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I know the B747-8 uses electro-hydraulic actuators as does the 787, but what about the 737 MAX?

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    $\begingroup$ an electric hydraulic system - what do you mean? $\endgroup$
    – Simon
    Commented Aug 24, 2015 at 12:04
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    $\begingroup$ I'm guessing Ethan is asking about the use of electro-hydraulic actuators and I have edited the question accordingly. See also airliners.net/aviation-forums/tech_ops/read.main/343070 $\endgroup$
    – RedGrittyBrick
    Commented Aug 24, 2015 at 13:30

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The Max will have hydraulic systems very similar to the NG airplanes, except for the spoilers; those will be "fly-by-wire" and electrically controlled, but still hydraulically actuated. (Edited to correct what I had wrong in the original post. The comments are correct.)

Discussion of the FBW spoilers' capabilities

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  • $\begingroup$ Very close, but the spoilers are still hydraulically actuated. The actuators themselves are unchanged from the NG. The valves that allow pressure to reach the actuators are electrically controlled now instead of mechanically. The spoiler mixer referenced in your link controls valves the allow pressure to reach the actuators. Now that the valves are electric, ground and flight spoilers are controlled by the spoiler control electronics also referenced in your link. If the spoilers were electrically actuated, there would be no hydraulics required at all as is the case with 787 brakes. $\endgroup$
    – PaNerdicon
    Commented Jul 8, 2017 at 21:18
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    $\begingroup$ Electrically commanded servo valves but powered by conventional hydraulic systems with high pressure lines running throughout the aircraft, is what I understand from the article. This is not the same as electrically actuated. The 737 family uses a common type rating, spoiler actuation is a 50 year old, proven design. The A320 fly-by-wire ailerons and elevators are hydraulically actuated.. $\endgroup$
    – Koyovis
    Commented Jul 8, 2017 at 21:28
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No. 737 MAX hydraulic power is the same as 737 NG hydraulic power. There are pumps in the engines and wheel well. More info can be found here. http://www.b737.org.uk/hydraulics.htm

Edit: It appears some took my link to be an answer about the NG. It wasn't. It was about the system being unchanged. The spoilers are still actuated hydraulically, but the control valves providing hydraulic pressure to the actuators are electrically controlled now. The command is now electronic, but they are still moved by the same hydraulic actuators they always were.

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    $\begingroup$ That's info on the B737NG. How about the spoiler actuators on the 737MAX ? $\endgroup$
    – Koyovis
    Commented Jul 1, 2017 at 9:20
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    $\begingroup$ The actuators are exactly the same as the NG. The control valves the allow pressure to reach the actuators are electrically controlled now, and commanded by spoiler control electronics. Ralph J above is fundamentally incorrect, but the downvote on this answer prevents me from commenting on that answer. If the spoilers were electrically actuated, then that would mean the actuators were electric. If you want to know more about that, you can dig into 787 braking systems. Those are electrically actuated with no hydraulics running to them at all. $\endgroup$
    – PaNerdicon
    Commented Jul 8, 2017 at 21:02
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    $\begingroup$ That sounds plausible. $\endgroup$
    – Koyovis
    Commented Jul 8, 2017 at 21:08

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