This morning's plane crash on the outskirts of Tehran has thrown up more questions than answers, especially over the circumstances surrounding the disaster.

The flight took off from Tehran International Airport at 6.12 a.m. on Wednesday local time and lost contact just two minutes later, according to flight tracker Flightradar24.

Why did the plane crash?

There have been conflicting reasons given for the tragedy, and Ukrainian authorities have signaled that an answer will only be provided after a full investigation has been made.

This comes after Iranian state news initially said the crash was caused by engine difficulties. But Ukrainian authorities have said they are looking at a range of possibilities.

Is it linked to Boeing ongoing technical problems?

The plane is a Boeing 737-800, a predecessor to the company's 737 Max, which has been grounded since March after its involvement in two fatal crashes that killed 346 people.

It could add to the crisis Boeing has been grappling with over the different jet, but there has been no indication yet that this is a manufacturing issue.

What will happen to the black box?

Under international rules, the investigation into an air crash is held by the state of occurrence -- in this case Iran.

Iran’s Civil Aviation Authority head, Ali Abedzadeh, said they will not hand the flight data recorders to Boeing or the United States.

It is unclear whether this is because Iran is leading the investigation, and has the capacity to analyse recorders within its borders, or whether it's over ongoing animosity between the two nations following the killing of top Iranian commander Qasem Soleimani.