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The Spirit of Aviation is part of human's natural formation and it is so virtual... The Spirit of Aviation is neither confined as a monopoly of birds nor individuals... It is inherent in everyone... While being inactive or dormant as waiting to be explored and developed in some people, It could be well manifested in the others. The spirit of aviation is an excellent feeling satisfying humanly desires and fantasies, likings or pleasures including; commanding aloft, tasting the sense of absolute freedom, how it feels to be charmed by aerial view etc. Indeed, all the people living in the world is kind of flying. The name of the aircraft we are all on is called The Earth. All the while The Earth whirls on its axis with its vertiginous speed, every living being fly indeed on this very old, tremendous, engineless, wingless but very live and powerful craft that may be called; "Spaceship The Earth"... We, as airmen/women, as pilots and flight crews use additional means to fly over and around the earth. It's like flying around a very huge space ship by means of different kinds of flying crafts... Human's ability is diverse, dissimilar. As some people have an excellent ability, say, to be a painter or artist, some people don't. Nevertheless, everyone has enough talent to scratch some drawings on a paper to define something. Continue to meditate for a moment: As anyone can sing or play an instrument, a professional musician's performance is something... Yes folks, same logic for the pilots is valid as well. As every future flyer's flying ability would be different, there may be found various degrees of talent in each individual who is willing to fly. Dormant, nevertheless, ready to be explored, trained, developed, processed and utilized. Initial desire for flying might have come from human's observation of birds with envy. Later on, the unfortune greedy nature of human might have opened the door into the new era of military air assets, forcing the peaceful nations to the promotion of their defence systems, in an effort to be able to counter possible attacks from and/or conduct preemptive attacks to their greedy enemies. And lastly, the people living on the world realized that, the world has gotten smaller as they flew... Thanks to air transportation, nameless heroes who participated to the process of the development of air transportation, you can dine in, say, New York and have breakfast in Paris... The heroes who were first to try to penetrate the sound barrier, also were first to lose their lives losing controls of their airplanes due to harsh shock wave, coffin corner and aileron buzz episodes that they had never heard of, and/or high altitude severe upset occurances. Just for the sake of aviation exploration, had they never initiated their brave endeavors, Paris to New York or vice versa wouldn't have been that close. If Wright Bro's had never tried their first flight in 1903 to set the pace of universal aviation, the pace of world's aviation wouldn't have been that impressive to the mind and spirit of human. Having meditated on the essence of aviation, we can now have a look at the Transonic Flight Regime: The transonic flight regime of jet transport aircraft is a complex aerodynamic region. Aircraft flight characteristics are effected by the formation and movement of shockwaves. The jet transport aircraft in general behave differently in accordance with their tail structure, engine mount and wing structure at high transonic mach numbers. The information on specific types, might be provided from the manufacturers, as based on wind tunnel tests, engineering analysis and actual flight tests. Mach Tuck, Aileron Buzz, Coffin Corner and other highspeed / overspeed and high mach characteristics are some of the occurences / incidents of high performance jet transport aircraft either in normal or upset speed spectrum. All aircraft as they approach the speed of sound shall experience shock wave formation and transonic effects. These effects can vary from catastrophic to barely perceptable, depending on the aircraft and control system design. An approach to the speed of sound can be made either intentionally with a properly designed supersonic jet airplane or unintentionally with any transonic jetliner or business jet aircraft. I would call the latter case as an UPSET CONDITION... Yes folks, unfortinately an extreme or severe upset can easily take a transonic jet transporter into a condition of horrific shock wave onset, making things very difficult to recover in IMC or Night conditions when no or very poor visual clues are available. In such cases cool, positive and timely intervention is essential for a successful recovery. A mishandling or a malpractice of the situation may easily cause loss of flight control surfaces and precious lives. Now, I would like to bring forward some of the transonic flight upset recovery procedures that I believe most of the aviation enthusiasts and aviators may derive benefit from... UPSET RECOVERY ON TROUBLED BIG JETS *High altitude abrupt control maneuvers on manual flights, *unfortunate uncommanded rudder, yaw or roll commands of today's sophisticated electronic flight control systems, *severe turbulent weather encounters, *improper control inputs on high level cruise engine malfunction occurrences, *improper rudder, thrust or flight technique as bleeding off the airspeed down to drift down speed when necessary, *thunderstorm clouds underneath a high level engine failure case, *concurrent clear air turbulence with an engine failure case on a hot, high and heavy flight, *high or low level windshear, *unexpected and undesired obligated in-flight-deck-combat with intruders on hi-jacked or commandeered jetliners, *over controled negative or positive "g" or excessive bank angle situations aimed to disable the hijackers and other countable inputs, can easily put a large jet or jetliner into an upset situation. Environmental factors to be considered are: 1. Day or night: Day or night conditions is of utmost importance. In case of daylight with visual cues, recovery is almost a piece of cake for an avarage pilot on the condition to be very smooth on the controls neither to over stress nor to stall the big jet. Remember, safe flight speed spectrum lessens in regard to the subjected "g" loads. So, be smooth on the controls. Jetliners or big corporate jets are no fighters. They have limited positive and negative "g" load factors to resist. Recovery in daylight in IMC (instrument meteorological conditions) shall be the same as night IMC. Night conditions can be in two. a. Night condition with visual cues (Night VMC): In such case, visual cues can make the recovery easier. This condition may be compared with a VMC daylight upset. b. Night condition with no visual cues ( night IMC) : Pitch black night upset is the worst. This condition may arise either when totally in the clouds, or there may be sea, desert, swamp or any other place with no residential lights underneath and clouds on top of flight altitude (no visual cue of stars). 2. Weather conditions during upset: Weather conditions during upset is of vital importance as well. Imagine an unexpected upset due to whatever reason in turbulent weather, thunderstorm cloud or in the vicinity of a tornado or hurricane area. I know you wouldn't want to imagine that. But as a pilot, you should imagine and plan ahead what you would do in the worst unexpected cases of upsets. In any case; *If the pitch is extremely low (in case of unfortunate very deep pitch attitudes), identifing the pitch and bank condition of the iron bird may turn out to be impossible. In such a case, speed increases tremendously causing air to build up in front of the leading edge of the wings, causing creation of a shock wave to ride on the wings, with an ultimate buzz and extreme buffet disabling the aircraft aerodynamic flight controls. Heavy airframe buffet, "g" loads, panic, disorientation, vertigo, turbulence, lightning flashes, flight controls buzz, shock wave, screams coming from the cabin, all of the terrible feelings will be there, sharing the horrible moments with you. Forget all and just remember the following to recover back to life and your loved ones. They are only severel steps next to you: Recognize and confirm the situation. In case of a nose low recovery: *Disconnect the Auto/Pilot and Auto/Throttle. *Recover from stall if required. *If attitude and speed is severe: "thrust levers idle" no matter where the engines are mounted ! ! ! *Try to locate and identify the attitude index if it is visible...Is it rotating like a whirlpool or if you're lucky enough, is it visible and steady at some point? Identify correctly... *Roll in shortest direction to wings level. Carefully apply a slight rudder input on the rotation side of the index if necessary...( meaning a rudder input on the opposite side of the turn/spin if you are in a nose down stall)... *Unload the subjected "g" load and roll if bank is more than 90 degrees. *Recover to level flight. *Apply smooth nose up elevator, assisted with nose up trim. Most of todays jetliners' and big corporate jets' horizontal stabilizer surfaces are much larger than elevators'. In extreme situations, pulling on the elevators only without the aid of elevator trim, may cause separation of elevator out of it's stabilizer hinges, causing an inevitable catastrophic accident. Remember to assist with short and controlled pulses of elevator trim, but please also remember that excessive use of pitch trim or rudder may aggravate an upset situation or may result in loss of control and/or high structural loads. *As recovering to horizon, adjust thrust and drag as required. *If speed is severe, attitude and bank angle could not be identified: *Immediately extend landing gear down, regardless the max speed limit. As landing gear extend, the iron bird shall pitch up some degrees and that would help the pitch attitude and bank angle to be identified on the ADI/EADI or the standby ADI. Then continue as described above. *After recovery, do not retract landing gear, leave them down for a safe landing. Plan to land at the nearest suitable airport. Remember a crashed airplane's landing gear is worthless. But a safe landing can always be made even if the landing gear system is crippled. Landing to the nearest suitable airport, might be so important especially for the passengers and flight attendants. Excessive "g" loads might have caused brain bleeding or spinal injuries. There may be undetected medical need conditions back there. In case of a nose high recovery: I consider nose high recoveries as less harmful than of nose low. *Disconnect A/P and A/T. *Have first officer or pilot not flying to communicate the ATC of the situation and report heading sector. As precise heading shall continue to change in rolling type of recovery techniques, reporting sector only may aid ATC controllers to clear nearby traffics out of the incident area). *Apply nose-down elevator and appropriate nose down stab trim. *Roll to a bank to obtain a nose down pitch rate. *Onboard tail-mounted engined jetliner or big jet: Add thrust as necessary to control ailing airspeed. *Onboard underwing-engined jetliner or big jet: Reduce thrust as necessary to aid a nose down pitch rate to the horizon. *When approaching the horizon, roll to wings level, establish proper pitch attitude, check airspeed and adjust cruise thrust, have flight attendants check passengers and their medical needs, decide accordingly whether to continue the destination or land at the nearest suitable airport. In case of a nose high recovery remember, excessive use of pitch trim or rudder may aggravate an upset or may result in loss of control and/or high structural loads. Especially a stall or a near stall condition may be very fragile into an inevitable spin when combined with excessive rudder control made with whatever intention or as a reflex maneuver. Under all circumstances feel fit for contingencies, expect the unexpected and you all have safe and nice flights. By, Captain USKENT Copyright (c) 2002 Savas Uskent By,Airline Commander Pilot & Aviation Author htt |
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| TRANSONIC FLIGHT AND AIRMANSHIP |
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| ABOUT THE AUTHOR: Serving as a Commander Pilot (Captain in Charge / Pilot In Command) in one of the flag carriers of the "Old Spaceship The Earth", Captain USKENT is holder of; ATP & CFI & IP licences. Regarding the "large category commercial jet airplanes", is type rated on: Airbus-310; Next Generation Boeing-737 / 800, Boeing 737/400-500, British Aerospace-146, Challenger-601/3A, Learjet-60, Learjet-55C, Learjet-35A, Caravelle SE-210, Grumman's S-2 aircraft... Having extensive worldwide experience in all expects of aviation, he also has an international corporate jet flight dept mgr, senior and chief pilot background that was on top of an ex-naval aviation career, as a Commander, Test, Tactical & Flight Instructor, examiner and Check Pilot. School of journalism enhanced his writing proficiency. |
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| FEB.10.2009 |
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