Jump to content

HYD PUMP ELEC 2 (A) and ELEC 1 (B) - when to turn on ???


Bulva
 Share

Recommended Posts

HYD PUMP ELEC 2 (A) and ELEC 1 (B) - when to turn on ???

I watched some on  YT videos of B733 booting from Cold & Dark state and saw various times when people turn on HYD PUMP ELEC 2 (A) and ELEC 1 (B).
Some do it after plugging in the GPU, others after starting the APU, and still others after starting the main engines.
What is the correct procedure?
 

1.jpg.3ec857c0f567b00c227e7a90fe2f8a68.jpg

Link to comment
Share on other sites

The ELEC pumps usually stay on "all day" - you turn them on in the morning (before the first flight) and then shut them down in the evening (when leaving the aircraft).

You need to have clearance from ground personell to turn them on, often the guy doing the outside check will knock on the plane skin and then give you a thumbs-up when all flight surfaces are clear (because they can move when turning on the ELEC HYD). You do need AC power to turn them, so you will need GPU or APU supplying the main AC buses.

They are turned on very early in the preparation, because running them has the advantage of supplying power to the brakes (in case the accumulator wears down during extended ground time) and also being able to spot leakage during the outside check.

You will normally not turn them off during "the day" - the only reasone I can think of right now is the supplementary procedure "Push back with no bypass pin installed" - where you need to depressurize the A system during pushback.

Cheers, Jan

 

  • Like 1
  • Upvote 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...