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Baghdad A300 Incident Discussion
Instructor Seminar 2004 Baghdad A300 Incident Discussion DHL flight hit by missile in BAGDAD TRIBUTE TO ERIC, STEEVE AND MARIO
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TRIBUTE TO ERIC, STEEVE AND MARIO
The facts How could it fly? Flight mechanics with thrust only pitch control roll control Bringing the A/C back to the ground Conclusion Baghdad A300 Incident Discussion
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THE FACTS November 22nd, An A300-B4 cargo-transformed, S/N 094, operated by DHL, takes off from Baghdad to Bahrain. Crew : Capt ERIC, F/O STEEVE, FE MARIO. Trip is short, payload is light (Mail) and TOW: 100t (to be compared to 165.9t MTOW) A special Take Off procedure is applied to minimize ground proximity time and threat exposure duration: Take off with slats only and maximum thrust Early retraction of slats Climb at optimum climb speed (215kts) Baghdad A300 Incident Discussion
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THE FACTS (continue) Passing 8000ft, a strong impact shakes the structure. Immediately, Mario announces the loss of two hydraulic circuits (green and yellow). Twenty seconds later, Eric feels the controls stiffening as the last hydraulic circuit (blue) is lost. Baghdad A300 Incident Discussion
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BOTH ENGINES ARE STILL RUNNING
THE FACTS (continue) A/C configuration is then the following: All hydraulics lost Ailerons, rudder and elevators are «floating» in the wind (zero hinge moment) THS is frozen Spoilers are inoperative and prevented to deflect (sucked by the airflow) by a non return valve. But one of them is slightly leaking. Slats and flaps configuration are retracted and frozen Left wing in fire and associated fuel tank is emptying A significant amount of the left wing surface is missing BUT: BOTH ENGINES ARE STILL RUNNING Baghdad A300 Incident Discussion
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THE FACTS (continue) Baghdad A300 Incident Discussion
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THE FACTS (continue) Eric, Steeve and Mario have then to learn how to fly and land an asymmetric aircraft by thrust application only. Let’s do the same (but in the quietness of the conference room…). Baghdad A300 Incident Discussion
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How could it fly? Flight mechanics with thrust only: pitch
From a trimmed position, an A/C like the A300 (with engine in wingpod) will react to a step change of thrust by: An immediate pitch change (increase of thrust induces a nose up motion) An immediate speed change along with the thrust change (but it will not last !) Baghdad A300 Incident Discussion
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How could it fly? Followed by a so called «phugoid» (long period lightly damped oscillation at constant angle of attack, exchanging altitude and speed around the stabilized situation) Pitch , Vc Pitch , Vc Pitch , Vc Baghdad A300 Incident Discussion
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How could it fly? When the controls froze, A/C was stabilized at a certain speed, with a given thrust and a given THS position A thrust variation (decrease) will create a pitch (down) moment This pitch down motion will continue until: The thrust is restored at the adequate level, or The speed has increased sufficiently so that the down lift of the tailplane compensates the pitch down moment created by the reduction of thrust. Baghdad A300 Incident Discussion
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How could it fly? To sum up: THE THRUST BECOMES A PITCH CONTROL
Speed becomes a consequence of the chosen combination of pitch and thrust. Note that against intuition (and initial reaction), a thrust reduction will finally induce a speed increase and vice versa. Baghdad A300 Incident Discussion
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How could it fly? Flight mechanics with thrust only: roll
In normal flight with no sideslip, lift is symmetrical. The only way to control the lateral axis is the use of assymetric thrust. Baghdad A300 Incident Discussion
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How could it fly? Increasing the thrust on one engine, will first generate sideslip Baghdad A300 Incident Discussion
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How could it fly? And thanks to sideslip, the asymmetric lift will allow to generate some bank, but with a delayed response of the A/C With left sideslip (more thrust on left engine), the airplane yaws, then rolls to the right. Baghdad A300 Incident Discussion
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How could it fly? On top of it, in their case, the aircraft was in an evolutive assymetry (Surface missing, airfoil modified, massive fuel leak on the left wing). It then had a permanent tendency to roll, evolving as the fuel leaks and probably wing parts fly away. Globally, the roll remained contained during two minutes, without any roll-specific crew action, between 12° right and 22° left, final stabilized state. Two minutes after the explosion, the crew had to cope with the final asymmetry with some permanent sideslip. Baghdad A300 Incident Discussion
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How does it fly? Synthesis:
Symmetrical change of thrust application will allow to control pitch and then vertical speed. But pitch control can be loose due to the phugoïd, making slope visualization very difficult. Thrust being used for pitch control cannot then be used for speed control. Speed must be accepted as an undesired result of the desired slope. When controlling the flight path, the crew will then have to accept the resulting speed and to control the slope through an active control of the pitch via the thrust. Asymmetrical thrust application will allow to control the roll, but with a delayed response of the aircraft. Therefore, A/C control is achievable, but (at the least) demanding… Baghdad A300 Incident Discussion
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Bring the A/C to the ground
The crew had no PowerPoint slides to learn these flight mechanics. First they manage to control the pitch, extending the landing gear to limit the speed increase. At this time the A/C is more or less stabilized in slight turn. Then they learn to control the roll, going through some roll excursions beyond 30°. Baghdad A300 Incident Discussion
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Bring the A/C to the ground
Having learned to manage the flight path, the crew decides to attempt the landing. What about you? Are you comfortable with this new way of controlling the airplane Don’t forget that the left wing is on fire !… So, it may be time to come back and land. Baghdad A300 Incident Discussion
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THE FACTS (continue) Baghdad A300 Incident Discussion
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Bring the A/C to the ground
They elect for the 33R, the longest of the 2 runways. Good news: 20kt turbulent wind from the 290! After some downwind leg, they come back for long final in a right turn (although the aircraft tends to roll left by itself). In addition to the flight path, they closely monitor the left tank, ready to open the crossfeed despite the leak and the fire (not intuitive is it?): the engines must stay alive at all price! Baghdad A300 Incident Discussion
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Bring the aircraft to the ground
Approximate trajectory Missile hit Basic principles understood Baghdad A300 Incident Discussion
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Bring the A/C to the ground
Finally the 33L was closer from their final flight path The crew piloted the A/C down to the flare, coping with the phugoïd, the asymmetry in roll and the Xwind 25 min after missile impact, the A/C was landed (NOT crashed): On the runway 33L, with a controlled touch down (Vz below 10ft/s), a positive pitch With some divergent heading (8°) and some bank to the right (10°) Baghdad A300 Incident Discussion
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Successful landing on 33L
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Runway exit Baghdad A300 Incident Discussion
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Thrust reversers were used
Baghdad A300 Incident Discussion
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Bring the A/C to the ground
A/C exit runway rapidly, but reversers associated to rolling in the sand provide a good substitute to poor braking. After 1km of deceleration, A/C stops. Baghdad A300 Incident Discussion
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Bring the A/C to the ground
Disregarding some light damage on the landing gear (deflated tires), aircraft is intact (but for the wing !) No injuries for the crew or people on ground Baghdad A300 Incident Discussion
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Conclusion Each such situation is unique and cannot be trained for in advance. Crew will have to adapt himself, applying the following basic principles: Pitch is controlled by thrust Speed MUST be DISREGARDED (provided vertical speed is controlled) Roll is controlled by differential thrust with considerable time response DO NOT RETARD thrust at flare Baghdad A300 Incident Discussion
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Well done Mario, Eric, Steeve
Well done Mario, Eric, Steeve! You really did write a nice page of aviation history! Baghdad A300 Incident Discussion
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AN EADS JOINT COMPANY WITH BAE SYSTEMS
This document and all information contained herein is the sole property of AIRBUS S.A.S. No intellectual property rights are granted by the delivery of this document or the disclosure of its content. This document shall not be reproduced or disclosed to a third party without the express written consent of AIRBUS S.A.S. This document and its content shall not be used for any purpose other than that for which it is supplied. The statements made herein do not constitute an offer. They are based on the mentioned assumptions and are expressed in good faith. Where the supporting grounds for these statements are not shown, AIRBUS S.A.S. will be pleased to explain the basis thereof. AN EADS JOINT COMPANY WITH BAE SYSTEMS Baghdad A300 Incident Discussion
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