Aircraft Don't Have More Useful Load, So We'll Have to Count Differently

In the wake of the US Air Express Beech 1900D crash, and due to earlier studies, the FAA has revised its definition of the "average" passenger. Whereas we used to weigh 180 pounds in the summer and 185 in the winter, and check 25-pound bags, Now we weigh 190 all year 'round, and our checked bags weigh 30 pounds. (Carry-on bags weigh 20.) Kids, who used to weigh 80 pounds, still do.

That's the jist of new regulations, effective for a year, that the FAA has released this week. The effect of these regs (N8300-112) will be to lower the takeoff weight of airliners -- or possibly to bring back the passenger scales that went out of style in the 1960s.

There's a survey going on, and the FAA's being tactful.

The FAA is conducting a survey to determine just how close these new numbers are, to reality. Unfortunately, they're not using actual weights -- airlines are going to ask passengers how much they weigh. Fortunately, the FAA says that the reported weights are to have 10 pounds added -- "to accommodate for the passenger’s personal items." And, presumably, passenger optimism.

The results of a just-completed survey confirmed that teh FAA's new regs are headed in the right direction: "On March 12, 2003, operators affected by N 8400.40 reported the results of their surveys.  After reviewing the data collected from each survey, the following deficiencies were noted. When compared to the current guidance contained in AC 120-27C, survey passenger weights indicated an average weight increase of +20.63 pounds, carry-on bags indicated an average weight increase of +5.72 pounds, and domestic checked bags indicated an average weight increase of +3.81 pounds."

We have been getting heavier. That's a problem. Aircraft are still certified using real weights; but peoples' weights have been estimated. Since actual average weight has been increasing (in every study, the American adult has been growing), the effect is that we're getting closer to overloading our airliners. (In the case of the 1900, there is high-level, public speculation that the full airplane, in addition to other possible problems, was overweight.)

If a miscalculation on a 21-seater can be a deciding factor in controllability, it surely can't be overlooked in a 400-seat airplane, especially one in which the cargo hold is also filled to capacity. (At least in the downstairs, the items have been properly weighed.) The addition of ten pounds per pasenger becomes a two-ton problem at the end of the runway; and the CG implications are chilling, as well. The FAA's step, while it effectively may lower useful load, may also prevent a "legally-loaded" aircraft from being over gross. The laws of Physics are not subject to legislation...

FMI: www.faa.gov/avr/afs/notices/N8300-112.htm