The subject line might be worded poorly.  I simply meant that on the 737, the aircraft would follow the speeds set into the FMC on approach.  Now, in the 777, it puts in that purely "placeholder" speed of 170 knots over the threshold, and requires the pilot to intervene via the MCP to set speeds as the plane slows for landing.  The old system seemed much more automated; this seems kind of a step backward.  I'm sure PMDG modeled it perfectly, but does anyone know why Boeing chose to do it that way?

 

Joe Legander

Other than knowing that parts of the automation is by a different vendor, just guessing. I believe this implemention is more realistic of how the aircraft is operated. I doubt any 737 gets to stay on LNAV/VNAV all the way to the approach. ATC is assigning speeds for spacing, vectors for traffic and so on. Boeing worked closely with it's customers and government all the way through the design with the goal of being ETOPS ready on day one, first plane to do that much to the consternation of Airbus who was trying to sell its A340. This collaboration worked and I'm sure the way the 777 operates reflects the desires of the community.

Sure, I knew that almost never would anyone just let the aircraft be guided all the way down to landing that way.  It just seemed an odd change.  Even with the old system, intervention was always possible, and just as easy.  Why take away an option?  Also, after the 777 went down at KSFO, perhaps due to some variation in speed controlled by auto-throttle, I couldn't help but think how it seemed a bit confusing and different as I first approached it.

 

Joe Legander

Other than knowing that parts of the automation is by a different vendor, just guessing. I believe this implemention is more realistic of how the aircraft is operated. I doubt any 737 gets to stay on LNAV/VNAV all the way to the approach. ATC is assigning speeds for spacing, vectors for traffic and so on. Boeing worked closely with it's customers and government all the way through the design with the goal of being ETOPS ready on day one, first plane to do that much to the consternation of Airbus who was trying to sell its A340. This collaboration worked and I'm sure the way the 777 operates reflects the desires of the community.

 

The 737 will stay on LNAV/VNAV if they are shooting a RNAV (RNP) approach...which are becoming more and more popular.

Keep in mind the NG was developed after the 777 too. The 777 was first delivered in 1995 and the NG in 1997. They were developed by two different teams at Boeing, the FMCs are from different avionics vendors etc.

 

The other thing playing into this is commonality with the other glass cockpit "Big Boeings" - namely the 757/767 and the 747-400. Airlines probably wanted the 777 to operate in a very similar way to how pilots were used to flying those other models. I don't know for sure, but I suspect the 787 is probably the exact same way too. (I know a 787 pilot actually, I'll ask him)

 

Automation dependency is becoming a real problem in the industry too - we've had some major accidents this year and over the last few years prior (ie AF447) that all appear to have been related at least in some way to pilots not paying attention to what the automation was (or more importantly was not) doing. There may be a desire to actually decrease the ability for these airplanes to just fly entire flights unattended. Automation is intended to aid the pilots and reduce workload, not to replace manual piloting skills.

The 737 will stay on LNAV/VNAV if they are shooting a RNAV (RNP) approach...which are becoming more and more popular.

 

The 777 has this capability too. What it doesn't do is automatically slow down to ref speed - this really is not a big deal though, pilots are very used to speed intervening on this airplane.

What it doesn't do is automatically slow down to ref speed - this really is not a big deal though, pilots are very used to speed intervening on this airplane.

 

I would've thought few flights don't eventually require the use of FLCH eventually anyway (in Europe at least).

I would've thought few flights don't eventually require the use of FLCH eventually anyway (in Europe at least).

 

You don't need to go to FLCH to change the speed window. Just press the speed knob in and dial up the speed you want.

You don't need to go to FLCH to change the speed window. Just press the speed knob in and dial up the speed you want.

 

I know, I wasn't implying you had to go into FLCH. I was merely pointing out it's incredibly common to end up in FLCH which forces you to take control of the speed.

I know, I wasn't implying you had to go into FLCH. I was merely pointing out it's incredibly common to end up in FLCH which forces you to take control of the speed.

 

Oh I see, as in ATC requirements etc. Good point.

I know, I wasn't implying you had to go into FLCH. I was merely pointing out it's incredibly common to end up in FLCH which forces you to take control of the speed.

That is the case in the real world yes.

 

And then you have to re-engage VNav again (if you want to shoot a VNav approach) and press speed intervention to slow the plane down and configure flaps.

Probably to keep the pilot in the loop? After the MD-11 I miss the auto-speed reduction (especially on config change) but I see the logic in removing it, too. In fact despite the capability in the MD-11 I still end up using speed intervention.

 

Not a big deal - just need to remember *I alone* control it.

 

Best regards,

Robin.

This is why real life pilots can't fly a bunch of different types at once for an airline. Imagine trying to keep straight all the differences between the 737, 777, and an A330 or something in your head.

The 777 has this capability too. What it doesn't do is automatically slow down to ref speed - this really is not a big deal though, pilots are very used to speed intervening on this airplane.

 

I know I personally always intervene on approach...even on Airbus models.  I find that, usually, the aircraft wants to slow down long before I'm ready for it to.  I like to keep 210 until around 15 out.  The airplane wants to slow me down to well below that...especially if I'm light.