F16C/D (BLOCKS 50 AND 52+). FLIGHT MANUAL (15 OCTOBER 2002) - page 19

T.O. GR1F16CJ1

1136

AUTOPILOT OPERATION

The autopilot is fully engaged when the PITCH

switch is not in A/P OFF. Autopilot options are

selected by positioning the PITCH switch (ALT

HOLD, A/P OFF, or ATT HOLD) and the ROLL

switch (HDG SEL, ATT HOLD, or STRG SEL). Stick

trim is inoperative with the autopilot engaged. The

manual trim is operable and may be used while the

autopilot is engaged. However, due to the limited

authority of the autopilot, engagement of any mode

in other than a trimmed flight condition degrades

autopilot performance.

The autopilot loop in the FLCC receives inputs from

the INS and CADC by means of the AMUX bus. A

lack of data, inaccurate data, or degradation/failure

of the AMUX disconnects the autopilot and activates

the FLCS FAULT caution light and the FLCS A/P

FAIL PFL message. The sensor information used by

the autopilot does not include the redundancy of the

FLCS so its use must be closely monitored at low

altitude or in close formation.  If AOA is greater than

15 degrees, the autopilot will disconnect and the

FLCS FAULT caution light and the FLCS A/P FAIL

PFL message will activate.

Additionally, the FLCC monitors autopilot operation

for a failure to maintain the selected mode and for

prolonged engagement outside of autopilot attitude

limits with no stick inputs. Detection of a failure

results in activation of the FLCS FAULT caution

light and the FLCS A/P DEGR PFL message.

Positioning the PITCH switch to ALT HOLD enables

the FLCS to use  CADC information to  generate

commands to the  horizontal  tails  which  result  in

the aircraft maintaining a constant altitude. The

FLCS limits the pitch command to +0.5g to +2g.

Engagement  of  altitude hold  at  rates  of  climb or

dive less than 2000 fpm selects an altitude within the

pitch command g limits. Engagement above rates of

2000 fpm causes no unsafe maneuvers; however, the

engaged altitude may not be captured. Control

accuracy of 

"

100 feet is provided to 40,000 feet

pressure altitude for normal cruise conditions. The

altitude reference may be changed by depressing the

paddle switch, changing altitude, and releasing the

paddle switch. ALT HOLD in the transonic region

may be erratic.

Positioning the PITCH switch to ATT HOLD allows

an attitude signal from the INU to be used to

maintain the selected pitch attitude. This mode does

not function if pitch angle exceeds 

"

60 degrees;

however, the PITCH switch remains engaged.

Positioning the ROLL switch to HDG SEL allows the

FLCS to use a signal from the HSI to maintain the

heading set on the HSI. Adjusting the HSI heading

reference marker to the aircraft heading prior to

engagement maintains the existing aircraft head

ing; otherwise, when the autopilot is engaged with

the ROLL switch in HDG SEL, the aircraft turns to

capture the heading indicated by the heading

reference marker on the HSI. The roll command does

not exceed a 30degree bank angle or a 20degree/se

cond roll rate. This mode does not function if bank

angle exceeds 

"

60 degrees; however, the ROLL

switch remains engaged.

Positioning the ROLL switch to ATT HOLD allows

the FLCS to use an attitude signal from the INU to

maintain the aircraft at selected roll attitude. This

mode does not function if bank angle exceeds 

"

60

degrees.

Positioning the ROLL switch to STRG SEL allows

the autopilot to steer the aircraft to the selected

steerpoint using roll commands. The roll command

does not exceed a 30degree bank angle or a 20

degree/second roll rate. This mode does not function

if bank angle exceeds 

"

60 degrees; however, the

ROLL switch remains engaged.

ADV MODE Switch

ADV MODE switch is a twofunction switch. The

ACTIVE light, which is located on the top half of the

ADV MODE switch, illuminates whenever ATF is

engaged. Depression of the ADV MODE switch when

the NVP is in an operate mode engages ATF. The

STBY light, which is located on the bottom half of the

ADV MODE switch, illuminates when PITCH

autopilot is engaged and the NVP is in an operate

mode. This configuration engages the TF/PITCH

autopilot blending mode; depression of the ADV

MODE switch at this point deselects the blending

mode and illuminates the ACTIVE light (ATF). The

STBY light also illuminates from the ATF mode if the

paddle switch is depressed, indicating that ATF is

ready to assume control (when paddle switch is

released).

STICK STEERING

Stick steering is operable only with the pitch and roll

attitude hold modes. Stick steering operation is

accomplished by applying force to the stick. With

ATT HOLD selected, a force applied in the

appropriate axis large enough to activate stick

steering causes the autopilot to drop the selected

reference and the system accepts manual inputs

from the stick.

T.O. GR1F16CJ1

1137

AOA SYSTEM

The system consists of two AOA transmitters located

on each side of the nose radome, AOA ports on the

fuselagemounted air data probe, a PSA, an AOA

correction device in the CADC, an AOA indexer, and

a vertical scale AOA indicator. In flight, the airflow

direction is sensed by the conical AOA probes and the

AOA ports of the fuselagemounted air data probe.

The AOA signals from all three sources are sent to the

input selector/monitor of each of the four FLCC

branches.

The AOA indicator, AOA indexer, and HUD AOA

bracket display the correct AOA until NLG WOW.

Therefore, accurate AOA indication is available

throughout twopoint aerodynamic braking. When

NLG WOW occurs, all AOA indications are based on

zero degrees.

The first AOA input signal or sensing failure is

indicated by the FLCS FAULT caution light and the

PFL message FLCS AOA FAIL on the PFLD and the

FLCS MFD page. A second failure is indicated by the

FLCS warning light and the FLCS AOA WARN PFL

message on the PFLD. When a first AOA failure is

identified, the failed input is set to 11 degrees AOA.

If a second AOA failure subsequently occurs, the

11degree signal existing in the first failed branch

prevents hardover AOA inputs and may provide AOA

information for landing.

During DBU operation, AOA failures are not reported

and a first AOA failure is not set to 11 degrees.

AOA Indicator

Refer to figure 152. The AOA indicator, located on the

instrument panel, displays actual AOA in degrees.

The indicator has a vertically moving tape display

indicating an operating range of -5 to approximately

+32 degrees. The tape is color coded from 917 degrees

to coincide with the colorcoded symbols on the AOA

indexer. 

GR1F-16CJ-1-0053X37

AOA Displays

INDICATOR

INDEXER

HUD DISPLAY

ATTITUDE

15

13

11

SLOW

HIGH AOA

ON SPEED

OPTIMUM AOA

FAST

LOW AOA

Figure 152.

T.O. GR1F16CJ1

1138

AOA Indexer

Refer to figure 152. The AOA indexer, located on the

top left side of the glareshield, consists of three

colorcoded symbols arranged vertically. The indexer

provides a visual headup indication of aircraft AOA

by illuminating the symbols individually or in

combinations as shown. The indexer lights display

AOA correction (based on approximately 13 degrees

AOA). This correction may be used during landing

approaches as visual direction toward optimum

landing AOA. The AOA indexer operates continu

ously with the LG handle up or down.

A dimming lever, located on the left side of the

indexer, controls the intensity of the lighted symbols.

The indexer lights are tested by activation of the MAL

& IND LTS switch on the TEST switch panel. The test

should be performed with the dimming lever in the

bright position.

HUD AOA Display

Refer to figure 152. The HUD AOA bracket and

flightpath marker provide a visual headup indica

tion of aircraft AOA. The flightpath marker aligned

with the top of the bracket indicates 11 degrees AOA.

The flightpath marker centered on the bracket

indicates 13 degrees AOA. The flightpath marker

aligned with the bottom of bracket indicates 15

degrees AOA. The HUD AOA display is only available

with the NLG lowered.

AIR DATA SYSTEM

Refer to figure 153. The air data system uses probes

and sensors to obtain static and total air pressures,

AOA, sideslip, and air temperature inputs. These air

data parameters are processed and supplied to

various systems.

Proper AOA transmitter and fuselage air data probe

operation is essential for safe flight operation.

Interference from foreign objects (especially ice,

internal or external) or improperly installed AOA

transmitters can result in erroneous AOA data at

weight off wheels. Reporting of false high AOA

concurrently from two sources can cause the FLCC to

command full nose down pitch which is impossible for

the pilot to stop. Ground use of probe covers protects

the system from foreign objects and moisture

intrusion. Ice on/in the probes is eliminated by using

probe heat prior to takeoff.

Air Data Probes

Two air data probes provide data inputs to the air

data system. One air data probe (pitot probe) is

mounted on the nose and provides a dual source of

static and total pressure. The other air data probe is

mounted on the forward right side of the fuselage and

provides a source of AOA, sideslip, static pressure,

and total pressure.

AOA Transmitters

The AOA transmitters are mounted on each side of

the radome and each provides sensor data to the

FLCS proportional to local AOA. The probe of the

transmitter protrudes through the radome to align

with the airstream.

Total Temperature Probe

The total temperature probe provides the CADC with

an analog signal which is required for true airspeed

and air density computation. The probe is located on

the underside of the right forebody strake.

Static Pressure Ports

Two flushmounted static pressure ports used for

measuring sideslip are located on the fuselage left

and right sides aft of the forward equipment bay

doors. These two ports provide inputs to a differential

pressure sensor for angleofsideslip measurement.

The measurement is also used to compensate the

third AOA source error and to verify the AOS derived

from the INS.

Probe Heat Monitor

The probe heat monitor monitors current flow to the

pitot, fuselage air data, and AOA probes (total

temperature probe current is not monitored). If the

current flow decreases below a certain value, the

monitor illuminates the PROBE HEAT caution

light. The monitor operates anytime the aircraft is

airborne, regardless of the PROBE HEAT switch

position.

T.O. GR1F16CJ1

Change 11139

GR1F-16CJ-1-0054A37

ALTIMETER

FIRE CONTROL SYSTEM

AOA INDICATOR

IFF TRANSPONDER

PROPULSION

NAVIGATION

ECS

FLIGHT CONTROLS

AUTOPILOT

USING SYSTEMS:

TOTAL

TEMPERATURE

PROBE

CENTRAL AIR DATA

COMPUTER (CADC)

AOA INDEXER

LEGEND:

= TOTAL PRESSURE

= STATIC PRESSURE

= AOA

= PROBE STATIC PRESSURE

= STATIC PRESSURE, LEFT

= STATIC PRESSURE, RIGHT

LEFT SIDE

FLUSH STATIC PORT

FUSELAGE-

MOUNTED

AIR DATA

PROBE

HEMISPHERICAL

(Portion of fuselage-

mounted air data probe)

RIGHT SIDE

FLUSH STATIC PORT

SIDESLIP DIFFERENTIAL

PRESSURE SENSOR

AOA TRANSMITTER

LEFT/RIGHT SIDE

FLIGHT CONTROL

COMPUTER

VERTICAL VELOCITY IND

ALTIMETER

AIRSPEED/MACH IND

PT1
PT2

PS1
PS2

PT

PS

P

P

P

P

SL

SR

PS3

PT3

P

P 2

P 1

P 2

PSL

PSR

P 1

LE FLAP COMMAND

SERVO

Air Data System Schematic (Typical)

   ELECTRICAL

CAUTION LIGHT PANEL

AOA

CSFDR

CADC

NOSE-MOUNTED AIR

DATA (PITOT) PROBE

PNEUMATIC

SENSOR

ASSEMBLY

(PSA)

(HUD AND       FCC,         MMC)

PX II

PX III

Figure153.

T.O. GR1F16CJ1

1140

PROBE HEAT Switch

The PROBE HEAT switch is located on the TEST

switch panel. The pitot, fuselage air data, AOA, and

the total temperature probe heaters are on anytime

the aircraft is airborne, regardless of the PROBE

HEAT switch position.

Functions are:

D

PROBE HEAT-On the ground, this position

energizes the pitot, fuselage air data, AOA, and the

total temperature probe heaters and the probe heat

monitor.

D

OFF - On the ground, circuits deenergized.

D

TEST-On the ground and in flight, this position

performs a functional test of the probe heat

monitoring system. The PROBE HEAT caution

light flashes 35 times per second. If the caution

light does not illuminate or if it illuminates but does

not flash, the probe heat monitoring system is

inoperative. The test feature does not verify proper

operation of probe heaters.

PNEUMATIC SENSOR ASSEMBLY (PSA)

The PSA converts pneumatic inputs from the nose

air data probe and the fuselage air data probe into

electrical signals. The PSA supplies static and

impact pressure signals and single AOA signals to

the input selector/monitor of each branch of the

FLCC. A ratio of impact to static pressure is

generated within the FLCC and used with AOA and

static pressure to schedule the LEF's and for gain

scheduling. The input selector/monitors also are

capable of detecting single and dual malfunctions of

the air data sensor signals. Single static or impact

pressure failures illuminate the FLCS FAULT

caution light and the FLCS ADC FAIL PFL on the

PFLD and MFD. A dual malfunction of static or

impact pressure signals results in the following:

D

Illumination of the FLCS warning light, continued

illumination of the FLCS FAULT caution light, and

the FLCS ADC FAIL (for first failure) and STBY

GAINS PFL messages.

D

Activation of FLCS standby gains. Refer to

STANDBY GAINS, this section.

Pitot probe tip icing results in erroneously low

airspeed indications, illumination of the FLCS

FAULT caution light with an FLCS ADC FAIL PFL

message, and flight control gains scheduled for low

airspeed conditions.

CENTRAL AIR DATA COMPUTER (CADC)

Refer to figure 154 for a signal flow diagram

showing the systems interacting with the CADC.

The CADC receives total and static pressures, AOA,

and total temperature inputs, converts the inputs

into digital data, and then transmits the data to the

using systems. The CADC has continuous BIT and

initiated BIT features; initiated BIT is run during

the FLCS BIT.

CADC Caution Light

The CADC caution light, located on the caution light

panel, illuminates whenever a malfunction in the

CADC is detected. If there is a mach signal failure

from the CADC, the ENGINE FAULT caution light

also illuminates and the ENG MACH FAIL PFL is

displayed on the PFLD. A CADC malfunction may

result in an FLCS AOS FAIL PFL and deactivation

of the AOS feedback function.

WARNING, CAUTION, AND

INDICATOR LIGHTS

Refer to figure 155. Warning, caution, and indicator

lights are used throughout the cockpit to call

attention to a condition or to allow an item to be easily

read. Red warning lights and the amber MASTER

CAUTION light are all located on the edge of the

glareshield. All of the lights, except the MASTER

CAUTION light, are described under their respective

systems.

The warning and caution lights (except MASTER

CAUTION) are not presstotest or presstoreset

lights. Pressing these lights releases them from their

modules and deactivates them. To reengage a

released light, pull it out slightly and then press to

reengage the module.

T.O. GR1F16CJ1

1141

CADC and Interfacing Systems

CADC STATUS

AIR DENSITY RATIO

GR1F-16CJ-1-0055A37

TRUE TEMPERATURE

PRESSURE ALTITUDE (29.92)

TRUE AIRSPEED

CALIBRATED AIRSPEED

AOA

MACH NUMBER

PRESSURE ALTITUDE (BARO)
COMMAND WORD

PRESSURE ALTITUDE (BARO)
CADC RESET

AOA L, R

CADC TEST ENGAGE

CADC TEST PASS

DISCRETE BASED ON

CALIBRATED AIRSPEED,

PRESSURE ALTITUDE, AND

PRESSURE ALTITUDE RATE

TOTAL PRESSURE

STATIC PRESSURE

NOSE-MOUNTED

AIR DATA (PITOT)

PROBE

TO/LDG

CONFIG

FLIGHT

CONTROL

COMPUTER

V V I

CAUTION LIGHT

PANEL

AOA INDICATOR

PROPULSION

CONTROL SYSTEM

AOA INDEXER

ELECTRICAL POWER

ENVIRONMENTAL

CONTROL SYSTEM

IFF TRANSPONDER

ALTIMETER

TOTAL

TEMPERATURE

PROBE

TOTAL TEMPERATURE

PRESSURE ALTITUDE (29.92)
BAROMETRIC SETTING

AIMS CODE

PRESSURE ALT VALID

PRESSURE ALTITUDE

MACH NUMBER

DISCRETES

MACH NUMBER

AOA

CADC FAIL STATUS

CENTRAL

AIR DATA

COMPUTER

(CADC)

FLIGHT CONTROL

PANEL

PRESSURE ALTITUDE (29.92)
PRESSURE ALTITUDE (BARO)
CALIBRATED AIRSPEED

TRUE TEMPERATURE
AOA

MACH NUMBER

CRASH

SURVIVABLE

FLIGHT DATA

WARNING

CADC RESET

VERTICAL VELOCITY

RECORDER

(CSFDR)

AVIONIC

SYSTEMS,

PW229

GE129

EMSC

AND

EMSC

EMSC

EDU,

115 VAC, 1 , 400 Hz

Figure154.

T.O. GR1F16CJ1

1142

GR1F-16CJ-1-0056-1A37

LG CONTROL PANEL

THREAT WARNING

FLCP

ENG

& JET

START

CONTROL

PANEL

C DF

EPU CONTROL

PANEL

ELEC CONTROL

PANEL

THREAT WARNING

Warning, Caution, and Indicator

Lights       (Typical)

TEST SWITCH PANEL

AOA

INDEXER

ADVANCE

MODE

SWITCH

ECM CONTROL PANEL

C

DF

Figure155.(Sheet 1)

T.O. GR1F16CJ1

1143

GR1F-16CJ-1-0056-2A37

AR STATUS/NWS

INDICATOR

DATA ENTRY DISPLAY

NWS CONTROL

BUTTON/

INDICATOR

CAUTION LIGHT PANEL

DF

PILOT FAULT LIST DISPLAY

MARKER

BEACON

CMDS

WARNING LIGHTS

ARE RED WITH BLACK

LETTERING

PX II

PX III

OXY LOW

OBOGS

PX II

PX III

Figure155.(Sheet 2)