Phone charger plugged in 110v/400hz...

[Dutch250]

Hey guys..

Just a quick question regarding using phone/tablet charges on board.
I know the planes generate voltage at 400hz. But is it safe to use e.g a IPhone charger on board that uses 50/60hz ?

Thanks for all the info.

[PDR1]

I seriously doubt it - the inductor won't resonate properly.

[HamishMcBush]

Nope, you cannot successfully use a normal 50/60 Hz device onboard at 400Hz.
Don't most planes have some USB sockets now, into which you could plug a more suitable charger lead? Please don't risk an incident by attempting to use sockets designed for 400Hz equipment for your domestic electrical stuff

[wiedehopf]

If it's a socket for a passenger it won't be 400Hz and should be labeled accordingly.

[Denti]

Most modern phone/tablet chargers are switched mode power supplies and can accept a huge frequency range of input power. They do not have any problem at all with 400 Hz and work just fine. However, they are not officially certified for that use, nor are the power outlets.

It might be a customer mod, but our in seat power outlets for passengers have 110V with 60 Hz, same for the power outlets at each pilot seat, the maintenance outlet in the flight deck, same as the vacuum cleaner sockets and the medical outlet in the cabin have 400 Hz with 115 V.

We have to use the low frequency outlets for our iPad chargers, however the reason, according to our technical staff, is not the frequency but rather a grounding problem with the 400 Hz outlets that can lead to very high residual voltages and a high risk of electrical shock. For our former EFB we used the 400Hz socket, but needed specially protected power supplies to prevent that risk.

[CL300]

Woaw... and no cabin manufacturer had ever put a converter anywhere ?

[Dutch250]

Thanks for al the info..

Problem with my airline is that they provide an Ipad for aviobook and lido. But we do not have a proper charge socket for it. Also no usb port.

So thats why many of us do use the onboard socket. I have never had any problems, not even a warm feeling charger.
But just recently I had a duscussion with a colleague who was totally against using it.

So I thought, lets get some facts Straight.

[safelife]

In the Airbus the socket above the circuit breakers has 110V//400 Hz and may not be used, while those under the microphone where the flight kits are has 110V/60 Hz and may be used.
But those are an option, not all Airbus have them.

[CaptainMongo]

We use the iPad as an EFB. We are only authorized to use the Apple charger plugged into the rear panel plug for charging, no other charging devices may be plugged into that receptacle.

About 1/2 of our busses have tablet interface modules (one per pilot below moveable window) with two USB ports, a main (2.1 amp) tablet charging port and an aux (~.3 amps) charging port for another device. These TIM's also allow for blue tooth connectivity to the aircraft, but this feature hasn't been exploited (nor do I think it will be)

The rest of our non Airbus fleet is being retrofitted with 110 volt plugs. The concern is in the future USB charging will go away.

[tom775257]

Step one of an AC to DC switch mode power supply is generally to rectify to DC/filter before chopping up at high frequency (in the KHz). It couldn't care less within reason the frequency of the AC input voltage. Whether certified or not is a different matter.

In the unlikely event you have a mobile device with a power supply which accepts only say 60hz/120v DO NOT use on 400hz. The switch mode PSUs will take say 110-240v 50-60hz.

[Intruder]

I've used many chargers on a 400Hz circuit, with no problems.

[Uplinker]

Seems to be a lot of confusion about this.

We have been told we may only use the socket on the rear CB panel on the ground, NOT in flight. They cite interference as a reason.

Any Airbus B2s got any more info?

[underfire]

Most modern phone/tablet chargers are switched mode power supplies and can accept a huge frequency range of input power. They do not have any problem at all with 400 Hz and work just fine. However, they are not officially certified for that use, nor are the power outlets.

I've used many chargers on a 400Hz circuit, with no problems.

The chargers may/may not be officially certified. The use at 400Hz will shorten the battery life of the device significantly. With a iPad or other device without replaceable batteries, this is a significant issue.
In the case of Apple products, while they say it will work, and are certified for use on deck, they will not warrantee the use because of the battery issue.

There is a certified, approved, and warranted charger available.

Dutch50 and others, on inquires, tell them Brian sent you!

The GNS USB flight deck portable EFB charger is a simple and effective device born out of necessity for flight crews to charge their iPads in-flight after extended use. It uses the 28VDC bus, not the 115VAC/400 Hertz outlet that can be a potentially noisy EMI transmitter and a fire hazard for consumer grade chargers designed for 50/60Hertz. The internal DC-DC circuit is 85% efficient converting 28VDC to iPad voltage and supplying 10+ watts of power with overload and short circuit current limit protection. Each channel also has dual input fuse to protect the aircraft 28VDC supply bus at all cost providing fail-safe protection from an overload before, during and after the USB power conversion. See our product datasheet for additional specifications and lab reports. (hyperlink to product datasheet). Current models include 3 common aircraft plug configurations.

http://globalnavigationsciences.com/wp-content/uploads/2016/11/gns-products-1.jpg

Products - Global Navigation Sciences (http://globalnavigationsciences.com/products/)

[Denti]

I wonder, what does the frequency of the AC power supply to the charger that in turn produces DC supply to the device have to do with the devices battery life that only receives a DC charge, no matter where the charger is socketed in?

They had no problem with the normal warrante for our EFB iPads, and battery degradation was not a bigger problem than usual for the first generation iPad Air we just switched out after four years or so.

[wiedehopf]

Shorten the battery life? How would that work?
While i doubt it the chargers may supply less than their rated current but that would only mean slower charging.
To shorten battery life you would need overcharging ... which would be dangerous and highly unlikely as the charge-controller is not even in the wall adapter but rather the device.

As there are dangerous and EMI emitting wall adapters out there higher standard chargers would of course be a good idea.

[underfire]

it is the 400hz issue vs 60 hz. Aircraft use 400hz, as the alternators can be smaller, (lighter) but the associated output is then subject to wide fluxuations in output.
The power at 400hz, when the voltage fluxuates, the reactive drops through the system are even more significant, up to 7 times the difference. Typical chargers are not set up to handle this voltage swing, especially the drops.
The batteries are then subject to this flux, and it degrades them in respect to 60hz charging.


Not to be flippant. In regards to battery degradation, not certain of the duration of flight/charge that your airline experiences. Did you experience the need to charge devices inflight very often?

[PENKO]

I'm a bit confused. Why would you use the 400 HZ socket? Most pax jets have regular 50/60 HZ outlets in the cabin.

[Lancelot de boyles]

Possibly, because running an extension cable from a passenger seat all the way into the flight deck is going to raise all sorts of problems...?

I and many many colleagues have managed to use MagSafe and latterly, iPad 12w chargers from the 400hz socket, with much success for a decade or more. Some folk get all excited about it, but then, they're the type that expect an sop with exact measurements on how to wear a hat.

[CaptainMongo]

If your company SOP allows the use of these chargers in the cockpit, what's your point? You and your colleagues are simply complying with SOP as all good pilots do.

[MurphyWasRight]

but then, they're the type that expect an sop with exact measurements on how to wear a hat.

Would love a copy of that SOP, would not be surprised if it actually exists.

Long time ago I saw an ATT&T, aka 'the (American) phone company' manual that had over 10 pages on how to use a screwdriver. Wish I had kept a copy.

As to chargers, as many have stated almost all are now switch mode that have a very wide input range and frequency tolerance.

Suggestions that input power quality would affect the (typically) 5V output which in turn would affect the devices internal battery controller are false and possibly marketing driven. (Resist temptation to start a 'golden ears' flame war on gold plated welding cable for speaker wire :)

Grounding difference are possible but doubtful they would be a safety issue since any 2 prong device has to be double insulated to be safe in normal use.

Grounding could affect EMI but even that is likely more sensitive to cable placement than anything else.

All that said when it comes to cockpit use it is either SOP/approved or not and anyone deciding that it is not relevant is on their own.

[Intruder]

Aircraft use 400hz, as the alternators can be smaller, (lighter) but the associated output is then subject to wide fluxuations in output.
Why would it be subject to such fluctuations? In my experience in the 747, generator output is VERY stable once power transfers are complete after start...

Besides, if a charger is rated at 100-240V, why would a fluctuation matter to the output? I suppose the charger electronics could fail early with repeated fluctuations, but why would they carry over to the battery being charged?

[Uplinker]

@ underfire
it is the 400hz issue vs 60 hz. Aircraft use 400hz, as the alternators can be smaller, (lighter) but the associated output is then subject to wide fluxuations in output.
The power at 400hz, when the voltage fluxuates, the reactive drops through the system are even more significant, up to 7 times the difference. Typical chargers are not set up to handle this voltage swing, especially the drops.
The batteries are then subject to this flux, and it degrades them in respect to 60hz charging.


I too am struggling to understand this, and I was trained in electronics.

Could you explain this a bit further? What are the 'fluxations' and the 'drops' you speak of?

[Avtrician]

The power at 400hz, when the voltage fluxuates, the reactive drops through the system are even more significant, up to 7 times the difference. Typical chargers are not set up to handle this voltage swing, especially the drops.
The batteries are then subject to this flux, and it degrades them in respect to 60hz charging.


A 400Hz 115 volt alternator is extremely stable, as they are mounted to systems that keep their rotation speed constant (it called a constant speed drive for that reason) If the voltage fluctuated, then there are a lot of electronic systems that would be damaged. ( alternator is controlled by a voltage regulator to keep it stable). Yes, output power can vary, that is due to changing requirements of the load.. IE the current supplied varies due to changing demand.

If the plug pack works at 400 Hz (I have never tried to do it) then its output will be the required 5/9/12/20 volts that it is designed to provide. If the power pack has a transformer in it, then its impedance will be very high at 400 Hz (about 6.5 to 8 times higher depending on its design frequency) then its ability supply current will be reduced.

[FullWings]

One of the reasons why 400Hz was originally used in aircraft is that you could use smaller and lighter inductive components (mostly transformers) which had the same performance as much larger/heavier ones designed for 50/60Hz.

The main problem with using these components outside their specifications is when the input frequency is lower, which reduces the impedance so allowing higher currents to flow which can overheat the device, e.g. using 400Hz equipment with 50/60Hz input = bad.

Modern SM power supplies are tolerant of input voltage/frequency within quite a wide band because of the way they work.

I would speculate that non-approved devices are disallowed from using power outlets on the flight deck not because they are expected to burst into flames but because of the possibility of a fault causing an fire in the supply wiring, which would be inaccessible in flight. Power sockets designed for in-flight use have much more in the way of protection built in, compared to the ground service ones. It may be as simple as that.

[Chu Chu]

Run an AC current through a rectifier, and you'll get DC with a very significant ripple. That could have an effect on the electronics downstream in a switching power supply.

In the abstract, a 400 HZ ripple should be easier to smooth out than a 50/60 HZ ripple (e.g. a smaller capacitor would be required). But it does seem possible that a system designed for 50/60 HZ and not tested at 400 would end up having problems at the higher frequency.

[On-MarkBob]

I concur with FullWings entirely. As the chief technical Captain for no less than three airlines I have repeatedly encountered this issue and discussed the matter with both Boeing and Airbus.
A very simplistic way to visualise the problem is this:-
If you laid out 400 paving slabs end to end to a garden shed at the bottom of your garden, you could walk effortlessly to your garden shed. Now consider laying out a pathway of 50 slabs alongside the 400. To take that path would require a great deal of energy as you jump from one slab to the other. 400 slabs in this case represents your 400Hrz. circuit and 50 slabs represent the 50 Hrz. circuit. Thus the energy supplied by the system to power your 50 Hrz. device is increased.
I have encountered on two occasions where the running of 50Hrz. units has caused the main ground power circuit breaker to run hot, but not enough for it to trip. However, the continual use in this condition lead to premature failure of the ground power circuit breaker. This is a NO GO item, Why? Because:-
On most big Aircraft the ground power circuit breaker supplies the Fire Detection and Extinguishing functions, loss of this circuit leaves you with no way of extinguishing a fire on the ground AND in flight.
Let this be known to all Cabin Services Departments who think they can just introduce DV players, telephone battery chargers an the like to the aircraft electrical system without a properly approved and certified modification. They CANNOT.
Some aircraft are modified to except 50Hrz equipment through special outlets, in particular to supply medical equipment. No doubt more modern aircraft will come with compliant power outlets. If you don't have such outlets you cannot use the 400Hrz supply unless you are using a certified appliance.

[wiedehopf]

@On-MarkBob

could you elaborate as to what the exact scenario was making the circuit breaker run hot?

[Airbubba]

I've used many chargers on a 400Hz circuit, with no problems.

Same here, both notebook computer and phone chargers work fine on 400 Hz. :ok:

Or, so I'm told... ;)


A very simplistic way to visualise the problem is this:-
If you laid out 400 paving slabs end to end to a garden shed at the bottom of your garden, you could walk effortlessly to your garden shed. Now consider laying out a pathway of 50 slabs alongside the 400. To take that path would require a great deal of energy as you jump from one slab to the other. 400 slabs in this case represents your 400Hrz. circuit and 50 slabs represent the 50 Hrz. circuit. Thus the energy supplied by the system to power your 50 Hrz. device is increased.

I'm not rightly sure that's how it works with a modern switching power supply. You are saying that a 400 Hz input to a power supply that works on 50Hz somehow delivers more energy? Your slab argument may work for cold fusion or frogs and lily pads but I don't think it is applicable in this case.

And you claim that a little 100 watt computer brick can somehow overload a ground power CB on an airliner? :confused: A 757 has a 90 KVA ground power connection, right?

[tom775257]

It is an interesting topic, having spent a little time looking at typical switch mode circuits it seems to me that the answer is, sadly, it depends. (warning, not a professional just a keen amateur wrt electronics)

If your power supply is a traditional linear power supply (Transformer->bridge rectifier->smoothing cap) it certainly will not work at 400hz.

If you have a switch mode power supply it appears initially to be simple as the AC is first rectified to DC then smoothed so what difference does input freq make? The higher the frequency input the smaller the input smoothing cap needs to be so it should work well at 400hz. Indeed looking at the smaller switch mode circuits I can see no reason they will not work well.

My only concern would be a switch mode power supply with passive power factor correction (PFC mandated on SMPS above 75 watts in the EU, this is more powerful laptop than ipad/phone territory). The point of the filter is to pass line frequency and block harmonics of the input frequency. 400Hz I think would be filtered by the PFC, I can't imagine it would do the inductor much good trying to run a SMPS with passive PFC on 400hz.

Does anyone here know more about PFC / AC harmonics/ power factor etc and can give professional opinion?

[Airbubba]

If your power supply is a traditional linear power supply (Transformer->bridge rectifier->smoothing cap) it certainly will not work at 400hz.

Actually, years ago working with the Naval Air Development Center in Warminster, PA we were able to certify the AC power supply of the Hewlett-Packard HP-67 calculator for use on 400 Hz aircraft power. I've got a couple of the power bricks in the closet, I believe that they are of the conventional transformer-rectifier design that you describe. In this instance, the units ran cooler on 400 Hz, perhaps because the small transformers were more efficient at the higher frequency. At 400 Hz RF issues weren't a significant player and in this case the ni-cad batteries did not overcharge or run hot.

And, I believe some electronic flight kit tablets are currently FAA authorized to charge (but not operate) off 400 Hz cockpit outlets.

Even though I've seen various chargers and power supplies used successfully on 400 Hz power over the years, the folks that say it's not authorized certainly have a valid point. If anything happens and the feds take a closer look, your Personal Electronic Device plugged into an unauthorized power source will be under the microscope. :eek:

[CaptainMongo]

Same here, both notebook computer and phone chargers work fine on 400 Hz. :ok:

Or, so I'm told... ;)





So your anecdotal evidence is a substitute for your: engineering department, training department, maintenance department, aircraft manufacturer, regulatory authority and others.

Accident reports are riddled with pilots who believed SOP either did not apply to them or was beneath them.

[ImbracableCrunk]

My company uses that gear. I've had some that work fine, but a fair percent can barely maintain a charge. I've actually had some lose power while "charging."

[MurphyWasRight]

Same here, both notebook computer and phone chargers work fine on 400 Hz. :ok:

Or, so I'm told... ;)



I'm not rightly sure that's how it works with a modern switching power supply. You are saying that a 400 Hz input to a power supply that works on 50Hz somehow delivers more energy? Your slab argument may work for cold fusion or frogs and lily pads but I don't think it is applicable in this case.

And you claim that a little 100 watt computer brick can somehow overload a ground power CB on an airliner? :confused: A 757 has a 90 KVA ground power connection, right?

The garden slab analogy is actually quite good, unfortuanatly it was used opposite of the actual situation:
The 400Hz corresponds to the supply frequency, not the rated input frequency of the device.
It nicely illustrates how a higher input (supply) frequency reduces the needed size of input filter capacitor.

Old (heavy) linear supplies that have a stepdown transformer at the input will probably work at 400Hz, but depending on the core material might run a bit warmer due to increased hysteresis losses.

What will most definitely not work on 400 Hz if designed for 50/60 is anything that uses the frequency to control something, one example is a synchronous motor. For those 50/60 will make a difference, in some cases does not matte much, fan speed, in others a lot; record player or electric clock.

Interesting question pon power factor correction in larger supplies, although almost all are active not just magnetic filters.

[underfire]

My company uses that gear. I've had some that work fine, but a fair percent can barely maintain a charge. I've actually had some lose power while "charging."

I believe some electronic flight kit tablets are currently FAA authorized to charge (but not operate) off 400 Hz cockpit outlets. Airbubba, an often overlooked nuance, that in reality, is not enforceable. Use inflight, charging inflight, and charging while use inflight are all issues to be looked at. The temptation to charge other devices is also uncontrollable.

As noted by several posters, there are issues with the 115v chargers. Potential for EMI is there, as these chargers do not offer 2 way protection. While the aircraft 115v system has protections built in, it depends where, and what happens back to the protection.
The typical chargers were never meant to run on 400HZ. Switching supplies have PFC controllers and they don't work properly at 400 Hz. The controllers can cause considerable amounts of leakage current back into the equipment grounding conductor. this is where the 115v 400 Hz plug falls short.

The power plug referenced at the beginning is a DC plug and offers full protection including EMI. It is important to note that this is safe for all of these devices Apple, and non-Apple.

The iPad is not the only tablet of device in use on the flightdeck. Are phones permitted to be charged on the flightdeck? With that plug, other devices can be charged safely and without EMI. I dont have any vested interest in that plug, other than its use.
I really dont think the quality control on the out of the box charges is sufficient, even from a company like Apple.

[On-MarkBob]

I didn't write the 'garden slab' analogy for the benefit of a university degree course in electrical engineering. It was written as a 'Visualisation' for the benefit of airline cabin crew. Those that wish to deride the idea should work on a better way of explaining the matter to those who have no electrical or mechanical expertise. That would be more constructive, so take it in the manner for which it was intended.
The 'Ground service' circuit breakers that were burnt out, were because the airline concerned decided that they would supply DVD players to the passengers and the players were charged by the ground service receptacles on board. This decision was made without any consultation with maintenance nor myself at the time. I discovered what they were doing on a flight to the USA. The later failure of the ground service CBs were attributed to the charging of those units on board by Boeing. If you need to argue the point please contact them, but I can tell you now what they will say. You cannot plug anything into the aircraft that is not approved. You're effectively modifying the aircraft's electrical system and for that you require a minor or major modification, which in this case would include an electrical power and supply assessment. Sadly, there is always someone on Pprune who wants to argue even when the argument has been concluded, so those who wish to connect to the aircraft will need to show the modification approval obtained to do that or a notification from Boeing, Airbus or whoever made your aircraft in the form of a letter stating “NO TECHNICAL OBJECTION”, until then you CANNOT connect to the aircraft power outlet.

[hoss183]

The point is that 50hz chargers might work ok, but they might not. You simply have no idea of the internal design . Some could well overheat, or cause trips.
Simply beacuse some people have found it works does not make it right or safe.
It strikes me that deviance from standards like this is a worrying trait in a pilot.

(Degree qualified electronics engineer with 25 years experience)

[underfire]

On-Mark, hoss, others.

Thank you for details and experience. This is not simply approved for use, but the conditions and nuances.

As noted, depending on the ac and use, the chargers do not work that well, and there have been studies, where the chargers do not charge very well and do reduce battery life. As with many things, lab studies and ac certs do not translate to reality, but in real use, with the longer term studies, the issues have come to light.

One should also note the very specifics of the approval. I noted before, there are approvals for use on the flight deck, but dont stop there. That is not blanket approval for charging on the flight deck, nor charging while in use. Several airline cert do say approved for use, but are not approved for charging while in use, nor approved for charging on the flightdeck.
The use of these electronic devices is fairly new, and now that longer term information is available, one can see how the rules and regs are developing accordingly.

[Derfred]

A lot of points on this thread are very valid.

However, in response to the OP's question, Apple 5W, 10W and 12W iPhone and iPad chargers with A-type US connectors are certified for 115V/400Hz. There is a pretty good reason for that.

https://support.apple.com/en-us/HT202916 - this reference on Apple's site is dated 21 June 2017 but it has been around a lot longer than that.

However, before you go and plug one in, you would also need to comply with whatever EFB approvals are in place by your operator to be approved to use that power outlet for your EFB.

[Airbubba]

Here's the text from the Apple web page cited above:

iPad USB power adapter certifications

Every iPad comes with an Apple USB power adapter that is certified to meet government safety standards in countries where iPad is available.

Many of these countries, including the United States, have adopted the Safety of Information Technology Equipment standard, IEC/UL 60950-1. Learn about the certifications for iPad USB power adapters.

Depending on the model, iPad comes with a 5W, 10W, or 12W power adapter. All three Apple USB power adapters are designed for use with power sources rated to provide 100V AC to 240V AC at 50Hz to 60Hz. Find more information about iPad USB power adapter compatibility.

The Type A (flat parallel-blade design) Apple 5W as well as the 10W and 12W USB power adapters (with Type A AC plug attached) also comply with the IEC/UL 60950-1 standard for use with power sources rated to provide 115V AC at 400Hz.

Published Date: Jun 21, 2017


Elsewhere Apple states that the iPad chargers can be used to charge an iPhone:

Using iPad power adapters with your iPhone, iPad, and iPod

Apple USB power adapters for iPad can also be used to charge iPhone, iPod, Apple Watch, AirPods, and other Apple products.

You can use Apple 12W and 10W USB power adapters to charge your iPad, iPhone, iPod, Apple Watch, and other Apple accessories, like AirPods and Siri Remote. Just connect your device to the power adapter with the Lightning to USB Cable, 30-pin to USB cable, or Apple Watch charger that came with your device.

https://support.apple.com/en-us/HT202105

But as everybody points out, it will probably work fine but might still be illegal unless you get a stack of approvals from the feds, the airline, the unions, the manufacturer etc.

However, before you go and plug one in, you would also need to comply with whatever EFB approvals are in place by your operator to be approved to use that power outlet for your EFB.

And the original question was about using an iPhone, not iPad, power adapter on 400 Hz. I've seen it done with no problem in years past. But, it is probably not legal and not covered under Apple's warranty if the phone, adapter or cable bursts into flames. ;)

[Flash2001]

Let me add a little something to OMB's discourse. When aircraft adopted the 400 Hz standard, there was no such thing as a switch mode power supply.

As well as the filter caps the weight of iron in the transformers of all the avionics could be substantially reduced.

After an excellent landing etc...

[On-MarkBob]

Indeed, Flash2001,
Also when the concept of power outlets was introduced, mobile pone chargers and the like had barely been invented. As technology improves, more airlines will require this stuff and aircraft will be fitted with suitable outlets I'm sure. Let us not forget that the manufacturers know their aircraft far better than we do and if they tell us we can't use the current type of outlet for reasons they were not intended for, then we should take the responsible attitude and do as we are told by them, and if we can't do that we are in the wrong industry.
My advice to all is before you plug any commercial bit of equipment into any aircraft in any way, go and discuss the matter with your Chief Technical Captain. He will have access to the engineering manager and the aircraft manufacturer and will be able to, thus, get an answer of yes or no.

[underfire]

Exactly,
The certification labels from Apple.
iPhone charger 5V at 1000mA
iPad charger 5.1V at 2100 mA
https://images.apple.com/power-adapters/images/ipad2.jpg
iPad w retinal 5.2V at 2400mA
https://images.apple.com/power-adapters/images/ipad.jpg

The reason why some of you have had problems charging and some have not, depends on which charger you have.
If you are using the 10W charger, the 2100mA is not enough to charge the iPad if it is in use.
If you are using the 12W charger, the 2400mA is enough to charge while the iPad is in use.

[MurphyWasRight]

Indeed, Flash2001,
Also when the concept of power outlets was introduced, mobile pone chargers and the like had barely been invented. As technology improves, more airlines will require this stuff and aircraft will be fitted with suitable outlets I'm sure. Let us not forget that the manufacturers know their aircraft far better than we do and if they tell us we can't use the current type of outlet for reasons they were not intended for, then we should take the responsible attitude and do as we are told by them, and if we can't do that we are in the wrong industry.
My advice to all is before you plug any commercial bit of equipment into any aircraft in any way, go and discuss the matter with your Chief Technical Captain. He will have access to the engineering manager and the aircraft manufacturer and will be able to, thus, get an answer of yes or no.


Is there an 'approved use' list for either type of cockpit ac outlets, either 400Hz or 60Hz?
The manufactures/airline customers must have had something in mind when they were added.

Even the touted 28V dc to USB charger (BTW does look like a useful device, especially for small aircraft) is not 'certified' for cockpit use, from their data sheet:
The conclusion of all test show EMI levels well
within the standards necessary for flight deck use. The following test results
are provided as reference for maintenance engineering groups to coordinate
with their own independent EFB system tests.

In other words a system approach is needed to ensure compatibility and safety for cockpit use.

Under seat outlets in the cabin are intended for use with arbitrary devices up to a certain power level so the 'plug ... in any way' comment is a bit too broad a statement.

Agency certifications (EMI/UL/din/whatever) rely mainly on testing over specified ranges, not design review (although there is some).

With the exception of some Apple chargers that are tested at 400Hz most certs will typically be for 100-240V 50/60Hz so use of chargers on 400Hz is outside the certified range, even though they will work just fine.

One last comment is that much of the discussion centered on questioning unsupported claims such 400Hz power reducing battery life and similar, not legality which is a different thing altogether.

There is a lot of misinformation around, not that anyone would rely on a rumor web site to bless a cockpit system.

[underfire]

Even the touted 28V dc to USB charger (BTW does look like a useful device, especially for small aircraft) is not 'certified' for cockpit use, from their data sheet:

That is because of the myriad of systems, each carrier must get approval based on their aircraft and equipage.
From the FAA: Authorization for the use of Apple and Microsoft COTS PED's as an EFB are obtained by the operators, rather than the manufacturer.

The engineering department must provide to the regulators, the testing results. Therefore, there is no 'list' where you can just get what is on the list. Its all custom approved. Devices such as the iPad and others, have been through the testing for the device, such as the pressure test, pressure drop tests, and a whole list of other requirements. That does not mean you can simply begin using one on the flightdeck. It must be certified for use on that aircraft, with that equipage. I have seen systems that the charging cable itself cannot be used, and a special one is provided, due to interference.

(BTW does look like a useful device, especially for small aircraft) This is not meant for small aircraft, notice the plug. Looking at the chargers for smaller ac, notice that while the Apple charger is $20, a properly shielded and approved unit is $350?

One last comment is that much of the discussion centered on questioning unsupported claims such 400Hz power reducing battery life and similar, not legality which is a different thing altogether. Sorry, but that is supported, with quite a bit of experience on the issue and with Apple themselves. Do YOU have any evidence to refute the claim?

With the exception of some Apple chargers that are tested at 400Hz most certs will typically be for 100-240V 50/60Hz so use of chargers on 400Hz is outside the certified range, even though they will work just fine. Not true, sorry. The largest airline in the US is converting for good reason. From the FAA on the Apple charger
Other: The Type A (flat parallel-blade design) Apple 5W as well as the 10W and 12W USB power adapters (with Type A AC plug attached) comply with the IEC/UL 60950-1 standard for use with power sources rated to provide 115V AC at 400Hz. Type A plug only, and Comply is the operative word.


In other words a system approach is needed to ensure compatibility and safety for cockpit use.
There is one, ask the carriers that have them. Again, according to the FAA:EFBs employing rechargeable lithium batteries must ensure the lithium ion batteries meet airworthiness standards appropriate for the battery size and intended function. The use of rechargeable lithium batteries in portable devices is the responsibility of the operator (see AC 120-76 for applicable guidance).
The engineering, cert and validation process to put an EFB on the flight deck is significant, and the conditions of use should be adhered to.

EFB that are connected to the IFE wifi are a particular problem as well. The wifi even though connected, maintains a search mode as part of the connection, and uses a significant amount of power.