Are Airliners Too Heavy?
Next time you fly, take note of the other passengers in the boarding area. How many do you think weigh 170 lbs?
Now I am in pretty good shape. I am about 6 feet tall and weigh 190 pounds. If you run the BMI (Body Mass Indicator) calculator, you will see the government thinks I am overweight, not obese but overweight. Good grief, they think I need to lose another 30 plus pounds.
So why am I bringing my weight in an airliner story?
Safety. There are four forces at work when an airplane flies. Thrust versus drag. Gravity versus lift. When all four are in balance, the plane flies. When they are not, trouble.
When the plane is roaring down the runway, it is trying to generate huge amounts of lift to overcome gravity and leap into the air like a big tin bird. Nice. Lift is generated on top of the wing. Sorry folk, the song about lifting under the wing is wrong. The difference of the distance air has to flow over the top of the wing compared to the flow under the wing creates lift. The captain will put some flaps down, and in some cases some slats on the front of the wing, so all of that air has to go a longer distance over the top than the bottom to generate more lift. When the flaps and slats are down, we say the plane is dirty. When the flaps and slats are up, the plane is clean. The plane needs to be dirty to generate lots of lift for takeoff and for landing.
Now consider thrust and drag. In order to generate all of that lift in the dirty condition, you need lots of power. That is why everything is rattling like it does. The throttles are pushed way up there. But what happens, God forbid, if one of those powerful engines quits?
When an engine quits, pilots say they have lost an engine. No, that does not mean they cannpt find it, it means that the damn thing stopped running. It only takes a millisecond to make that discovery. The engine still running will turn the plane to the direction of the engine that quit. The pilot will have to stomp on the rudder, that big tall part of the tail, so the rudder will bring the nose back to normal. One foot is clear to the floor. That is the good or working engine. One foot will be on vacation. That is the bad or dead engine. In pilot lingo, dead foot dead engine.
There are some critical speeds along the takeoff path that help the pilot decide what to do next. Those speeds are called V speeds. The critical decision speed is V1. When the plane reaches that speed, the pilot is going to put the plane in the air, lost engine or not. Before V1, the pilot will stop on the runway.
Everything should work fine if the plane is in the envelope. The envelope is a set of engineering standards provided by the airplane manufacturer which will tell the pilot what the plane is capable of doing when it has to fly on one engines. Part of those calculations are based on a load of passengers who all weigh 170 pounds each.
170 pounds each? When was the last time you weighed 170 pounds? When was the last time any American adult weighed 170 pounds?
Take another look around at the boarding area. Do you think if you took all of those folks; added up their weights; and divided the total by the total number of seats on the plane that the figure would be 170 pounds? Would it be 10 pounds more? 20?
On a 250 seat plane, 10 pounds more would be an additional 2500 pounds. At 20 pounds, that would be an additional 5,000 pounds. That’s almost two tons of additional weight that remaining running engine must overcome to get that plane to fly.
That’s the dirty little secret. As airlines put more pressure on the aircraft manufacturers to extend the fuselage to add additional seats, the problem becomes bigger.
The good news is pilots are drilled in the simulator on how to fly those planes on one working engine and well, a Boeing is a Boeing. The bad news is, the simulator conditions, based on the flight manual numbers, are understated and wrong.
Just be thankful our planes and their engines are so very well built and reliable and the pilots flying them are so very well trained and if you are over 170 pounds, just pass on the extra peanuts.
Kenny Miller has been in the creative business for over 30 years. He has created two advertising agencies and is the author of two books: an aviation thriller, The Last Flight of Kilo Mike; and a touching short story collection, A Visit to Hartington. Kenny is also a highly experienced professional pilot; a published photographer; and a top-notch storm chaser. If it interests him, Kenny does it You should, too! His site is http://www.nebraskawriter.com
Tags: airline accidents, airline safety, airlines, airplane crashes, airplane safety, airplanes
