15.07

Question 1

What unit is commonly used to express noise

Answer 1

Effective Perceived Noise deciBel (EPNdB)

Question 2

When replacing the cascade segment,what must you make sure

Answer 2

It is the correct cascade arrangement for the engine position

Question 3

What are the 2 methods used in order to reduce the noise level of an engine

Answer 3

1. Design

2. dampen external and internal noise sources

Question 4

What is the main task of the exhaust system on jet engine

Answer 4

To accelerate the airflow

Question 5

What type of nozzle is used for pressure ratios of more than 2:1

Answer 5

Convergent-divergent nozzle

Question 6

pneumatic reverser actuation systems are only used on what type of thrust reverser

Answer 6

Cascade type with translating sleeves

Question 7

What do thrust reverser do?

Answer 7

Produce the breaking force by deflecting the exhaust gas stream to the opposite direction

Question 8

What is the subsystem inside the thrust reverse control system

Answer 8

Thrust reverser interlock System

Question 9

With a faulty reverser can the aircraft be released for service

Answer 9

Yes

Question 10

What is the role of a muffler in the exhaust duct

Answer 10

Reduce noise in APU

Question 11

What is the role of the control system

Answer 11

To activate the thrust reverser and to increase the engine power

Question 12

How are the two exhaust systems exhausted on modern high-bypass turbofan engine

Answer 12

Separately

Question 13

What is the role of the reverser actuation system

Answer 13

Either pneumatic or hydraulics component. It moves the airflow deflection mechanism by signals from the reverser control system

Question 14

What does the green reverse light indicate

Answer 14

Fully deployed and throttle interlock released (engine power can be increased)

Question 15

What are the three subsystem for a reverser System

Answer 15

Control system
actuation system
Airflow deflection system

Question 16

What is the main task of the exhaust system in a turboprop engine

Answer 16

Safely guide the exhaust gases overboard

Question 17

What guides the exhaust gases from the rear of the turbine into the atmosphere

Answer 17

Exhaust system guide

Question 18

What is a disadvantage of of a thrust reverser

Answer 18

The compressor can stall

Question 19

Why should high gas velocity must be avoided

Answer 19

Because they decree the propulsion efficiency

Question 20

What is the angle of the gas stream when deflected

Answer 20

45-60 degrees

Question 21

What is an advantage of a common exhaust nozzles

Answer 21

It reduces the very high gas velocity by mixing the two gas flow

Question 22

How is the exhaust airflow caused

Answer 22

By the pressure ratio between the turbine discharge and ambient pressure

Question 23

What does a reverse unlock message indicate

Answer 23

That the reverser is not safe in its stowed position

Question 24

When can you use thrust reversers

Answer 24

On on ground due to safety

Question 25

What angle should the exhaust gas be deflated for most efficient reverse thrust

Answer 25

180 degrees

Question 26

What is the main component of the control system

Answer 26

Thrust reverse lever in cockpit

Question 27

How do you guarantee a laminar vortex free and axially orientated exhaust gas flow

Answer 27

By expanding the exhaust gases completely in the exhaust nozzle

Question 28

What is the role of the airflow deflection system

Answer 28

Direct the airflow in the optimum direction for safe reverse thrust

Question 29

When would you use CD nozzle

Answer 29

When aircraft fly faster than speed of sound