28 | Flight International | 22-28 May 2018 flightglobal.com
COVER STORY
with Claffy without using the aircraft’s
inter-phone.
PITCH ENVELOPE PROTECTIONS
With the high-altitude work complete, we
started a descent towards a medium-altitude
block for some low-speed handling evalua-
tions. In the descent, I accelerated the G500 to
its maximum operating speed (MMO) of
M0.925 and, once lower, its 340KIAS VMO.
Ample warnings are provided of the high-
speed condition both on the PFD and cali-
brate air speed (CAS). At the limit speed/
Mach the FCL raise the nose to slow the air-
craft, as well as prohibiting further pitch trim.
At MMO a “high speed protect active” (advi-
sory) CAS message alerted me that the FBW
protections had kicked in. Additional for-
ward sidestick pressure had no effect, the
G500 could not be oversped. While not active
on our aircraft, the latest software loads will
also use the auto-throttle to reduce thrust and
further slow the aircraft. At both MMO and
VMO I put in a number of sharp small-ampli-
tude control inputs in each axis. As expected,
the aircraft’s response to these was deadbeat,
with no residual oscillations. Speed brake ex-
tension at these high speeds caused a minor
nose-up pitching moment, easily countered
by forward pressure on the sidestick.
After our speedy descent from altitude, we
levelled at 15,000ft, where I again used the
speed brakes to slow the aircraft, retracting
them before extending the landing gear at just
below its limit speed of 225KIAS. The flaps
were then extended to 20°, a typical configu-
ration for just after take-off. With the power
set to 81%N1, the G500 slowed in level flight.
For test day conditions the top of the slow
speed amber band in the PFD was 132KIAS.
Slowing further sounded an audible “air-
speed low” warning.
These cautions were purposely ignored as I
applied full aft sidestick, slowing the G500 to
its alpha limit of 110KIAS for our conditions.
At the limit, a “FCS AOA limiting” (advisory)
CAS message was displayed. In the G650 this
slow speed would have triggered the slow-
speed stick-shaker. For the G500, Gulfstream
has made significant improvements to theslow-speed protection scheme, fielding a ro-
bust system that allows the stick-shaker to
trigger at speeds below the red band.
Satisfied with the G500’s slow-speed han-
dling and warnings, I advanced the thrust le-
vers to power out of the slow-speed condition
in level flight. As the G500 has apparent
speed stability built into it, I used the sides-
tick’s trim button to relieve stick forces as we
cleaned up and accelerated to 250KIAS for
our transit back. During the transit, I lowered
the HUD and turned on the enhanced vision
system. After a short cooling period I found
the dual infrared-band cameras presented a
crisp view of the low-country marshes and
sloughs as we manoeuvred towards Savan-
nah/Hilton Head International.
While at altitude I had familiarised myself
with Symmetry’s flight management system
(FMS), using the CCD to graphically select
and define a number of waypoints in our
working area. I had found its operation to be
straightforward and quite powerful. Return-
ing to Savannah/Hilton Head International,
Claffy helped me install our planned ap-❯❯
Supercritical wing features large
single-panel barn-door trailing-edge flaps
Gulfstream