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777 FLCH getting stall protection

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777 FLCH getting stall protection

Old 30th Apr 2019, 04:34
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777 FLCH getting stall protection

Along with some other modes.....

Older planes in fleet......
Note: The autothrottle will not automatically activate to support stall protection when the pitch mode is FLCH SPD or TO/GA.

Note: The autothrottle will not support stall protection when the A/T mode is HOLD.

Note: During a descent in VNAV SPD with the autothrottle armed and not active, the autothrottle can automatically activate in HOLD mode and will not advance thrust levers to support stall protection.

Newer planes in fleet.....
If the pitch mode is FLCH SPD, VNAV SPD, or VNAV PTH and A/T is in HOLD or THR mode, and speed decreases into the amber band, the A/T will change from HOLD to THR mode. Thrust will increase proportional to amount speed has decreased into the amber band.

If the pitch mode is TOGA during takeoff, and the A/T is in HOLD mode, and thrust has been manually set below the TO thrust reference, and a low speed condition is encountered, then the A/T mode will change from HOLD to THR REF and will advance thrust towards the selected TO thrust reference while airspeed is within 10 kts of stick shaker speed.

Note: During a descent in VNAV SPD or FLCH SPD with the autothrottle armed and not active, the autothrottle automatically activates in THR mode and advances thrust to a throttle position corresponding to the relative distance speed has decreased into the amber band so that if speed continues to decrease, thrust will reach the CLB thrust limit as stick shaker is activated.
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Old 30th Apr 2019, 12:36
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So is this a Boeing admission that this feature contributed to accidents or incidents ?

A positive view is ‘well done’ Boeing for improving a weak system to enhance safety.
The tacit recognition of the difficulties arising from human factors and the need to change system design opposed to ‘retrain’ pilots.
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Old 30th Apr 2019, 15:47
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A positive view is ‘well done’ Boeing for improving a weak system to enhance safety.
The alternative view is "about bloody time".
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Old 30th Apr 2019, 20:01
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Originally Posted by PEI_3721 View Post
So is this a Boeing admission that this feature contributed to accidents or incidents ?

A positive view is ‘well done’ Boeing for improving a weak system to enhance safety.
The tacit recognition of the difficulties arising from human factors and the need to change system design opposed to ‘retrain’ pilots.
Now if only Airbus would follow...
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Old 30th Apr 2019, 21:13
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Check Airman,
? Specifics ?

So how are the risks with the existing inservice 777 systems to be managed.
Reliance on the fallible human and hope for the best.
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Old 1st May 2019, 03:08
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The tacit recognition of the difficulties arising from human factors and the need to change system design opposed to ‘retrain’ pilots.
It was a stupid system. Period.

Maui, suck it up!
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Old 1st May 2019, 06:42
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Now if only Airbus would follow...
Check Airman what exactly you feel airbus should change to? Alfa floor is available in all modes.
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Old 1st May 2019, 07:33
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Originally Posted by Smooth Airperator View Post
VNAV on the 787 is 31 years behind managed climb and descent that is available on the Airbus
What are you talking about. The VNAV descents are miles ahead on the 777 than the 330/320 with their ridiculous level segments.
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Old 1st May 2019, 07:47
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Originally Posted by dctPub View Post
What are you talking about. The VNAV descents are miles ahead on the 777 than the 330/320 with their ridiculous level segments.
Can you explain what are these?
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Old 1st May 2019, 09:59
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10+ years Boeing
9+ years Airbus

I can say that the Boeing was way simpler and easier.....
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Old 1st May 2019, 11:15
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Originally Posted by dctPub View Post
What are you talking about. The VNAV descents are miles ahead on the 777 than the 330/320 with their ridiculous level segments.
I believe constant descent is an option. Unfortunately our company doesn’t have it. I agree that the way managed DES flies level segments before and during approaches is ridiculous, along with the coding that puts the decel waypoint AT the level off point instead of slightly before, resulting in a burst of thrust during level off unless the pilot intervenes. It is a system designed by engineers with no thought on how to operate with finesse.
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Old 1st May 2019, 13:23
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Any one of you actually flown a 787 VNAV descent? (I admit not having flown a 777, maybe that is better than the 787). The 787 one is shite probably because it's a straight port of the 777 one. I.e. Boeing, in what now appears to be a habit, has failed to update the logic which tells VNAV that the 787 is a much more slippery aircraft. This is basic, absolute BASIC QA and in over 5 years of operation, Boeing have not dealt with the issue despite it being reported by numerous airlines. Says a lot really.

Last edited by Smooth Airperator; 2nd May 2019 at 15:29.
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Old 1st May 2019, 13:52
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Originally Posted by vilas View Post
Check Airman what exactly you feel airbus should change to? Alfa floor is available in all modes.
Not speaking specifically about stall protection. Airbus does a pretty good job at that. As much as I like the plane, I still feel that the uncoupled sidesticks and stationary thrust levers are design flaws. Granted, that's harder to fix than the FLCH logic on the 777. Unfortunately, if they didn't admit that after AF447, they probably never will.

As to the FINAL APP logic, yes, it's stupid with the level segments. I read on the Honeywell or Thales site that the A330 fmc has an update where it will fly a constant descent using the geometric path used for the rest of the descent. They don't seem to be interested in putting that in the 320 though.
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Old 1st May 2019, 15:11
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Originally Posted by Smooth Airperator View Post
Any one of you actually flown a 787 VNAV descent? (I admit not having flown a 777, maybe that is better than the 787). The 787 one is shite probably because it's a straight port of the 777 one. I.e. Boeing, in what now appears to be a habit, has failed to update the logic which tells VNAV that the 787 is a much more slippery aircraft.
^^yes. What he said. 787 VNAV descent = "DRAG REQUIRED".
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Old 1st May 2019, 16:12
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Originally Posted by Fursty Ferret View Post
^^yes. What he said. 787 VNAV descent = "DRAG REQUIRED".
That's funny as I was just about to post the same thing
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Old 2nd May 2019, 09:56
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I have taken to starting the stopwatch at top of drop and accepting bets on how long before we get the drag required message. Often it’s less than two minutes. Some clever F/Os I fly with alter the anti-ice on altitude in the descent winds page of the FMC which allegedly helps but I haven’t worked out how that actually works. Sorry for he thread drift
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Old 2nd May 2019, 10:47
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Old 16th May 2019, 16:24
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Originally Posted by vilas View Post
Check Airman what exactly you feel airbus should change to? Alfa floor is available in all modes.
Just reading up on this system now for the new course. Not in Alternate Law(if that is considered a mode).
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Old 16th May 2019, 16:43
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Originally Posted by Check Airman View Post
As to the FINAL APP logic, yes, it's stupid with the level segments. I read on the Honeywell or Thales site that the A330 fmc has an update where it will fly a constant descent using the geometric path used for the rest of the descent. They don't seem to be interested in putting that in the 320 though.
It is a customer option for the A320 as well. As so much these days is. There are some of those options that not many airlines choose, like this one, or FLS for example.
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Old 16th May 2019, 18:59
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Originally Posted by Denti View Post
It is a customer option for the A320 as well. As so much these days is. There are some of those options that not many airlines choose, like this one, or FLS for example.
Didn't know that. The 2 operators I've flown for decided against that option, it seems. It's endlessly frustrating to watch.
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