Hi all,
This is a (fairly pedantic) issue that's been bugging me for a while regarding the extinguisher (squib) test on the 737. (Specifically NG, but I don't believe there's much of a difference between them here).
The EXT TEST switch on the Overheat/Fire Protection Panel is spring loaded to centre and has 2 positions for testing the squib circuit continuity: 1 and 2.
I'm trying to find a definitive answer on what specifically each position tests. Bill Bulfer's 737NG Cockpit Companion says:
- Position 1 tests the #1 and #2 squib on LEFT bottle and APU squib
- Position 2 tests the #1 and #2 squib on RIGHT bottle and APU squib
This page however says otherwise:
B737NG - ATA26 - FIRE PROTECTION
It says that:
- Position 1 tests the #1 squib on LEFT and RIGHT bottles and APU squib.
- Position 2 tests the #2 squib on LEFT and RIGHT bottles and APU squib.
Can anyone confirm which is correct? Cheers!