DA-42 Engine/Fuel

Question 1

When I flip the engine master on, what is getting power?

Answer 1

Engine, Engine Preheat System (glow plugs), Un-feathering accumulator

Question 2

How does the fire protection work?

Answer 2

Bi-Metal switches, heat at different rates, bend and contact a switch. 250 C

Question 3

When does the L/R Fuel Low warning come on?

Answer 3

When there is 4 +- 1 gal in the tank.

Question 4

What does the check valve on the bottom of the fuel tank do?

Answer 4

Allows air to enter

Question 5

What does the relief pressure valve do?

Answer 5

Allows air and fuel to exit

Question 6

What is the horsepower at 2300 RPM’s?

Answer 6

135

Question 7

What does the pressure relief valve protect agains?

Answer 7

Protects against a high pressure

Question 8

What is the common rail?

Answer 8

High Pressure fuel reservoir that supplies fuel to the injectors

Question 9

What is the fuel pressure in the rail measured by?

Answer 9

The rail pressure sensor

Question 10

What does a higher fuel pressure do?

Answer 10

Ensures better vaporization and therefore better combustion.

Question 11

Where is the high pressure pump getting the fuel from?

Answer 11

The low pressure fuel pump

Question 12

What is a bar in relation to PSI?

Answer 12

14.5

Question 13

What does the fuel metering unit do?

Answer 13

Ensures that only the required quantity of fuel is compressed.

Question 14

What controls the rail pressure?

Answer 14

The rail pressure valve

Question 15

How much excessive fuel is brought in?

Answer 15

4,5l/min

Question 16

What does the extra fuel do?

Answer 16

Cool and lubricates the high pressure pump

Question 17

What does TVD stand for?

Answer 17

Torsion Vibration Damper

Question 18

What is the maximum permitted engine speed?

Answer 18

2300rpm

Question 19

What is the maximum engine overspeed?

Answer 19

2500rpm max for 20 seconds

Question 20

Engine MCT (%)?

Answer 20

100% load

Question 21

Fuel temperature temp range?

Answer 21

-30/+75*C

Question 22

Oil pressure range?

Answer 22

1.0/6.5 bar

Question 23

Oil quantity (per engine)?

Answer 23

Quantity Min 4.5/ max 6.0 ltr consumption - 0.1 ltr/hr

Question 24

Oil temp range?

Answer 24

-30/+140*C

Question 25

Gearbox max temp?

Answer 25

120\*C

Question 26

Coolant temp range?

Answer 26

-30\*C/+105\*C freezing point of coolant is -36\*C

Question 27

Voltage range? Amperage max?

Answer 27

24.1/32 V 60 Amps

Question 28

Prop steps

Answer 28

12\* - low pitch 15\* - start lock 81\* - feathered

Question 29

Restart envelope of TAE-02-99?

Answer 29

Max PA 8000' ASI 80/120 KIAS

Question 30

What are the fuel tank capacities (useable)?

Answer 30

MAIN - 2\*25USG AUX - 2\*13.2USG

Question 31

Describe the Pressure Accumulator function

Answer 31

The pressure accumulator is a nitrogen oil type. It is connected to the gearbox oil circuit via an electric valve at the accumulator, which is operated with the ENGINE MASTER switch. When the ENGINE MASTER switch is set to ON the valve is opened. When the engine is running, the accumulator is filled with oil at a pressure of approximately 20 bar (290 PSI). During engine operation the accumulator makes sure that enough oil pressure is available even if the oil feed by the gearbox oil pump is decreasing due to negative acceleration.

Question 32

Describe the journey of the fuel from the tanks to the engine and back

Answer 32

On each engine fuel is injected with high pressure directly into the cylinders. The injection nozzles (one per cylinder) are supplied with fuel by the common rail. Pressure inside the rail is generated by a high pressure pump which receives fuel from a low pressure pump. Depending on the power setting the rail pressure is controlled by the ECU through an electric valve. Both pumps are powered mechanically by the engine. Fuel that is not injected is fed back into the appropriate wing tank.

Question 33

Describe the MAIN and AUX fuel tanks

Answer 33

**MAIN** * consists of three aluminum chambers which are connected by a flexible hose. * (1 US gal) of fuel in each wing are unusable, so that a total quantity of 94.6 liter (25 US gal) in each wing is usable * There are two tank vents. One includes a check valve with a capillary and one includes a relief pressure valve, which operates at 150 mbar (2 PSI) **AUX** * The vent line for the auxiliary fuel tank has a check valve with capillary. It allows air to enter the tank but prevents flow of fuel to the outside. The capillary equalizes the air pressure during climb

Question 34

Describe the cooling system

Answer 34

Each engine is liquid cooled. The liquid cooling system consists of a radiator and a bypass to this radiator. The bypass is in operation when coolant temperatures are low. It therefore allows the engine to warm-up quickly. Upon reaching a certain temperature (approximately 88 °C or 190 °F) the radiator is activated by a thermostat valve. Additionally a coolant to air heat exchanger is provided for the cabin heat system. The flow through the heat exchanger is independent of the coolant temperature. An expansion tank helps to adjust the pressure in the system. The system is protected against over pressure by means of a pressure relief valve.

Question 35

Describe the oil systems of the DA42

Answer 35

1. **Lubrication System (Engine and Turbo-Charger)** wet sump lubrication system; oil is cooled by a separate cooler on the underside of the engine. 2. **Gearbox and Propeller Governor System**

Question 36

What is the waste gate based on?

Answer 36

The bypass is controlled by the ECU through the waste gate valve. A manifold pressure sensor behind the compressor allows the ECU to calculate the correct position of the waste gate valve

Question 37

Why do you cool the air after you make it hot?

Answer 37

Cooler air makes it more dense

Question 38

Describe the engine induction system (+ turbo)

Answer 38

Question 39

Describe the DA42 FIRE DETECTION SYSTEM

Answer 39

consists of an overheat detector in the hot area of each engine. In case of an increase of the engine compartment temperature above 250 °C (480 °F) the overheat detector closes the electric circuit and a warning message appears in the annunciation window of the G1000 PFD. CAUTION If the aural alert or the warning does not appear, an unscheduled maintenance is necessary.

Question 40

How many ECUs make 1 FADEC?

Answer 40

2 ECUs make 1 FADEC

Question 41

Your DA42 can use diesel, and the airfield you land at offers you to put in diesel. Can you do it?

Answer 41

No, only JET A1 may be used (CTC SOP)

Question 42

What is the oil guidance on the DA42? How much can you dispatch with? What is the recommended level for dispatch?

Answer 42

* -The absolute minimum oil level required as stated in the AFM is 4.5 Litres. * Plan to land with minimum 4.5 Litres. For land-away flights, take a spare bottle per engine. (if unused, return after flight). * -In order to ensure oil will remain sufficient throughout the flight, dispatch with a minimum of 5 Litres. * - The oil level shall be between 5 and 6 Litres, about 1/2cm above the bottom red mark