Tuesday, 7 September 2010

A Transatlantic Flight Aboard Concorde

The scene on the ramp at Heathrow's Terminal Four, with two needle-nosed, ogival wing-shaped Concordes in British Airways' livery and nary another aircraft type visible, had been like discovering an advanced time pocket in which a science fiction setting of exclusively supersonic aircraft had formed an integral part of this future society's air transportation system. But what had made this vista particularly awe striking had been the fact that, in 1994, that this scene had been played out for almost two decades. Aircraft G-BOAC, operating as Flight BA 189 to Washington-Dulles, and aircraft G-BOAG, operating as Flight BA 003 to New York-JFK, had been in the process of being serviced for their daily, evening transatlantic supersonic crossings, while a third had conducted its nose-high flare in the distance. I would bullet across the pond on the second of the two.

Pushed back from the gate at 1900 local time by the tug connected to its elongated wheel strut well below its needle nose, the aircraft had extended its visor and nose cone to the five-degree position before maneuvering away from Terminal Four under its own power with a brief throttle advancement.

Inter-tank fuel transfer, ensuring an aft, 53.5-percent center of gravity and increased take off wing lift, had been coupled with a 1.5-unit, pre-set stabilizer trim. The ogival wing's design itself, incorporating camber, twist, taper, and droop, along with its significant area, had precluded the necessity for leading or trailing edge high-lift devices, thus decreasing structural weight and drag, and its long chord, obviating the need for separate elevators, had permitted the effective replacement of six trailing edge elevons which had been operated by an equal number of power flying control units fed by 4,000-psi hydraulic fluid systems pressurized by engine-driven pumps and activated by electrical, or fly-by-wire, signaling. Two identically powered vertical tail surfaces had completed Concorde's hinged devices, for a total of eight.

Turning on to the threshold of Runway 9-Right and throttling into its acceleration roll, Concorde G-BOAG, unleashing a deafening roar with its four Rolls Royce/SNECMA Olympus 593 turbojets, ate the runway with deep, throaty determination, inducing its rotational pitch by its six, upward-angling elevons at a 194-knot V1 speed and disengaging itself from the ground at a 217-knot V2 to cater to its 177,800-kg gross weight, trailing a thick smoke plume. Fuel added to its afterburner gases dilated its exhaust nozzles with fire-like fury, increasing its thrust capability by 17-percent and producing a 1.7-greater thrust-to-weight ratio than the Air Namibia 747 which had preceded it into the sky.

Ceasing afterburner light one minute, 15 seconds into the flight due to overland supersonic speed restrictions, the now power-depleted aircraft dipped its nose downward to assume a shallower ascent profile.

Having completed its initial departure course left bank and two right ones, it had proceeded on a westerly heading over Reading toward the west coast of Great Britain, climbing through 5,500 feet at a Mach 0.57 airspeed over the ground's green patchwork quilt whose geometric pattern receded in size beneath the 70-degree swept ogival wings.

A slightly pink-hued mist off the port side, where the sun had begun to inch toward the western horizon, had brush-stroked the sky's canvas, but Flight 003 would outpace the day's denouement to its destination, never eclipsing the line between light and darkness.

Climbing through 9,000 feet at 500 knots, or Mach 0.71, the aircraft, with its nose and visor having been intermittently raised, shifted its center of gravity to 55 percent. Its 13-tank fuel system, located in its delta wings and arranged in three groups according to "engine feed," "main transfer," and "trim transfer," had been the design's only method of center of gravity shift, although the tanks' equal distribution throughout the wings' planform had ensured that it would remain constant during in-flight fuel burn unless transfer had necessitated pitch changes, such as those during descent.

Passing out over the glass-appearing surface of the Bristol Channel, south of Cardiff, Wales, at 51 degrees north latitude, the aircraft had completed its transonic checklist and the throaty grind of its engines had indicated full throttle applications and afterburner re-alighting. As if unleashed from hitherto invisible moorings, the needle-nosed aircraft, emitting fire-trailing, fuel-burning, thrust-producing projections from its two Olympus turbojet pairings with a barely detectable forward lurch, had transcended the speed and pressure of sound and settled into the Mach 1.00 eclipsing, altitude-gaining, nose high-projecting flight profile for which the engineers had intended it during its 15-year development period. Closely carrying its engines next to its narrow, arrow-like fuselage beneath its ogival wing, and generating no horizontal tail air resistance, the aircraft had entered the rock-steady, motionless void between the pale blue of the channel below and the indigo blue of sky above south of Ireland, accelerating through Mach 1.24, an envelope no present subsonic airliner had ever experienced. For Concorde, it had been "home."

Three thousand four hundred thirty miles had separated Flight 003 from its destination, a distance to be devoured at a little less than double its current 860 knots. Passing over a contrail emitted by a subsonic airliner which had undoubtedly been at the peak of its service ceiling, it had reached an altitude just over half of its own.

Shrouded in roaring slipstream and ascending through 43,000 feet at a 1,090-knot, or March 1.70, airspeed, the aircraft had discontinued afterburner use, its climb angle no longer supportable by their excess power.

As Concorde's needle nose had pierced the tropopause at supersonic speeds, a delicate balancing act had begun: with the engine's insatiable, 50,000-pounds-of-fuel-per-hour thirst at full throttle settings, the aircraft would quickly exceed its maximum design speed due to in-flight burn-off and a resultant decrease in gross weight. Instead, the airspeed increase would be counteracted by a gradual ascent through its assigned block altitude, its auto flight system ensuring a Mach 2.00 velocity.

Delicate cirrus wisps moved well below the delta wings at a velocity I had never previously experienced.

A five-course dinner, paralleling British Airways' subsonic Club World business class service, had commenced in the narrow, single-aisle cabin.

Cocooned in the slender, tapering fuselage on the lower fringes of space where the earth's curvature had just become visible and trailing an invisible, cone-shaped wave whose thunderclap-like explosion could only be heard by an Atlantic surface-plying vessel, delta-winged Concorde G-BOAG had cruised ten miles above the planet, devouring 23 miles with every sweep of the clock's second hand, friction-induced heat producing 127-degree Celsius temperatures on its nose, 92 degrees at it wing root, and 98 degrees at its tip. Wing tank-located fuel rose to the 200-degree boiling point. The tiny, 46 passenger windows lining either side of the fuselage, had been hot to the touch, yet, because of the aircraft's 10.7 pounds-per-square-inch pressure differential, its cabin elevation had been the equivalent of 5,600 feet, 2,400 feet lower than that traditionally created by a subsonic airliner cruising at 37,000 feet. The radiation meter in the cockpit, running from 0.1 to 1,000 millirons, with "10" the "alert" reading and "50" the "action" position, had hovered between 0.7 and 0.9, a level higher than that of a subsonic, but Concorde's speed had exposed its passengers and crew to this level for a shorter period of time.

Pursuing the Atlantic by latitude and longitude coordinate waypoints, each separated by minutes and progressive fuel burn off-induced weight reductions, the aircraft had paradoxically seemed suspended, without motion, over the ocean-blanketed white fleece-like cumulonimbus whose pattern had resembled an intricately connected mosaic of pack ice south of Greenland, one of the crossing's untouched land masses. In fact, it would not encounter land until it had reached a point just miles from its assigned runway.

Having pinnacled at 57,000 feet, and having subjected its aluminum-alloy fuselage to an eight-inch, heat-generated, enroute expansion, the supersonic transport, maintaining altitude, retarded its four engine throttles to an initial 18-degree and subsequent 34-degree position at Mach 1.60. Attaining a 1,000-knot indicated air speed, it had been subjected to its second cooling-heating cycle as it had begun to penetrate lower-altitude, higher-temperature air. Retransferring fuel to the forward wing tanks and activating its anti-atmospheric devices, such as its pitot tube heat, it had maintained a 5,000 foot-per-minute descent rate until it had intercepted 39,000 feet, the upper realm of subsonic travel.

Recrossing land for the first time since Great Britain, Concorde had passed over the western tip of Rockaway Beach, unleashing its long-strutted undercarriage into the slipstream and extending its nose to its full, 12-5-degree position.

Crossing Rockaway Inlet and southern Brooklyn, Flight 003 had been handed off from terminal radar approach control to the JFK Tower, executing the Belt Parkway-paralleling Canarsie Approach to Runway 13-Right. Its flapless, ogival-shaped wings, which had required long main gear struts to cater to its high flare angle clearance requirements, had necessitated final-stage, height-to-ground radio altimeter readings: 500 feet...400...300...

Making a final right bank to 130 degrees, Concorde, with its drooped nose and hawk-like, outstretched main wheel struts, had passed over the airport-perimeter roadway and runway-protective blast fence at a 155-knot Vref speed to overcome its 105,433-kg landing weight. Flaring on to the strip with an additional one-degree backward yoke movement, it had entered ground effect, cushioned between the surface and its underside at 100 feet, which had required a further elevon application in order to maintain its pitch angle. The radio altimeter had continued to unwind: 50 feet...40...30...20...

Closing its throttles at 15 feet, it bit into the concrete with main wheel tire erupting smoke puffs before applying sufficient forward yoke pressure to rotate the nose wheel to the surface, yet maintain a small enough cushion effect to do so.

Decelerating to 100 knots, it had throttled its two outboard engines into their idle reverse thrust settings, mimicking the action with its two inboard engines at 75 knots, their secondary nozzle buckets closing, like clamshell doors, over the exhaust and deflecting it up- and downward.

Making the 180-degree turn on to taxiway echo to the inner perimeter, aircraft G-BOAG, whose glowing, energy-absorbing brakes had intermittently heated up to 300 degrees Celsius, had raised its nose to the five-degree position a final time and taxied to Gate 5 of the British Airways Terminal, now inundated on the ramp by a fleet of widebody, subsonic 747, DC-10, and 767 intercontinental equipment, appearing strangely out-of-place, like a design of the future which had somehow returned to the past.

Defeated in numbers, but triumphant in speed, Concorde, shutting down its engines at 1750 local time and causing its trailing edge, hydraulic power-severed elevons to gravity-snag downward, had completed the 3,458-mile transatlantic crossing in three hours, 19 minutes, or half the time of an intercontinental subsonic.

Having made the subsonic crossing myself on countless previous occasions, I exited the slender forward, left aircraft door and tunneled through the jetbridge to the terminal, somewhat disoriented. I had clearly been in New York, but what had happened to the other half of the journey, I had wondered? Somewhere over the Atlantic, in a three-sided equation of time, speed, and distance, lay the answer...

A graduate of Long Island University-C.W. Post Campus with a summa-cum-laude BA Degree in Comparative Languages and Journalism, I have subsequently earned the Continuing Community Education Teaching Certificate from the Nassau Association for Continuing Community Education (NACCE) at Molloy College, the Travel Career Development Certificate from the Institute of Certified Travel Agents (ICTA) at LIU, and the AAS Degree in Aerospace Technology at the State University of New York - College of Technology at Farmingdale. Having amassed almost three decades in the airline industry, I managed the New York-JFK and Washington-Dulles stations at Austrian Airlines, created the North American Station Training Program, served as an Aviation Advisor to Farmingdale State University of New York, and devised and taught the Airline Management Certificate Program at the Long Island Educational Opportunity Center. A freelance author, I have written some 70 books of the short story, novel, nonfiction, essay, poetry, article, log, curriculum, training manual, and textbook genre in English, German, and Spanish, having principally focused on aviation and travel, and I have been published in book, magazine, newsletter, and electronic Web site form. I am a writer for Cole Palen's Old Rhinebeck Aerodrome in New York. I have made some 350 lifetime trips by air, sea, rail, and road.

Article Source: http://EzineArticles.com/?expert=Robert_Waldvogel

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