TEHRAN — Other than Iran’s energy, auto, finance and tourism sectors, the country’s aviation industry — one of the hardest hit by Western sanctions — is seen as a major beneficiary of the July 14 nuclear deal with six world powers.

Decades-long restrictions on Iranian imports of Western-made planes and spare parts have left the Islamic Republic with an aging fleet. With an average age of 23 years, Iranian passenger aircraft are nearly twice as old as the international average. This has had a grave impact on flight safety. According to the International Flight Safety Foundation, 1,672 people have lost their lives in airplane-related disasters in Iran since the country’s 1979 revolution. The most recent crash, in August 2014, claimed 39 lives.

Given the current state of Iranian aviation, it is hard to imagine that four decades ago, Iran Air — the flag carrier — was ranked as the world’s second safest for having been accident-free for at least 10 consecutive years. Strikingly, Iran Air was also the region’s leading airline, and by the late 1970s, the fastest-growing carrier in the world.

To keep its fleet operational, Iran launched the Iran Aircraft Manufacturing Industrial Company (HESA) in 1997. However, major maintenance problems still exist. Of the 250 planes reportedly in the Iranian fleet, a whopping 110 are grounded due to an urgent need of repair and spare parts.