ToGa Vnav?

Printable View

06-01-2007, 09:14 AM
sas550

ToGa Vnav?

Using the latest PmMCP, GC and CDU. When I take off I set to/ga mode and I see that HDG mode is autoselected. When I press lnav the plane keeps it hdg and neglect to follow the route until I choose vnav, flc or v/s. This can't be the right behaviour. Can someone confirm seeing this?
06-01-2007, 09:57 AM
Bob Reed

It is right. When you push TOGA you activate the hdg. If you turn the hdg your ac will turn.
06-01-2007, 10:27 AM
Michael Carter

Airplanes have come a long way.

The only thing the TO/GA buttons on the 727 throttle do is pitch the bat wings to the proper pitch attitude on the flight director!:p
06-01-2007, 10:44 AM
sas550

Tnx for your answers.

Quote:

Originally Posted by Bob Reed

It is right. When you push TOGA you activate the hdg. If you turn the hdg your ac will turn.

I can live with that but if I choose lnav during toga mode it doesn't work. I have to choose a different vertical mode before lnav kicks in. It shows lnav on the announciator but the plane doesn't follow the route. That is my problem.
06-01-2007, 01:40 PM
touwersl

Hi,

Maybe an extremely stupid question; Do you engage the autopilot?
When you don't you will be in flight director mode and the aircraft will not follow the route automatically.

Regards,
06-01-2007, 02:00 PM
Bob Reed

Lnav does not work from the ground.
06-01-2007, 02:07 PM
sas550

Quote:

Originally Posted by touwersl

Hi,

Maybe an extremely stupid question; Do you engage the autopilot?
When you don't you will be in flight director mode and the aircraft will not follow the route automatically.

No I don't activate the ap but the flight director should lead me on to the route as soon as I engage lnav. I usually engage lnav at 1000-1500ft and then it should work
06-01-2007, 02:17 PM
Bob Reed

So you are not trying to get it to fly the plane, but direct you?
06-01-2007, 02:56 PM
sas550

I usually hand fly the plane the first part of the departure. But the flight director is supposed to give lnav guidance when lnav is engaged but it doesn't until engaging vnav, flc or v/s. That's not logical.
06-01-2007, 08:07 PM
NicD

Thats true, and most RL crews like to hand fly departures following the flight director ... often up to transition altitude. Flying would be pretty boring otherwise.

Cant check now - but I think there is a setting in the MCP.INI file that controls what mode is engaged on TOGA after liftoff.
06-09-2007, 04:07 PM
sas550

Hmm it turned out I hadn't set the thrust reduction altitude in the cdu.:roll:
06-12-2007, 03:58 PM
sas550

Nope this was not the solution. Reverting back to a build from last summer fixed the prob. There has to be something fishie with the new one. Am I the only one experiencing this?
06-13-2007, 02:05 PM
sas550

The bug/error is confirmed by Jonathan so hopefully it will be sorted out eventually.
06-14-2007, 04:42 AM
michelmvd

For the B744, LNAV and VNAV must be armed on the ground during Preflight. When airborne in FD mode, LNAV should guide the aircraft from 400ft and VNAV from 50ft. This isn't the case with the PM software at this moment.
Also when CLB thrust reduction is set in the CDU, as soon A/P is activated the aircraft comes in CLB mode. Also this isn't correct. It only should command the CLB thrust at the moment when it reach the altitude set in the FLAP retraction/ thrust reduction settings of the FMC/CDU. Support is aware.
B. rgds
Michel