A US passenger flight was forced to turn around after a human heart was found on board.
The heart was being sent to a tissue processor to recover a valve for use in a future transplant.
But someone forgot to unload it before the Southwest Airlines flight left Seattle for Dallas.
It wasn't until the flight was over Idaho that it was discovered and the captain announced to passengers that they were turning back.
Deanna Santa of Sierra Donor Services in Sacramento, California, said the organ-procurement organisation sent the heart through a courier, who picked it up in Sacramento for shipment to Seattle. The delay did not impair the heart's usefulness and no patient needed it imminently.
Dr Andrew Gottschalk, who was on the flight, said passengers agreed with the decision to turn the plane around.
But, he added in an interview with KOMO-TV, it may not have been necessary.
He said: "At the time everyone was saying to save a life, we're happy to do that. But what I said about a human heart only existing for several hours outside of a recipient, that's not true at all for a heart valve."
The flight took off again for Dallas after a five-hour delay.