Disarmed on press 2?

[learsimmer]

In pursuit of accuracy in a computer simulation, could Boeing drivers please clarify which of the following autopilot modes, for their model, can be disengaged and/or disarmed by pressing the engage button relevant to that mode for a second time?

Auto Throttle
Speed
Lateral Nav
Vertical Nav
Flight Level Change
Heading Hold
Vertical Speed
Altitude Hold
Localiser
Approach.

Thanks
Nick

[NutLoose]

if u dont get a reply may be of some help

http://www.b737.org.uk/

http://www.757.org.uk/sops/index.html

[learsimmer]

if u dont get a reply may be of some help

http://www.b737.org.uk/

http://www.757.org.uk/sops/index.html

Thanks, NutLoose, for those references. The 757 site had a fairly detailed explanation of selecting AP modes but was silent on my question, so I'd really like to hear from 757 pilots if they would be so kind.

I couldn't find anything as detailed on the 737 site, so, again, would love to hear from a 737 pilot or two about disengaging modes by pressing the engage button for a second time!

Nick

[Sky Wave]

In the absence of any other responses I'll give you what I believe to be the correct answers for the 737NG with a health warning that I don't go on the 737 conversion course until January but I do have 36 hours 737 sim time.

The basic rule is that whenever the buttons are lit they are de-selectable.

Auto Throttle Switch - is de-selectable
Speed – De-selectable and results in throttle arm
N1 – De-selectable and results in throttle arm
Lateral Nav – De-selectable and results in HDG SEL
Vertical Nav – De-selectable and results in ALT HLD(plus THR ARM I think)
Flight Level Change - De-selectable and results in CWS PITCH (and a throttle mode? N1 I’d guess)
Heading Hold – De-selectable and results in CWS ROLL
Vertical Speed – De-selectable and results in CWS PITCH and N1 modes.
Altitude Hold – De-selectable and results in CWS PITCH
Localiser - Not de-selectable, another mode must be selected.
Approach. - Not de-selectable, another mode must be selected.

As I said I am no expert and I could wrong so perhaps a 737 pilot confirm or deny the above.

SW

[learsimmer]

Thanks, Sky Wave, that is most helpful.

The basic rule is that whenever the buttons are lit they are de-selectable.

... and the AP generally reverts to a default mode, most often CWS PITCH and CWS ROLL - CWS standing for "capture with sync" I assume?

Do you guys make regular use of CWS?

Nick

[SIDSTAR]

CWS means "Control Wheel Steering". Basically, you are flying the a/c 'manually' with the yoke but the signals are sent to the autopilot to actually move the control surfaces.

[learsimmer]

CWS means "Control Wheel Steering". Basically, you are flying the a/c 'manually' with the yoke but the signals are sent to the autopilot to actually move the control surfaces.

Thanks, SIDSTAR, for correcting my assumption. Is there a "capture with sync" button on the yoke? Pressing such a button would disengage AP, and releasing it would cause AP to maintain pitch and roll (within limits) at the values they held when the button was released.

Nick

[NutLoose]

Forgot one helpful link

http://www.smartcockpit.com/

[learsimmer]

Forgot one helpful link

http://www.smartcockpit.com/

Thanks, NutLoose, that last site has a downloadable .pdf on automatic flight for the 737 that reinforces Sky Wave's point that

The basic rule is that whenever the buttons are lit they are de-selectable.

Nick

[learsimmer]

The basic rule is that whenever the buttons are lit they are de-selectable.
Auto Throttle Switch - is de-selectable

I'm told that the 747 differs from the 737 on this point. Could any 747 pilots confirm?

Nick

[Sky Wave]

Is there a "capture with sync" button on the yoke? Pressing such a button would disengage AP, and releasing it would cause AP to maintain pitch and roll (within limits) at the values they held when the button was released.

It sounds like you are describing Control Wheel Steering. Only there is no button, you use the control wheel to select the pitch and roll.


Can't comment on 747-400 except to say that the Autothrottle switch is the same and I'm 95% certain that if switched off it disengages the AT system.

SW