F16C/D (BLOCKS 50 AND 52+). FLIGHT MANUAL (15 OCTOBER 2002) - page 44

T.O. GR1F16CJ1

Change 1367

When landing is assured:

12. Throttle - Verify engine responds normally to

throttle movement from IDLE to MIL; set as

required.

If suitable thrust cannot be attained:

11. ENG CONT switch-

C

 

DF

 PRI, 

DR

 NORM.

12. Throttle-AB (if required to sustain level

flight).

13. 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.

11. 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 prepared to land (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.

12. 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.

13. 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.

Nozzle Failure 

PW 229

Exhaust nozzle malfunctions and nozzle control

system malfunctions can result in the nozzle being too

far open or too far closed. These malfunctions can

result in loss of AB capability, engine stalls, or low

thrust. Separation of the nozzle assembly from the

engine is also possible and results in low thrust. The

ENG THST LOW PFL is displayed for failed

open/missing nozzle events.

A failed closed nozzle results in normal thrust below

AB and stalls when AB is attempted.

Low or insufficient thrust can be caused by a failed

open, damaged, or missing nozzle or a nozzle control

system malfunction. If thrust is too low to sustain

level flight, turn immediately toward the nearest

suitable runway and establish 250 knots. With a

missing nozzle, level flight may not be possible above

8000 feet MSL.

Thrust available should increase as altitude de

creases. The airspeed at which thrust required for

level flight is the lowest is approximately 250 knots.

Indications of a nozzle loss are as follows:

S

An initial loud bang or pop, similar to a compressor

stall, but rpm is stable above 60 percent; in PRI

MIL, engine rpm is approximately 5 percent lower

than normal and FTIT is approximately 250

_

C

lower than normal; fuel flow is lower than normal;

the nozzle is likely indicated in the full closed

position; and thrust is decreased. Malfunctions of

the exhaust nozzle control system may have

symptoms similar to a missing nozzle, but the

nozzle may indicate full open since the nozzle

actuation system is intact.

S

Presence of the ENG THST LOW PFL indicates

that the DEEC has detected the malfunction and

has activated logic to increase the thrust available

in PRI. AB is inhibited. Remain in PRI if possible,

as it should provide a sufficient level of thrust while

also maintaining safe engine operation.

T.O. GR1F16CJ1

368

S

If level flight cannot be attained by 1000 feet above

minimum safe ejection altitude or minimum safe

altitude with the ENG CONT switch in PRI, select

SEC. Set the throttle as required to maintain 250

knots. Continuous operation above 850

_

C in SEC is

likely to result in catastrophic engine failure and

fire in as little as 5 minutes.

If thrust is low and a failed open, damaged, or missing

nozzle is suspected:

1.

Throttle-MIL or below.

2.

Stores - Jettison (if required).

3.

Airspeed - 250 knots.

If thrust is sufficient to reach a suitable landing

field:

4.

Land as soon as possible. Plan a flameout

landing. Refer to FLAMEOUT LANDING, this

section.

If unable to reach a suitable landing field and level

flight cannot be maintained by 1000 feet above

minimum recommended ejection altitude or mini

mum safe altitude, whichever is appropriate:

5.

ENG CONT switch - SEC.

NOTE

SEC should only be selected when it

becomes apparent that sufficient

thrust cannot be achieved in PRI. SEC

eliminates the additional thrust and

the engine protection benefits pro

vided by the DEEC in PRI. The nozzle

loss logic holds the engine in PRI for

these reasons.

6.

Throttle-As required to maintain 250 knots in

level flight above minimum recommended

ejection altitude or minimum safe altitude,

whichever is appropriate.

With nozzle loss, catastrophic engine

failure and fire are probable with

prolonged high power settings above

850

_

C FTIT while in SEC.

If airspeed drops below 250 knots, trade

altitude to reacquire 250 knots. Do not

descend below minimum recommended

ejection altitude or minimum safe

altitude, whichever is appropriate.

7.

Land as soon as possible. Plan a flameout

landing. Refer to FLAMEOUT LANDING, this
section.

AB Blowout/Failure To Light 

PW 229

An AB blowout is indicated by the nozzle opening

then closing after the throttle is advanced to AB. If an

AB blowout occurs and the throttle is left in AB, the

DEEC automatically recycles the AB up to three

additional times (each cycle indicated by the nozzle

opening and closing). An AB nolight is indicated by

the nozzle failing to start open within 5 seconds of

advancing the throttle to AB (nozzle remains closed

or shows minimal movement). If an AB no light occurs

and the throttle is left in AB, the DEEC automatically

attempts to relight the AB up to 3 times. The initial

attempt and 3 subsequent no lights could take up to

20 seconds. A combination of no lights and blowout

recycles could take longer. If further AB attempts are

required and the DEEC has completed all recycle

attempts, then the throttle must be retarded to MIL

or below and advanced to AB.

If the AB blowout/failure to light was not

accompanied by an ENGINE FAULT caution light,

flight may be continued. If an ENGINE FAULT

caution light also occurred, refer to ENGINE FAULT

CAUTION LIGHT 

PW 229

, this section.

ENGINE STALLS 

PW 229

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 an engine stall is

not expected. However, under some departure

conditions, inlet flow distortion may induce engine

stalls. Hardwareassociated stalls may result from a

failed nozzle, control system malfunctions, antiice

system failed on, or FOD.

Stalls may be caused by an antiice valve failed in the

open position at high thrust settings (throttle above

midrange). The engine should be operable with this

condition by limiting throttle position to midrange or

below. If flight conditions permit, place the ANTI ICE

switch to OFF.

T.O. GR1F16CJ1

369

The first indication of an engine 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 engine rpm.

When a stall is sensed, the DEEC cancels the AB (if

throttle is in AB range), opens the nozzle, and

decreases fuel flow until the stall clears. FTIT and

NOZ POS may fluctuate in response to the stall

recovery signal. If the engine auto transfers to SEC,

automatic stall recovery and overtemp protection are

not available. A malfunction such as engine internal

damage or primary control system failure could result

in a stall, an automatic SEC transfer, and possible

FTIT overtemp. Throttle reduction is appropriate as

a first response to clear any engine stall.

If the engine stalls at low altitude, an immediate

climb should be initiated, and stores jettison should

be considered. Retarding the throttle may clear the

stall. During a high thrust stall that is self recovering,

there will be an immediate thrust loss. In PRI, the

DEEC gradually restores thrust to the original level.

If engine response at low altitude is not sufficient to

maintain or gain altitude and a suitable landing field

is not available, ejection may be required.

If a stall occurs at MIL or below, retarding the throttle

may clear the stall. Further throttle movement

should be limited to midrange or below.

ABAssociated Engine Stalls 

PW 229

ABassociated stalls are normally accompanied by a

loud bang or pop and a series of fireballs from the

engine exhaust and occasionally the engine inlet. This

is followed by an erratic flame from the engine exhaust

if the stall is nonrecoverable. These characteristics

could be mistaken for an aircraft fire. Whenever a stall

occurs while operating in AB, the DEEC automatically

cancels AB and activates stall recovery. This may be

accompanied by a nozzle swing to full open for a few

seconds and an associated temporary reduction of

thrust. The throttle should be snapped out of AB to

MIL. This action usually clears the stall and restores

normal operation; however, stalls may continue at MIL

and can be severe. They may be characterized by bangs

or pops of low intensity or engine vibrations severe

enough to preclude reading engine instruments. Refer

to NONAB ENGINE STALLS 

PW 229

, this section.

NonAB Engine Stalls 

PW 229

NonAB stalls may occur if the engine is malfunction

ing, particularly during throttle transients near

IDLE. NonAB stalls are often a symptom of a serious

engine problem. NonAB stalls may be inaudible; the

first indication may be a lack of throttle response

which may be difficult to differentiate from abnormal

engine response. However, nonAB stalls can also be

severe. They may be characterized by bangs, pops,

low intensity or severe engine rumble or vibration. A

momentary nozzle swing to near full open may occur,

causing a temporary reduction in thrust, as the

DEEC activates stall recovery. An erratic orangeyel

low flame from the engine exhaust may be present.

This exhaust flame should not be mistaken for an

engine fire. If the stall is confirmed, the throttle

should be immediately retarded to IDLE which may

clear the stall. Further throttle movement should be

limited to midrange or below.

Prolonged engine operation with FTIT

in excess of 1000

_

C can result in

significant engine damage and may

cause a nonrecoverable engine failure.

Engine Stall Recovery 

PW 229

If an AB stall(s) occurs:

1.

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.

3.

ANTI ICE switch-OFF when conditions

permit.

NOTE

Stalls may be caused by antiice valve

failing to close at high thrust setting

(throttle above midrange).

If stalls continue at idle and engine rpm is less than 60

percent with no rpm response to throttle movement:

4.

Throttle-OFF. Initiate airstart. Refer to AIR

START PROCEDURES 

PW 229

, this section.

Shutting down the engine with an

engine alternator failure (indicated by

zero or erroneously low rpm, illuminated

SEC caution light, illuminated ENGINE

warning light, and normal thrust)

results in no ignition for an airstart.

T.O. GR1F16CJ1

370

If nonAB stall(s) clears:

5.

Throttle-Midrange or below.

If a nonAB stall clears, maintain throttle at

midrange or below unless required to sustain

flight.

6.

Land as soon as possible.

If AB stall(s) clears:

2.

Throttle-As required.

If an AB stall clears, the engine is safe to

operate in the IDLE to MIL range, provided

no other abnormal indication is observed.

Attempt further AB operation only if needed

to sustain flight.

INLET BUZZ 

PW 229

Inlet buzz occurs at supersonic airspeeds if the engine

control system fails to maintain adequate engine rpm

when the throttle is retarded below MIL. Inlet buzz

causes moderate to severe vibration within the

cockpit and probably results 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, the engine must be shut down and restarted.

ENGINE FAILURE OR FLAMEOUT  

PW 229

Engine failures can result in rpm decrease with no

abnormal vibration or sound (flameout), rpm

decrease with abnormal vibration and/or stalls, or

stable rpm with abnormal vibration and/or low

thrust.

If the engine flames out, fuel starvation or

mechanical failure has occurred. A flameout is

indicated by decrease in FTIT and engine rpm

decaying below approximately 60 percent. Loss of

thrust and lack of response to throttle movement

confirm the flameout. The ENGINE warning light

illuminates when engine rpm is below 55 percent.

Additionally, the MAIN GEN and STBY GEN lights

illuminate below 45 percent rpm and the EPU should

start running. Do not mistake a loss of ECS noise as

an engine flameout.

If the reservoir tanks do not contain fuel, an airstart

is impossible. If fuel starvation was due to a

temporary lack of fuel, restart should be possible. If

fuel quantities appear normal, the flameout may

have been caused by fuel contamination. In this case,

placing the throttle to OFF may clear the

contaminated fuel and allow an airstart.

Main fuel pump failure or tower shaft geartrain

failure also causes flameout. Both present similar

symptoms:an abrupt decrease of indicated fuel flow

to less than 500 pph; loss of main generator, standby

generator, and FLCS PMG and EPU activation; no

throttle response; and illumination of the SEC

caution light even though the ENG CONT switch is in

C

 

DF

 PRI, 

DR

 NORM.

If only the main fuel pump has failed, the rpm

indication reflects a gradual spooldown. The JFS can

be started and the engine can be motored at

approximately 25 percent rpm. If the SEC caution

light remains on (with ENG CONT switch in 

C

 

DF

PRI, 

DR

 NORM and engine rpm at 12 percent or

above), the engine probably cannot be restarted;

therefore, place primary emphasis on a flameout

landing while continuing airstart attempts. If unable

to make a flameout landing, refer to EJECTION, this

section.

Tower Shaft Failure 

PW 229

Failure of the engine tower shaft or its associated

geartrain results in loss of all rotation to the engine

gearbox and the ADG. Loss of rotation to the engine

gearbox renders the engine alternator, main fuel pump,

and oil pump inoperative resulting in a zero rpm

indication, zero oil pressure, illumination of the

ENGINE warning and SEC caution lights, and engine

flameout due to fuel starvation. The initial symptoms

are similar to main fuel pump failure; however, the

primary difference is that the rpm and oil pressure

indications drop immediately to zero with a tower shaft

failure since the engine alternator is not being driven.

Additional symptoms caused by loss of rotation to the

ADG include loss of hydraulic systems A and B, main

and standby generators, and FLCS PMG and

subsequent activation of the EPU. It may be possible to

regain engine operation using the JFS and performing

an SEC airstart. The JFS drives the ADG and the

engine gearbox (through the PTO shaft), restoring

rotation to both hydraulic pumps, FLCS PMG (at a

reduced output), main fuel pump (SEC caution light

goes off in PRI until SEC is selected), engine alternator

(cockpit rpm signal, DEEC power, and engine ignition),

and oil pump (oil pressure increases). Without the load

of the engine, the JFS produces an rpm indication

fluctuating between 3050 percent which is the speed of

the engine alternator, not the actual engine rpm. This

rpm may be high enough to restore standby generator

power; however, main generator power may cycle on

and off line with the rpm fluctuations. If the ENG

CONT switch is still in 

C

 

DF

 PRI, 

DR

 NORM, the SEC

caution light goes off when fuel pump pressure is

restored; however, a PRI airstart is not possible since

T.O. GR1F16CJ1

Change 1371

the rpm signal to the DEEC is in error. Perform an

SEC airstart. Since the JFS is not preserving rpm,

maintain 250 knots minimum during the airstart

attempt, which should assure adequate actual engine

rpm for the airstart.

Low Altitude Engine Failure or Flameout 

PW 229

Refer to figures 37 and 38. 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. At low airspeed, the climb may be only

enough to insure a safe ejection altitude. Above 350

knots, more time is available by a zoom climb using

a 3g pullup to 30degree climb approaching the

desired airspeed (use approximately 50 knots lead

point) and then initiating a zero g pushover. Below

350 knots and above the minimum recommended

ejection altitude, more time is available by perform

ing a constant altitude deceleration to the desired

airspeed. If below the minimum recommended

ejection altitude and below 350 knots, primary

concern should be to trade excess airspeed for altitude

in preparation for ejection.

If required, jettison stores as soon as possible to aid in

gaining or maintaining altitude and maneuver

toward a suitable landing field, if available. If the

zoom results in an altitude below 4000 feet AGL,

there will probably be insufficient time to achieve an

airstart prior to 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 the zoom results in

an altitude between 400010,000 feet AGL, there is

probably time for one airstart attempt prior to

minimum recommended ejection altitude. This

attempt shall be performed in the control mode

selected by the DEEC.

If low altitude engine failure or flameout occurs:

1.

Zoom.

2.

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 jetti

soned and jettison again if required.

3.

Perform airstart (if altitude permits). Refer to

AIRSTART PROCEDURES 

PW 229

, this section.

Below 4000 feet AGL, there may be

insufficient time to perform an airstart

prior to minimum recommended ejec

tion altitude.

AIRSTARTS 

PW 229

Refer to figure 39. Factors such as altitude, airspeed,

weather, etc., must be considered in determining

whether to try an airstart, accomplish a flameout

landing, or eject. Jettisoning of stores reduces

altitude loss during an airstart and improves glide

ratio during a flameout landing.

Oil pressure is directly related to rpm. Do not confuse

a low oil pressure indication due to windmilling rpm

as an oil system malfunction.

If the engine seized due to an oil system malfunction

or flamed out due to total fuel starvation or

mechanical failure, either a flameout landing or

ejection is required.

The most likely reason to perform an airstart is that

the engine has shut down due to a PRI system failure

or hardware failure or to clear a stall. The DEEC

assesses any faults or internal failures and

automatically transfers to SEC, if required. The first

airstart attempt should be made in the engine control

mode selected by the DEEC

 

except when a tower shaft

failure is suspected it shall be performed in SEC.

Procedures for SEC and PRI airstarts are identical

except for ENG CONT switch position and JFS assist

minimum airspeed requirements.

There are two airstart options available. One option

is a spooldown airstart, for which the throttle is

advanced from OFF to midrange as rpm is

decreasing. There is no specific envelope within

which a spooldown airstart should be initiated, but

once the decision to perform an airstart is made,

airspeed should be adjusted to maintain 250400

knots/0.9 mach. The secondary option is a

JFSassisted airstart which differs from a spool

down airstart in that once the JFS RUN light is on

and PRI mode is confirmed, airspeed can be reduced

to achieve maximum range or maximum endurance

(

C

 200 or 170, 

D

 205 or 175 knots respectively, plus

5 knots per 1000 pounds of fuel/store weights and

plus 5 knots if CFT's are installed). The minimum

airspeed for PRI JFSassisted airstarts is 170

knots. The minimum airspeed for all SEC airstarts,

including JFS assisted, is 250 knots.

Figure 37.

T.

O

. GR1F

16CJ

1

372

0

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

0

2

4

6

8

10

12

1F-16X-1-4028X

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 F100-PW-229

DATA BASIS ESTIMATED

LG   UP

10

8

6

4

2

0

0

100

120

140

160

180

200

220

240

260

280

300

320

340

360

380

400

420

440

INITIAL AL

TITUDE   1000 FT AGL

GR1F16CJ11120X37

MINIMUM RECOMMENDED

EJECTION ALTITUDE

Low Altitude Airstart Capability

DATA BASIS ESTIMATED

GW = 23,000-25,000 LB

DI = 0-50

LG   UP

30  DIVE TO DESCENT KIAS OR 3G PULLUP

TO 30  ZOOM CLIMB INITIATED FROM THE

AIRSPEED/ALTITUDE EXISTING AT FIRST

RECOGNITION OF ENGINE FAILURE (60 PER-

AIRSTART INITIATED AT START OF DIVE OR

ZOOM

60 SECONDS ASSUMED AFTER

THROTTLE ADVANCE TO ACHIEVE

USABLE THRUST
DESCENT AIRSPEED IS 250 KIAS

CONFIGURATION:

CONDITIONS:

ENGINE F100-PW-229

INITIAL AIRSPEED   KIAS

(JFS RUN LIGHT ON)

9

7

5

3

1

CENT RPM)

460

480

500

520

30  DIVE TO 250 KIAS   3G PULLUP TO 30  ZOOM CLIMB

T.

O

. GR1F

16CJ

1

373

Figure 38.

T.O. GR1F16CJ1

374

Engine RPM and FTIT Response During

Spooldown and Airstart

ENGINE F100-PW-229

0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

MACH NUMBER

0

10

20

30

40

50

AL

TITUDE   1000 FEET

400 KIAS/0.9 MACH

JFS ENVELOPE

AIRSTART ENVELOPE

30  DIVE

A

B

POINT B TO

SL = 7.9 MIN/40 NM

CONDITIONS:

DRAG INDEX = 0

KIAS = 250

NO WIND

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 400 KIAS/0.9 mach is used to quickly reduce altitude to below

30,000 feet where airspeed can be reduced to 250 KIAS (Point A to B).

GW = 20,000 LB

1F-16X-1-1039A

PRI SPOOLDOWN OR

SEC SPOOLDOWN/JFS

ASSIST-250 KIAS

MIN KIAS WITH JFS

RUN LIGHT ON

AND PRI MODE

CONFIRMED-170

Figure 39.(Sheet 1)