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 The Pilot's Weight and Balance The Pilot’s Weight and Balance
by Richard A. Hansen, M.D., AME
Last January, a British Airways commuter plane took off from Ronaldsway Airport, with 33 passengers plus crew. The jet was configured with 64 seats, with passengers spaced in the usual fashion for weight and balance calculations. Shortly after takeoff, a hydraulic seal failed at the front left cabin door. This allowed the fluid to escape in the form of a fine mist, depleting the contents of the main hydraulic system. This misting was perceived by the cabin crew as smoke, and they informed the flight crew accordingly. The intensity of the misting in the forward section of the cabin led the cabin crew to reposition the passengers towards the rear of the cabin. As a result, the aircraft’s center of gravity position moved abruptly beyond the operator’s specified aft limit.
An emergency was declared to ATC and the aircraft returned to the airport. During approach, the EGPWS system alerted the crew to an incorrect flap setting for landing. Fortunately the plane landed, though with immediate difficulties encountered in the nosewheel steering system. Passengers deplaned safely, though one person with asthma was treated briefly in a local hospital. Although the captain was informed of the flight crew’s action, the sudden shifting of aircraft CG could have been disastrous, and greatly jeopardized the landing.
In general aviation, weight and balance flight calculations are just as essential. Not long ago, two pilots crashed on takeoff with loss of life, after a sudden nose dive into water associated with a stall. The pilot weighed over 300 pounds, and in the right seat was a prospective buyer of the plane, this man also considerably overweight. The two-seater Globe GC-1 Swift didn’t have enough power, to climb out in the pattern. Trees at the runway’s end provided enough obstacles that a sudden pulling up of the yoke stalled the aircraft. Local flight instructors sadly shook their heads, saying, “it was an accident waiting to happen.”
While most pilots will check passenger weights and calculate fuel not only by gallons but also in pounds, there is often that get-there-itis which shortcuts these essentials. In every POH there are charts and graphs to make these calculations easy. Pilots-in-training early learn to calculate the plane’s CG and make sure it is in the ‘envelope’ for normal or utility flying.
One way to be sure there is enough margin for a two tankfuls of fuel is to keep the pilot’s weight in the well-trimmed category. Physicians use the Body Mass Index (BMI) for the best guide to a healthy weight. Between 19 and 25 is considered normal. From 26 to 30 is overweight, and over 31 (occasionally up to 40+) is termed obesity. You can find such charts on many web sites for your personal calculation. BMI uses the formula: Weight in kg. divided by Height in meters squared. It takes no more and no less self-control to manage the pilot’s weight than to manage your airplane’s weight by adjust passenger seating, amount of fuel, allowed baggage, etc.
Either way, it may make the difference in a safe flight, a quick stall recovery, or a stabilized approach to landing. You may save the nose wheel someday by paying attention to your weight. You may save yourself a heart attack by keeping the weight in the safety zone. Or, you may avoid diabetes, with its threat to your ‘medical certificate’ renewal, by keeping the weight in bounds. Dietary choices and exercise are the keys to a healthy body weight, and often lead to better balance in disembarking your favorite hobby machine. For further information or personal help with the details, please visit our web site today.
 [Doctor Hansen, author of the popular book on home health care, Get Well At Home, is a private pilot and currently serves as medical director of the Emerald Valley Wellness Clinic. Dr. Hansen is an AME and enjoys helping pilots improve their health and keep the medical certification so they can continue to fly! For further information or inquiries, contact: www.emeraldwellness.com.]
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