September 2009 Issue

Failure To Climb

Flying an airplane loaded to or over its max gross weight can pose special challenges.

Almost 20 years ago, I rode coach from JFK to Osaka, Japan on a Northwest Airlines 747-400. Taking my time in deplaning, I managed to sneak a peek at its cockpit and chat briefly with the crew. I was astonished to learn the airplane weighed nearly 900,000 lbs at takeoff, close to or at its maximum gross, and burned almost half that weight in fuel before landing. I can presume the airplane’s handling characteristics at takeoff versus landing. While transport pilots routinely operate at maximum weight, the rest of us rarely do. So, on our first gross-weight takeoff in, say, 10 years, the airplane’s desire to roll farther and climb more slowly than we’re accustomed can be an eye-opener. I’ve written previously in these pages about how my airplane’s FAA-approved maximum gross weight is 250 pounds heavier than its manufacturer intended, thanks to wingtip fuel tanks installed pursuant to a supplemental type certificate (STC). That STC comes with various paperwork, but does not include revised performance charts showing expected takeoff or climb performance. From experience, I know a climb at the higher gross weight requires patience.

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