We Dropped the Passenger Masks
January 20, 1988
My FO George P. and I had spent the night in Mexico City. We were ready for the trip home, with a stop in Brownsville for fuel and customs. Upon takeoff from Benito Juarez International on runway 05L it's a long takeoff run at that density altitude. So ... rotate, positive rate, gear up, and we're climbing. But George is tapping at something on the glareshield annunciator panel. He says nothing, the airplane is flying normally, and I don't want to be distracted, so I wave his hand away. Cleaned up and climbing through 10,500 feet (which isn't that far of a climb off of Mexico City), the red cabin altitude warning light comes on. Oops. Forgot to open the air valves and the cabin isn't pressurizing.
Our normal takeoff procedure in the Hawker was for the pilot flying to command "air valves open" upon rotation, and the for the pilot not flying to just open them anyway. I was the PF and George the PNF and I forgot and he didn't. I suppose that was what the tapping was about. Anyway, you can't just pop the air valves open when the cabin pressure is already several thousand feet above the controller-selected cruise altitude pressure. Not too comfortable on human ear drums. So I had George ask ATC for "maintain VFR, altitude our discretion", and when we got that clearance, levelled off at about 12,500 feet in CAVU conditions so we could deal with the cabin altitude controller and gently introduce normal cabin pressure.
The funny part of the story is that while we were dealing with that our lone passenger strolled up to the cockpit doorway, stuck his head inside, and asked one of those "what the hell is going on around here?" type questions. We turned around and saw that the passenger oxygen masks had dropped. Which, of course, they're supposed to do somewhere around that cabin altitude, give or take. We admitted we had goofed, that we were dealing with it, and that it wouldn't be any further problem. Other than all those masks dangling from the overhead. We'd stow them back on the ground at Brownsville. But later, well out of his earshot, we were asking each other: why hadn't he donned a mask when it deployed, like he's supposed to?
Anyway, it was a day everybody screwed up a little bit, no harm done, just red faces, including from lack of oxygen as well as embarrassment? Because I've always wondered: maybe on takeoff from MMX we were slightly hypoxic after a day and a night at 7,500 feet? Maybe all three of us were just a little - err - stupid?
11-29-2022
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