Ask the pilot

The pilot protests the destruction of a defenseless Iraqi airliner. Plus: Geeky details about flaps, ailerons, spoilers and slats. But not flaperons.

Published April 18, 2003 7:30PM (EDT)

As part of our march toward heaven-ordained glory in Iraq, U.S. forces recently took over Saddam International Airport west of Baghdad. A resulting news icon has been footage of the bombed-out hulk of an Iraqi Airways jetliner, resting in a heap of burned aluminum on the Saddam tarmac. The tail remains relatively intact, and it's clear the wreckage is a Boeing 727. One thing Ive noticed is a missing -- not destroyed, but removed -- number-two engine, leading me to believe the plane was derelict, perhaps parted-out for spares, long before troops reached the capital.

What's to be gained by demolishing an obviously unflyable civilian airliner is, I suppose, for the generals to decide, but I was saddened by the image of the dead plane, a gesture of conquest that seemed inordinately pointless. Iraq will need an airline again, eventually, and who's to say this old Boeing couldn't have been repaired and pressed into service?

Perhaps I should organize a protest? Imagine planespotters the world over picketing in front of terminals. The nerve of the imperialist thugs, bombing a defenseless 727. Al-Jazeera could bring in its cameras and fire up some pan-Arab revulsion. They'd be rioting at airports in Cairo and Damascus, burning effigies of Air Force One.

Iraqi Airways was founded in 1945 and has operated primarily American-built equipment. Its attractive green and white livery was once seen at airports throughout the Near and Middle East, where it was considered one of the best and most reliable airlines for many years. But no-fly restrictions following the Gulf Bore, er War, of 1991, grounded most of the fleet.

According to 2002 data, Iraqi Airways still has 16 planes on its roster, most of which have been flown for safe storage to places like Amman and Tehran (we'll get them in the next war). Two of the airline's 747s are named Tigris and Euphrates, respectively. Another jet is called Babylon. The future of those airplanes is uncertain.

During fighting, airliners often become a sort of civilian casualty. Iraq should know, as it destroyed several jets owned by Kuwait Airways during its short-lived occupation of that country.

I was pleased to spot an intact Ariana Afghan 727 at the airport in Delhi, India, last spring, though I can't vouch for the remaining eight planes said to exist in the Ariana fleet. The airline of Afghanistan was established in 1955.

Something dubbed Palestinian Airlines was started up in 1994, based at Gaza. The carrier has operated a handful of turboprops and even an ex-Turkish Airways 727. Two regional jets were on order as well. I do not know the status of this airline or its planes, and even its Web site has disappeared. I'd venture to guess the company's viability, if not its physical existence, qualifies as tentative.

All-out warfare isnt the only thing that catches an airliner in the crossfire; it's terrorism too. The photos and videos of those 757s and 767s are still fresh in our minds from 2001, but they are hardly the only examples. Who can forget the pictures of Lockerbie, for instance?

Another infamous incident, though hardly remembered today, was the Black September hijackings of 1970. In the space of three days in September of that year, five jetliners were seized over Europe and the Middle East by a radical faction called the Popular Front for the Liberation of Palestine. Two of the planes were American -- the property of Pan Am and TWA. The others belonged to Swissair, BOAC (precursor to British Airways), and Israel's El Al.

Although all the passengers were eventually released, four of the five airplanes were destroyed. Only the Israeli 707 survived. After its hijackers were overcome by passengers and onboard El Al security guards, the flight diverted safely to London.

The Pan Am jet was flown to Cairo and blown up, while the remaining three were routed to Dawson's Field, an old RAF military base in the Jordanian desert, which the militants renamed "Revolution Airport" for the occasion. After nearly a week of negotiations, those planes too were strapped with explosives and blown up.

The 1970s and 1980s were an era rife with hijackings and bombings of civilian airliners -- something we've forgotten in light of more recent, more destructive examples. But Black September was a spectacle of audacity not to be outdone for more than 30 years.

When I was a high school freshman in the early 1980s, the library at St. John's Prep had a book -- it may even have been an old copy of Life magazine -- with a two-page photograph of the commandeered planes in Jordan exploding into flames. I can still remember the exact shelf on which it was found. For me, that image was a type of junior pilot porno. Sometimes, in a spell of morbid attraction I could never quite understand, I would open to the photo and just stare at it -- the fuselage of the BOAC VC-10 bursting into an angry black cloud of debris.

I'm often perplexed by the number of moving parts on a plane's exterior. There are panels that flap up and down, some that fold backward, others that swing forward, etc. What do all these things do?

When a bird needs to maneuver or slow down, it does so by twisting or bending its wings and tail, something pioneer aviators emulated by incorporating wing bending in the first biplanes. But airplanes today are built from aluminum, titanium, and high-strength composites, not wood, fabric, or feathers. Thus, they are augmented by various contrivances that help a plane climb, descend, turn and decelerate. Passengers often speak collectively of these devices as "flaps," but technically they consist of flaps, slats, ailerons, elevators, rudders and spoilers.

Let's take a typical airliner, from back to front:

Atop the rear fuselage of every plane is the tail, aka its vertical stabilizer, which functions exactly as its presence suggests -- by keeping the plane straight. Hinged to the tail's back edge is the rudder. Unlike a boat rudder, it complements but does not control turns; its function is chiefly one of stability, tempering a plane's side-to-side swerve, or "yaw." Pilots move the rudder by means of foot pedals in the cockpit. I'll admit that sounds quaint, and in reality the autopilot systems and an apparatus called a "yaw damper" actually do most of the work. Flying a four-seater requires some literal legwork, but pretty infrequently do you wrassle with the rudder pedals of an airliner. The rudder can be divided into different sections, each with particular limitations pertaining to airspeed and angles of travel. Such restrictions are taken care of electronically or mechanically by the rudder system itself.

Beneath the tail, or occasionally attached to it, are two small wings. These are the horizontal stabilizers, the hinged rear portions of which are known as elevators. The elevators command a plane's nose-up/nose-down pitch. This is something of a simplification, as aerodynamics 101 teaches us that climbs and descents are also affected by adjusting power. But for practical purposes, elevators point the nose up or down, as directed by the forward or aft motion of the cockpit wheel or joystick.

Which brings us to the wings -- the heart and soul of every airplane. A plane is built around its wings the way a car is built around a chassis or a bicycle is built around a frame. To get aerodynamically correct, we're supposed to think of the wing in singular -- there are not two wings as much as one, bisected by the fuselage. But let's not do that; the aesthetic nature of airplanes makes it difficult not to behold separate, left and right entities, and for the purposes of this discussion we'll assume two wings.

As most passengers know, wings are fitted with an array of supplemental components -- namely flaps, slats, ailerons and spoilers. I remember, as a kid in a window seat on a Boeing 727 just aft of the wing, how the entire structure seemed to disassemble itself during descent. Big, triple-segmented flaps would come barreling down, the spoilers and ailerons would flutter and wave, while up front the slats and leading edge flaps would drop into position. Magically, almost, you could see right through the very center of the wing, with houses and trees visible in the spaces where the sections had slid apart.

The faster a plane flies, the more lift its wings generate, but when it slows they need help. Flaps, which trail backward and downward, enhance the wing's camber, allowing safe, stable flight at lesser speeds. Airliners take off and land with their flaps extended, though the exact positioning varies with weight and other factors. There are normally inboard and outboard subsets of flaps, which themselves can be segmented horizontally.

Slats, which roll forward from the front of a wing, perform a similar function. There can be several slats along the leading edge, deployed as needed depending on speed.

Ailerons, located along the trailing edge, are responsible for turns. Pilots steer via the control wheel or joystick, which in turn directs the ailerons up or down. They are interconnected and apply opposite forces: When the aileron on the left wing goes up, the one on the right wing goes down. (An up aileron reduces lift on that side, dropping its wing, while a down aileron raises its wing.) The smallest twitch of an aileron will provide a good deal of turn, especially when going fast, so you can't always spot them moving. If you're seated over the wing, it might seem a plane is banking without anything having budged, but in fact the ailerons have done their thing, if ever so slightly. On most large planes there are two ailerons on each wing -- an inboard and an outboard -- which work either together or independently as speed dictates. Thus there are actually four ailerons, not two, working in pairs.

Spoilers are the rectangular planks that spring from the wing's upper surface. Their use is most obvious on touchdown, when they pop to full deflection to assist in deceleration. A raised spoiler greatly disturbs airflow across the wing, reducing lift while simultaneously adding drag. During flight, spoilers are used to increase rates of descent and to decrease airspeed. Additionally, they are often linked with the ailerons to aid in turning.

So, yes, this gets complicated: A simple turn is often a choreography of rudder, aileron and spoiler, all directed from the cockpit along with the flaps, spoilers, and everything else described above. But before you picture a hapless pilot kicking his feet and grasping madly for levers, keep in mind that many of these individual surfaces are linked to single controls, so that a simple turn of the wheel or lowering of the flap lever will cause any combo of movements outside. And during much of a flight, it's the autopilot that's coordinating the physics of turns, climbs and descents (under guidance and instructions from the crew, of course).

Adding to the confusion, rudders, elevators and ailerons are frequently equipped with smaller tabs that operate independently from the main surfaces. These "trim" tabs help fine-tune the motions of pitch, roll and yaw. And remember those horizontal stabilizers out back? They too are commonly trimmable, lightening the forces of pitch.

If you're still with me, you'll be thrilled to hear that various aircraft also incorporate their own idiosyncratic versions of all these things. One plane I used to fly had some spoilers that were used only after landing, others that assisted with turning, and still others employed strictly for inflight deceleration. The cargo jet I flew had no slats at all, but "slots" that opened at the front of each wing. And certain Boeing models are equipped not only with conventional flaps like those we've discussed but also ones that lower from beneath the leading edge as well, in addition to the slats. The Concorde has no horizontal stabilizers, so it has no elevators. But it does have "elevons." Meanwhile, we'll save "flaperons" for another time.

And no, by the way, to answer a question I'm bound to be asked, a plane cannot fly with one wing. With safety in mind, aircraft components -- everything from navigational systems to engines -- often exist in duplicate or triplicate, but alas, this spirit of redundancy cannot extend to something so wholly integral to flight itself.

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By Patrick Smith

Patrick Smith is an airline pilot.

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