US planes manufacturer Boeing said it cannot resume sale of passenger planes to Iran just yet even if President Barack Obama has already signed a directive allowing the export of civilian aircraft to Iran.

“There are many steps that need to be taken should we decide to sell airplanes to Iran’s airlines,” said a Boeing Middle East spokesperson. “For now we continue to assess the situation.” ?

It is unclear how long the approvals process Boeing requires for the sale of its commercial planes to Iran might take.

The lifting of nuclear sanctions on Iran is expected to unlock billions in frozen assets, which would help address the required funding to overhaul its ageing aircraft fleet.

The Irani government has repeatedly alluded that as soon as the nuclear deal was signed in July that they were in talks with both France’s Airbus and the US’ Boeing for the supply of new aircraft.

Both firms over the past few months had indicated that they cannot start dealing with Iran until the sanctions are officially lifted and until they obtain clearance from their governments to sell aircraft to Iran.

Iran, however, announced an order for 114 Airbus planes the day after the nuclear sanctions were lifted.

Apart from funding, the key issue with Iran’s aircraft demand is delivery. Both Airbus and Boeing have a heavy backlog comprising more than 1,000 aircraft from Middle East airlines alone and it is believed that it could take years prior to Iran receiving its brand new aircraft from either manufacturer.

It has been suggested that Iran could tap the secondary market to meet its immediate aircraft demand, which is estimated to be around 80-90 aircraft annually over the next five years.