While foreign ministers raced to Geneva for a crucial phase of talks over Iran's nuclear activities earlier this month, passengers with the country's national airline faced a little-noticed drama on the other side of the world.
As a 37-year-old Boeing 747 climbed out of Beijing bound for Tehran, the Iranian crew received a cockpit alert that one of the jumbo jet's four Pratt & Whitney engines was on fire.
The Iran Air pilots shut the engine down, activated a fire suppression system and flew back to the Chinese capital.
Both the Nov. 8 incident and the actions taken to remedy it, as reported by accident database Aviation Herald, highlight the juggling act needed to keep Iran's fleet in the air after years of sanctions and challenges in procuring parts.
The relief plane that was dispatched to pick up stranded passengers is not just a jet but a time capsule, symbolizing the 34-year chill in ties between the United States and Iran.
It entered service weeks before the 1979 hostage crisis and is the only original 747-100 jumbo still flying passengers. Its resale value of $60,000 would not pay for fuel for the trip.
For years, aircraft such as these have been kept in service through parts imported on the black market, cannibalised from other planes or reproduced locally, aviation sources say.
Now, following last week's interim deal to ease a decade-long standoff over Iran's nuclear activities, Tehran will be allowed limited purchases of aircraft parts and repairs.
The immediate problem Iran faces is that some of its aircraft are so old that parts may not be readily available. The 747-100 was first launched in 1966 and Boeing hasn't built a new one since 1982.
"The last 747-100 we saw was about 10 years ago," said Mark Gregory, head of Europe's largest aircraft recycling company, UK-based Air Salvage International.
On paper, Iran's need for parts could be a boon for salvage firms and any second-hand stockists who have had unwanted bits of the oldest types used by Iran accumulating dust for years.
"Everybody is lucky if somebody wants to buy because it is a dead market. These parts don't sell like fresh bread from the baker," said Derk-Jan van Heerden, general manager of Netherlands-based Aircraft End-of-Life Solutions (AELS).
Barring a full lifting of sanctions, the volumes involved are not enough to make much difference to the profits of global aerospace firms and parts manufacturers, analysts say.
But the renewal of old business relationships marks