Baghdad A300 Incident Discussion BeCA. 28 October 2004 2004 Presented by Capt. Jacques ROSAY Airbus Chief Test Pilot Baghdad A300 Incident Discussion DHL flight hit by missile in BAGHDAD TRIBUTE TO ERIC, STEEVE AND MARIO Customer Services
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
THE FACTS November 22nd, 2003. 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
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
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 significative amount of the left wing surface is missing BUT: BOTH ENGINES ARE STILL RUNNING Baghdad A300 Incident Discussion
THE FACTS (continue) Baghdad A300 Incident Discussion
THE FACTS (continue) Eric, Steeve and Mario had then to learn how to fly and land an asymmetric aircraft using the only thrust control Let’s do the same Baghdad A300 Incident Discussion
How could it fly ? Flight mechanics with thrust only : pitch From a trimmed position, an A/C like the A300 (with underwing engine) will react to a step change of thrust with : 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
How could it fly ? This is followed by a so called « phugoid » (long period lightly damped oscillation at constant angle of attack, exchanging altitude and speed around the stabilised condition) Pitch , Vc Pitch , Vc Pitch , Vc Baghdad A300 Incident Discussion
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
THE THRUST BECOMES A PITCH CONTROL 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
Flight mechanics with thrust only : roll 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
How could it fly ? Increasing the thrust on one engine, will first generate sideslip Baghdad A300 Incident Discussion
How could it fly ? The sideslip will induce asymmetric lift; this 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
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 tendancy 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 assymetry with some permanent sideslip. Baghdad A300 Incident Discussion
How does it fly ? Summary: Symmetrical change of thrust on both engines will allow to control pitch and then vertical speed. But pitch control will be loose due to the phugoïd, making slope visualisation very difficult. Thrust being used for pitch control cannot then be used for speed control. Speed must be accepted as an uncontrolled 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 . Assymetrical 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
Bring the A/C to the ground First they managed to control the pitch, extending the landing gear to limit the speed increase. At this time the A/C was more or less stabilized in slight turn. Then they learned to control the roll, going through some roll excursions beyond 30°. Baghdad A300 Incident Discussion
Bring the A/C to the ground Having learned to manage the flight path, the crew decided to attempt the landing. Additionally the left wing was on fire and there was a fuel leak!… It was time to come back and land. Baghdad A300 Incident Discussion
THE FACTS (continue) Baghdad A300 Incident Discussion
Bring the A/C to the ground They elected runway 33R, the longest of the 2 runways. The wind was 290° at 20kt with turbulent conditions ! After some kind of downwind leg, they came back for long final in a right turn (although the aircraft was tending to roll left by itself). In addition to the flight path, they closely monitored the left tank, ready to open the crossfeed, despite the leak and the fire. It was vital for the engine to stay alive ! Baghdad A300 Incident Discussion
Bring the aircraft to the ground Approximate trajectory Missile hit Basic principles understood Baghdad A300 Incident Discussion
Bring the A/C to the ground Finally the 33L was closer at the end of the approach The crew flew 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
Successful landing on 33L Baghdad A300 Incident Discussion
Runway exit Baghdad A300 Incident Discussion
Thrust reversers were used Baghdad A300 Incident Discussion
Bring the A/C to the ground A/C exited the runway rapidely; reversers associated to rolling in the sand provided a good substitute to poor brake efficiency. The A/C stopped after 1000m roll out. Baghdad A300 Incident Discussion
Bring the A/C to the ground Disregarding some light damage on the landing gear (deflated tyres), aircraft was intact (but for the wing !) No injuries for the crew or people on ground Baghdad A300 Incident Discussion
Conclusion Adaptation and tasks prioritization were the key of the success. The basic tasks distribution were still applied: FLY NAVIGATE COMMUNICATE MONITOR THE SYSTEMS Baghdad A300 Incident Discussion
Conclusion Each such situation is unique and cannot be trained for in advance. In this particular case, the following basic principles apply: 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
Conclusion In terms of airmanship, Eric, Steeve & Mario had done a remarkable job They managed the priorities They worked as a Team They shared properly the work : FLY NAVIGATE COMMUNICATE MONITOR Baghdad A300 Incident Discussion
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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