From the 744 ops manual;
Thrust (THR) Switch
Operative from 400 feet after takeoff until landing; used to select climb thrust after takeoff or go-around.
Push –
Light remains extinguished (thrust limit function)
• after takeoff with VNAV or FLCH selected, changes reference thrust limit to armed climb thrust limit, or CON if engine inoperative
• after go-around, changes reference thrust limit to CLB, or CON if engine inoperative or CON selected
Note: Reference thrust limit remains GA when flaps in landing position or pitch mode is G/S.
Light illuminates (A/T mode function) - Changes A/T mode to THR REF when:
• reference thrust limit is CLB, CLB1, CLB2, CRZ, or CON and pitch mode is ALT or V/S
• reference thrust limit is GA and pitch mode is G/S or FLARE, or pitch mode is ALT or V/S and flaps in landing position
Got all that?
