what's the difference between THR and THR REF modes? does one command speed and one just limits it, or something like that?

THR commands the throttles to maintain a speed (MCP or FMC). THR REF holds the throttles at a certain high power position (TOGA, derated TO, etc) and modulates PITCH to maintain a climb speed with VS resulting in whatever value it turns out to be.- Neeraj

I didn't come that far in the manual yet but I know that THR itself doesn't excist, so I think it's the same as THR REF.

so would i be right in saying THR would be active in modes such as climb, cruise etc? if so, would THR REF be active any time other than takeoff? p.s. is it possible to choose between THR and THR REF

>so would i be right in saying THR would be active in modes>such as climb, cruise etc? if so, would THR REF be active any>time other than takeoff? THR-REF will be active in climb, but not in cruise, because cruise is done with "speed setting" in mind (FMC or MCP) which then the AP uses as a reference to set whatever throttle setting is needed.I am not sure if the takeoff will be THR-REF or TO. Maybe it's called TOGA or TO-1 or TO-2? >p.s. is it possible to choose between THR and THR REFAny time you command the AP to use a specific throttle value, which happens only in TO and a (non-specified vertical speed) CLIMB, it will say "THR-REF" .. so you do not have a direct control over it, depends upon which mode you are in.In descent you also might you a "specific" throttle value, but that is "ZERO" normally when the autothrottles are in "ARM" mode. Later,- Neeraj

THR -Engaged: Required thrust is applied to maintain commanded vertical speed.THR REF - Engaged: Thrust is set to reference thrust limit displayed on upper EICAS.ref - PS1Bob...