Roll Ratio Switch

AUTO -  Provides normal system functions
EMERG - Removes hydraulic pressure from the hydromechanical roll control
        system which causes the roll ratio to drive to a midrange and lock.
        Mechanical ARI is also disabled.  The ARI is the Aileron-Rudder 
        Interconnect.

The Roll Ratio control is part of the F-15s lateral control system.

Lateral stick motion positions the ailerons rudders and stabilators to 
provide roll control.  The ratio of aileron/differential stabilator deflection
to lateral stick motion (roll ratio) is adjusted automatically for different
airspeeds, longitudinal stick position and gear position.  This provides
the same roll response for a given stick deflection regardless of airspeed.
Aileron and differential stabilator deflection are washed out to prevent
adverse yaw when longitudinal stick deflection is combined with lateral stick
deflection.  At subsonic speeds, the roll ratio is reduced.  With the landing
gear down, full aileron/differential stabilator is available at any 
longitudinal stick position.  If UTL A and PC2A hydraulic pressures are lost
or the roll ratio switch is in EMERG, the roll ratio system drives to mid-rang
and locks.  A spin recovery aid provides full lateral control authority, 
regardless of longitudinal stick position, when the yaw rate exceeds 60 degrees
per second.  Full lateral authority will be discontinued when the yaw rate
is less than 60 degrees per second.

The mechanical aileron-rudder interconnect (ARI) adjusts the control system 
such that lateral stick motion results in varying rudder deflection dependant
on longitudinal stick position.  With the control stick aft of neutral, lateral
stick motion causes rudder deflection in the same direction as stick motion.
With the control stick forward of neutral, lateral stick motion causes rudder
deflection in the opposite direction of the stick motion.  In addition, when 
the flaps are down, the amount of rudder deflection for lateral input is
increased.  The ARI is disengaged at supersonic speeds and on landing.  If the
anti-skid system detects a malfunction or the landing gear circuit breaker is
OUT, the ARI may remain engaged at wheel spin up, adversely affecting 
crosswind landing characteristics.

Turning the anti-skid switch OFF or PULSER will insure ARI disengagement. If
UTL A and PC2A hydraulic pressures are lost or Pitch or Roll Ratio switch is
in EMERG, the ARI is inoperative.  If the mechanical system is inoperative,
the differential stabilators (through roll CAS) will provide lateral control
for moderate manuvers including landing.

Landing and Taxi Lights

The landing and taxi lights are on the nose gear strut.  They are controlled by
a toggle switch on the miscellaneous panel. The lights are off, regardless of
switch position, on aircraft through 73-107 when the nose wheel is not down
and locked, or on aircraft 74-081 and up, when the landing gear handle is in the
up position.

OFF   - Lights are off.
LDG
LIGHT - If the nose gear is down and locked through 73-107 or the landing gear
        handle is down (74-081 and up), the landing light is turned on.
TAXI  - If the nose gear is down and locked through 73-107 or the landing gear
        handle is down (74-081 and up), the taxi light is turned on.


Inlet Ramp Switch

An inlet ramp switch for each inlet is on the miscellaneous control panel.
The switch is lever locked, and has positions of AUTO and EMERG.

AUTO   - The AIC automatically controls the air inlet system.  This is
         the normal position.

EMERG  - Removes electrical power from the ramp and bypass door actuators,
         causing them to move hydraulically to the emergency (ramps locked up
         and bypass door closed) position.  If hydraulic pressure fails, 
         airloads will force the ramps and bypass door to the emergency position.


Anti-Skid System

NORM     - The anti-skid is on when the gear is down.  However, illumination of
           the ANTI-SKID warning light activates the brake pulser system
           and ARI is disengaged with the gear down.

PULSER   - Turns off normal anti-skid protection, turns on the ANTI-SKID and
           MASTER CAUTION lights, and activates the brake pulser system.
           The ARI is disengaged with the gear handle down.

OFF      - Turns off the normal anti-skid and brake pulser systems.  Disengages
           ARI with the gear handle down.
 

Operational information on this page taken from TO 1F-15A-1, Change 1 - 15
August 1984