T.O. BMS1F-16CM-1
BMS 4.34 Change 2.00
BMS 4.34 Dash 1
© Red Dog 2012-2019
Page: 137
1.12.1.2. Roll FLCS
The main purpose of the Roll FLCS is to prevent roll-coupled departures by limiting the roll rate.
Four parameters contribute to a roll-coupled departure:
AOA (the higher it is the more critical)
Elevator position (the higher it is the more critical)
Dynamic pressure (the lower it is the more critical as dynamic pressure is lower at high altitude)
Rudder position commanded by the Yaw FLCS module
As a consequence pilots should be very aware of roll-coupled departure when performing low speed
barrel rolls at high altitude, which assaults two limiters at the same time (roll and pitch).
The CAT switch also plays a part in Roll FLCS by limiting the roll rate. In CATIII the aircraft is more
prone to roll coupled departure due to higher gross weight and position of the centre of gravity. The
maximum commanded roll rate is thus further reduced by 40% of the maximum commanded roll rate
in CAT I.
1.12.1.3. Yaw FLCS
Since the rudder is mostly controlled in flight by the FLCS through the ARI (Aileron Rudder
Interconnect) the pilot should in theory have no need to use the rudder in flight. To prevent pilot
induced rudder movement which can create adverse effects the FLCS automatically limits its use.
Rudder authority is reduced as a function of AOA, roll rate and CAT config to prevent departure from
controlled flight.
In CAT I the maximum deflection starts to be limited around 14° AOA and reaches zero deflection
possible at 26° AOA.
In CAT III the maximum deflection starts to be limited at 3° AOA and reaches zero deflection at 15°
AOA.
The ARI provides automatic coordinated turns by moving the rudder along with the ailerons to
compensate for aileron induced yaw effect.
Nevertheless in a crosswind take-off/landing situation the pilot may need to put the rudder and ailerons
in the same direction to compensate for winds. To allow this the ARI is inactive when the main gear
speed is greater than 60 knots or if AOA exceeds 35°.
When the gear is retracted the wheels slow down and thus the ARI becomes active again (usually 2
seconds after landing gear up). If the gear is kept down the ARI may take longer to become active
again.
1.12.2. TAKEOFF & LANDING gains
The FLCS automatically switches to Takeoff & Landing gains whenever the following conditions are
met:
-
Landing Gear in the down position or
-
ALT FLAPS switch in EXTEND position and below 400 knots or
-
AIR REFUEL door switch in OPEN position and below 400 knots
1.12.2.1 Pitch FLCS
The Pitch FLCS operates as a pitch rate command until 10° AOA. It means that the pilot commands a
pitch rate and not a G value as in Cruise gains. As a consequence when no pressure is applied the
FLCS maintains a 0° pitch rate, the nose will stay steady and the FPM will move up and down
according to AOA.
Above 10° AOA the FLCS commands pitch in a blended mode of pitch rate and AOA command. This
was created to give more feedback to the pilot for landing; indeed constant back pressure will be
required for the nose to keep its attitude, giving classic feedback for non-fly-by-wire aircraft during
landing.
Summary of Contents for F-16C/D 4.34
Page 30: ...T O BMS1F 16CM 1 BMS 4 34 Change 2 00 BMS 4 34 Dash 1 Red Dog 2012 2019 Page 30 ...
Page 56: ...T O BMS1F 16CM 1 BMS 4 34 Change 2 00 BMS 4 34 Dash 1 Red Dog 2012 2019 Page 56 ...
Page 121: ...T O BMS1F 16CM 1 BMS 4 34 Change 2 00 BMS 4 34 Dash 1 Red Dog 2012 2019 Page 121 ...
Page 134: ...T O BMS1F 16CM 1 BMS 4 34 Change 2 00 BMS 4 34 Dash 1 Red Dog 2012 2019 Page 134 ...
Page 176: ...T O BMS1F 16CM 1 BMS 4 34 Change 2 00 BMS 4 34 Dash 1 Red Dog 2012 2019 Page 176 ...
