"Of course it helps, thank you.
But your above stated logic does not hold true in the example of HDG and LNAV, according to the replies I received above."
"I assume then that the same happens when on an intercept to our flight plan "magenta line" while in HDG mode, and engaging LNAV? LNAV light goes ON but the HDG light will once again remain ON until the A/P captures and tracks the magenta line?"
nope.... the replies to your querry r all correct... the LNAV light comes on immediately and LNAV would annunciate on the FMA as engaged (provided LNAV capture critera was met when you pressed LNAV)... the HDG light would immediately extinguish... and the HDG annunciation would go(replaced by LNAV)
"the logic for the lights is that a light on the MCP illuminates for a ARMED mode (in this case APP) as well as for an engaged mode(eg., HDG) except once engaged in certain modes the light may be extinguished to indicate the mode cannot be deselected.
hope this helps...."
the logic hold even in the LNAV and HDG case because LNAV does not have a 'armed' mode....hence it only 'engages' when selected and capture criteria are met.
its all a little confusing if you havent actually used it... then its a cake...
