Flight makes u-turn, returns to Seattle after human heart found on board The heart was being shipped from California and was intended to be delivered

FlightAware's flight tracking map shows Southwest Airlines flight 3606 turning around over Idaho and returning to Sea-Tac International Airport. FlightAware's flight tracking map shows Southwest Airlines flight 3606 turning around over Idaho and returning to Sea-Tac International Airport. Photo: FlightAware Screenshot Photo: FlightAware Screenshot Image 1 of / 36 Caption Close Flight makes u-turn, returns to Seattle after human heart found on board 1 / 36 Back to Gallery

They didn't leave their heart in Seattle -- and that's why they had to go back to drop it off.

A Southwest Airlines flight that took off from Sea-Tac International Airport bound for Dallas made a u-turn over Idaho on Sunday when a donor human heart was forgotten on board. It was supposed to be left in Seattle. It had made the journey from Sacramento aboard Southwest flight 3606, The Seattle Times reported Wednesday.

It was a three-hour detour, and after returning to Seattle, the "life-critical cargo shipment" was unloaded from the plane, Southwest spokesman Dan Landson told the Times by email. "Nothing is more important to us than the safety of our customers and the safe delivery of the precious cargo we transport every day."

Passenger Dr. Andrew Gottschalk told the Times that those on board didn't mind the delay because they were "happy to save a life."

However, no Seattle-area hospitals said the heart was meant for them, the Times reported, and LifeCenter Northwest told the Times they only use private flights for organ donors intended for transplants.

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Southwest also did not immediately say what the heart's destination was, USA Today reported Thursday. The organ was shipped on Southwest Cargo.

"We made the decision to return to Seattle as it was absolutely necessary to deliver the shipment to its destination in the Seattle area as quickly as possible," Southwest told USA Today in a statement.

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Though the heart had a three-hour delay from its intended arrival time, Dallas-bound passengers had a longer wait.

USA Today reports the flight had an "unrelated mechanical issue." Because of that, a different plane was brought to Sea-Tac to continue the trip to Dallas.

FlightAware data shows the first flight departing Sea-Tac International Airport at 3:02 p.m. and returning to Sea-Tac at 5:56 p.m. A later flight 3606 departed Sea-Tac at 11 p.m. and arrived in Dallas at 4:22 a.m.

On Dec. 2, flight 3606 departed Sea-Tac at 3:09 p.m. and arrived in Dallas at 8:37 p.m.

Update: The heart was reportedly bound for a valve recovery, which will eventually be donated. No patient has been named yet. Read the full update here.

Producer Natalie Guevara can be contacted at natalie.guevara@seattlepi.com.