T.O. BMS1F-16CM-1
BMS 4.34 Change 2.00
BMS 4.34 Dash 1
© Red Dog 2012-2019
Page: 228
4.3 Category Loading
Unlike popular belief, the CAT config switch does not limit G. It limits AOA, which as a consequence
limits maximum G available that the pilot can request according to his speed.
CAT I is the least limiting position and is intended for a clean configuration (centreline and A-A
weapons can be carried). The pilot can request from -3G to +9G. AOA is limited to 25°.
AOA remains a factor in the maximum possible G. At 20° AOA it will reach 7.3G and at 25° AOA the
max G reachable is 1G (level flight).
Rudder deflection is slightly limited in CAT I to limit the roll rate (induced roll). Maximum Rudder
deflection starts to be limited around 14° AOA and reaches zero deflection possible at 26° AOA.
CAT III is the most limiting position and is intended to protect the aircraft from departures when
carrying heavier loads on the wing stations (e.g. fuel tanks, A-G bombs, etc).
AOA is limited from a certain angle to prevent higher G being reached. This AOA limit is around 15.5
–
15.8° AOA. That means that in CAT III below 15° AOA, the airframe might be able to pull 9G, but as
soon as the AOA reaches 15° the CAT III limits additional AOA increase, therefore limiting the number
of available G.
In CATIII the aircraft is more prone to roll-coupled departures due to higher gross weight and position
of the centre of gravity. To prevent departure the maximum commanded roll rate is thus further
reduced by 40% of the maximum commanded roll rate in CAT I.
Maximum rudder deflection is also limited in CAT III and starts to be limited at 3° AOA and reaches
zero deflection at 15° AOA.
Although the FLCS, through the CAT limiting switch, offers further protection against departure the
pilot still has to be careful with heavier (and especially asymmetric) loads (CAT III) or at slow speeds
with lighter loads (CAT I).
4.4.
Departure from controlled flight
Departure from controlled flight is something any fighter pilot will strive to avoid. By nature fighter
aircraft and especially F-16s are unstable (the FLCS actually provides artificial stability to the aircraft)
and depending on the configuration and stores loading, recovery from departure might be impossible.
Departure (stalling) is not a direct function of speed but rather a direct function of angle of attack.
When a critical angle of attack is achieved the wing doesn’t generate lift anymore because the airflow
is turbulent. The wing stalls and the aircraft may depart controlled flight.
The FLCS limits the potential for departure by limiting AOA, as seen in the previous chapter.
Nevertheless by assaulting two limiters at the same time (maximum commanded roll coupled with
either maximum aft stick, or exceeding the maximum bank angle change limits) departure from
controlled flight is possible and pilots should know how to deal with the situation.
4.4.1 Rudder input
The Aileron Rudder Interconnect (ARI) automatically provides rudder input according to pilot roll input
to reduce sideslip during turns. Pilot induced rudder does not improve turn performance, but actually
increases departure possibility.
4.4.2 Flight with stores
Stores increase instability, inertia and gross weight. Although stores will lead to stricter limits from the
FLCS (in CAT III), departure remains possible. Avoid abrupt controls commands that may assault 2
limiters at the same time; AOA & roll for instance.
Summary of Contents for F-16C/D 4.34
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