F16C/D. FLIGHT MANUAL (2002)

T.O. GR1F16CJ1

Change 1384.1/(384.2 blank)

A throttle cable internal failure or a throttle linkage

disconnect results in an automatic transfer to SEC;

however, control of the engine with a failed throttle

cable or linkage disconnect is not possible in SEC. In

SEC, a throttle cable internal failure is character

ized by a possible rpm increase but no decrease with

throttle movements; a linkage disconnect results in

no response to throttle movements. In this situation,

control of the engine at idle and above can be

regained in PRI by cycling the ENG CONT switch to

SEC, then back to

PRI,

NORM. The engine

logic for this failure is such that the engine remains

in PRI after cycling the ENG CONT switch. After

landing, shutdown of the engine must be accom

plished either with the FUEL MASTER switch or

maintenance personnel action to position the MEC

throttle input shaft to off.

If SEC caution light illuminates when supersonic:

Throttle-Do not retard below MIL until

subsonic.

Retarding throttle below MIL while

supersonic may induce inlet buzz

which produces severe cockpit vibra

tion and probable engine stalls.

When subsonic or if SEC caution light illuminates

when subsonic:

Throttle-Verify engine responds normally to

throttle movement from IDLE to MIL; set as

desired.

AB operation is inhibited and exhaust nozzle

is closed.

If the engine is operating normally in SEC:

ENG CONT switch-Do not cycle.

The switch may remain in PRI or may be

placed to SEC. If the switch is placed to SEC,

do not place switch back to PRI.

Cycling the ENG CONT switch in an

attempt to regain PRI may result in

reoccurrence of the original malfunc

tion or a more severe condition.

Land as soon as practical.

During landing in SEC, idle thrust is

approximately twice that in PRI with a

normal nozzle.

T.O. GR1F16CJ1

Change 1385

If the engine is operating abnormally in SEC:

Failure to monitor sink rate and height

above terrain while applying low

thrust recovery procedures can result

in ejection outside ejection seat perfor

mance envelope.

ENG CONT switch-Position to SEC, then

back to

PRI,

NORM.

Airspeed-250 knots (If thrust is too low to

sustain level flight).

Land as soon as possible.

NOTE

A broken throttle cable or throttle

linkage disconnect causes a transfer to

SEC and abnormal engine response in

SEC. Reselecting PRI restores normal

engine operation for flight; however,

engine shutdown after flight requires

either use of the FUEL MASTER

switch or maintenance personnel action

to position the MEC throttle input shaft

to off.

If thrust is too high to permit a safe landing:

NOTE

If throttle is stuck, control might be

regained by depressing the cutoff

release, rotating the throttle outboard,

and applying necessary force.

Plan a flameout landing. Refer to FLAMEOUT

LANDING, this section.

Do not start the JFS if engine seizure

has occurred or is anticipated or if

engine failure is a result of fuel

starvation. Starting the JFS may

result in no brake/JFS accumulator

pressure for the brakes.

When landing is assured (normally high key):

Delaying engine shutdown can result

in a long, fast landing. Wheel braking

is less effective due to lack of WOW and

there is an increased probability of a

missed cable engagement.

Throttle-OFF.

If throttle is stuck or engine does not respond,

shut down the engine with the FUEL

MASTER switch. At MIL, the engine flames

out in approximately 6 seconds. At IDLE, the

engine flames out in approximately 45

seconds.

HOOK switch-DN (if required).

The hook may miss the cable if the

aircraft is not slow enough to compress

the MLG struts sufficiently to make

WOW or if forward stick pressure is

held.

FTIT Indicator Failure

129

The engine does not use FTIT as a control parameter.

However, routine missions should not be continued

since FTIT cannot be monitored.

Zero RPM/Erroneous RPM Indication

129

If the RPM indicator fails to zero or displays

erroneous RPM indication, it indicates either a

malfunction within the indicator itself or within the

engine alternator. Total alternator failure also

causes an automatic transfer to SEC. The ENGINE

warning light also illuminates for engine alternator

or RPM indicator failure. Engine transfer to SEC

due to certain partial or total alternator failures,

results in loss of most engine fault reporting. Partial

alternator failure may not result in automatic

transfer to SEC. If the engine does not transfer to

SEC, fault reporting continues. Partial alternator

failure may also result in transfer to hybrid

operation with AB operation inhibited. In this case,

ENG HYB MODE and ENG A/B FAIL PFL's occur.

Routine missions should not be continued without a

functional RPM indicator.

T.O. GR1F16CJ1

386

If SEC caution light is illuminated:

Go to SEC CAUTION LIGHT, this section.

If SEC caution light is not illuminated:

Land as soon as practical.

Abnormal Engine Response

129

Refer to LOW THRUST ON TAKEOFF OR AT LOW

ALTITUDE (NONAB)

129

, this section, if

appropriate.

If thrust is too low to sustain level flight, turn

immediately toward the nearest suitable runway and

establish 250 knots airspeed. Consider jettisoning

stores to increase flying time available to complete

actions designed to restore usable thrust and improve

range in the event those actions are unsuccessful.

NOTE

In a partial thrust situation, thrust

available may increase as altitude

decreases. 250 knots approximates the

airspeed at which thrust required for

level flight is the lowest.

Abnormal engine response is varied and generally

indicated by abnormal thrust in relation to throttle

position, engine oscillations (either continuous,

momentary, or recurring), a complete lack of engine

response to throttle movement, autoacceleration/de

celeration, exhaust nozzle failure, or insufficient

thrust. A PRI malfunction can cause these abnormal

engine responses as well as overtemperature or

overspeed indications. During AB operation, if engine

anomalies occur in region 1, the throttle should be

moved out of the AB range and AB should not be

selected again for the remainder of the flight.

Exhaust nozzle control or oil system malfunctions

can result in the nozzle being too far open, too far

closed, or unstable. Insufficient thrust may result if

the nozzle is more open than normal. SEC should be

selected and, if the nozzle goes fully closed, engine

operation should be continued in SEC. If the nozzle

does not close in SEC, the ENG CONT switch should

be moved back to

PRI,

NORM as more

thrust results and AB lightoff may be attainable at

lower altitudes. AB should only be used when

required to sustain flight.

If the exhaust nozzle is positioned more closed than

normal, thrust is adequate, but engine stall may

occur if AB is selected. Automatic transfer to SEC

should occur for most exhaust nozzle malfunctions.

NOTE

Certain PRI malfunctions may not

result in an autotransfer to SEC. If the

engine operates abnormally, do not

rely upon an autotransfer to SEC.

Timely selection of SEC may preclude

further engine problems.

If thrust is still insufficient to make a safe landing

after selecting SEC or abnormal engine response is

still present, reattempt PRI.

If the throttle is stuck and thrust is suitable for

sustained flight, attempts to free the throttle should

be delayed until within gliding distance of a suitable

landing field. If throttle is stuck in AB, placing the

ENG CONT switch to SEC terminates AB and

provides SEC MIL thrust. If throttle is stuck or

otherwise prevented from normal movement,

control might be regained by depressing the cutoff

release, rotating the throttle outboard, and applying

necessary force.

If thrust is too high to permit a safe landing, use

excess thrust to climb and maneuver toward the

nearest suitable airfield. Once high key for a

flameout landing is assured, follow procedures as

outlined in FLAMEOUT LANDING, this section.

Activate the JFS and EPU and then shut down the

engine as soon as landing is assured (normally high

key) by placing the throttle to OFF or, if necessary,

by placing the FUEL MASTER switch to OFF.

If abnormal engine response occurs:

Failure to monitor sink rate and height

above terrain while applying low

thrust recovery procedures can result

in an ejection outside ejection seat

performance envelope.

If the throttle is stuck and thrust is

suitable for sustained flight, attempts

to free the throttle should be delayed

until within gliding distance of a

suitable landing field.

Idle PRI thrust with nozzle closed is

approximately 50 percent greater than

idle SEC thrust.

T.O. GR1F16CJ1

Change 1387

If in AB or if supersonic:

Throttle - Retard to MIL.

Retarding throttle below MIL while

supersonic may induce inlet buzz

which produces severe cockpit vibra

tion and probable engine stalls.

If subsonic or problem still exists:

ENG CONT switch - SEC.

NOTE

Transfer to SEC may be accomplished

while supersonic if the throttle

remains at MIL.

Airspeed-250 knots (if thrust is too low to

sustain level flight).

Throttle-Verify engine responds normally to

throttle movement from IDLE to MIL; set as

desired.

AB operation is inhibited and exhaust nozzle

is closed.

If a safe landing can be made with the current thrust:

Land as soon as practical.

During landing in SEC, idle thrust is higher

than normal.

If thrust is insufficient to make a safe landing or

abnormal engine response is still present:

ENG CONT switch-

PRI,

NORM.

NOTE

If the exhaust nozzle is failed open,

additional thrust to sustain flight may

be attained by selecting AB at low

altitudes.

Land as soon as possible.

If thrust is too high to permit a safe landing:

NOTE

If throttle is stuck, control might be

regained by depressing the cutoff

release, rotating the throttle outboard,

and applying necessary force.

Plan a flameout landing. Refer to FLAMEOUT

LANDING, this section.

Do not start the JFS if engine seizure

has occurred or is anticipated or if

engine failure is a result of fuel

starvation. Starting the JFS may

result in no brake/JFS accumulator

pressure for the brakes.

When landing is assured (normally high key):

Delaying engine shutdown can result

in a long, fast landing. Wheel braking

is less effective due to lack of WOW and

there is an increased probability of a

missed cable engagement.

Throttle-OFF.

If throttle is stuck or engine does not

respond, shut down the engine with the

FUEL MASTER switch. At MIL, the engine

flames out in approximately 6 seconds. At

IDLE, the engine flames out in approxi

mately 45 seconds.

HOOK switch-DN (if required).

The hook may miss the cable if the

aircraft is not slow enough to compress

the MLG struts sufficiently to make

WOW or if forward stick pressure is

held.

AB Blowout/Failure To Light

129

AB blowouts are characterized by a thrust loss, a fuel

flow decrease, and nozzle closure. The DEC attempts

to relight the AB as long as the throttle remains in

AB.

Refer to Figure 117. If AB is selected in region 1 and

fails to light within 10 seconds or if the AB blows out

in any region, retard throttle out of AB. AB operation

should not be reattempted for the remainder of the

flight.

T.O. GR1F16CJ1

388

AB operation in region 2 may include AB no lights or

delayed lights if unfavorable AB lightoff conditions

exist. If these are encountered, the throttle may be

left in AB. If the throttle is retarded, an AB light may

be attempted.

ENGINE STALLS

129

The three primary causes of a stall are inlet flow

distortion, AB instabilities, and hardware malfunc

tions. During normal aircraft operation, inlet flow

distortion severe enough to cause engine stall is not

expected. However, under some departure condi

tions, inlet flow distortion may induce engine stalls.

Hardwareassociated stalls may result from a failed

nozzle, control system malfunctions, or FOD.

The first indication of a stall at high thrust settings

may be a loud bang or pop. At lower thrust settings,

the first indication may be loss of thrust, lack of

throttle response, or decreasing rpm. The throttle

should be retarded at the first indication of a stall.

Engine stalls are divided into two types:ABasso

ciated engine stalls and nonAB engine stalls.

ABAssociated Engine Stalls

129

Types of ABassociated engine stalls are:

AB initiation - Stall at AB lightoff.

AB sequencing - Stall during AB sequencing as the

AB fuel flow increases with the throttle in AB.

AB cancellation - Stall during throttle retard from

AB.

AB blowout/relight - Stall occurs during relight

after a blowout in stabilized AB. May be preceded by

AB rumble.

ABassociated engine stalls are normally accompa

nied by a loud bang or pop and a possible fireball from

the engine exhaust and occasionally the engine inlet.

These characteristics could be mistaken for an

aircraft fire. Whenever a stall occurs while operating

in AB, the throttle should be snapped out of AB to

MIL. This usually clears the stall and restores

normal operation. The stalls may continue at MIL

and are characterized by bangs or pops of lower

intensity than AB stalls. If stall condition persists,

refer to NONAB ENGINE STALLS

129

, this

section.

If an ABassociated engine stall occurs

below 30,000 feet MSL or while

supersonic, IGV system damage may

occur. Throttle movements after the

stall clears should not be rapid.

FTIT fluctuation and decreasing rpm will probably

accompany stalls. The throttle should be retarded to

IDLE if the stall continues for a few seconds. The

engine may continue to stall at IDLE but may not be

audible, particularly at high altitudes. The engine

instruments should be monitored for indications of

stall. FTIT may rise while rpm decreases.
If the engine stalls at low altitude, an immediate

climb should be initiated. Retarding the throttle to

MIL may clear the stall. If engine response at low

altitude is not sufficient to maintain or gain altitude

and a suitable field is not immediately available,

ejection may be required.

NonAB Engine Stalls

129

NonAB engine stalls may occur if the control system

is malfunctioning, particularly during throttle

transients. NonAB engine stalls are often a

symptom of a serious engine problem. NonAB

engine stalls may be inaudible; the first indication

may be a lack of engine response to throttle

movement which may be difficult to differentiate

from abnormal engine response. However, nonAB

engine stalls may be characterized by bangs, pops,

low intensity engine rumble or vibration, and/or

erratic orangeyellow flame from the engine

exhaust.
This exhaust flame could be mistaken for an engine

fire. FTIT fluctuation and decreasing rpm will

probably accompany stalls. If a stall is confirmed,

the throttle should be immediately retarded to

IDLE. The engine may continue to stall at IDLE but

the stall may not be audible, particularly at high

altitudes. The engine instruments should be

monitored for indications of stall. FTIT may

increase while rpm decreases. If the stall continues,

place ENG CONT switch to SEC. If the engine

recovers, throttle movements should be minimized

and made slowly until landing is assured.
If stall continues, initiate airstart. Refer to

AIRSTARTS

129

, this section. When trying to

clear a stall with an airstart, the throttle should be

maintained in OFF for a few seconds to allow the

stall to clear. If the stall continues after the airstart,

the engine may have a serious hardware problem.

The focus should shift to using available thrust to

land at the nearest divert field.

T.O. GR1F16CJ1

389

Prolonged engine operation with FTIT

in excess of 980

C can result in

significant engine damage and may

cause a nonrecoverable engine failure.

Engine Stall Recovery

129

If an AB stall(s) occurs:

Throttle - Snap to MIL.

If AB stalls do not clear or stall(s) occurs below AB:

NOTE

NonAB stalls may be inaudible.

2. Throttle-IDLE.

If stalls continue:

ENG CONT switch-SEC.

If stalls continue:

Throttle-OFF for a few seconds, then

initiate

airstart. Refer to AIRSTART PROCEDURES

129

, this section.

NOTE

For serious hardware problems, the

engine may operate normally at idle

rpm but exhibit stall/vibration condi

tions at thrust settings above idle rpm.

Attempting additional airstarts will

not clear the condition. Use the highest

thrust setting below the stall/vibra

tion condition to sustain flight.

If stall(s) clears:

Throttle-MIL or below. Minimize throttle

movements and make necessary movements

slowly.

NOTE

If stall(s) occurred in AB at 30,000 feet

MSL or above and while subsonic, the

engine is safe to operate in the IDLE to

MIL range provided no other abnormal

engine indications are observed.

If stall(s) occurred at MIL or below, or in AB below

30,000 feet MSL or while supersonic:

Land as soon as possible.

INLET BUZZ

129

Inlet buzz occurs at supersonic airspeeds if an engine

control system failure or a CADC mach signal failure

results in insufficient airflow or if the throttle is

retarded below MIL while operating in HYB or SEC.

Inlet buzz causes moderate to severe vibration

within the cockpit and may result in multiple engine

stalls.

If inlet buzz occurs, do not move the throttle until

subsonic. Decrease airspeed to subsonic as quickly

as possible by opening the speedbrakes and

increasing g. If engine stalls occur and persist, the

throttle should be retarded to IDLE when subsonic.

If the stalls do not clear, retard the throttle to OFF

for a few seconds, then advance to midrange. Refer

to AIRSTART PROCEDURES

129

, this section.

BIRD STRIKE

129

In the event of a bird strike or suspected bird strike,

AB should be used only if absolutely necessary. It is

possible to lodge bird remains in the AB system such

that liner damage and subsequent duct burn

through occurs if AB is used. There is no concern of

liner damage during any nonAB operation. Refer to

ABNORMAL ENGINE RESPONSE

129

, this

section, if appropriate.

ENGINE OVERSPEED

129

An overspeed occurs when engine rpm exceeds 109.5

percent. If an overspeed condition occurs, an MFL is

recorded and the engine control attempts to reduce

rpm below maximum limit. However, if the DEC

malfunctions and engine rpm reaches 113 percent,

the overspeed protection in the MEC closes the

overspeed fuel shutoff valve resulting in a flameout.

To restore fuel, retard the throttle to OFF then

advance to midrange.

Refer to AIRSTART PROCE

DURES

129

, this section.

ENGINE FAILURE OR FLAMEOUT

129

If the engine flames out, fuel starvation or

mechanical failure has occurred.

A flameout is indicated by a decrease in FTIT and

engine rpm decaying below inflight idle (approxi

mately 70 percent rpm). Loss of thrust and lack of

response to throttle movement confirm the flameout.

T.O. GR1F16CJ1

390

The ENGINE warning light illuminates when

engine rpm is below 60 percent. Additionally, the

MAIN GEN and STBY GEN lights illuminate below

50 percent rpm and the EPU should start running.

Do not mistake a loss of ECS noise as an engine

flameout.

A flameout indicates an engine control failure, fuel

starvation, fuel system malfunction, or fuel cutoff

due to engine overspeed protection. If the engine

flames out, two features may instantly restart the

engine. There is an autorelight feature and the

capability to automatically transfer to SEC if certain

faults are detected in PRI. If these features work, the

restart may take place instantly and the flameout

may not be noticeable (except for the illumination of

the SEC caution light). In this situation, remain in

SEC. (Refer to SEC CAUTION LIGHT, this section.)

If the flameout progresses to the point that it is

noticeable, retard the throttle to OFF, then advance

to midrange. Refer to AIRSTART PROCEDURES

129

, this section.

Tower Shaft Failure

129

Failure of the engine tower shaft or its associated

geartrain results in engine flameout due to fuel

starvation. A restart is not possible; primary

emphasis should be on a flameout landing. If unable

to make a flameout landing, refer to EJECTION

(TIME PERMITTING), this section. Because tower

shaft failure results in the loss of rotation to the

enginedriven gearbox and ADG, the initial symp

toms are similar to main fuel pump failure. The

primary differences are that the rpm indication drops

immediately to zero and ENGINE warning light and

the SEC caution light illuminate since the engine

alternator is no longer providing power to the DEC.

The JFS should be started immediately upon

entering the JFS envelope to conserve EPU fuel. The

JFS drives the ADG and the engine gearbox which

restores rotation to both hydraulic pumps and

provides a reduced FLCS PMG output. Depending

on JFS performance and load, rpm may even be high

enough to restore standby generator power;

however, main generator power may cycle on and off.

Without the load of the engine, the JFS produces a

3055 percent rpm indication, which is the speed of

the engine gearbox and not the actual engine rpm.

The true engine rpm is unknown.

Low Altitude Engine Failure or Flameout

129

Refer to figures 310 and 311. Initial reaction to any

malfunction at low altitude should be to trade excess

airspeed for altitude. Higher altitude translates

directly to either additional time to achieve an

airstart or to additional glide range to reach a

suitable landing field. Above 310 knots, more time is

available by performing a zoom climb using a 3g

pullup to 30degree climb until approaching the

desired airspeed (use approximately 50 knots lead

point) and then initiating a zerog pushover. Below

310 knots, more time is available by performing a

constant altitude deceleration to the desired

airspeed; if required, climb to achieve minimum

recommended ejection altitude.

If the zoom results in an altitude below 4000 feet

AGL, there may be insufficient time to achieve an

airstart prior to reaching minimum recommended

ejection altitude. In that case, primary consideration

should be given to preparing for ejection; do not delay

ejection below 2000 feet AGL.

If low altitude engine failure or flameout occurs:

Zoom.

Stores-Jettison (if required).

If stores jettison is attempted after main and

standby generators drop off line but before

EPU generator powers the SMS (approxi

mately 5 seconds delay), stores will not

jettison.

NOTE

Visually confirm the stores have

jettisoned and jettison again if re

quired.

Perform airstart (if altitude permits). Refer to

AIRSTART PROCEDURES, this section.

Below 4000 feet AGL, there may be

insufficient time to perform an airstart

prior to minimum recommended ejec

tion altitude.

AIRSTARTS

129

Refer to figure 312. Airstarting the engine does not

require exact airspeeds or rpm ranges, but there are

key events in the airstart sequence that must be

performed in a timely manner in order to have the best

chance for an airstart. The key events are initiating

the airstart while engine rpm is still high, selecting

SEC if there is no lightoff prior to rpm decaying below

50 percent in PRI (or immediately when below 10,000

feet AGL), and preserving engine rpm prior to

lightoff.

. GR1F

16CJ

391

160

180

200

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

INITIAL AIRSPEED KIAS

INITIAL AL

TITUDE 1000 FT AGL

1F-16X-1-4025X

GW = 23,000-25,000 LB

DI = 0-50

WINDMILLING OR SEIZED ENGINE

30-DEGREE CLIMB MAINTAINED TO 170/250 KIAS

CONFIGURATION:

CONDITIONS:

3G PULLUP TO 30

ZOOM CLIMB TO

ACHIEVE:

250 KIAS

170 KIAS

Low Altitude Zoom Capability

ENGINE F110-GE-129

DATA BASIS ESTIMATED

LG UP

Figure 310.

100

120

140

160

180

200

220

240

260

280

300

320

340

360

380

400

420

440

INITIAL AL

TITUDE 1000 FT AGL

MINIMUM RECOMMENDED

EJECTION ALTITUDE

30 DIVE TO DESCENT KIAS OR 3G PULLUP

TO 30 ZOOM CLIMB INITIATED FROM THE

AIRSPEED/ALTITUDE EXISTING AT FIRST

RECOGNITION OF ENGINE FAILURE

AIRSTART INITIATED AT START OF DIVE OR

ZOOM BY CYCLING THROTTLE TO OFF AND

THEN MIDRANGE

45 SECONDS ASSUMED AFTER

THROTTLE ADVANCE TO ACHIEVE

USABLE THRUST (ASSUMES AIRSTART

DESCENT AIRSPEED IS 170 KIAS

CONDITIONS:

ENGINE F110-GE-129

INITIAL AIRSPEED KIAS

(SEC) (JFS RUN LIGHT ON)

INITIATION AT 25 PERCENT RPM)

GR1F-16CJ-1-0120A37

Low Altitude Airstart Capability

DATA BASIS ESTIMATED

CONFIGURATION:

GW = 23,000-25,000 LB

DI = 0-50
LG UP

. GR1F

16CJ

392

Figure 311.

T.O. GR1F16CJ1

393

1F-16X-1-4024-1A

ENGINE F110-GE-129

0.2

0.4

0.6

0.8

1.0

1.2

1.4

MACH NUMBER

TITUDE 1000 FEET

JFS ENVELOPE

AIRSTART ENVELOPE

POINT B TO

SL = 8.5 MIN/44 NM

CONDITIONS:

DRAG INDEX = 0
KIAS = 250

NO WIND

MIN KIAS

(WITH JFS

OPTIMUM FLIGHT PATH DURING AN AIRSTART (TYPICAL)

Engine out descent flight path maintains the aircraft in the required airstart envelope.

A 30-degree dive to descent KIAS is used to approach the airstart envelope

(Point A to B).

DIVE

170 KIAS

Airstart is enhanced by increased airspeed, altitudes below 30,000 feet, and light-off

at highest possible engine rpm.

GW = 26,000 LB

400 KIAS/0.9 MACH

RUN LIGHT

ON)

250 KIAS

(RECOMMENDED)

Engine RPM and FTIT Response During

Spooldown and Airstart

Figure312.(Sheet 1)

T.O. GR1F16CJ1

394

1F-16X-1-4024-2X

TIME SECONDS

90 100

LIGHT-OFF

RATE OF ENGINE RPM AND FTIT DECAY AND RECOV-
ERY FOR SPOOLDOWN AIRSTARTS AT 25,000 FEET.

Following the rapid FTIT rise and peak after light-off, FTIT
slowly decreases approximately 50 C.

Airstarts initiated between 25-50 percent engine rpm are

slow to light-off and may take up to 90 seconds to regain

usable thrust.

TIME SECONDS

RPM %

FTIT C

800

700

600

500

400

300

200

900

LIGHT-OFF

100

LIGHT-OFF

RATE OF ENGINE RPM AND FTIT DECAY AND
RECOVERY FOR JFS-ASSISTED AIRSTART AT

Following the rapid FTIT rise and peak after light-
off, FTIT slowly decreases approximately 50 C.

Airstarts initiated between 25-50 percent engine

rpm are slow to light-off and may take up to 90
seconds to regain usable thrust.

20,000 FEET.

Figure312.(Sheet 2)

T.O. GR1F16CJ1

395

Oil pressure is directly related to rpm. Do not

confuse a low oil pressure indication due to

windmilling rpm as an oil system malfunction.

Factors such as altitude, airspeed, weather, etc.,

must be considered in determining whether to try

an airstart, to accomplish a flameout landing, or to

eject. Jettisoning stores reduces altitude loss

during an airstart and improves glide ratio during

flameout landing. If gliding distance is not a factor,

maintain 250 knots or more in order to reduce rpm

rate of decay until the JFS can be started. The

engine can be airstarted with airspeeds from

170400 knots/0.9 mach; however, 250 knots

provides the best tradeoff of altitude loss, range,

and airflow for the engine.

In flight, the throttle must be retarded to OFF then

back to the operating range for only four reasons: to

reset the overspeed protection logic, to clear a stall,

to begin the airstart procedure, or to terminate a

hot/hung start. Exact throttle position is not

important for an airstart, so any position between

IDLE and MAX AB is acceptable; however, the

midrange position is preferred because of possible

throttle misrigging at IDLE or possible engine

overspeed shutdown at MIL or above.

Once the throttle is retarded to OFF and then back

to the normal operating range, do not retard the

throttle to OFF again during the airstart unless a

hot/hung start occurs. Unnecessarily retarding the

throttle to OFF terminates any start attempt which

may be in progress.

A successful restart depends on many variables:

cause of flameout, type of fuel, altitude, airspeed,

and engine rpm when the airstart is attempted. High

engine rpm is the most important variable and

provides the best chance of a successful restart.

Therefore, do not delay the initiation of an airstart

in an attempt to reach a particular flight condition.

Initiate the airstart as soon as it becomes apparent

that engine rpm has decayed below inflight idle

(approximately 70 percent rpm) or illumination of

the ENGINE warning light, engine instrument

indications, and no response to throttle movement

confirm a flameout. The best conditions for airstart

are below 30,000 feet MSL, at 250 knots or more, and

with high engine rpm.

At medium and high altitudes, the airstart attempt

should be started in the engine control mode selected

by the DEC. The DEC contains diagnostic logic

designed to identify PRI engine control failures and

may automatically transfer to SEC. If there is no

indication of a lightoff before rpm decays below 50

percent, place ENG CONT switch to SEC (even if the

SEC caution light is on) and continue the airstart

attempt. At low altitude (below 10,000 feet AGL),

SEC should be selected as soon as possible after

initiating the airstart.

Of equal importance to selecting SEC when required

is preserving engine rpm. The JFS should be started

as soon as the aircraft is in the JFS envelope. The

advantage of using the JFS to assist the airstart is

that once the JFS RUN light is on, airspeed can be

reduced. Under normal conditions the JFS will

motor the engine at a minimum of 25 percent.

An airstart can be rapid if lightoff occurs above 60

percent rpm. Airstarts initiated between 5025

percent engine rpm are slow to light off and may take

up to 90 seconds to regain usable thrust. If altitude

is available, increasing airspeed can assist engine

acceleration and decrease the time to regain usable

thrust once a lightoff is achieved. As long as engine

rpm continues to increase, this condition should not

be considered as a hung/no start. Spooldown

airstarts initiated below 25 percent rpm have been

successful during flight tests, but spool up to usable

thrust may take more time than is available. Keep

engine rpm at 25 percent or above during spooldown

airstarts, if possible.

Following the rapid FTIT rise and peak of a lightoff,

FTIT slowly decreases approximately 50

C. There

fore, do not confuse a drop in FTIT as an unsuccessful

airstart unless accompanied by decreasing rpm as

well.

High Altitude Airstart Considerations

129

As altitude is increased above 30,000 feet MSL, the

probability of a successful airstart can be improved by

attempting the airstart as soon as possible (before

rpm decays below approximately 50 percent) and by

quickly descending to altitudes below 30,000 feet

MSL after the airstart is initiated. Airspeeds above

250 knots (400 knots/0.9 mach maximum) should be

considered as a means to reduce altitude and increase

the probability of a successful airstart. Spooldown

airstarts can be achieved with rpm as low as 25

percent, but not at all airspeeds and altitudes.

T.O. GR1F16CJ1

396Change 1

At high altitudes, dive as required to maintain speed

in the 250400 knot/0.9 mach range. Unless an

airstart is obviously impossible (total lack of fuel,

tower shaft failure, engine seizure, etc.), do not

become tempted to establish a maximum range or

maximum endurance glide. The first consideration

should be an immediate spooldown airstart attempt

even if the engine fails for no apparent reason. If a

spooldown airstart is not successful before reaching

20,000 feet MSL, a JFSassisted airstart should be

attempted. When below 20,000 feet MSL, turn JFS

on. Activating the JFS above 20,000 feet MSL is

prohibited since successful JFS start/motoring of

engine is unlikely and the brake/JFS accumulators

will be depleted. If the JFS RUN light is on, airspeed

may be reduced to achieve maximum range or

maximum endurance (

200 or 170,

205 or 175

knots, respectively, plus 5 knots per 1000 pounds of

fuel/store weights). Time constraints due to EPU fuel

consumption must also be considered. A maximum

range or maximum endurance glide from above

approximately 35,000 feet MSL may exhaust EPU

fuel prior to landing. (Refer to T.O. GR1F16CJ11,

figure B63.) With the JFS running, EPU fuel

consumption is also reduced.

Low Altitude Airstart Considerations

129

Initiate the airstart as soon as possible. After

initiating a zoom climb and jettisoning stores (if

required), retard the throttle to OFF then advance

the throttle to the normal operating range. Place the

ENG CONT switch to SEC and turn on the JFS

(START 2) to assist the airstart.

Following a zoom climb, plan to arrive at 250 knots

until the JFS RUN light is on; airspeed may then be

reduced to achieve maximum range or maximum

endurance (

200 or 170,

205 or 175 knots,

respectively, plus 5 knots per 1000 pounds of

fuel/store weights). If a higher airspeed is maintained

or an attempt is made to gain airspeed to delay the

rpm decay, available time may be reduced to the point

that an airstart is not possible.

During any low altitude airstart attempt, constantly

evaluate altitude above the ground relative to airstart

success. Do not delay ejection below 2000 feet AGL

unless the engine is producing thrust capable of

maintaining level flight or safely controlling the sink

rate or unless a flameout landing can be accomplished.

Airstart Procedures

129

To begin the airstart sequence, retard the throttle to

OFF; then immediately advance the throttle back into

the normal operating range, preferably midrange.

NOTE

If the throttle is retarded to OFF to

clear a stall, it should be maintained in

OFF for a few seconds to allow the stall

to clear.

After throttle advance, monitor for signs of a lightoff

before rpm decays below 50 percent (characterized

by a rapid rise in FTIT accompanied by a slow

increase in rpm). If rpm and FTIT continue to decay

after rpm drops below 50 percent, place the ENG

CONT switch to SEC (even if the SEC caution light

is illuminated).

If a hot/hung start occurs, retard the throttle to OFF

and allow the FTIT to drop to below 700

C before

advancing the throttle. Increasing the airspeed

(maximum of 400 knots/0.9 mach) should help the

next airstart to be cooler. If the condition persists,

retard the throttle to OFF, place the ENG CONT

switch to SEC, and allow the FTIT to decrease below

700

C before advancing the throttle.

After entering the JFS envelope, start the JFS to

assist in preserving rpm. With the JFS RUN light on,

airspeed may be reduced to achieve maximum

range/endurance.

If the JFS stops running or fails to run within 30

seconds, do not reattempt a JFS start until the

brake/JFS accumulators have had time to recharge.

Allow 1 minute of engine rotation (either windmil

ling or JFSassisted) at 12 percent rpm or above to

insure that the brake/JFS accumulators are fully

recharged. Recharging begins 34 seconds before the

JFS RUN light illuminates or 30 seconds after

selecting a start position (in the event of a JFS

failure to run). Recharging occurs regardless of JFS

switch position.

In the event of a JFS shutdown, the JFS switch does

not relatch in either start position while the JFS is

spooling down. Spooldown from full governed speed

takes approximately 17 seconds. The JFS switch

must be cycled to OFF and then START 2 to

reinitiate a JFS start. It is possible to complete the

spooldown before the brake/JFS accumulators are

recharged if the JFS ran for only a short time.

It is possible the engine may not respond properly to

throttle movement following an otherwise success

ful airstart. If this occurs or if thrust is insufficient

to ensure a safe landing, switch to SEC, or if already

in SEC, switch to PRI.

T.O. GR1F16CJ1

Change 1397

When the airstart is completed and usable thrust is

regained, turn the JFS off. Reset the main generator

using the ELEC CAUTION RESET button and

verify MAIN GEN and STBY GEN lights are off.

Cycle the EPU switch to OFF and then back to

NORM.

NOTE

The VHF radio is not powered when

the EPU is running.

To accomplish an airstart:

Throttle-OFF, then midrange.

FTIT should decrease rapidly when

throttle is OFF. If FTIT does not

decrease rapidly, verify that the

throttle is OFF.

Do not mistake a rapid initial FTIT rise

during an airstart as an indication of a

hot start. Typically, airstarts are

characterized by rapidly increasing

FTIT with a slow increase in rpm.

If a relight does not occur before rpm decays below 50

percent or if below 10,000 feet AGL:

ENG CONT switch-SEC (even if SEC

caution light is on).

Airspeed-Attain approximately 250 knots or

establish maximum range or endurance

airspeed (

200 or 170,

205 or 175 knots,

respectively, plus 5 knots per 1000 pounds of

fuel/store weights) with JFS RUN light on.

Above 30,000 feet MSL, airspeeds in the

250400 knot/0.9 mach range should be

considered to reduce altitude and increase

the probability of a successful airstart.

NOTE

If maximum gliding range is not a

factor, consider maintaining 250 knots

or more above 10,000 feet AGL to

provide best restart conditions (in case

of JFS failure). Below 10,000 feet AGL

with the JFS RUN light on, maintain

maximum range or maximum endur

ance airspeed.

JFS switch-START 2 below 20,000 feet MSL

and below 400 knots.

NOTE

If the JFS switch is erroneously placed

to START 1, leave it there.

If the JFS RUN light does not

illuminate or goes off once illuminated,

place the JFS switch to OFF and

reattempt START 2 when the brake/

JFS accumulators are recharged. The

JFS switch does not relatch in either

start position while the JFS is spooling

down.

Stores-Jettison (if required).

If stores jettison is attempted after main

generator drops off line but before EPU

generator powers the SMS (approximately 5

seconds delay), stores will not jettison.

NOTE

Visually confirm the stores have

jettisoned and jettison again if re

quired.

If engine rpm rolls back or hangs below inflight idle

(approximately 70 percent) and FTIT exceeds 935

Throttle-OFF, then midrange.

Allow FTIT to drop below 700

C before

advancing the throttle.

Airspeed-Increase (400 knots/0.9 mach

maximum).

If hung start/hot start persists:

Throttle-OFF.

ENG CONT switch-SEC, if in PRI; PRI, if in

SEC.

NOTE

In certain circumstances, the engine

may malfunction in SEC. Returning to

PRI may result in attaining usable

thrust.

The proximity of the ENG CONT

switch to the JFS switch makes the

JFS switch susceptible to being

bumped to OFF when selecting SEC.

10. Throttle-Midrange.

Allow FTIT to drop below 700

C before

advancing the throttle.

T.O. GR1F16CJ1

398Change 1

If engine does not respond normally after airstart is

completed:
11. ENG CONT switch-SEC.
12. Airspeed-250 knots (if thrust is too low to

sustain level flight).

13. Throttle-Verify engine responds to throttle

movement; set as desired.

If engine does not respond normally after an airstart

is complete in SEC, if thrust is still insufficient to

make a safe landing, or abnormal engine response is

still present:
14. ENG CONT switch-

PRI,

NORM.

15. Refer to FLAMEOUT LANDING, this section.
If engine responds normally:
16. JFS switch-OFF.
17. ELEC CAUTION RESET button-Depress.

Verify MAIN GEN and STBY GEN lights are

off.

18. EPU switch-OFF, then NORM.
19. ADI-Check for presence of OFF and/or AUX

warning flags.

If warning flag(s) is in view, refer to TOTAL

INS FAILURE, this section.

If only AUX flag is in view, pitch and

roll attitude information is likely to be

erroneous due to INS autorestart in

the attitude mode when other than

straight and level, unaccelerated

flight conditions existed.

20. Land as soon as possible.
21. Refer to ACTIVATED EPU/HYDRAZINE

LEAK, this section.

FLAMEOUT LANDING

The decision to eject or make a flameout landing

rests with the pilot. Considerations for attempting a

flameout landing must include:

Nature of the emergency.

Weather conditions.

Day or night.

Proximity of a suitable landing runway.

Proficiency in performing simulated flameout

(SFO) landings.

Due to the capabilities of the ejection seat, the entire

approach is within the ejection envelope; however,

ejection should not be delayed in an attempt to

salvage a questionable approach. When performing

a flameout landing, the aircraft can safely stop (dry

runway without arresting gear) in approximately

twice the computed ground roll distance (8000foot

minimum runway length recommended), assuming

a touchdown no more than 1/3 of the way down the

runway at 1113 degrees AOA.

To perform a flameout landing, turn immediately

toward the desired runway. Jettison stores and

establish maximum

range airspeed. Maximum

range airspeed may be less than the minimum

airstart airspeed. If range to the desired runway is

critical, the decision to attempt an airstart or a

flameout landing rests with the pilot.

NOTE

During an airstart attempt, do not

slow below the minimum airstart

airspeed.

If the engine is still running, but thrust

is insufficient to sustain level flight,

treat it as a flameout situation.

Maximum range airspeed varies only with GW and

is not affected by drag index. Maximum range

airspeed is

200 knots for a GW of 20,000 pounds,

205 knots for a GW of 21,000 pounds, and

increases 5 knots per 1000 pounds of additional GW.

For most circumstances, sufficient accuracy is

obtained by adding 5 knots per 1000 pounds of

fuel/store weights

PX III

and by adding 5 knots if

CFT's are installed.

NOTE

This formula is based on the average

aircraft operating weight. Refer to T.O.

GR1F16CJ11, PART 1, DRAG IN

DEXES AND WEIGHTS-BASIC AIR

CRAFT. If range to desired runway is

critical, maximum range airspeed may

be calculated using actual GW in excess

20,000 pounds,

21,000 pounds.

For a 10,000foot descent (LG up), each

10 knots above or below maximum

range airspeed decreases glide range up

to 1/4 nm.

T.O. GR1F16CJ1

Change 1399

The maximum range airspeed equates to approxi

mately 7 degrees AOA (any GW or drag index) and

provides a glide ratio of approximately 7 nm per 5000

feet AGL (a no wind condition).

Retaining stores or

flying into a headwind decreases glide range

significantly.

The EPU should be on and, if aircraft fuel is

available, the JFS should be started using START 2

when below 20,000 feet MSL and below 400 knots

unless the engine is either seized or anticipated to

seize. The EPU should provide a minimum operation

of 10 minutes (HYDRAZN light on) with normal

flight control demands before EPU fuel depletion.

Operating time can be extended to as much as 15

minutes if the JFS is running and flight control

inputs are minimized.

If expected time to landing exceeds expected EPU

operating time and excess energy is available, a

steeper/faster descent may be flown. The JFS also

provides hydraulic pressure for normal braking and

NWS after landing.

When bleed air is no longer available to operate the

EPU, confirm that the EPU is operating on

hydrazine (EPU run and HYDRAZN lights on) since

the JFS alone does not provide adequate hydraulic

pressure to land the aircraft. If the EPU is

inoperative, maneuver the aircraft as necessary on

JFSassisted hydraulic pressure to a more favorable

ejection envelope and initiate ejection.

There are two basic types of flameout landing

patterns:the overhead approach (figure 310) or

the straightin approach (figure 311). The overhead

approach is preferred as it affords the most

opportunities to properly manage available energy

while providing the best visual cues for pattern

corrections. The overhead approach may be entered

at any position, provided the proper altitude for that

point in the pattern can be obtained. The main

concern is to reach high key, low key, or base key at

or above the recommended minimum key altitudes.

A straightin approach is an alternate approach

when the overhead approach cannot be attained. For

both approaches, the initial aimpoint should be

approximately 1/3 of the way down the runway.

Overhead Approach

Refer to figure 313. Plan to arrive over the landing

runway (high key) at 700010,000 feet AGL. The

high key position may be approached from any

direction.

The recommended key altitudes are based on flying

a 360degree descending turn from high key with the

LG down. The altitudes vary with GW and with

additional drag due to stores. The recommended

high key altitude is

7000,

7500 feet AGL plus

500 feet per 1000 pounds of fuel/store weights

PX III

and plus 500 feet if CFT's are installed. The

recommended low key altitude is

3000,

3250

feet AGL plus 250 feet per 1000 pounds of fuel/store

weights

PX III

and plus 250 feet if CFT's are installed.

These formulas include compensation for stores drag

effects; thus, no additional correction is required.

If altitude will be

significantly higher at high key,

some form of altitude dissipating maneuver such as

a dive, gentle Sturns, or a 360degree descending

turn should

be used. Speedbrakes also may be used

to lose excess altitude. However, if the speedbrakes

are not closed when a satisfactory flightpath

reached, the added drag may preclude a successful

flameout approach

After departing high key, all attention should be

directed toward a successful landing. If actual

altitude at high key was below the recommended

altitude, fly maximum range airspeed with the LG

up until a satisfactory flightpath is reached and then

lower the LG. Optimum LG down airspeed is 10

knots less than maximum range (LG up) airspeed.

Minimum LG down airspeed is 20 knots less than

maximum range (LG up) airspeed and provides

sufficient maneuverability to arrest the high sink

rate associated with a flameout approach. Optimum

angle of bank is 50 degrees with the LG up and 55

degrees with the LG down. Bank angles more than

10 degrees above/below optimum result in a

significant increase in altitude loss per degree of

turn and may preclude a successful flameout

approach.

NOTE

Delaying LG extension until low key

allows successful completion of the

overhead approach from as low as 1500

feet below the recommended high key

altitude

Altitude loss for a 360degree descend

ing turn with the LG down increases

up to 500 feet for every 10 knots above

optimum LG down airspeed.

Altitude loss for a 360degree descend

ing turn with the LG down increases

up to 500 feet for each 5 degrees

above/below the optimum bank angle.

F16C/D. FLIGHT MANUAL (2002) - page 24

F16C/D. FLIGHT MANUAL (2002) - page 24