Questions tagged [electrical-system]

The part of an aircraft providing it with electrical power including Generators, Alternators and Ram Air Turbine.

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2answers
83 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 ...
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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 ...
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102 views

Where to find general A320 E&E Compartment Information?

I'm student in electrical engineering and write my thesis on some topic of the e&e compartment. The main focus is on the computers of the A320 flightcraft, actually called E&E Compartment. ...
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Why was the Tu-104 so prone to navball-disabling electrical power failures?

Of the (rather numerous) accidents involving the Tu-104, several were either caused or aggravated by major electrical failures, which disabled the aircraft's navballs, which caused the pilots to ...
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1answer
292 views

What's the plug used on airliners for ground power?

What's the plug pair called? What's the ISO/whatever standard involved? What do they look like close-up? Is it pretty standard today worldwide? Is the plug identical for the hugest airliners as for ...
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3answers
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What powers an aircraft prior to the APU being switched on?

I know that APUs are power plants for non-propulsion related purposes and that they are turned on before takeoff. What powers an airplane prior to the APU being turned on?
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1answer
257 views

Why does the B737NG need electrical power for aircraft towing?

I have read the AMM for towing and one of the mentioned steps is to supply electrical power. Is it because you need power to turn on the hydraulics in order to pressurize your brakes? For B737NG
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66 views

Where can I find electrical pinout of C152 microphone jack and DC bias?

Would anyone have the pinout and/or specs of the C152 passenger/pilot microphone jack? I'd also like to know what DC bias voltage, if any, the plane provides to the microphone. Here's what I have so ...
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164 views

What is the source of emergency power for a 727?

I've found a couple of sources that state the 727's APU cannot be started while flying, as it draws air from the wheel well. It drew air from inside the wheel well, so it was only for use on the ...
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1answer
179 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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158 views

What is the working principle of VFG [duplicate]

How does the VFG make various frequencies? And while it makes the other value of frequency, how the generator apply consistent 400Hz to the other component?
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1answer
3k views

What happens to Cessna electric flaps that are moving when power is lost?

On final in a C182T you move the flap control arm from 20 to FULL, and when halfway there, the breaker pops (or BUS1 fails, a wire falls off, etc.) Does the flap stay where it is, slide back to 20°, ...
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515 views

How can the F-16 remain stable when there is a loss of hydraulic power?

Edit for justification: This question is different from If the EPU (Emergency Power Unit) on a modern fighter jet fails, will the aircraft drop out of the sky? for the following reasons: The ...
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Has there ever been an airliner design involving reducing generator load by installing solar panels? [duplicate]

Has there ever been a trial/project/design, in which solar panels were incorporated in the design of a commerical airliner (e.g. on the wings), with the aim to reduce fuel consumption by lowering the ...
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Is aluminum electrical wire used on aircraft?

Aluminum electrical wire got a bit of a bad reputation in household wiring due to reacting badly with terminals not properly rated for aluminum. Properly handled, it works fine, but it's so ...
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1answer
550 views

What are possible causes for the flaps not deploying on a Cessna 172?

I would like to seek some expert opinion on why my flaps failed to deploy when I took it to Flaps 20. I was turning from Downwind to Base when I took flaps 20 and noticed that my speed was creeping ...
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68 views

Are there required standards for gate power cable maintenance?

I am looking for reference(s) addressing gate power cable maintenance, for both 28V DC and 400Hz. Do the FAA or any manufacturers have standards for measuring the connector pins to determine wear?
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Ground Power KVA when on stand

How much power from a GPU would a jet, say a Boeing 737, require when boarding passengers or just sat idle on the air bridge? I’m guessing the Aircraft would only consume the full 90kVA ground power ...
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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)....
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What is the “off-side engine generator” on an A320?

For the A320 family, is the "off-side engine generator" the same as the "emergency generator driven by the RAT"? I can't find the location of the "off-side engine generator" on the A320.
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560 views

Why does load shedding still occur in jetliners (e.g., 787) when there is so much power available?

I had a few questions about how electrical generator works on an aircraft, the 787 to be specific although I know it is similar for all aircraft. So the 787 engines have 2 VFSG each which are rated ...
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127 views

What is a Ground Power Dispatch Switch?

I've been going over the new Master Minimum Equipment List (MMEL) for Textron Aviation Model 500 Series Citations and on page 36 a Ground Power Dispatch Switch is mentioned but I can't find any ...
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1k views

What is the standard power supply and voltage supply on modern airliners?

I'm looking at reducing the weight footprint of some of the computer systems on a commercial liner. A big consumer of weight seems to be in power supplies and conversion. Being a computer guy, I don't ...
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596 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 ...
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1k views

What is an “all-electric APU”?

Understand that the APS5000 used in the B787 is the first all-electric APU for large commercial aircraft. Source: http://www.pwc.ca/en/engines/auxiliary-power-units Sorry if this sounds too ...
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143 views

Is it possible to 'retrofit' electric flight control actuators to replace existing hydraulic actuators on aircraft?

Read a bit about the potential cost savings of replacing existing hydraulic aileron actuators on large commercial aircraft such as the A350/380 with electrohydraulic/electromechanical actuators. ...
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1answer
204 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 ...
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78 views

Where can I find power and heat specifications for EFIS and IFE systems?

I am working on an MSc. thesis project about the electrification of aircraft. Since the rule of thumb is to design the generators for the worst case scenario, I would like to include as much ...
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71 views

Is there a standard place to find detailed wiring circuit and component information for different aircraft?

Today I was looking into the systems that are affected by the STDBY ATTD (#1 and #2) circuit breakers in a SR22 and I accidentally stumbled upon something that I find very interesting and I've been ...
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6k views

What happens when all electrical systems in a helicopter fail?

I was thinking of asking this question at Worldbuilding, because it is for a book I am writing, but I hope this site will fit better. You can migrate this question if you find Worldbuilding more ...
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1answer
141 views

What type of batteries are used in airline planes? [closed]

In Embraer 145 and Boeing 777 I mean material, recharge cycle, nominal current and voltages. From the comments I don't understand the difference if the plane is turboprop or turbofan.
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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).
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2k views

Why is there an altitude limit if we have an IDG failure on the A320?

In my company’s MEL there is an altitude restriction if we have an IDG failure of 33500 feet why is that?
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1answer
378 views

What are the “Start & Acc” and “Pitch stab” circuit breakers for on the Piper Dakota?

I am learning to fly a piper dakota and I found two circuit breakers for which I can't find an explanation: Start & Acc circuit breaker. I understand that 'Start' is for the starter. What does '...
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412 views

How are batteries cooled in passenger aircraft?

What sort of systems are used to cool batteries in the air? Liquid cooled? Air cooled? I am interested in lithium chemistry batteries in the form of either pouch cells or 18650 batteries inside of ...
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2answers
1k views

How do electric anti-icing systems work?

How do they work for GA propeller planes? More specifically, how is it implemented on the leading edge of the wing and propeller blades? I'm more interested in the mechanics of electric heating, not ...
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1answer
469 views

What's field excitation in an electrical system?

"A field relay in the GCU (generator control unit) allows or prevents field excitation within the generator. When open, the field relay deprives the associated power relay of its ground, which causes ...
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641 views

Am I correct about what AC/DC BAT BUS does?

The purpose of the AC/DC BAT BUS is to distribute either A/C electrical power and D/C electrical to the things in the aircraft that need them. For example, I think he whole ECAM system and displays ...
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4answers
2k views

Can quadrotors be used for commercial passenger flights? [duplicate]

Recently, I have been conducting research on more efficient means for vertical lift transportation. One direction I was thrown in was the use of a quadrotor system with vector thrust and artificial ...
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206 views

Can you identify this (electrical) part?

I've been given an assignment regarding this very small piece, but my professor says he has no information about it other than: It's an electrical insulator of sorts Is used in an aeronautical ...
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1answer
4k views

What will happen to the IDG disconnection mechanism if we press and hold it for more than 3 secs?

I read in the Elec systems chapter that if we press and hold the IDG pushbutton for more than 3 secs it’ll damage the disconnection mechanism. What exactly happens? Also it says that not to disconnect ...
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4answers
477 views

What prevents companies like Cessna and Piper from connecting multiple alternators to a single engine?

Firstly, I'm not even sure if there's only one alternator connected to the engine in a C172-like aircraft. But if that is true, then why don't manufacturers connect multiple alternators to a single? ...
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2answers
676 views

How is a lead acid battery and a Ni-Cd battery charged on an aircraft?

How is a lead acid battery and a Ni-Cd battery charged on an aircraft, such as an A320? Is it constant current or voltage?
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8k views

How much electrical power does one generator produce on a large turbofan?

From my related question, now I want to know just how much power does the generator produce? In other words, what is the max rating of the generator? It looks so small and that surprised me, but since ...
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9k views

Where is the generator in a large turbofan of a commercial airliner?

So, where do you put the electrical generator? If it's gonna be coaxial, the only place is the rear (it will be burnt) or the front (it will get in the way of intake). If it's gonna be coupled to a ...
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1answer
733 views

How are the navaids that are on the airport ground powered?

How are navaids (such as the ILS localizer) that are on the airport ground powered? Are they connected to the airport's power? Do they have their own backup power?
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569 views

Do propellers generate static electricity in flight and how is that handled?

How is the risk of tribocharging (static electricity generation) by the propeller managed on an airplane? Regardless of airplane size, it seems the rotation of the propeller or engine blades could ...
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2k views

What's the point of separating the Alternator and Battery switches?

What's the point of having a different button for the battery? Why does the alternator turn on simultaneously with the battery? I need an easy and short explanation, if possible.
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What is the shed bus in the Phenom 100?

I recently came across a part of the electrical system of aircraft named SHED BUS. I am specifically asking for the Embraer Phenom 100. Source (Page 122), Added ...
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How stable is the “customer” power on a commercial aircraft?

This question on Travel.SE got me thinking... Just how stable is the power that's available via the outlets in the passenger cabin on a modern, commercial aircraft? My assumption in my answer that it'...