Technical problems — not missiles — may have downed Ukrainian airliner in Iran, say some intel experts

All 176 people on board died.

The Ukrainian airliner that went down just after liftoff in Tehran, killing all 176 people aboard, probably suffered a technical malfunction and was not brought down by a missile — that's what various Western intelligence sources are now saying.

The Ukraine International Airlines Boeing 737-800 dropped from about 8,000 feet to earth in a fireball shortly after take-off from Tehran.

No investigation has been conducted yet, though — and Iran will not give the black box of the crashed Ukrainian airliner to planemaker Boeing, the head of Tehran's civil aviation organization was quoted as saying on Wednesday.

Ali Abedzadeh also said it was not clear which country Iran would send the box to so that its data could be analyzed, semi-official Mehr news agency reported.

Many questions remain.

From Reuters:

The Ukraine International Airlines Boeing 737-800, en route to Kiev and carrying mostly Iranians and Iranian-Canadians, crashed hours after Iran fired missiles at bases housing U.S. forces in Iraq, leading some to speculate that the plane may have been hit.

But five security sources – three Americans, one European and one Canadian – who asked not to be named, told Reuters the initial assessment of Western intelligence agencies was that the plane had suffered a technical malfunction and had not been brought down by a missile. There was evidence one of the jet's engines had overheated, the Canadian source said.

"We are in contact with our airline customers and stand by them in this difficult time. We are ready to assist in any way needed," Boeing said in a statement earlier Wednesday, declining further comment. Its shares fell 1.1% today.

The plane that crashed was a three-year-old Boeing 737-800NG.

It had just received scheduled maintenance on January 6, according to Ukraine International Airlines.

More: Technical problems behind deadly crash of Boeing jet in Iran: security sources

Various observations below. Again, no official known cause at this time — everyone is speculating, some are better at it than others.

PHOTO by LLBG Spotter, Ukraine International Airlines B738, UR-PSR, TLV. CC BY-SA 2.0