Utility light working without battery connected

[Fer109]

In a cold start, we can use Utility Light with Battery switch off. But according to DCS F-5E MANUAL page 271 (Electrical System picture), to provide with electrical power to 28-Volt DC Bus (where Utiliy light is located) Battery switch need to be in ON position.

 

So, I recommend that Utility light to work should need: Battery switch ON, or one engine and generator ON (it will get DC POWER through  Transformer Rectifier), or external power connected.