737 Aux nav power question
 

On the Classic B737 (300/500)

The question has come up "What power source does the Aux Nav radio recieve power?"

Senerio....
Capt or F/O is using the Aux Nav radio performing a F.D. or Autopilot approach. At G/S intecept the TR3 Disconnect relay opens, Will the Aux Nav radio loose power?


Thanks for the help!

J3

None of the radios or nav receivers will have their power interrupted. The purpose of the relay is to isolate the power sources so that in the event of a failure during approach the radios won't all be affected at the same time.

Here's a link to a very simplified schematic that'll answer your questions.

http://www.b737.org.uk/schemeelectxt.gif