Aseman Airlines’ flight EP3704, the daily departure from Tehran, took off as normal shortly after 8am to fly to Yasouj, 344 miles south. The aircraft involved, an ATR72, was 24 years old – which made it a relatively young part of the airline’s fleet. The average age is more than a quarter of a century, making it one of the oldest fleets in the world.

There is nothing inherently unsafe about old aircraft. Right now British Airways and Virgin Atlantic are flying Boeing 747s which are over 20 years old; a BA Jumbo jet is en route today to Delhi at the venerable age of 27. But these aircraft are meticulously maintained by well-resourced airlines.

It is far too early to know what caused the loss of EP3704, but the calamity draws attention to aviation in a country starved of the equipment and expertise which makes flying in the West so safe.

Two years ago, when sanctions against Tehran were eased, Iran’s airlines ordered hundreds of new planes. Aseman Airlines, whose aircraft was lost today, has 30 Boeing 737MAX jets on order. But until the planes arrive – possibly never, if President Trump decides to ban their export – the airlines’ engineers are having to make do with cannibalising grounded aircraft for parts.

Production of the Boeing 727 ended in 1984, over a third of a century ago. The three-engined jet is still flying scheduled passengers services in only one country: Iran. And the carrier: Aseman Airlines.