ENGINE INDICATION

Question 1

What 3 groups are engine indications divided into?

Answer 1

Performance (monitor limits, set thrust)

System (e.g oil and fuel systems, detect malfunctions quickly)

Engine trend (done on ground to detect engine problems early)

Question 2

What type displays show engine indications?

Answer 2

Analogue and digital.

Question 3

Where are Engine performance indications always shown?

Answer 3

At the top.

Question 4

What 2 indications can give engine thrust?

Answer 4

N1 speed

Engine pressure ratio (EPR)

Question 5

What is EGT?

Answer 5

Exhaust gas temperature.

Question 6

How is the engine performance data usually transmitted to indicators?

Answer 6

Electrically, measured by specific sensors or probes.

Question 7

What system does engine trend monitoring use information from?

Answer 7

ACMS (aircraft condition monitoring system)

Question 8

What 3 different types of ananlyses are done for engine trend monitoring?

Answer 8

• Thermodynamic (measures pressures and temps of gas flow path)
• Mechanic-dynamic (checks vibration and rotor speed signals)
• Oil consumption (alert when oil consumption exceeds certain limit)

Question 9

How are engine rotor speeds always expressed?

Answer 9

As a percentage of 100% design speed.

Question 10

What is the engine pressure ratio?

Answer 10

Ratio of total pressure at turbine outlet to total pressure at fan inlet.

Question 11

What is TIT?

Answer 11

Turbine inlet temperature (highest temps in engine)

Can be higher than 1400 Celsius.

Question 12

Where is EGT measured from?

Answer 12

Directly between HP and LP turbine or behind LP turbine. (Maximum can be between 600 and 900 Celsius)

Too hot in the TIT.

Question 13

What is the amber lime on EGT indications?

Answer 13

Max EGT for maximum continuous thrust.

Only allowed to exceed for take off or go around thrust.

Question 14

Where is oil pressure information transmitted?

Answer 14

Sent from the oil pressure transmission to the engine interface unit

Question 15

What are the two types of oil transmitter?

Answer 15

• bourdon tune

- strain gauge

Question 16

Low oil pressure warnings are always accompanied by what type of warning?

Answer 16

An acoustic warning.

Question 17

Where can the oil temperature sensor be located?

Answer 17

Scavenge System - senses hot oil upstream of oil cooler

Pressure system - senses temp of cooled oil

Question 18

What is the spectrometric oil analysis program? SOAP

Answer 18

Find internal wear of lubricated engine components

Find parts that filter can pick up ranging from sizes 0.01 - 0.02mm

Question 19

Where are SOAP oil samples taken from?

Answer 19

Oil tank on a regular basis

Question 20

What size particles are the filter elements in an oil system able to pick up?

Answer 20

Sizes above 0.015mm

Question 21

What is the issue with filters in oils systems?

Answer 21

It is not changed often and inspections take time.

Question 22

How can magnetic chip detectors be inspected?

Answer 22

Manually by removing

Automatically on modern aircraft and removed when necessary.

Question 23

How does the magnetic chip detector work?

Answer 23

Resistance will decrease when particles connect with the detector. Once below a value the ECU sends maintenance message.

Question 24

What units usually show the level of vibration?

Answer 24

0-6

Question 25

What is EVMU?

Answer 25

Engine vibration monitoring unit.

Question 26

What are engine vibration sensors made up of?

Answer 26

Accelerometers that measure the radial acceleration of the rotor system.

Question 27

What is the BB vibration sensor?

Answer 27

Broad band, unfiltered vibration signal from aft sensor.

Used when rotor signals not available

Question 28

What happens when a vibration level reaches a critical value?

Answer 28

Vibration indication starts pulsing.

Question 29

What does the fuel flow transmitter measure?

Answer 29

Flow of fuel between fuel control unit and the fuel nozzles.

Based on; force = mass x acceleration

Question 30

What position transducers in fuel flow transmitters measure the turbine angle?

Answer 30

Synchro or RVDT.

Question 31

Why do modern fuel flow transmitters not need an electric motor with a power supply?

Answer 31

Use the fuel itself to generate acceleration.