Electrical System Flashcards
What type of electrical system is used in the DA42?
28 VDC electrical system
This system is powered by a combination of a battery and engine-driven alternators.
What is the specification of the battery in the DA42?
One 24 VDC 10 amp-hour, sealed lead-acid battery
The battery is mounted behind the right-hand nose baggage compartment.
How many engine-driven alternators does the DA42 have?
Two 60 amp, engine-driven alternators
These alternators are critical for powering the electrical system.
What is a key difference in the DA42NG regarding the battery?
24 volt, 13.6 amp-hour, lead-acid battery
This is an upgrade compared to the original DA42 battery.
What is the specification of the alternators in the DA42NG?
Two 70 amp, engine-driven alternators
This provides increased electrical output compared to the standard DA42.
How are the alternators in the DA42 driven?
Driven by a serpentine belt on the rear of each engine
This belt is also responsible for driving the water pump for engine cooling.
What happens if the serpentine belt fails?
It will cause an alternator failure and result in engine overheating
This can lead to an engine failure.
What should not be reset in flight unless it powers equipment required for safety?
A circuit breaker that trips
Resetting circuit breakers in flight can lead to unsafe situations unless absolutely necessary for safety equipment.
What is connected to the Hot Battery Bus and can drain the main battery if not turned off?
The overhead pilot-side map light
This light receives power even when the master switch is off.
What are the main components of the simplified electrical distribution system?
- Hot Battery Bus
- Battery Bus
- LH and RH main Busses
- Avionics bus
- Relay bus
These components help manage the distribution of electrical power in the aircraft.
What color indicates switches that receive power when the LEFT ENGINE MASTER is turned ON?
Magenta
This color coding helps pilots quickly identify powered systems based on engine status.
What color indicates switches that receive power when the RIGHT ENGINE MASTER is turned ON?
Yellow
Similar to magenta switches, yellow coding assists in identifying powered systems for the right engine.
What is the purpose of the alternator excitation batteries?
To generate electrical current for engine-driven alternators
They are wired in series to provide 24 VDC.
How many alternator excitation batteries are used and what is their capacity?
Two dedicated 12 VDC 1.3 amp-hour batteries
Located in the aft section of the nose baggage compartment.
What happens when the Engine Master switch is turned ON?
Connects that engine’s alternator field to the excitation battery
This is crucial for generating electrical current.
What do the ECU backup batteries provide?
24 VDC current to the ECUs
They allow continued engine operation for 30 minutes in case of total electrical system failure.
Where are the ECU batteries located?
Under the rear passenger seats
They are wired in series to provide 24 VDC.
What is indicated by L/R VOLTS LOW?
Alternator output drops below 25 VDC
This warning alerts the pilot to a potential electrical issue.
What should be done if both alternators fail?
Follow the Abnormal Operation Procedures checklist
This includes reducing electrical load and preparing for a possible engine stop.
What is the function of the alternator switches?
Connect or disconnect the left and right alternators from the main busses
They should be in the ON position during normal operations.
What does L/R ALTN FAIL indicate?
The alternator has failed
This message prompts further investigation of the electrical system.
Where is the external power connection located?
Underneath the aircraft nose, forward of the nose gear wheel well
This connection can be used to aid engine start in very cold weather.
What is the warning associated with using external power for starting?
The aircraft should not be flown until the battery has been inspected by an authorized mechanic
This is important to ensure safety.
What is a key difference in the DA42NG?
Two 12 VDC 1.3 amp-hour ECU backup batteries
These provide power to the associated left or right ECUs as well as the alternator field circuits.
Fill in the blank: If both alternators fail, expect battery power to last ______.
30 minutes
This is a critical time frame for emergency procedures.
True or False: The alternator switches can be used to reset an alternator.
False
The switches are for connection purposes only.
What type of power does the Horizon Emergency Switch connect to the AH?
30 VDC from a lithium battery pack
The battery pack has a capacity of 1.3 amp-hour and is mounted behind the PFD.
What is the life-limit of the battery connected to the Horizon Emergency Switch?
90 minutes of power
This power supports the AH gyro and glare shield flood light during a complete electrical system failure.
What must be done to activate the Horizon Emergency Switch?
Break copper witness wire, lift switch cover, and push the switch down
The witness wire must remain intact for IFR flight.
What messages are indicated by the Electrical System CAS?
- L/R ALTN AMPS
- L/R ALTN FAIL
- L/R VOLTS LOW
What is the primary function of the Horizon Emergency Switch?
To provide power to the AH during electrical system failure
Fill in the blank: The Horizon Emergency Switch connects AH to a _______ battery pack.
lithium
True or False: The Horizon Emergency Switch provides unlimited power to the AH in case of failure.
False
What is mounted behind the PFD related to the Horizon Emergency Switch?
A 30 VDC, 1.3 amp-hour lithium battery pack
What happens if the witness wire on the Horizon Emergency Switch is not intact?
The aircraft cannot fly under IFR conditions.
