Questions tagged [electrical-system]

The parts of an aircraft that produce electrical power (such as generators/alternators, batteries, and ram air turbines) and distribute it to the aircraft's systems.

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1 answer
141 views

Use of Fuses in modern Aircraft Systems

Are Fuses allowed in the control electronics of an airplane? Are Fuses allowed in the electronic power paths which supply actuators? Thank you in advance.
3 votes
3 answers
460 views

Can both AC ground and DC ground connect to the same Ground STUD

Can both AC ground and DC ground connect to the same Ground STUD in a plane?
6 votes
4 answers
6k views

Can electricity be harvested from magnets in jet engines?

I was reading about bleedless-787 power system but found out it still requires a gearbox. What if you put coils around the "tube" part of the jet and tiny magnets in the end of the fan/...
12 votes
1 answer
4k views

What is the process to disconnect ground electric power before pushback?

While commercial airliner are parked at the gate, they have electrical power connected to the aircraft (if available at the airport). This needs to be disconnected before pushback - what is the ...
2 votes
1 answer
71 views

Charging system in a Lancair Columbia 350

The bus volts indication on my G1000 is pegged at 29.2 volts for both the left and right bus. I have a 24 volt system. What might that mean?
21 votes
4 answers
4k views

How do jet engines generate electrical power?

I am interested in understanding how electric power is generated in Jet engines. If a pilot continuously keeps altering the throttle to suit the flight requirements, how does the jet engine maintain ...
5 votes
2 answers
251 views

If alternator fails and I'm running on battery power, what equipment can I turn off to conserve power?

For a PPL, if the alternator goes out and I'm running on battery power, the typical advice is turn off what you can to conserve power. But what exactly is safe/unsafe, or order in which to turn off ...
1 vote
1 answer
140 views

How do GA aircraft flaps stay in place?

On most small GA aircraft such as the well-known Cessna 172P "Skyhawk", the flaps are electrically actuated. Now - how do they stay at the setting selected by the pilot after extension ? Is ...
0 votes
1 answer
156 views

Who is the manufacturer of the power inverter used by Ampaire electric aircraft?

Please see the picture within this article.
2 votes
4 answers
2k views

How does the battery master switch activate the battery contactor in Cessna 152?

I have trouble understanding how the battery master switch activates the battery contactor in this schematic from the Cessna 152 manual. This is the model from 1979 or later with an Alternator Control ...
1 vote
1 answer
458 views

C172 alternator field circuit breaker(5a) vs alternator pull off circuit breaker(55a)

what’s the different with alt circuit breakers between 5a vs 55a?? If alt field circuit breaker pops out does that mean alternator is not producing electricity? And if al current circuit breaker(55a) ...
23 votes
3 answers
58k views

Why is Hydrazine used to power the F-16's EPU?

Why does the military use hydrazine to power the F-16's Emergency Power Unit (EPU)? What is so unique about Hydrazine fuel that it's needed to power the EPU? Why not use a less volatile and less ...
4 votes
5 answers
1k views

What are the hurdles to overcome before purely electric commercial aircraft can fly?

What are currently the largest issues with purely electric commercial aircraft (large scale ones like the size of a Boeing 737)? Are there any organizations right now that are trying to solve those ...
20 votes
6 answers
6k views

Why are Li-ion batteries not being used in aircraft but are widely used in electric vehicle industry?

This might seem a very naïve question. Maybe the comparison of electric vehicle to aircraft is hugely inappropriate. But I couldn't find a clear answer in web search. Lithium-ion batteries have a high ...
4 votes
2 answers
1k views

Why is the King Air avionics switching system wired normally closed?

In the King Air 200 and B200 (perhaps other King Air models as well), the avionics electrical bus relays are normally closed. With the Avionics Master switch in the "OFF" position—which is ...
5 votes
1 answer
802 views

Why is the generator turned back off for starting the second engine on a King Air?

The engine start procedure for the Beechcraft King Air B200 says (emphasis mine): Right Ignition and Engine Start Switch – ON [R FUEL PRESS] annunciator – OFF Right Condition Lever – LOW IDLE (...
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0 answers
133 views

What components does AC bus1, AC bus2, AC EssBus, DC bus1, DC bus2 & DC EssBus supply to in A320?

Under chapter 24 (electrical) of Technical training manual downloaded from this website ( https://vdocuments.mx/reader/full/a320-chapter-24-electrical-power ), What components does all the buses ...
5 votes
1 answer
207 views

The Fokker Universal has a crank you have to spin rapidly upon startup. What is it?

The Fokker Universal is one of my favorite aircraft. There is only one complete representation of it in existence at a museum in Canada. A video series I saw on YouTube tells the story of its ...
6 votes
1 answer
893 views

Why are the 737's variable-speed generator drives so unreliable?

The 737 Classic has two different possible styles of engine-driven generators, distinguished by the generator's drive mechanism: the constant-speed drive (CSD) and the variable-speed constant-...
23 votes
3 answers
13k views

How does the A350/380 operate on Variable Frequency AC generators?

To keep a constant frequency of 400 Hz, most aircraft have a CSD (Constant Speed Drive) associated to the AC generator. On most types (e.g. A320, A330, B737, B747, B777) an Integrated Drive Generator (...
6 votes
1 answer
321 views

Do I need a ferry permit for an alternator repair ferry flight within a mode C veil?

My Cessna 172 SP's alternator died while stationed at a class D airport, less than 10 miles from my home field (another class D). Both airports are within the mode C veil of a nearby B airport. ...
24 votes
2 answers
15k views

How are fly-by-wire airliners controlled in case of complete electrical failure?

In this comment, it is postulated that even fly-by-wire aircraft (Airbus) are demonstrated to fly without any electrical systems. All Airbus aircraft are demonstrated controllable with complete ...
6 votes
1 answer
586 views

What is the battery voltage for a Supermarine Spitfire?

I am used to modern aircraft being 28V systems. I found an article saying that a trolley AC plug in battery used to start WWII aircraft was 12V. I'm trying to confirm or disprove this.
10 votes
2 answers
2k views

What are the advantages of using DC electric power over AC, as e.g. done in the EMB 135/145?

In this question I can see the advantages of using AC electric power over DC in large aircraft. However, Embraer decided to produce a "DC aircraft": the ERJ 135/145. What are the advantages ...
16 votes
9 answers
20k views

Can rotorcraft pick up a dangerous electric charge?

So, I was re-watching The Hunt For Red October, (in light of current Russian shenanigans with Sweden), and there was a scene in which a crew-member on the ground was electrocuted by making contact (...
3 votes
4 answers
2k views

What component of an aircraft generates its electric power?

What component of an aircraft generates the electric power to start the aircraft's engine? For a Rotax 912 engine, I think the magneto generates the electricity, but I'm not sure; I also think about ...
7 votes
3 answers
3k views

Why does the low voltage warning light not illuminate when the alt switch is on, but the engine is off?

As part of the pre-flight inspection, one of the checks is to verify that the low voltage light is illuminated when switching just the battery on. This makes sense; there's a low voltage and the ...
4 votes
1 answer
2k views

If an A320 loses an engine why does the landing category go to CAT3 single?

Following an A320 engine failure, why does the the landing category go to CAT3 single even if the APU has been started and is powering the AC bus that was lost by the failed engine?
-1 votes
3 answers
218 views

What amount of electricity could we get from the Seebeck effect on a kerosene turbofan?

Edit: I rewrote my post. To downvoters, can you comment on your reasons? As a kind reminder: Downvote questions that don't show any research effort or don't contain enough information to be clear and ...
4 votes
2 answers
473 views

Why is the alternator connected only to one electrical bus in the C152?

I am a noob in electrics so pardon my ignorance. What I see from an electrical system of C152 (pasted below): there are two busses, connected to each other, but alternator is fed only to the first bus....
5 votes
1 answer
1k views

Why battery voltage is lower than system/alternator voltage

I’m a noob in electricity so pardon for my ignorance. Why the battery voltage is always lower than whole system and alternator voltage (considering light aircraft electrical system). E.g. In Cessna ...
6 votes
1 answer
407 views

Can I do an alternator check at idle in a C152?

I have one question about alternator check in Cessna 152. During engine run-up we should check whether alternator is working or not, so we switch it off and then the warning light should illuminate. ...
2 votes
2 answers
878 views

Are the A320's A and B electrical buses both energized all of the time during flight?

I'm a novice reading a quick study guide. For electric power, I notice that the A320 has two buses: A and B. Are they both energized all of the time during flight? If not, is there a way to switch ...
1 vote
1 answer
999 views

Why are these steps performed on the A330 emergency electrical checklist?

For an Airbus A330 in emergency electrical configuration with both generators and APU FAIL (both engines working), why does the checklist ask you to select RAT MAN ON before slat extension and then ...
0 votes
1 answer
286 views

Where can I find maintenance manuals for the A380?

My friend recently acquired an external green light from an A380. They are the only details i have from him. I tried hunting the internet for maintenance manuals, technical details, schematics, ...
6 votes
2 answers
3k views

Why is the battery turned off for checking the voltage on the A320?

Preliminary cockpit preparation section requires BAT check for 25.5V with BAT off (The beginning step). Since BAT indicator always show respective voltage, why they must be switched off?
6 votes
2 answers
1k views

How does the automatic battery cut off logic prevent complete battery discharge on ground in the A320?

I was reading in the electrical systems of the a320 FCOM and in one of the notes it stated that the batteries have an automatic cutoff logic which prevents them from getting completely discharged when ...
19 votes
3 answers
4k views

Can a completely drained battery be recharged via ground power on an airliner like the B737?

When accidentally leaving the battery switch or something powered by the hot battery bus on over night, an aircraft's battery could completely discharge. Normal startup, where the battery is switched ...
29 votes
8 answers
7k views

Why do we still need ammeters?

I just received my private pilot's certificate 2 weeks ago, yay! Earlier today, a fellow at work who has 700ish hours walked in and asked my office-mate-electrical-engineer "why do we still need ...
2 votes
2 answers
162 views

Can I safely plug something that draws 6 amps into the cigar lighter (power port) in my Piper Archer lll?

Can I safely plug something that draws 6 amps into the cigar lighter (power port) in my Piper Archer lll ?
1 vote
1 answer
189 views

Will reducing the electricity power in an aircraft save fuel?

I was wondering if I reduce the power consumed by the aircraft, would the generator produce less power and if that would save some fuel.
1 vote
6 answers
323 views

Would a piston or turbine engine be best suited for a small UAV flying 8000miles?

I am trying to devise a concept that would airdrop medical supplies around remote regions of Africa: vaccines, medicine, blood... etc. I image the payload would be anywhere between 1-2 ton. I think a ...
4 votes
1 answer
504 views

What is the most commonly occurring fault with this type of electrically driven gyro?

I have an examination tomorrow about advanced avionics systems (EASA module 13) and we are required to troubleshoot a fault with the compass system. What is the most commonly occurring fault with a ...
2 votes
0 answers
112 views

How many smoke detectors does the A340 cargo deck have, and how are they wired?

I am a student of Aerospace Engineering, currently I am one year away from completing my degree. For my Electric Routing class I was asked to recreate in Catia the fire system in the cargo bay of an ...
2 votes
0 answers
130 views

What is the cost of electricity generated in the E175-E1?

I'm comparing two types of cabin illumination, and I'm having a difficult time to estimate the cost that will be saved by utilizing lights with a lower power consumption. What are the costs of ...
5 votes
1 answer
604 views

Why can APU supply both bleed air and electrical power up to 10.000 feet but bleed air alone up to 17000?

I am reading my company's FCOM and I saw there the following information. APU Bleed + Electrical Load: Max Alt 10000 ft. APU Bleed: Max Alt 17000 ft. APU Electrical Load: Max Alt 41000 ft. If APU ...
10 votes
3 answers
3k views

What happens with the avionics if in midair there is loss of power or fuel flow interrupted? [duplicate]

What happens if in midair there is loss of power, how will the avionics perform in such a situation (cockpit display, flight plan)?
2 votes
1 answer
305 views

What does Phase 3A mean for avionics?

I've learned about Phase 1, Phase 2, and Phase 3 electrical systems. But recently I've faced an issue about replacement of Phase 3 Common Display System (CDS) Display Units (DUs) with new Phase 3A CDS ...
8 votes
2 answers
5k views

What is the typical voltage used on jet airliners?

I have seen several parts that use 28 Volts DC, is this a standard for jet airliners (e.g., Airbuses and Boeings).
2 votes
3 answers
725 views

Does the 2020 ADS-B -Out requirement apply to aircraft with only a wind-driven generator (electrical system)?

Since my J3 Cub was was not originally certificated with an engine-driven electrical system it's clear the 2020 ADS-B-Out mandate (U.S.) does not apply (except where specifically noted in FAR part 91)....