The aeroplane shall have such stability in relation to its other
flight characteristics, performance, structural strength, and
most probable operating conditions (e.g. aeroplane configurations
and speed ranges) as to ensure that demands made on
the pilot’s powers of concentration are not excessive when the
stage of the flight at which these demands occur and their
duration are taken into account. The stability of the aeroplane
shall not, however, be such that excessive demands are made
on the pilot’s strength or that the safety of the aeroplane is
prejudiced by lack of manoeuvrability in emergency conditions.
The stability may be achieved by natural or artificial
means, or a combination of both. In those cases where
artificial stability is necessary to show compliance with the
Standards of this part, it shall be shown that any failure or
condition that would result in the need for exceptional pilot
skill or strength for recovery of aeroplane stability is extremely
improbable.