Free Cockpit Confidential by Patrick Smith Page B

ATC and must also maintain visual contact with one another.
    As for seeing people through the windows, this is classic PEF and something that I hear all the time. Even when an airplane is parked at the gate, a few feet away and stationary, it can be difficult to see anyone inside. Aloft, you have never been remotely close enough to another plane to see its occupants, trust me.
    People have a habit of embellishing even the basic sensations of flight. They can’t always help it—nervous flyers especially—but the altitudes, speeds, and angles are perceived to be far more severe than they really are. During turbulence, people sense that an airplane is dropping hundreds of feet at a time, when in reality the displacement is seldom more than ten or twenty feet—barely a twitch on the altimeter ( see turbulence ). It’s similar with angles of bank and climb. A typical turn is made at around 15 degrees, and a steep one might be 25. The sharpest climb is about 20 degrees nose-up, and even a rapid descent is no more severe than 5 or 6 degrees nose-down.
    I can see your letters: you will tell me that I’m lying, and how the plane you were on was definitely climbing at 45 degrees, and definitely banking at 60, and how you definitely saw people through the windows. And you’re definitely wrong. Sorry to sound so bossy, and I wish that I could take you into a cockpit and demonstrate. I’d show you what a 45-degree climb actually looks like, turning you green in the face. In a 60-degree turn, the G forces would be so strong that you’d hardly be able to lift your legs off the floor.
How dangerous are collisions between airplanes and birds?
    Bird strikes are common, and the damage tends to be minor or nonexistent—unless you’re looking at it from the bird’s point of view. As you’d expect, aircraft components are built to tolerate such impacts. You can see web videos of bird carcasses being fired from a sort of chicken-cannon to test the resistance of windshields, intakes, and so forth. I’ve personally experienced several strikes, and the result was, at worst, a minor dent or crease.
    I should hardly have to mention, however, that strikes are occasionally dangerous. This is especially true when engines are involved, as we saw in 2009 when US Airways flight 1549 glided into the Hudson River after colliding with a flock of Canada geese. Modern turbofans are resilient, but they don’t take kindly to the ingestion of foreign objects, particularly those slamming into their rotating blades at high speeds. Birds don’t clog an engine but can bend or fracture the internal blades, causing power loss.
    The heavier the bird, the greater the potential for harm. Flying at 250 knots—in the United States, that’s the maximum allowable speed below 10,000 feet, where most birds are found—hitting an average-sized goose will subject a plane to an impact force of over 50,000 pounds. Even small birds pose a threat if struck en masse. In 1960, an Eastern Airlines turboprop went down in Boston after an encounter with a flock of starlings.
    Your next question, then, is why aren’t engines built with protective screens in front? Well, in addition to partially blocking the inflow of air, the screen would need to be large (presumably cone-shaped) and incredibly strong. Should it fail, now you’ve got a bird and pieces of metal going into the motor. The incidents above notwithstanding, the vast improbability of losing multiple engines to birds renders such a contraption impractical.
One sometimes hears of icing after an accident. How are ice and snow hazardous?
    Ice or snow on an airplane is potentially very dangerous, especially when adhered to the wings. The devil isn’t the added weight, but the way it disrupts the flow of air over and around a wing’s carefully sculpted contours, destroying lift. You’ve also got slick runways to contend with and assorted other