737 Max 8 Loses Electric Power Mid Flight

[BragRaindrop933]

ISSUE DESCRIPTION

Description of the issue:

The latest update to the 737 Max has an issue where the aircraft electrical systems power down mid flight. Leading to a completely dark cockpit and avionics, but the engines are still running and the aircraft still flying (under AP control?).

To me it’s almost like the generator switches are not engaging GEN1 and GEN2 so the aircraft is being powered electrically by batteries during flight, which then run out? (just a guess). But I’m sure I heard a switch like sound just before it went dark.

Aircraft is not usable with this bug. I have only tried it in free flight mode, not career mode yet.

Did you experience this issue before you joined the Beta?

No, this is new.

If applicable, which aircraft is experiencing this issue:

Asobo 737-MAX-8

[PC Only] Did you remove all your community mods/add-ons? If yes, are you still experiencing the issue?

Yes

FREQUENCY OF ISSUE

2 of 2 flights so far, 2 other reports of same ting happening from other users
Other user report here-

[MSFS2024] Boeing 737 Max 8

Same here a bit after starting descent. All screens black. But everything running.

and here-

[MSFS2024] Boeing 737 Max 8

Had the same thing happen, hitting the ground power switch restarted all my systems to normal, had to do it twice same flight. I’m thinking it has to do with the new electric system updates almost feels like something getting tripped

How often does this occur for you (Example: Just once, every time on sim load, intermittently)?

So far every flight (2 of 2)

REPRODUCTION STEPS

Try setting up and flying the Max for more than 30mins. It happens to me < 1hr into a flight.

Please list clear steps you took in order to help our test team reproduce the same issue:

1. Set up the Max
2. Go on a 30+min <1hr flight
3. Watch for all lights/screens etc to power down mid flight

YOUR SETTINGS

If the issue still occurs with no mods and add-ons, please continue to report your issue. If not, please move this post to the User Support Hub.

What peripherals are you using, if relevant:

TM Hotas One & Pedals

[PC Only] Are you using Developer Mode or have you made any changes to it?

NO

[PC Only] What GPU (Graphics Card) do you use?

3090

[PC Only] What other relevant PC specs can you share?

5950 + 3090 + 64GB RAM, Win11 24H2

MEDIA

[END OF FIRST USER REPORT]

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For anyone who wants to contribute on this issue, Click on the button below to use this template:

Do you have the same issue if you follow the OP’s steps to reproduce it?
•

Provide extra information to complete the original description of the issue:
•

If relevant, provide additional screenshots/video:
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[younghoonee71]

Do you have the same issue if you follow the OP’s steps to reproduce it?
• yes. same issue.

Provide extra information to complete the original description of the issue:
• plane is controllable (roll, yaw, pitch) but landing gear, flap, spoiler does not work.

If relevant, provide additional screenshots/video:
•

[St54Kevin]

Same thing happened to me with the DC-3. Mid flight I had a power loss with the avionics stack, artifical horizon etc. stopping to work

[BragRaindrop933]

Makes me wonder if it’s a 737 thing or a general issue with the ‘Aircraft Core → Electricity System’ updates that they changed quite extensively.

Aircraft Core Systems

Electricity system

Sim Update 2 Beta (1.4.7.0) Release Notes - March 25, 2025

[image] RELEASE NOTES Sim Update 2 Beta - 1.4.7 If you are playing on PC, outdated packages in your community folder may have an unexpected impact on the title’s performance and behavior. If you suffer from stability issues or long loading times, move your community package(s) to another folder before relaunching the title. Memory Logging in the Sim Update 2 Beta Memory logging will be enabled in the first Sim Update 2 Beta build, which will cause a small decrease to performance (in part…

[Fadros6669]

Do you have the same issue if you follow the OP’s steps to reproduce it?
• YES

Provide extra information to complete the original description of the issue:
• Engine Generator not recharging batteries, have to leave APU on all time or else everything will black out

If relevant, provide additional screenshots/video:
•

[BragRaindrop933]

Another clue perhaps?

After starting both engines - which required messing around with the ELEC1 and ELEC2 hydraulic switches to do so. I turned Gen1 and Gen 2 on and APU Gen OFF/APU bleed off, but I am seeing 2 symptoms-

1. An ELEC warning on the dash
2. An OHP Battery discharge warning which probably means the gens are not working.

ELEC warning

OHP battery discharge warning

I currently haven’t found a way to get the battery to stop discharging when in this state, but in the time I took to write this note it disappeared. There was a long delay though which is strange. Definitely something weird going on.

EDIT: UPDATE
And there I have it, on same flight I get black screens and lights and OHP etc during cruise. Presumably when battery drains.

Electrics & lights & screens suddenly all OFF during cruise

EDIT: UPDATE2
As someone else suggested turn on GROUND POWER (in cruise LOL) and everything is back working like it never stopped in the first place. You have to keep GROUND POWER ON though, turn it off and everything goes dark again.

All working and illuminated after turning on GROUND POWER switch during cruise

[AbatedFir725923]

i’ve the same problem. It is already the third time that happens to me only with the boeing 737 max 8 and once all the electric power restart randomly after a few minutes that they were gone down

[CaptRick4038]

I too recognize the battery drain. So I had to switch on the APU for the entire flight and switch to one of the APU buses

[BragRaindrop933]

Why do that when you have ground power available the whole flight

[BragRaindrop933]

Sounds promising in 1.4.9

Fixed alternators not being usable after activating the GPU

[BragRaindrop933]

Having flown several flights in the aircraft since 1.4.9 I can say that there has been no more electrics loss during flight since that patch so I think the issue has been solved with the release of SU2 1.4.9. and the 737 alternator being fixed. You can close this bug please mods.