I ... feel ... [aircraft] with augmented control are more prone to landing incidents
The Airbus and Boeing 787 FBW with augmented control have some similarities.
This 2012 ICAS paper: "FLY-BY-WIRE AUGMENTED MANUAL CONTROL - BASIC DESIGN
CONSIDERATIONS" discusses Boeing and Airbus augmented control systems and its effect on piloting technique
See 4.2.
4.2 Piloting Technique for Disturbance Compensation
The influence of manual augmented control on the optimal
piloting technique is significant. For conventionally
controlled aircraft the task of stabilizing the
aircraft on the desired flight path after an external disturbance
is left to the pilot, but the pilot has no suitable
indication of flight path deviation on his PFD. For
that reason pilots are still used to react to a change of
attitude angles. As the attitude angles are easy to derive
either from the outside view or from the PFD that
puts the main focus on the aircraft attitude control, the
main control references for manual control are still the
pitch angle for longitudinal control and the bank angle
for lateral control.
However, the application of manual augmented control
in modern FBW aircraft has influenced the distribution
of tasks between the pilot and the flight control
system with respect to the compensation for external
disturbances.
For lateral motion control, Airbus uses a roll rate command
and bank angle hold system which actively tries
to keep the bank angle at zero after a lateral disturbance.
The B777 FBW lateral control is basically a
Direct Control mode without feedbacks and a roll attitude
hold feature, so the airplane responds to a lateral
disturbance like a conventionally controlled airplane.
The B787 has an integrated lateral/directional control
algorithm that provides basically roll rate command/
roll attitude hold control, similar to the Airbus design.
The latter type of designs provide more roll attitude
stiffness and thus require less pilot compensation for
external disturbances. For those control algorithms a
strong reaction of the pilot in response to rotational
rates or attitude angle changes might lead to adverse
effects due to a significant interaction between pilot
and the flight control algorithm.
In 2010 DLR performed a study on a Airbus A330
Full Flight Simulator, where the aircraft was disturbed
by a simulated wake vortex encounter while the pilots
revealed
that numerous pilots aggravated the impact of
the wake vortex on the aircraft response by generating
to strong and to abrupt inputs on the stick, although
they were informed that a wake encounter could occur
[23]. This was especially observed for pilots with
little experience on FBW aircraft. The final report
recommends that the pilots should react to the lateral
and vertical flight path deviation with extremely
smooth inputs on the stick rather than trying to overcompensate
for the change in attitude angles [23].
These recommendations are similar to those given
by Airbus for manual control during wake-vortex encounters
[21].
Hence, the piloting technique should change from a
continuous compensatory control to an intermittent
control strategy, because the short-term control task
of continuous pitch and roll attitude stabilization is
performed by the control algorithm. In many current
airline training programs no emphasis is put on the
adaptation of the piloting technique that is needed to
safely operate a FBW aircraft with manual augmented
control in case of external disturbances. It seems that
in most cases the pilot still uses pitch angle as his primary
control variable. During the simulator study performed
by Gautrey several pilots commented on the
desirability of a flight path vector display, especially
for the unconventional systems without speed stability,
because this is the parameter which they are ultimately
trying to control [12]. For the majority of existing
Airbus FBW aircraft the flight path vector symbol
is only available in the PFD, if certain autopilot
modes are triggered. However, flight path information
is displayed in the head-up display which can be
optionally ordered for every Airbus FBW aircraft.