A320 INSTRUCTOR SUPPORT
NORMAL OPERATION
DATE: JAN 2001 Page 136 UDY0102
25 - FLIGHT CONTROLS - HIGHLIGHTS ON THE PROTECTIONS
One of the essential tasks of the crew is to keep the A/C within the LIMITS of the NORMAL FLT ENVELOPE.
But circumstances bring pilots to violate those limits, because of EXTREME SITUATIONS, or mishandling or
mismanagement of the A/C.
Protections have been built so as:
- to give FULL AUTHORITY to the crew to CONSISTENTLY achieve the BEST ACHIEVABLE A/C
PERFORMANCE in extreme conditions,
- to REDUCE the RISKS of overcontrolling / overstressing the A/C and
- to provide an INSTINCTIVE, IMMEDIATE procedure to the crew to achieve that BEST POSSIBLE
PERFORMANCE.
! Bank angle protections
± 67° in Normal Flight envelope (2.5 g level flight).
± 45° in High Speed protection.
The Bank protections prevents ANY MAJOR UPSET or pilot mishandling to bring the A/C in high bank situations where
the recovery technique is complex due to the difficulty to properly assess the situation thus to readily react. It provides
full authority to the crew to achieve MOST EFFICIENTLY any required roll maneuver.
! High speed protection
Beyond the design speeds VD/MD, which are greater that VMO/MMO, there are potentially aircraft control problems,
structural problems due to high air loads. Therefore the margin between VMO/MMO and VD/MD must be such that any
possible overshoot of the normal flight envelope does not cause any major problem.
In order to protect the A/C against dangerous phenomena which might be encountered in a dive or a vertical upset, the
high speed protection adds a positive NOSE UP G demand to the stick order. Incidently, this has allowed the margin
betwen VMO/MMO and VD/MD to be reduced.
Thus in a dive:
- STICK FREE, the A/C will slightly overshoot VMO/MMO and fly back towards the envelope and
- STICK FULL FORWARD, the A/C will significantly overshoot VMO/MMO without reaching VD/MD; at around
VMO + 16 / MMO + 0.04 the stick nose down authority is smoothly reduced to zero which does not mean that the
aircraft stabilizes at that speed.
Thus the pilot has full authority to achieve a high speed / steep dive escape maneuver when required with a REFLEX
action on the stick.
NOTE:
OVERSPEED warning is provided.
To Next Page
Loading...
Need help?
General
