Hi When I'm lined up on the runway, A/T armed and both FD's on etc, if I press ALT HLD on the MCP, the A/T starts advancing the throttles to which ever N1 setting was selected via the FMC. This is without pressing TOGA. Is this meant to happen? I thought the A/T would only advance the throttles once the TOGA button has been pressed. CMD A and B have not been pressed. On the PFD, once the ALT HLD has been pressed I get MCP SPD and ALT HLD.If I press ALT HLD first and then arm the A/T nothing happens. I know you should not be pressing the ALT HLD button while still on the ground. This happens on both types of MCP's and on 800 and 900 models. Can't see anything in the manuals about it. Is this a bug or not?? Matthew Smedley

I'm not really sure that you would ever employ this procedure on the ground, so i wouldn't worry about it? Maybe someone with more experience can shed some light on the subject.

No bug, according to FCOM Vol2 4.10.2"... A/T engages automatically when following AFDS modes are engaged: ... ALT HOLD ..." and more detailed in FCOM Vol2 4.20.10 "Autothrottle Engagement" "Moving the A/T Arm switch to ARM, arms the A/T for engagement in the N1, MCP SPD or FMC SPD mode....." and then later it depictes exactly your scenario "... if not in a VNAV mode, engagement of ALT ACQ or ALT HOLD automatically engages the A/T in the MCP SPD mode" edit and of course, no procedure recommended to be applied on the ground ..

The only time you would normally press ALT HOLD is to hold the plane at that exact altitude. You certainly would never press ALT HOLD while landing or taking off. ALT HOLD engages automatically when you reah the altitude set in the mcp.The ALT HOLD light will be out but it will be anunciated on the FMA. ( there is no ALT HOLD bug !!!!!)