BMS F-16C/D 4.34, Flight Manual

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T.O. BMS1F-16CM-1 BMS 4.34 Change 2.00
BMS 4.34 Dash 1
© Red Dog 2012-2019
Page: 229
4.4.3 Asymmetric loading
Asymmetric loading must be trimmed with the roll trim to lift the heavy wing. When roll trim is used the
ARI adds rudder input causing a yaw away from the heavy wing. Both yaw and roll trim requirements
will change according to the flight envelope.
Asymmetric stores therefore increase the chances of departure from controlled flight as increased roll
commands are required to turn away from the heavy wing. G increase also will require more roll trim
and consequent rudder input to maintain the heavy wing level. Therefore aft stick will increase roll
requirements, which in turn will increase the yaw away from the heavy wing through the ARI.
All the roll and yaw input to maintain the aircraft in level flight further decreases the flight control action
before reaching the limiters, as level flight already requires flight control inputs. It is therefore even
easier to assault multiple limiters at the same time. Departure from controlled flight with asymmetrical
stores may not be recoverable.
4.4.4 Type of departure
Yaw departure:
A yaw departure may occur when the sideslip increases beyond controllable range.
This may happen in CAT I with a centreline, high altitude 25000 feet, in the Mach 0.8
– 0.95 range and
light asymmetric stores, or CAT III in the same conditions with heavier asymmetric stores.
Yaw departure may self-recover, or induce a pitch departure that may turn into a deep stall.
Roll departure:
Normally roll departu
re shouldn’t be documented because more than a 360° continuous roll is
forbidden with this
aircraft. And 360° wouldn’t be enough to induce a roll departure. Still BMS being a
simulation, roll departure is a real possibility if rolls limits are exceeded. Roll departure will lead to pitch
departure.
Pitch departure: upright or inverted.
Occurs when the AOA exceeds the AOA limiters.
During a pitch departure the instruments will usually report erroneous low speed (0-150kts) and AOA
above positive (32°) and negative (-5°) instrument limits.
This may happen at slow speed, or as a consequence of a yaw departure, heavy stores (wing tanks)
and opened speedbrakes.
A typical inverted pitch departure may be caused by flying at the top of a loop with airspeed too slow.
Pitch departure may induce deep stalls; inverted pitch departure may induce inverted deep stalls.
In a pitch departure the horizontal tails are locked in place by the FLCS to limit AOA. Pitch stick
commands are ineffective without MPO (Manual Pitch Override) use.
4.4.5 Deep Stalls & Recovery
A deep stall is an out of control situation in which the aircraft stabilises at very high AOA and drops
with significant sink rates. Luckily the FLCS in BMS does a really good job of preventing such
conditions and the hardest thing to achieve is actually to induce the deep stall in the first place. There
is a real chance that a pressure driven HOTAS sticks will get damaged trying to induce a deep stall.
Deep stalls are easier to induce at slow speed in CATI and at higher speed in CATIII, especially with
asymmetric loads.
During a deep stall the AOA instrument is usually glued at the maximum value of 32° for upright deep
stalls and at the -5° limit for inverted deep stalls. The FLCS tries to return the AOA to normal, blocking
the horizontal tail in full deflection. However, full deflection is not enough to get the AOA back into the
normal range.
Airspeed indication is not correct and the instruments usually reports speeds between 0 and 150 kts.
Sink rates are usually between 10000 and 15000 feet per minute.