Zibo 737 - Checklist

“The checklist assumes uniform cooling,” Lena replied. “But the center tank sits above the air cycle machine. Ground power plus no fuel recirc means it’s actually colder. Zibo modeled that. The checklist didn’t.”

Below, the fog erased Cincinnati. Above, the 737 hummed north, its fuel warm, its checklist now bearing a tiny handwritten note in Lena’s script: Check center tank separately when OAT below -10°C. zibo 737 checklist

But Lena had flown the Zibo mod for 800 hours. Its quirks were predictable—unless something deeper was wrong. She ignored the checklist and toggled the fuel temp selector to the left main tank. +2°C. Right tank? +2°C. Center tank? -9°C. “The checklist assumes uniform cooling,” Lena replied

“The center’s nearly gelling,” she said. “If we take off, boost pumps could cavitate.” “The checklist assumes uniform cooling