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Old 5th Jun 2009, 14:00
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Jet_A_Knight

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It must be just bad timing with the A330 loss that this accident is not being discussed.

A truly unbelievable accident.

Section 3.15 "Findings And Conclusion" Pages 132-133



The abnormal situation on board started developing when the aircraft was at base leg, with landing gears extended and flaps 30 at 600 m. The aircraft was flying with the autopilot engaged and the autothrottle disengaged.

The autothrottle was disengaged (with the relative alert activated) earlier, at establishing 2100 m by the cruise split monitor due to the significant thrust split. The crew did not attempt re-engaging the autothrottle.

The Co-pilot was the PF during most of the approach. As he did not have basic skills of flying multiengine aircraft with spaced-apart engines, he synchronically shifted the throttles for manual speed control and thus created a significant yawing moment to the left due to the thrust split. The PIC (as the PM) was engaged in the radio communication and did not monitor the engine parameters. The crew did not attempt to match the N1.

The pilots did not apply rudder to compensate the yaw moment, which led to a constant left banking. The autopilot's ability to counteract it by right wheel inputs was decreasing as the airspeed was dropping and the aerodynamic efficiency of the ailerons was decreasing.

After the autopilot was saturated followed by 30° left bank, the Co-pilot, while compensating the roll, overrode the autopilot to the CWS ROLL and CWS PITCH mode.

Then, in the CWS mode, the Co-pilot inadvertently pressed the manual stabilizer pushbutton, which disengaged the autopilot, accompanied with the relative alert. The crew switched off the alert and did not attempt to re-engage the autopilot.

As the pilot lacked steady piloting skills, he could not monitor all the flight parameters (altitude, speed, roll and pitch) when flying manually. The flight was unstabilized with significant changes of altitude, speed, pitch and roll, and fluctuations of thrust. An increase in thrust led to a significant noseup pitching moment, high pitch attitude (up to 23°) and consequently to significant reduction of airspeed (three times – down to 112, 110 and 113 knots).

The PIC was leading lengthy discussions with the Controller and did not monitor the flight properly, only interfering with the flight control from time to time.

The crew did not follow the Controller’s instruction to terminate the approach and prepare for the second one.

At altitude about 1200 m with airspeed of 120 knots (10 knots lower than Vref) and left bank of about 30° the PIC, following the Co-pilot’s request, took control.

Not having proper situation awareness the PIC abruptly applied left wheel, increasing the left bank up to over 70°. Despite the correct remark from the Co-pilot after which he initially used right wheel (decreasing the left bank to 30°), the PIC then abruptly and disproportionately made several wheel inputs causing rapid left banking, followed by left overturn and deep descent with 65° nosedown pitch. It was impossible to recover from such upset at a low altitude.
Edited to show source

Last edited by Jet_A_Knight; 6th Jun 2009 at 00:00.
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