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Right IRS DC Power Supply System (737-400)

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Right IRS DC Power Supply System (737-400)

Old 13th May 2019, 09:20
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Join Date: May 2019
Location: Belgium
Posts: 1
Right IRS DC Power Supply System (737-400)

Dear 737 drivers,

I was wondering why the Right IRS DC Power Supply System is required to perform a dual channel autopilot approach (as per MEL)?
Is it linked to the bus powering the DC backup system?

Thanks a lot for your replies!
dri737 is offline  
Old 13th May 2019, 11:45
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Join Date: May 2005
Location: France / UK
Age: 64
Posts: 909
It’s been a long time but here’s an educated guess:

Both IRSs are required for a dual channel AP approach.
In the event of loss of AC power to the IRSs, the Left IRS has a dedicated supply from the battery bus.
To keep the right IRS going, a separate DC supply would be required.

Sounds reasonable?
eckhard is offline  
Old 13th May 2019, 15:12
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Join Date: Jan 2018
Location: Amantido
Posts: 848
Following a loss of AC power source, the right IRS will be powered by a DC power source (can't remember which now) for 5 minutes, then it is shut off to prevent quicker battery discharge.
Banana Joe is offline  

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