737 Electrics Part 1 - AC Power

[@eduardonunes3967]

Hello from Brazil Chiris Brady! I fly the 737NG for GOL Airlines in brazil. Your website, since the begining of the Ground school (almost 3 years ago) was a great help for me and the others pilots. I'm here to thank you for everything and say congratz for the amazing work!

[@ChrisBrady737]

Hi Eduardo, thank you for your kind words, I am glad it was all helpful. Maybe consider getting the book, it has even more information. Fly safe, Chris

[@neekoweeclearwater2305]

Thanks for breaking it down into something simple and digestible

[@ChrisBrady737]

You are very welcome

[@flyingnico380]

Many thanks Chris, these videos are perfect to go deeper on the systems for me as a young captain on the 737NG. Best regards.

[@ChrisBrady737]

You are welcome, thanks for watching

[@midfield214]

Thank you so much for the hard work and care given for each video. A treasure vault for b737 newbies! Book has been purchased!

[@ChrisBrady737]

You are welcome, thanks for watching and for getting a copy of the book 🙏

[@Dodidi95]

Thank you very much Captain Brady - Great video! It has really helped me devlop my knowledge further of the Boeing 737 Electrical System and I know other pilots will equally find these presentations helpful. Best wishes and thanks once again for all the hard work you are putting into the videos and your website.

[@ChrisBrady737]

It is my pleasure. I am happy to put something back into aviation as it has given me so much

[@dezerter86]

Dear Captain Brady! Thank you so much for all of your amazing work! It is extremally helpfull! I am a visual person so whenever I can see a picture of a certain device it helps me to understand it better. All the best!

[@ChrisBrady737]

Thank you for your kind comments. It is always rewarding to hear when people find my work helpful.

[@Wings797]

Hi Capt Brady, first I would like to appriciate and gratitude to your great video, as an airline pilot , I was trained in Boeing field Renton Seatle in year 2000 for B737 300 but now I got many more deeper with your video , thank you.

[@ChrisBrady737]

Thank you for your kind comments. I am pleased to hear that you are enjoying my videos.

[@ThePilot_USA]

Amazing amount of info. Just a quick correction at 39:37 The blue light GEN OFF BUS means the IDG is not powering the Transfer Bus. The respective generator can be running or not. The blue light APU GEN OFF BUS definition is correct. APU running but generator not powering the Transfer bus. The blue GRD POWER AVAILABLE means external power is connected and the quality is OK. Cheers..

[@ChrisBrady737]

You are absolutely correct

[@jasonbourne1451]

Without any price, it is good to reach these videos captain :) Because you know in aviation, generally you need money to have those kind of videos :D

[@ChrisBrady737]

Thanks Jason, As you can see I do not do this for the money but if you want to make a small donation then please buy a copy of my book. www.blurb.co.uk/b/10415699-the-boeing-737-technical-guide

[@elmin2323]

GOLD standard mate as always! just about to start line training and these video's are great! If your even in Australia ill buy you a beer or two..

[@ChrisBrady737]

Thanks, glad you found them useful. Not sure if I will find myself in Oz but I'd be up for a cold one if I ever do!

[@edw121]

Very nice video Chris, I'm busy prepping for another LPC. Blue Skies to you!

[@ChrisBrady737]

My pleasure, good luck

[@peppr-ovc]

Hello Chris, I'd like to know why the IFE was turned off at 41:43. Very good video! You're the best source of 737 system guides, how they work etc. keep it going!

[@ChrisBrady737]

Hi, this event happened to me around 15 years ago so I cant remember the full details but the DRIVE light had come on for some reason. I followed the QRH procedure to disconnect the IDG.

[@HAWK21M]

Another great video chris….all the best ahead

[@ChrisBrady737]

Many thanks Meljoe, welcome back to the 737.

[@inusaibrahimg.5355]

Thank You So Very Much Cpt Chris Brady always with you !!

[@ChrisBrady737]

You are very welcome

[@MarcoAlioli]

Hello there! I would like to thank you for your videos, they are excellent and they are helping me a lot preparing for the CU! Thanks a lot!

[@ChrisBrady737]

My pleasure, glad you found them useful.

[@kenlennon]

As an electrical engineer, that was an impressive presentation.

[@ChrisBrady737]

Thank you, high praise indeed. Glad you enjoyed it.

[@successkim7920]

i cannot thank you more for this

[@ChrisBrady737]

My pleasure, glad you like the videos.

[@telescope64]

Very thorough!Thanks Chris!

[@ChrisBrady737]

Thanks for all your help with it!

[@michiel6596]

Great stuff Captain Brady…complicated as it looks but made easy. Use it to prepare for Sim training and upcoming FAA check. Thanks!

[@ChrisBrady737]

Thanks for your kind comments, I really appreciate it. More videos are in the pipeline!

[@barendalberts460]

Awesome content. Thank you for sharing this.

[@ChrisBrady737]

No problem, glad you found it useful

[@allandunne2150]

Super video, great recap, many thanks!

[@ChrisBrady737]

No problem, I hope you enjoy the rest of the videos

[@nicolaslutun6361]

Very intresting Chris as usual. just a remark/question. at 04:21 I m surprised where you put the red mark; actually on the air starter and not on the CSD for the oil check as you were speaking about. is there a reason or am I mistacken ? anyway great thank you for your work

[@ChrisBrady737]

You are absolutely correct - I got the wrong sight glass! I think the CSD sight glass was obscured by the orange tag and in my haste I labelled the wrong sight glass. Good spot!

[@nicolaslutun6361]

@@ChrisBrady737 thank you for your answer Chris. it was a detail with no importance really; and more to show you that we watch your videos with great interest . I m looking forward for your next Video ( and use to watch several times the last ones ) . Great work !

[@germanschindler8781]

Great video, Chris. Thank you!

[@ChrisBrady737]

Glad you liked it!

[@navsperry9320]

You knowledge and content is just amazing 👌👌

[@ChrisBrady737]

Thank you, you are too kind.

[@navsperry9320]

@@ChrisBrady737 Your videos really helping me out for my Command prep. Really thankful to you 👏

[@ChrisBrady737]

@@navsperry9320 My pleasure, glad you are finding them useful. Best of luck with your command.

[@mattiassjogren2840]

Excellent video (as all of your other videos)! I have a copy of your book and love it! Just a question, at 38:20 "High oil temperature will not cause the FAULT light to illuminate..", I am confused by which FAULT light you mean? Thank you

[@ChrisBrady737]

Hi Mattias, Sorry my mistake, I meant the DRIVE light, there is of course no FAULT light.

[@mattiassjogren2840]

@@ChrisBrady737 Thanks for the reply. I thought you meant DRIVE, no prob, we all make mistakes! Congratulations for all your videos, they are excellent.

[@b2instructor166]

​@@ChrisBrady737 Hi, Captain Cris! Thank you for brilliant presentation. But I'd make some correction about this DRIVE light. The logic of this light doesn't diffirentiate between auto or manual disconnect. Only pressure and frequency monitored by GCU to turn on this light. So, even if you have thermal disconnect, the DRIVE light comes on due to low pressure downstream of IDG oil pump or due to generator underfrequency when it slows down. Hope this information will be useful.

[@awiator75]

Chris, what a fantastic job you doing, I was looking for such thing for quit some time now... thanks for your efforts a keep up the great job 👍👍👍👍

[@ChrisBrady737]

My pleasure, glad you are finding the videos useful

[@scorpeeno]

Wonderful! Great video!

[@ChrisBrady737]

You are very welcome, thanks for watching

[@jesper1010]

These videos are the best I've seen on the internet, and watching them also made me buy your book. I have seen every one in the technical series from start to finish. But now when I try to go back to review some of them, I find that even if the sections of the originals and the classics were interesting on my first pass, I tend to skip over them to only get the NG/MAX parts now when I'm trying to learn the systems better. Maybe it would be an idea to also release a cut down series of the systems videos just for the NG/MAX, since I guess that's what most of us are flying nowadays? Maybe it is not too much work either, just some cutting in your video editing software?

[@ChrisBrady737]

Hi Jesper, thanks for your kind words and for buying the book. I took the decision early on to cover each generation, partly for completeness but also partly to show how the systems evolved to where they are today. A case in point is my last video “The Rudder Story” this had its roots in older generations but caused changes in later generations. You are right it would be a relatively easy job to just cut out the Original and Classic info but I think I already concentrate more on the later generations. I won’t rule out your idea but I still need to be persuaded that it would be worth doing. Thanks for the feedback, I appreciate it.

[@carlocatalani2410]

Thank you very much for this videos....it's amazing 👍👍👍

[@ChrisBrady737]

My pleasure, please share amongst your colleagues and consider getting the accompanying book.

[@cpuwolf]

really like your presentation style. as a software engineer, I'm starting to learn speech skills. Thank you

[@ChrisBrady737]

Great to hear!

[@elliottd323]

You’re a genius, simply put.

[@ChrisBrady737]

Thank you, you are too kind.

[@BrightonCraig]

Just come across your videos and great to watch - I guess someone has already mentioned the Phase colours, but if you are old enough (sadly guilty) L1-R L2-Y L3-B are the standard colours used int he UK pre-EU Harmonisation of colours in 2004

[@ChrisBrady737]

Thanks for the clarification. Great to hear that you are enjoying the videos 👍

[@jayvete6665]

Great job

[@ChrisBrady737]

Thank you, my pleasure

[@iandudman9529]

Thanks again Chris

[@ChrisBrady737]

No worries, glad you enjoyed it

[@dploit]

Hi Cris Very good video please check the information related of the gen off bus light on the NG/MAX on this video. Warm regards!

[@ChrisBrady737]

Thanks Damien, I’ll get on it👍

[@mosihaghighat2463]

Amazing 🤩

[@ChrisBrady737]

You are most welcome

[@dogguyful]

Awesome 👍👍👌👌🙏🙏

[@ChrisBrady737]

My pleasure

[@Arcadiez]

Is there any fuel penalty for turning off the IDG since rest of the flight will be continued with the APU on? Doesn't state anything in the QRH 6.1 Drive or in the Inflight Performance part in the FCOM (What I can find). Sorry if it's a dumb question, I'm still learning. This video is amazing, even such small details as the 6pin GPU connector, I always wonder what those two smaller pins were for. Thanks again cpt!

[@ChrisBrady737]

There is no direct fuel penalty for turning off an IDG but of course there will be an associated fuel burn increase for running the APU. This should only be around 100kg/hr.

[@Arcadiez]

@@ChrisBrady737 Okay roughly 100kg/h. Thanks for the information

[@zimmimah]

@Chris Brady Hello! at time 39:48 youve mentioned about what the 3 blue lights. Unfortunately i could not find any reference to this in the FCOM. I was trying to explain the same thing to a colleague but unfortunate couldnt find any source material. Would appreciate your help thanks :)

[@ChrisBrady737]

FCOM Vol 2 6.10.9 "Ground Power Available (GRD POWER AVAILABLE) Light Illuminated (blue) - ground power is connected and meets airplane power quality standards."

[@zimmimah]

@@ChrisBrady737 yes but that is only about the ground power available. i actually meant about the other 3 blue lights. GEN OFF BUS and APU GEN OFF BUS. I ask this because we have a procedure to check the GEN frequency and AC volts before putting them on bus. Which i believe is an unnecessary step.

[@ChrisBrady737]

The AMM states "The GENERATOR OFF BUS lights comes on anytime the battery bus has power and the GCB is open. The operation of the GENERATOR OFF BUS lights depends on GCB position only. It is independent of engine operation or IDG output power quality." So, the eng gen off bus lights do not indicate power quality. I would say that checking GEN frequency and AC volts before putting them on bus is unnecessary as the generators will not connect to the bus if they are not of the required quality. The step is not required in any Boeing procedures.

[@zimmimah]

@@ChrisBrady737 Thank you for the prompt reply captain! I love your detailed Videos.

[@ChrisBrady737]

My pleasure

[@chunky6253]

Great video Chris thank you, but respectfully at 3 minutes 50 seconds, you've circled the oil sight glass for the Starter not the CDS/IDG.

[@ChrisBrady737]

Yes, this has been mentioned before in the comments. Unfortunately once the video is released it cannot be changed.

[@chunky6253]

@ChrisBrady737 cool, keep up the awesome work. I'm a B1/B2 engineer of 20 years on CL/NG and Max your videos are great to recap my knowledge and I ALWAYS learn something if not many things.

[@ChrisBrady737]

That is great to hear. I have learned so much from engineers over the years it is good to be able to give something back.

[@danstefanescu6899]

Thank you !

[@ChrisBrady737]

You're welcome!

[@alexroy7772]

Supremely helpful videos. Excuse my ignorance but what is typically a BUS? Like a circuit or what? Can you clarify?

[@ChrisBrady737]

They can take several forms but they are usually metal bars that you connect several other circuits to. If you open up the consumer unit / distribution board in your house you will see some in there for the live, neutral and earth feeds.

[@ilarikousa1500]

Thanks!

[@ChrisBrady737]

Welcome!

[@sampinnto8132]

Once again amazing video Captain, Thank you.. I have a small question (not sure if I am right). Could we charge the battery onboard the A/C with GPU and Ground service bus?

[@sampinnto8132]

sorry, disregard this question I found the answer..sorry.

[@ChrisBrady737]

No problem

[@aviator5038]

Hello Chris, thanks for this wonderful video, i have a question, to disconnect IDG physically from flight deck, engine must be running or start lever in IDLE position is enough to do that, thank you.

[@ChrisBrady737]

"engine must be running" is not specifically a criteria. "start lever in IDLE position" is the criteria - but of course the engine cannot run without the start lever being in the idle position! When you put the Gen Drive Disconnect switch to the disconnect position, power goes to a solenoid on the IDG if the engine start lever is in the idle position. The solenoid energizes and disconnects the CSD from the input drive shaft.

[@JaneHUANG-o8b]

May I know where can I find the schematics that is shown at 02:00?

[@ChrisBrady737]

This is taken from my book, The Boeing 737 Technical Guide available here www.b737.org.uk/book.htm

[@godlugner5327]

30:03 "we've been thrown off course by about half a million miles, the bumps you feel are asteroids smacking into the side of the ship, and were currently flying without any navigation" "Miss are you telling us absolutely everything?" "not exactly... We're also out of coffee" *PANIC* Moral of the story: never lose the IFE

[@philipjones4355]

Hi Chris first of all thanks for the outstanding videos, I have a question, why are there 2 APU generator switches on the electric panel with only 1 APU generator?

[@ChrisBrady737]

Thanks Philip, it is so that you can connect to either or both busses.

[@Heisseschoko]

may i know why in maintenance manual, the load shedding for 1 IDG operation is started from galley 2, then galley 1, and followed by both buses, lastly the IFE...

[@ChrisBrady737]

There are two different sequences of load shedding for the NG depending upon the date of manufacture and SB status. Both sequences are designed for importance, load and bus sequencing.

[@MrMR-sk8jm]

Is this the electrical system in the 737 Max 8? I have a school project for my aircraft systems class

[@ChrisBrady737]

This covers all generations

[@catchsomerayswithalisonmitchel]

Have you got a link in which we can download these PowerPoints thanks mate

[@ChrisBrady737]

Sorry, the presentations are not available for download. Much of the material is available in my book if you want a hard/electronic copy.

[@ChrisBrady737]

@catchsomerayswithalisonmitchel Update, by popular demand I am making a book with all of the presentations from these videos. Expect it out around April/May 2024.

[@pincophr1393]

Hello Captain Brady, thank you for your content as always. I have a question that's been bugging me for a while without ever finding an answer. Do you happen to know why the altitude horn sounds when AC power is removed from the aircraft?

[@ChrisBrady737]

I think you mean the IRS warning horn. This from FCOM Flight Management, Navigation - Navigation Systems Description - IRS Power: "If AC electrical power is subsequently removed from the airplane, the switched hot battery bus continues to supply electrical power to the IRS. The ON DC light illuminates, and the ground-call horn in the nose wheel well sounds to alert maintenance personnel that the IRS is on battery power."

[@pincophr1393]

@@ChrisBrady737 Thank you Captain for taking the time to answer, appreciate your dedication. I think this video will make myself more clear: kzbin.info/www/bejne/e5-baHagps6LsM0 At approximately 1:40, the engineer disconnects the ground power and what I believe to be the altitude warning horn sounds right after. This is the sound I am referring to. In this instance, the IRSs are off so their related warning horn is not going off, as expected. I hope I managed to convey the message a little better. Wish you a good day!

[@ChrisBrady737]

OK, I understand now. Unfortunately I have no idea why that happens, sorry!

[@elmin2323]

One question on the NG on the metering panel why if you select the BAT BUS or STBY PWR selections it only hows Volts not Amps to?

[@ChrisBrady737]

They should show both amps and volts with those selections.

[@Vejiita45]

Hello. Which devices are using AC?

[@ChrisBrady737]

Heavy loads, pumps, galley, motors, fans etc. Try this page for an overview www.b737.org.uk/electrics.htm

[@Vejiita45]

@@ChrisBrady737 Thank you

[@johnmilburn5715]

Interesting vid as usual! The RYB colours are what used to be the UK L1 L2 L3 colours until EU harmonisation. A white earth? Never! 😅

[@JamieHines]

My question is ground power related and an airplane design question. I'm a ramp crew chief and I got asked this question by a few of my TikTok followers on a video I did. "Why is the ground power connection on ac right and not left?" I'm not an engineer and don't know how to answer this, do you have an idea? Thanks

[@ChrisBrady737]

Hi Jamie, All of the aircraft servicing points (GPU, fuel, baggage) are on the right to keep them away from the passengers who always board and disembark from the left.

[@steffenleo5997]

Good Day Capt Brady, Do you step on brake or just move thrust lever to idle N1 @ around 20% when queue on runway to takeoff before get permission to takeoff from ATC?

[@ChrisBrady737]

You need to apply wheel brakes to come to a stop when taxiing.

[@darthsmack7090]

All this information will be excellent for practicing failures in the home simulator lol.

[@ChrisBrady737]

Home sim, actual sim or the real aircraft

[@youtubechannel231df]

Like!

[@ChrisBrady737]

You are welcome

[@rubemarangelo4940]

Hello Mr Brady!!! Greetings from Brazil!!! It's good to have a such useful knowledge on KZbin!!! I have a question about load shedding: In a single generator situation a load shedding starts automatically once the scenario has been detected right? However, if the System is unable to do that in auto mode, then pilots do by switching the respective switch. Am I right?

[@ChrisBrady737]

Hi, thanks for your kind comments. Yes if auto load shedding does not occur then manually switching off services like galley and cabin utilities is a good step.

[@Munnabhai_upwale]

I’m currently doing my b737ng cfm56-7B type course B1/B2, these vids will help me a lot especially for ata24 and probably ata22 and 34 aswell, thank you very much for that sir! 🫡

[@ChrisBrady737]

Glad I could help and thanks for watching.