PART III - HANDLING

     (c)  Airbrake
          
           (i)   The airbrake may be used throughout the speed
                 range.  Its use may cause the hydraulic warning light
A.L.1              and audio warning to flickcome on momentarily

           (ii)  Selection of airbrake causes moderate buffeting and
                 a momentary nose-down change of trim which
                 reverts to moderate nose-up trim change when the
                 airbrake is fully extended. Correcting the out-of-trim
                 forces at high IAS may lead to overcontrolling.

     (d)  Flaps
          
           (i)   At high mach number
           
                 As speed is increased from 0.9M to 0.94M a marked
                 nose-down in change occurs; lowering flap also
                 produces a marked nose-down change of trim, the
                 degree of out-of-trim increases with the amount of
                 flap selected and with speed. As mach. number is
                 increased beyond 0.92 elevator and tailplane
                 effectiveness decreases. Pilots will realize therefore
                 that if 0.9M is exceeded inadvertently with flap
                 lowered, or if flap is lowered inadvertently at high speeds
                 in excess of 0.9M longitudinal control will be very
                 substantially reduced and in the worst condition may
                 be lost completely.  If control is lost with any degree
                 of flap lowered, the flap should be raised
                 immediately.
                 
           (ii)  At high airspeed
           
                 If speed is increased inadvertently beyond 350 knots
                 with flap extended, the increasing air loads decrease
                 the flap angle which results in a nose-up change of
                 trim.
                 
     (e)  Changes of trim
     
          Increase and decrease               Nil
            power
          Operation of under-                 Negligible
            carriage
          Flap down                           Strong nose-down above
                                              200 knots.

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