a terrorist act was proven in EgyptAir case, France's Charles de Gaulle airport will be responsible as the takeoff airport is responsible for inspecting the passengers and the plane and providing the jet with all necessary services," said the former chief of the Egyptian Airports Company. 

The theory of a terror activity has been supported by Hassan Mosharafa, former chief of EgyptAir operations sector, who argued that "in case of a technical problem there would be enough time for the pilot to report and send distress calls or messages, which didn't happen."

"The plane was flying at 37,000 feet, nearly 12 km, and it needs from three to six minutes to fall, which is enough time to send distress signals or calls," Mosharafa told Xinhua, arguing a bomb or a missile attack are the likeliest possibilities behind the crash. 

"The plane was in service since 2003. Airbus is an airline with a very good reputation and A320 is a relatively new model," he said, arguing the French side reported no doubts regarding the plane maintenance conditions and the plane had already covered much of the distance in stable way. 

The expert said there are three ways to approach the truth: an eyewitness who saw the blast in the sky, a survivor to tell the details and the last hope is finding the two black boxes. 

France's aviation safety agency said earlier that Flight MS804 had transmitted automated messages indicating smoke in the cabin shortly before it plunged into the Mediterranean, yet the French foreign minister said no hypothesis on the cause of the crash had been ruled out. 

SILENCE OF TERROR GROUPS 

Claiming responsibility for their terror operations has been one of the traditions of powerful terrorist groups such as the Islamic State (IS) and Al Qaida, yet the silence of terrorist organizations on the crash this time does not rule out the possibility of a terror attack. 

After the October's Russian plane crash in Sinai, the IS claimed responsibility for the tragedy on the same day through its online media outlets. 

The group also claimed other recent attacks in Brussels, Jakarta and Paris, while its affiliate Sinai State group in Egypt never hesitated to do the same following each of its operations. 

"EgyptAir plane crash was not necessarily done by the IS as there are a large number of terrorist groups in the world that have various foreign targets, including the IS, Al Qaida and other regional organizations," said Diaa Rashwan, head of Cairo-based Al-Ahram Center for Political and Strategic Studies. 

Rashwan, also expert in Islamic groups' affairs, argued that the lack of claim for responsibility does not weaken the terror possibility, "especially that some of these organizations sometimes delay the claim until more suitable circumstances." 

"The clue is not restricted to an announcement of claim by a terrorist group, but it will be found out through the technical issues examined by the experts of the investigation committee," the top researcher told Xinhua. 

SEARCH, INVESTIGATION CONTINUE 

In its second report released Tuesday, the Egyptian Aircraft Accident Investigation Committee said it continues its work in searching and claiming the wreckage of the plane at its crash site at the Mediterranean Sea. 

"The Egyptian navy surveyed the area with the participation of the French navy accompanied by the committee's accidents investigators," the report said, noting the search process is going on in cooperation between Egypt, France and Greece. 

"Eighteen groups of wreckage were sent to the criminal research laboratories in Cairo and the prosecution decision was issued on taking DNA samples as forensic experts were to carry out DNA tests under full supervision of judicial authorities," the committee's report pointed out. 

The committee had said in its first report that it was "far too early" to make any judgments about the cause of the crash. 

President Sisi said in an earlier speech that an oil ministry's submersible that can operate 3,000 meters below sea level is currently being used to help with the search efforts, urging against speculation on the reason for the plane accident.