Ask the pilot

Giant nets to stop a brakeless Concorde? Just one of Hollywood's ham-handed attempts to fly. Plus, why icing on a plane is a slippery business.


Patrick Smith
February 8, 2003 1:30AM (UTC)

As expected, my mailbox was the target of alternating shots of praise and indignation after last week's book recommendations. But give me some credit for separating at least a cracker's worth of wheat (served in a tiny basket with an apple and a soapy towelette) from all the chaff.

It would have been more fun, maybe, compiling a list of my least favorite books. The literature of flight is a congested and overburdened genre, as the pages of industry catalogs can attest. If ever there was an argument against freedom of the press, it's the pulp churned out by the small companies who dominate aviation publishing. When they finally get around to re-regulating the airlines, maybe they should throw reins over the presses as well, slowing the cataract of shoddily written memoirs and the depressing assortment of would-be coffee table fare (one book is actually called "A Guide to Airport Airplanes").

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At the more cultivated end, of course, we discover yet another installment of that beauty-of-flight manifesto known as Ask the Pilot.

And in light of my earlier poetry samples, who knew the "Columbia Granger's Index to Poetry" would register no fewer than 20 entries under "Airplanes," 14 more for "Air Travel," and at least another five under "Airports." Names here don't include Smith, but do include Frost and Sandburg. (And I specifically recall an Allen Ginsberg poem in which he writes of the blue taxiway lights at an airport somewhere. Anyone know it?) John Updike's "Americana and Other Poems" was reviewed by Kirkus as "a rambling paean for airports and big American beauty."

As for other media ... Well, we've we've done music already -- I've listed Hüsker Dü songs and waxed a bit over "Rhapsody in Blue" -- so maybe Hollywood warrants a mention.

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It's debatable whether movies better lend themselves to the topic than other forms of art, but if they do, it is perhaps due to the film industry's having achieved a certain glamorous bloom simultaneously with commercial flight. One might parallel the 1950s' dawn of the Jet Age with a realized potential of Hollywood -- the turbojet and CinemaScope as archetypal tools of promise. But decades later there still appears to be some cordial symbiosis at work: A lot of movies are shown on airplanes, and airplanes are shown in a lot of movies.

You're expecting me to say so, but yes, I find myself roiling in frustration at Hollywood's artistic license with the facts of flight. I'll refrain from playing film critic lest I sound like an anal-retentive crank, but the most embarrassing thing I ever saw was "Airport '79" (John Davidson, Jimmie "J.J." Walker, Charo), which even in the 7th grade had me choking with incredulity at the idea of using giant nets to stop a brakeless Concorde from speeding off the end of a runway.

The crash plot is the easy and obvious device. But although we might theorize what part of the shattered fuselage those Uruguayan rugby players ("Survive," 1975) used as an abattoir when preparing their deceased teammates for consumption, the most thoughtful moments are when airplanes appear incidentally: the requisite farewell airport scene (always departing, never arriving), the silhouette of a 747 climbing away; the propeller plane dropping the spy off at some godforsaken shithole, or taking the ambassador and his family away from one; the beauty of the B-52's tail section snared in a tree along the riverbank in "Apocalypse Now."

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"Did you catch the Tupolev TU-154 in Krzysztof Kieslowski's 'Decalog, part IV'?"

"Yes, and there was an IL-18 in the background."

"You're right. [Wistfully] I wonder where the Tupolev was headed?"

"Dresden, perhaps?"

"No, Budapest, I'll bet! Maybe Prague? I'll check my 1987 LOT timetable to see where any midday Tupolevs were going from Warsaw."

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For most of us, airplanes are a snapshot means to an end and, often enough, the vessels of whatever exciting, ruinous, life-changing journeys we may embark on as human beings. There's romance in that, but the furtive glimpses capture it best, far more evocatively than any blockbuster disaster script.

One sometimes hears of "icing" after a crash. How can ice or snow cause a plane to crash?

During flight, ice can accumulate in different areas -- on the leading edges of wings, engine inlets, etc. (It will stick to the thinner, lower-profile areas, but usually not the larger expanses or fuselage -- a function of aerodynamics; let's not go there.) This occurs during visible precipitation, or when suspended moisture sublimates directly to the surface. The monster here isn't the weight of the frozen material, but the way it changes the contouring of the wings. Even a half-inch ridge of ice can wreak havoc with an airfoil. This is especially important during takeoff and landing, when the speed is slowest and the margin of lift is most critical.

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Sitting at the terminal, a plane will collect precipitation the same way your car does -- via snowfall, sleet, freezing rain or frost. Thanks to supercooled fuel in the wings, frost can form insidiously even during temperatures above freezing. But not to worry (you were waiting for that), as all of this is scouted out before flight. An airline's preflight de-icing checklist can take up several pages of a pilot's manual.

Whether aloft or gateside, rules and equipment are on hand for the occasion. Bringing us to the next question

What is the pink liquid used to de-ice snow-encrusted planes? And what about in the air? How do planes de-ice themselves during flight?

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The delicious-looking (apricot-strawberry) fluid used for ground de-icing is a heated combination of glycol and water. There are different mixtures for different conditions, varying in temperature and viscosity. It helps remove existing material and prevents the buildup of more. How long a plane is good for after application is not just a matter of giving it a look-see, but follows something called "holdover time," accounting for the rate and type of current precipitation and ambient temperature.

The fluid is often collected and recycled, but at $5 per gallon de-icing a plane is extremely expensive. When the costs of handling, storage and disposal are considered, relieving a single jet of unwanted ice or snow can cost tens of thousands of dollars. Making a messy situation worse, glycol is toxic. What does our de-icing future look like? It looks like a hangar: At a few airports, planes are steered through enclosures that use infrared heat instead of fluid. Continental now uses a facility like this at Newark.

All airliners are equipped with onboard gear to deal with the stuff encountered aloft. On smaller planes, pneumatically inflated boots will break ice from the leading edges of wings and stabilizers. On larger planes the wings, engine inlets and a few other spots are heated with air bled from the engine compressors. Windshields and various probes are kept clear electrically. These systems use redundant sources and are separated into independently operating zones to keep a failure from affecting the entire plane.

Offhand, I can't cite a single case of a large plane crashing from ice that accrued during flight, but there have been a handful of takeoff accidents over the years, most notoriously the one involving Air Florida flight 90 in Washington in 1982. In addition to buildup on the wings, iced-over engine probes gave a faulty, less-than-actual thrust reading after the crew had failed to run the engine anti-ice system. The most recent serious crash, a more true-to-form ice-on-the-wings scenario, was that of a USAir Fokker jet at La Guardia in 1992 (24 of the 51 occupants survived). Not bad, considering there have been about 12 million takeoffs in the country since then.

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It seems to me that some runways go a little bit uphill. Is this true, or are my eyes failing me?

Stop blinking. Runways often slope slightly, and some even dip toward the center and rise on both ends. The steepness of the grade often appears much greater than it is -- a trick of perspective. A typical grade is maybe 1 percent overall. And this is to accommodate the existing ground angle; runways are not intentionally canted to make takeoff or landing easier. Occasionally slight performance (weight) penalties apply on an uphill strip.

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Do you have questions for Salon's aviation expert? Send them to AskThePilot and look for answers in a future column.

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Patrick Smith

Patrick Smith is an airline pilot.

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