thrust reverser system - c141heaven

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THRUST REVERSER SYSTEM

443cl TECHNICAL TRAINING SQUADRON

443cl MILITARY AIRLIFT WING, ING (MAC)

ALTUS AIR FORCE BASE, OKLAHOMA

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FOR TRAINING PURPOSES ONLY

NOT NECESSARILY CURRENT AFTER DISTRIBUTION

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C-141 THRUST REVERSER SYSTEM

OBJECTIVES

When you have completed this program, you should be able to :

state the indication received when the Thrust Reverser doors

state the i ndication received when the Thrust Reverser doors

and locked.

state the purpose of the Thrust Reverser Interl ock.

state the purpose of the Thrust Reverser Limiter .

are , extended.

are NOT stowed

5 . list the limits imposed on the Thrust Reverser system.

Air Force OC, 15 May 70· 2M

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Page A

INTRODUCTION

This book is not arranged like an ordinary book. The page numbers are

in order, but the text does not follow the page numbers. Therefore, it will

not be necessary to read each page. There will be directions on each page .

to guide you.

Now TURN to Page 1 and begin the program .

.. From Page A Page 1

THRUST REVERSER SYSTEM

Each nacelle is equipped with an independent Thrust Reverser system,

operated through the THROTTLE CONTROL QUADRANT.

The system permits reverse thrust application of engine power during

landing (after touchdown) and during a rejected takeoff.

Are the Thrust Reversers used in flight?

a. Yes. TURN to page 3.

b. No. TURN to page 2.

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From Page 1 Page 2

You're right, the Thrust Reversers are NOT used in flight. The system

will function, but operation in flight is pPohibited. DON'T TRY TO USE

THRUST REVERSERS IN FLIGHT!

Please TURN to Page 4 .

From Page 1 Page 3

Sorry, but the Thrust Reversers are NOT supposed to be used in flight.

They will operate, but in flight operation is prohibited. DON'T TRY TO USE

THRUST REVERSERS IN FLIGHT!

Please TURN to Page 4.

,. From Page 2 or 3 Page 4

Two target-type Thrust Reverser doors are EXTENDED or STOWED by hydraulic

actuators acting through a mechanical linkage .

The picture above shows the Thrust Reverser doors:

a. Stowed. TURN to Page 6 .

b. Extended. TURN to Page 5.

,. From Page 4 Page 5

Your answer: "Extended."

Wrong . The Thrust Reverser doors ar e in t he STOWED position. When the

doors are STOWED, they form t he r ear portion of the cowling. If the Thrus t

Reverser s wer e extended, t hey would look like those below .

-- ,,_. - ---


From Page 4 Page 6

STOWED was your answer and this is correct. When the Thrust Reverser

doors are in the STOWED position, they form the rear portion of the cowling.

When the Thrust Reversers are extended, they are like this ...


From Page 5 or 6 Page 7

How can you tell when the Thrust Reverser doors are NOT stowed and locked?

Easy. On the center instrument panel there are four (4)

lights, one for each engine. These lights

illuminated when the Thrust Reverser doors

out of the STOWED and LOCKED position.

-------

j NO--_-l-THRUST - -, ; REVN_()T ~_()CKED

Wi ll the NO . I THRUST I REVt:!O_liOCKrn

lights be illuminated when the Thrust Reverser

doors are extended?

a. Yes . TURN to Page 8.

b . No. TURN to Page 9.

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From Page 7 Page 8 ---------

You said the NO. I THRUST I REV NOT LOCKED

lights would be i l luminated even when the ------

doors are extended and you are so right. The lights remain il l uminated after

the doors get to the full extended position.

Now what about the full Extended position?

TURN to Page 10 and read on .

• From Page 7

You said the I - - ---NO. I TH RUST I REVN9T LOCKED

Page 9

light would NOT remain illuminated when the

Thrust Reverser doors reach the full extended position. I t was a good try,

however it is NOT cor rect. The ·----- ~--

NO. 1 THRUST I REV NOT LOCKED

light remains illuminated

even after the Thrust Reverser doors have reached the ful l extended position.

Now what about the full Ext ended position?

TURN to Page 10 and read on .

From Page 8 or 9 Page 10

The lights are on the center instrument panel just below

the THRUST REVERSER NOT LOCKED lights . The r - - - j I ' ~ • ' '

I f ' ' f I ! ' ,, light will

i lluminate when the Thrust Reverser doors have reached the fuZZ extended

position.

Does the light illuminate as soon as the Thrust Reverser

doors crack from the stowed position?

a. Yes. TURN to Page 12.

b. No. TURN to Page 11 .

From Page 10 Page 11 ---- --. . .

Your answer: NO. You made a good choice. The light

will NOT illuminate until the Thrust Reverser doors are in the full EXTENDED

position.

There would now be two lights illuminated for each engine, the --· --·--··--

light and the 1 • I TI ' T ..

1 1. l , 1 r 1 1 1; light.

You're doing fine, please TURN to Page 13.

l~· ·-

NO. I THRUST REV NOT LOCKEDI

From Page 10 Page 12

Sorry you are wrong. Please RETURN to Page 10 and make another selection.

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The aft nacelle contour is composed principally of the Thrust Reverser

doors in the stowed position. Actuation of these target type doors is

accomplished by two hydraulic actuators located on top and bottom of the

engine. Take a look at the picture below .



The doors normally operate under a pressure of approximately 3000 psi,

but there i s NO indicator to tell you how much pressure is in the system.

The only indication of sufficient pressure are four Thrust Reverser

II I! lights, one for each engine . These lights ar e located

on the Flight Engineer ' s Panel and will illuminate when the supply pressure

Thrust Reverser system operation .


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Fro.m Page 14 Page 15

Review time. Answer the questions below .

1 . When the Thrust Reverser doors are fully extended a ~~~~~~~-

light illuminates. ~~~~~~~-

2. What indication is given when the Thrust Reverser doors are stowed and locked?

a.

b.

c .

' NO. I THRUST I REVNOT LOCKED

NO. I THRUST ,. REVNOT LOCKED

light illuminates.

light illuminates.

light extinguishes.

3. What do the Thrust Reverser pressure lights on the engineer's panel indicate?

Please TURN to Page 16 and check your answers.

..

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From Page 15

Please CHECK your answers and make any corrections necessary.

1.

2. "c". ---·

NO. I THRUST I REV NOT LOCKED light extinguishes .

3 . That the system pressure exceeds 1,000 PSI.

Satisfied with your answers? If so, please CONTINUE to Page 17 .

Page 16

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From P_age 16 Page 17

Up to this point we have discussed the indiaations that are seen in the

cockpit when the doors are STOWED or EXTENDED and the pressure light on the

Flight Engineer's panel that tells you system pressure exceeds 1,000 PSI.

sure in the system.

How is the Thrust Reverser system put into operation?

a. Thrust Reverser system operates when spoilers are deployed.

b. By the use of a t_oggle switch.

c. By throttle movement.

TURN to Page 20.

TURN to Page 19.

TURN to Page 18.

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Fram Page 17 Page 18

Correct! Thrust Reverser operation is initiated by retarding the throttle

levers to the IDLE START position detent and then lifting them 1 and 1/8

inches to clear the detent stop. Further aft movement of the throttle levers

causes the Thrust Reverser doors to extend. Extension time of the Thrust

Reverser doors is approximately 2 seconds. See the schematic below .



Well that was an excellent try; however, the onZy actions necessary to

extend the Thrust Reverser doors is to retard the throttles to the IDLE

START position, lift them approximately 1 and 1/8" over a stop on the

throttle quadrant and aontinue throttZe movement to the REVERSE position.

See the schematic below.



Excellent try; however, the only actions necessary to extend the Thrust

Reverser doors is to Peta.Pd the throttles to the IDLE START position, Zift

them approximately 1 and 1/8" over a stop on the throttle quadrant and

aontinue throttle movement to the REVERSE position. See the schematic below.


From Page 18, 19 or 20 Page 21

When the Thrust Reverser doors are fully extended, they deflect engine

exhaust gases forward to produce the desired reverse thrust.

Would you agree that if the Thrust Reverser doors didn't go to the

fu~ly extended position and power could be applied in the reverse range

that it would be the same as applying power in the forward thrust range.

a. Yes. TURN to Page 22.

b. No. Think about it and then TURN to Page 22.


You're right! If the Thrust Reverser doors do NOT

fully extend and power could be applied, the engine

would produce forward thrust. There would be no

deflection of the engine exhaust gases to produce the reverse thrust.

To prevent application of power in reverse thrust, unless the Thrust

Reverser doors are extended, a simple Mechanical Interlock system will

automatically prevent movement of the throttle control beyond the interlock

position. Each engine has its own independent interlock system.


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Since the Mechanical Interlock actually prevents the throttle from being

pulled into the reverse range if the doors don't extend, what would be the

results if the Thrust Reverser doors on number one engine failed to open?

a. All the throttles would be blocked.

b. Only the throttle for the affected engine would be blocked.

c. Only the symmetrical throttles would be blocked.

TURN to ~age 24.

TURN to Page 25.

TURN to Page 26.


You said "all the throttles would be blocked." Sorry, but that isn't

true. Perhaps you forgot that each engine is equipped with an independent

interlock system.

If one thrust reverser system fails, onZy the throttle for that engine

will be blocked. The remaining engine thrust reversers could be operated.

The Thrust Reverser Interlock prevents power applications in the reverse

xange unless the Thrust Reverser doors are fuZZy extended.



You remembered that each engine has a completely independent interlock

system and only the throttle for the affected engine would be blocked from

being positioned to the REVERSE position.

The Thrust Reverser Interlock prevents power application in the reverse

range until the Thrust Reverser doors are fully extended.

You're doing fine, please CONTINUE to Page 27.

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Your answer, "only the symmetrical throttles would be blocked." Sorry

that is incorrect. The onZy throttle that would be blocked would be the

throttle for the affected e.ngine.

The Thrust Reverser Interlock prevents power application in the reverse

range until the Thrust Reverser doors are fully extended.


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Please fill in the blanks in the questions below.

1. When the Thrust Reverser doors are not stowed and locked, it will be

indicated by a light.

2. What is the indication when the Thrust Reverser doors are fully

extended?

3. What does THRUST REVERSER pressure light on the engineer's panel

indicate? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

4. What is the purpose of the Thrust Reverser Interlock?


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From P_age 2 7 ~age 28

CHECK your answers and make any corrections necessary.

1. THRUST REV NOT LOCKED.

2. A THRUST REV EXTENDED Hght illuminates.

3. System pressure exceeds 1,000 PSI.

4. Prevents power application in the reverse range if the Thrust Reverser doors do not fully extend.

When you have checked your answers, TURN to Page 29 .

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The next item in the thrust reverser system that is to be discussed

is the THRUST REVERSER LIMITER. The knob is l ocated just below the copilot 's

throttles. Take a look .



The purpose of the THRUST REVERSER LIMITER is to limit the amount of

reverse thrust that can be applied. Numbers on the contour of the knob align

with an index mark above the knob to permit setting of the reverse thrust by

index number in accordance with a chart contained in T.O. 1C-141A-l-l.

What is the purpose of the Thrust Reverser Limiter?

a. Limits the amount of throttle travel.

b. Limits the reverse thrust by changing the mechanical advantage between the throttle and the fuel control.

c. Limits the amount of door travel .

TURN to Page 31.

TURN to Page 33 .

TURN to Page 32.

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Logical reasoning; however, it doesn't work that way. The amount of

throttle travel does NOT change. Rotating the Thrust Reverser Limiter

knob changes the mechanical advantage between the throttle and the fuel

control. In other words the fuel control can't travel as far in the reverse

range.

Nice try, please TURN to Page 34.


Nope! It doesn't limit the amount of door travel. The Thrust Reverser

doors are either stowed or extended. NO in-between position.

The purpose of the Thrust Reverser Limiter is to limit the amount of

thrust that can be applied in the reverse range by changing the mechanical

advantage between the throttle and the fuel control.

You're doing OK, please TURN to Page 34.

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You said the purpose of the Thrust Reverser Limiter was to Zimit the

amount of reverse thrust by changing the mechanical advantage between the

throttle and the fuel control. Congratulations. You are 100% correct.



The Thrust Reverse Limiter knob can correctly preset an engine fuel

control lever only if the related engine throttle is in the forward thrust

regime at the time the setting is made.

FIRST ...

THROTTLES ----:~~ AT IDLE START OR FORWARD


THEN .. .

SET THE LIMITER KNOB

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The Reverse 'Ibrust Limiter Setting chart in the performance data book

has a Pressure Ratio Limited line (never exceed line) which shows a

ma:tirrrum att01JJabZe setting of 10.9. 'Ibis should NOT be exceeded.


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From Page 35 Page 36 ·•

The last item for discussion is the use of the system and the limits

• imposed.

The Thrust Reversers should be operated in the following manner. The

copilot will observe that all four 1HRUST REV EXTENDED lights are

illuminated. After the nosewheel is on the runway, the pilot will move all

throttles smoothly to the desired reverse position.

At 80 knots, slowly advance all throttles back toward REV IDLE position

• so as to have all throttles at REV IDLE by 60 knots. The copilot will call,

-! "80 knots." After slowing to taxi speed, all throttles may be returned

to IDLE START position.


t


The following limits must be observed when using the Thrust Reversers.

1. When baaking the aircraft, limit application of reverse thrust to 30

SECONDS above idle maximum and then close the doors for better cooling.

2. When ta:r:iing DO NOT operate No. 2 engine in REV IDLE for more than ~

MINUTES with the APU operating. Prolonged mixing of engine exhaust

with APU .intake air can cause the temperature limits of the APU to be

exceeded.

3. Use of thrust reversers in flight is PROHIBITED.


• From Page 37

Before leaving the Thrust Reverser system lets REVIEW by answering

the questions below.

I. What indicator shows that the Thrust Reverser doors have extended?

Page 38

2. What is the indication when the Thrust Reverser doors are stowed and

locked?

3. What do the Thrust Reverser pressure lights on the engineer's panel

indicate?

4. What is the purpose of the Thrust Reverser Interlock?


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Please CHECK your· answers and make any corrections necessary.

1. THRUST REV EXTENDED light.

2. THRUST REV NOT LOCKED light extinguishes.

3. System pressure exceeds 1,000 PSI.

4. Prevents power application in the reverse range if the Thrust Reverser doors are not fully extended.


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From P_age 39

Please CONTINUE with the review .

5. The Thrust Reverser Limiter:

a. limits the amount of throttle travel.

b. limits the reverse thrust by changing the mechanical advan~age between the throttle and the fuel control.

c. limits the amount of door travel.

~i.'fo~

P_age 40

6. Reverse Thrust application for the purpose of backi.ng the aircraft is limited to:

a. Thirty (30) seconds above idle maximum and then close the doors for better cooling.

b. One (1) minute between cooli.ng periods.

c. One and one half (1 1/2) minutes between cooling periods.


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5. "b". Limits- the reverse thrust by changing the mechanical advantage between the throttle and the fuel control.

6. "a". Thirty (30) seconds above idle maximum and then close the doors for better cooling.

Please TURN to Page 42 and continue the review .

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Please CONTINUE the review.

7. When taxiing, with the APU operating, No. 2 engine cannot remain in REV IDLE longer than:

a. 5 minutes.

b. 10 minutes.

c. 15 minutes.

d. 20 minutes.

8. Thrust Reverser operation is allowed in flight.

a. True .

b. False .




7. "c". 15 minutes.

8. "b". False

This completes the Thrust Reverser system, if you have any further

questions, the instructor will be happy to answer them. An INDEX is

provided on Page 44 in case you wish to review any portion of the C-141

Thrust Reverser System.

From P_age 43 ~age 44

• INDEX

SUBJECT PAGES

Thrust Reverser Doors 4 thru 6, 13

Thrust Reverser Indicator Lights 7 thru 11, 14

Thrust Reverser System Operation 18 thru 20

Thrust Reverser Interlock 22 thru 26

Thrust Reverser Limiter 29 thru 35

Use of Thrust Reversers 36 and 37 ~

thrust reverser system - c141heaven

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