The EgyptAir flight that crashed last week showed no technical problems before taking off from Paris according to an aircraft technical log signed by its pilot before takeoff, Egypt’s state-owned newspaper al-Ahram has said.

Al-Ahram published on Tuesday a scan of the log on its website. The paper said EgyptAir flight MS804 transmitted 11 electronic messages starting at 21.09 GMT on 18 May, about three and a half hours before disappearing from radar screens with 66 passengers and crew on board.

The first two messages indicated the engines were functional. The third message came at 00.26 GMT on 19 May and showed a rise in the temperature of the co-pilot’s window. The plane kept transmitting messages for the next three minutes before vanishing, al-Ahram said.

Earlier on Tuesday, the head of Egypt’s forensics authority dismissed as premature a suggestion that the small size of the body parts retrieved since the Airbus 320 jet crashed indicated there had been an explosion on board.

Investigators struggling to work out what happened are looking for clues in the human remains and debris recovered from the Mediterranean Sea.

The plane and its black box recorders, which could explain what brought down the flight Paris-to-Cairo flight as it entered Egyptian air space, have not been located.

An Egyptian forensics official said 23 bags of body parts had been collected, the largest no bigger than the palm of a hand. Speaking on condition of anonymity, the official said their size pointed to an explosion, although no trace of explosives had been detected.

But Hisham Abdelhamid, head of Egypt’s forensics authority, said this assessment was “mere assumption” and that it was too early to draw conclusions.

At least two other sources with direct knowledge of the investigation said it would be premature to say what caused the plane to plunge into the sea.

“All we know is it disappeared suddenly without making a distress call,” one of them said, adding that only by analysing the black boxes or a large amount of debris could authorities begin to form a clearer picture.

The investigators do have a few scraps of data in the form of fault messages sent by the plane in the last minutes of flight, logging smoke alarms in the forward lavatory and an electronics bay just underneath, but they are tantalisingly incomplete.

“The difficulty is to connect these bits of information,” said John Cox, executive of Washington-based Safety Operating Systems, who co-authored a report on smoke and fire risks by Britain’s Royal Aeronautical Society.

There are too few messages to fit a typical fire, which would normally trigger a cascade of error reports as multiple systems fail, he said, and too many of them to tie in neatly with a single significant explosion.

Investigators will need to understand why, for example, there was no message indicating the autopilot had cut off, progressively handing control back to the pilots as systems failed and computers became unsure what to do.

The Frenchman, who headed a three-year inquiry into the 2009 loss of an Air France flight in the Atlantic, said the published data appeared insufficient for any conclusion.

Egypt has deployed a robot submarine and France has sent a search ship to help hunt for the black boxes, but it is not clear whether either of them can detect signals emitted by the flight recorders, lying in waters possibly 10,000ft (3,000 metres) deep. The signal emitters have a battery life of 30 days.

Although government officials have acknowledged the need for international assistance, the US Navy said Egypt had not formally requested US support beyond a P-3 Orion surveillance aircraft, which was deployed on Thursday.

Eighteen loads of debris have been recovered in a search operation assisted by French and Greek aircraft, the Egyptian investigation committee said.

The plane had just crossed from Greek into Egyptian airspace when it vanished off radar screens but, five days after the crash, air traffic controllers from the two countries were still giving different accounts of its final moments.

In Greece, two officials stood by earlier statements that Greek radar had picked up sharp swings in its trajectory – 90 degrees left, then 360 degrees right – as it plunged from a cruising altitude to 15,000ft before vanishing.

But Ehab Mohieldin Azmi, head of Egypt’s air navigation services, said Egyptian officials had seen no sign of the plane making sharp turns and that it had been visible at 37,000 feet until it disappeared. “Of course, we tried to call it more than once and it did not respond,” he said.

Relatives of the victims were giving DNA samples at a hotel near Cairo airport on Tuesday to help identify the body parts.

Amjad Haqi, an Iraqi man whose mother Najla was flying back from medical treatment in France, said the families were being kept in the dark and had not been formally told that any body parts had been recovered.

“All they are concerned about is to find the black box and the debris of the plane,” he said. “That’s their problem, not mine. And then they come and talk to us about insurance and compensation. I don’t care about compensation, all I care about is to find my mother and bury her.”