Hi to all,I have had this problem at least twice before. I start a take-off run but there are no flight director bars. Both FDs are turned on and 'FD' is displayed on the PFD. As a result it is not possible to engage the autopilot.I reloaded FSX and set up another flight and the take bars were there. Is there something I am doing wrong or is another 'feature'.CheersKeith B.

The flight director is not required for autopilot actiovation. If you cannot have the bars working, probably you have no active modes (and so also the AP will do nothing as you have not commanded it.The way to see if a bar must be present or not is to check the FMA (the area on the display below the word FD) and see the active pitch and roll modes.If FD is on, a pitch and/or roll mode is active, the FD will show pitch and/or roll bars.

FCOM vol 2 page 215-216 (4.20.3-4.20.4). Basically, you have to have a vertical and lateral mode engaged. In other words, my guess is you haven't armed the Autothrottle and used the TO/GA switch to activate TO/GA mode which will fulfill th erequirements for the FD to display. If you have no other lateral modes armed, your FMA will display N1 | HDG SEL | TOGA which will display the FD bars.EDIT: In order to definitely get the command bar(s) at takeoff, you must activate both F/D's, and then press the TOGA switch to begin takeoff. You don't necessarily have to arm the autothrottle, however I think pressing the TOGA switch with the A/T disarmed will command max thrust regardless of any current thrust limits imposed by the FMC.

Edited February 15, 201214 yr by adamant365

That happens when I forget to turn both FDs off between flights. Then I just have to turn them off and on again to make 'em work.

Hi,If you switch on the FD and do nothing, then hit TOGA, depending if the aircraft commands WINGS LVL or HDG SEL, you may just be presented with vertical guidance.As stated, if no mode is active, then no bars are displayed unless you press TOGA.Best regards,Robin.