Early morning at the gate, powering up the jet from cold. Flow-scan the overhead panel, as you have done so many times before. Up and down, left to right. All the switches are in their usual positions. Last is the air panel — six switches and two rotary selectors. A quick glance shows they are good. You call for the checklist. The first officer’s first challenge is “Pressurization?” Your eyes go to the landing altitude rotary selector on the air panel. “Set,” you reply.
It is still dark after takeoff. Climbing through 3,000 ft, the first officer, the flying pilot, calls, “Flaps up, ‘After Takeoff’ checklist.” You run your hands around the overhead panel, turning off the ignition and auxiliary power. Pressurization check: A peek at the differential gauge shows that it is off the lower peg. Just then the controller instructs you to contact departure. After acknowledging, you pick up the checklist. “Pressurization?” Remembering your earlier glance at the gauge, yo…
