Hi,

 

 

I have watched some Beta videos and i noticed that at takeoff after the engines go to THRUST REF,the engines go to HOLD mode and you can hear the engines slowing down just before lift off.Does this happen every time you perform and automated takeoff???

 

 

 

Thanks,

 

 

Daniel

 

 

Does this happen every time you perform and automated takeoff???

 

1. This is not an automated takeoff.  As far as I'm aware, there is no such thing.
2. What's happening is they're using TO/GA mode with the autothrottle (A/T), and there is a setting where you can allow your hardware to override the A/T in HOLD/ARM modes.
3. In the real plane, servos keep the physical throttle levers synced with the commanded throttle position.  In your sim hardware, this is not there, so if you use that override mode and your throttle isn't perfectly synced, you'll get a change in thrust.
4. If you're referring to one of the videos I put up, rewatch the first one, where I specifically note that it's my hardware causing it, and not the sim.

Yeah it's incase of an RTO I believe. Happens till 400ft AGL then THR REF / LNAV / VNAV SPD will annunciate and AT will take over.  

 

1. This is not an automated takeoff.  As far as I'm aware, there is no such thing.
2. What's happening is they're using TO/GA mode with the autothrottle (A/T), and there is a setting where you can allow your hardware to override the A/T in HOLD/ARM modes.
3. In the real plane, servos keep the physical throttle levers synced with the commanded throttle position.  In your sim hardware, this is not there, so if you use that override mode and your throttle isn't perfectly synced, you'll get a change in thrust.
4. If you're referring to one of the videos I put up, rewatch the first one, where I specifically note that it's my hardware causing it, and not the sim.

 

Ok.I have another question.When you disengage A/P before landing,Do you also disengage A/T so that you could control the speed manually?

Thanks!

Ok.I have another question.When you disengage A/P before landing,Do you also disengage A/T so that you could control the speed manually?

Thanks!

It's not common to disengage the A/T when manually flying the 777.

OK so do we have to use that HOLD mode?  I see Air Canada uses it, but I really don't want my hardware overriding anything.  

Craig,

 

Much like the NGX there is an option to have your hardware never override the A/T.

 

The HOLD mode will still annunciate, and the main difference is that if you want to reject a takeoff you have to disengage the A/T and then close the thrust levers, otherwsie the airplane will ignore your commands.

 

 

It's not common to disengage the A/T when manually flying the 777.

 

Preston, I personally always disengage A/T at the same time as A/P, you don't have to do so but I wouldn't call it uncommon practice.

 

The airline Boeing SOPs I'm familiar with actually mandate the disengagement of A/T at the same time as AP for visual approaches, for example.

Push your hardware throttle fully forward into the Null zone instead of leaving it partial thrust as the TO/GA mode rolls up to takeoff thrust. That way your hardware throttle is technically sending either 'full thrust' or 'no information' to the sim. 

 

Or turn off the "Hardware throttle overrides Autothrottle in THR HOLD/ARM" option... however then, if you need to Abort Takeoff, you will have to disconnect Autothrottle first, then press F1 and pull hardware throttle to the aft null zone, as pulling the hardware throttle to idle on it's own will not be seen at all, and your on-fire single engine 777 will continue at full thrust.

 

You also won't be able to do that funky thing where you can add some thrust in FLCH descent to reduce your rate of descent while on autopilot in FLCH mode.

 

Seriously, making sure you have a null zone in the Throttle axis, and pushing the hardware throttle full forward as you engage TO/GA is the best solution.

(ok, second best solution... the best is to have a full sized 777 simulator that you sit in with Servo motors on the throttles that move for you... http://flightcity.com.au/worldflight-2013/ )

HOLD is not an option we made, it a real A/T mode on the real airplane. It engages when the A/T servos that move the thrust levers disconnect. It's there for multiple reasons in the real airplane - it allows the pilot to adjust thrust manually during idle descents to account for unanticipated headwinds, shallow paths etc. On takeoff it's there so that you can reject the takeoff by pulling the thrust levers back to idle.

 

We have several options to account for this (this is exactly like the NGX):

 

A/T OVERRIDE:

 

NEVER - your physical hardware will never override the A/T while it's displaying an active mode in the FMA
IN HOLD ONLY - your throttle will control thrust if the A/T mode is HOLD (this is the default)

ALWAYS - your throttle is always capable of overriding the A/T even if the servo controlled modes (this is the most realistic option)

 

We also have an option that adds a blue joystick position arc to the EICAS N1 gauges so that you can see where your physical throttle is positioned vs. the white commanded thrust arc.

I personally use IN HOLD ONLY with this joystick position arc on. This way the physical throttle is locked out in SPD mode, which is what you see in FLCH, VNAV etc, but I still have control over it in descent or for RTOs. The NEVER option is going to prevent you from doing those things.

hmm, how come the plane doesn't just automatically adjust for proper speed during a shallow descent?  Why the need for human intervention?     

hmm, how come the plane doesn't just automatically adjust for proper speed during a shallow descent?  Why the need for human intervention?     

 

Because that's not how the real thing works. If you get below 15 knots slow it will kick the A/T in to put it back up to the target, but the main methodology used is idle thrust descents.  

 

If you guys are expecting 100% automation with this airplane you're going to be in for a rather rude awakening. Boeing designed the airplane with a lot of automation for non-flying related things like failure handling, checklists, management of fuel, electrical and air systems etc, but they firmly believe that the pilots are still pilots. This airplane requires you to use things like speed intervention, FLCH, HDG SEL, V/S etc. It is not a "sit and watch LNAV and VNAV and the AT do everything" airplane, especially in descent and approach.

especially in descent and approach.

 

Different from the NG so this is why I'm surprised.  Some reason I thought Boeing would just use the same A/T technology for the 777.  Anyhow I'm sure I will be able to set my throttle properly so I get good results using the feature.  

 

 

Because that's not how the real thing works.

 

 

I knew that when I posted.  I wasn't asking how come the PMDG version did something.  Now I know Boeing's thoughts!  Thanks Tabs.  

 

 

Preston, I personally always disengage A/T at the same time as A/P, you don't have to do so but I wouldn't call it uncommon practice.
 
The airline Boeing SOPs I'm familiar with actually mandate the disengagement of A/T at the same time as AP for visual approaches, for example.

 

Are you sure that the SOPs you're referring to are for the T7 and not earlier Boeings?  Why would you disable A/T, that removes your protection for under speed situations and gives you no advantage over manual control of your throttles.  

 

 

Preston, I personally always disengage A/T at the same time as A/P, you don't have to do so but I wouldn't call it uncommon practice.
 
The airline Boeing SOPs I'm familiar with actually mandate the disengagement of A/T at the same time as AP for visual approaches, for example.

Are you sure this isn't just one of those "737isms"? The 777's A/T should allow you to fly manually and it provides underspeed protection. It also retards automatically even without A/P engaged.

 

The 737 "requires" that you disengage the A/T because of the thrust-pitch coupling. When its A/T changes the thrust setting the pilot or A/P must compensate the plane's tendency to change its pitch. This problem is alleviated in the 777 by the FBW system.

Because that's not how the real thing works. If you get below 15 knots slow it will kick the A/T in to put it back up to the target, but the main methodology used is idle thrust descents.  

 

If you guys are expecting 100% automation with this airplane you're going to be in for a rather rude awakening. Boeing designed the airplane with a lot of automation for non-flying related things like failure handling, checklists, management of fuel, electrical and air systems etc, but they firmly believe that the pilots are still pilots. This airplane requires you to use things like speed intervention, FLCH, HDG SEL, V/S etc. It is not a "sit and watch LNAV and VNAV and the AT do everything" airplane, especially in descent and approach.

 

 

HOLD is not an option we made, it a real A/T mode on the real airplane. It engages when the A/T servos that move the thrust levers disconnect. It's there for multiple reasons in the real airplane - it allows the pilot to adjust thrust manually during idle descents to account for unanticipated headwinds, shallow paths etc. On takeoff it's there so that you can reject the takeoff by pulling the thrust levers back to idle.

 

We have several options to account for this (this is exactly like the NGX):

 

A/T OVERRIDE:

 

NEVER - your physical hardware will never override the A/T while it's displaying an active mode in the FMA

IN HOLD ONLY - your throttle will control thrust if the A/T mode is HOLD (this is the default)

ALWAYS - your throttle is always capable of overriding the A/T even if the servo controlled modes (this is the most realistic option)

 

We also have an option that adds a blue joystick position arc to the EICAS N1 gauges so that you can see where your physical throttle is positioned vs. the white commanded thrust arc.

 

I personally use IN HOLD ONLY with this joystick position arc on. This way the physical throttle is locked out in SPD mode, which is what you see in FLCH, VNAV etc, but I still have control over it in descent or for RTOs. The NEVER option is going to prevent you from doing those things.

 

 

HOLD is not an option we made, it a real A/T mode on the real airplane. It engages when the A/T servos that move the thrust levers disconnect. It's there for multiple reasons in the real airplane - it allows the pilot to adjust thrust manually during idle descents to account for unanticipated headwinds, shallow paths etc. On takeoff it's there so that you can reject the takeoff by pulling the thrust levers back to idle.

 

We have several options to account for this (this is exactly like the NGX):

 

A/T OVERRIDE:

 

NEVER - your physical hardware will never override the A/T while it's displaying an active mode in the FMA

IN HOLD ONLY - your throttle will control thrust if the A/T mode is HOLD (this is the default)

ALWAYS - your throttle is always capable of overriding the A/T even if the servo controlled modes (this is the most realistic option)

 

We also have an option that adds a blue joystick position arc to the EICAS N1 gauges so that you can see where your physical throttle is positioned vs. the white commanded thrust arc.

 

I personally use IN HOLD ONLY with this joystick position arc on. This way the physical throttle is locked out in SPD mode, which is what you see in FLCH, VNAV etc, but I still have control over it in descent or for RTOs. The NEVER option is going to prevent you from doing those things.

Ryan,

 

This is the perfect time to show that excellent video "Children of Magenta" .  This 25 minute video is about pilots becoming too dependent on autopilots.  Here is the youtube link.  If it does not automatically link just copy and paste it to the URL line in your browser.

 

http://youtu.be/h3kREPMzMLk