Autopilot on ground ?

[DrumsArt 270]

Hello,I noticed that you can engage the autopilot on ground...?I'm not talking about process, I know it. I would just like to know if it is normal. Many aircraft do not permit that.Not sure to have seen this before the patch.Some real pilot advice are welcome...Thank youRegards,Richard Portier

[MrKen 3]

You can arm the ap modes, but they won't actualy engage until certain conditions are met after takeoff.

[scandinavian13 5,192]

Are you engaging the AP (CMD button) or the AP Modes (LNAV, VNAV and so on) on the MCP? You can pre-select LNAV and/or VNAV in certain situations, along with some of the other modes. You should not be able to select CMD (either one).

[masneoquil 66]

Also depends on witch MCP you choose, i think that the Collins is the one that let you arm the modes on ground, and the Honeywell don't...... Or is the other way around.....

[DrumsArt 270]

I can engage CMD with the Honeywell or Collins, I can engage also hdg or/and AltHold on ground !? Normal or not in the real plane ?Regards,Richard Portier

[Tabs 2,790]

Was checked in the real aircraft - what we modeled is exactly what you can actually do.There's actually been several recent incidents involving the 777 too where the AP was inadvertently engaged on the ground during the takeoff roll, causing an out of trim situation - they had to modify the AFDS software to prevent it.

[Guest]

I have always dreamt about an autopilot using micro " LNAV " points that drives you through taxiways !!I know you are referring to another feature but if I had an autopilot for taxiways it would be gorgeous !-

[Cras 6]

Why would you ever want to arm CMD when on the ground? Or was the deal with the B777 an inadvertant arming of the CMD?I don't even flip the A/T switch to on until I am line up on the runway.

[FLEX1978 373]

The 777 incident was due to the PF selecting the A/P instead of the Auto throttle arm before take off, they nearly didn't rotate the aircraft.I wasn't aware that there was more then one incident.It is quite strange that you can do it on quite a few aircraft. On the A3xx you can engage the A/P on the ground but it will disconnect as soon as you start an engine. Maybe it is a maintenance thing

[DrumsArt 270]

It does not seem like proper Boeing Logic !!

Yes I agree, it's for this reason that I asked.

Was checked in the real aircraft - what we modeled is exactly what you can actually do.There's actually been several recent incidents involving the 777 too where the AP was inadvertently engaged on the ground during the takeoff roll, causing an out of trim situation - they had to modify the AFDS software to prevent it.

Thank you Ryan for the clarificationRegards,Richard Portier

[Cras 6]

The 777 incident was due to the PF selecting the A/P instead of the Auto throttle arm before take off, they nearly didn't rotate the aircraft.I wasn't aware that there was more then one incident.It is quite strange that you can do it on quite a few aircraft. On the A3xx you can engage the A/P on the ground but it will disconnect as soon as you start an engine. Maybe it is a maintenance thing

Ok then. I just can't imagine why a pilot would arm the autopilot on purpose whilst on the ground. And I can't imagine why any plane would allow the CMD to arm in the first place with the wheels still on the ground. There is no reason for that.And thanks for the information by the way.

[FLEX1978 373]

Anythings possible, airlines today work flight crew to the limit. No excuse for risking lives but picture this (and I have seen this happen) Long haul drivers already tired arrive at a destination completely drained, hotel at the layover is sub standard and some holiday makers are having a 2 day party in the room next door, time for your return trip under too much pressure to call in sick, you are a professional and can handle it, neither crew notice the incorrect gross weight being selected or without thinking select the wrong switch or button without thinking. It happens a lot more then you think and eventually a minor mistake will be a major screw up and get a flight crew on the news, if they are lucky worse case they are out of a job.Regards

[ccarter06 3]

Thank you FLEX for including hotel issues as part of the problem. With companies always trying to ring every extra cent they can out of operating costs, hotel quality has taken a major hit. The kind of hit where you end up in a hotel with a VERY active train track running through the back parking lot (but the hotel was nice enough to provide ear plugs).Those scenarios do happen, and because it's NEVER the same set of issues or circumstances twice, crews easily get caught off guard.

[RYR738 9]

Yes, the autopilot buttons ( CMD A or CMD B ) can be pressed while on the ground.One good use for this would be to press either CMD button and then move the controls to feel the amount of force required to disengage the autopilot.You could also turn on the FD's and engage Heading select and Alt Hold to verify that the flight director bars appear.you could even change the heading to make sure the " roll " bar deflects as it should.None of the above is in any way standard procedure and could cause the plane to move if for eg. the autothrottle was to be accidently engaged.You also will not see any reference to this in the FCOM's.No harm to play with it though !!!............especially in a sim. Fred.

[rocketfs 2]

Also remember:- for the 737: don't look at the MCP for mode verification.- look at the mode annunciator on the PFD!Bert Van Bulck