OK.... Think Ive got it.
PTU is definately no fluid transfer. Just A fluid operating a motor that is attached to a pump that has B fluid in it.
The LTU is a different animal, in normal operation it sends A fluid to the landing gear selector valve. If • airborne
• No. 1 engine RPM drops below a limit value
• LANDING GEAR lever is positioned UP
• either main landing gear is not up and locked.
then a shuttle valve slides within the LTU and it sends B fluid to the landing gear selector valve.
Anyone disagree?