sudden
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If To Ignore Windshear Warning

Wed Feb 10, 2016 8:07 pm

I was onboard EK A380 the other night where the pilot aborted the approach as the computer advised the pilot to abort due to wind. He came on the PA to tell us just that.
This raised a question. Can modern jets as the A380, A350 or 787 actually abort the approach themselves if the pilot were to ignore the warning/advise?

Thanks.
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mmo
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RE: If To Ignore Windshear Warning

Wed Feb 10, 2016 9:08 pm

Quoting sudden (Thread starter):
Can modern jets as the A380, A350 or 787 actually abort the approach themselves if the pilot were to ignore the warning/advise?

In a word, NO! Should the crew elect to disregard the W/S warning the aircraft will not assume control and execute a missed approach. If the crew decides to accomplish a go around and hit the TOGA button, the aircraft will fly the missed approach procedure that is loaded into the FMS.
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sudden
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RE: If To Ignore Windshear Warning

Wed Feb 10, 2016 9:47 pm

Thanks for clarification.
It just reminded me of the AF A320 that decided to take control over pilot's input, and we know how that ended. I know that issue was resolved long ago though.
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bueb0g
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RE: If To Ignore Windshear Warning

Wed Feb 10, 2016 10:27 pm

Quoting sudden (Reply 2):
It just reminded me of the AF A320 that decided to take control over pilot's input, and we know how that ended. I know that issue was resolved long ago though.

The AF A320 didn't 'decide to take control', and the aircraft's software still functions today exactly as it did in 1988.

I recommend reading the report.
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hivue
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RE: If To Ignore Windshear Warning

Wed Feb 10, 2016 11:19 pm

Quoting sudden (Reply 2):
It just reminded me of the AF A320 that decided to take control over pilot's input, and we know how that ended.

The details of this event are well known -- but I'll be charitable and assume you are not trolling.  
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sudden
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RE: If To Ignore Windshear Warning

Thu Feb 11, 2016 7:31 am

Quoting hivue (Reply 4):

No trolling going on.
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mmo
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RE: If To Ignore Windshear Warning

Thu Feb 11, 2016 8:36 am

Quoting sudden (Reply 2):
It just reminded me of the AF A320 that decided to take control over pilot's input, and we know how that ended. I know that issue was resolved long ago though.

The flight controls did exactly they what they were designed to do. Respond to the pilot's input. Suggest you might want to re-read the accident report. IIRC, the flight idle of the CFM was changed to allow a quicker spool-up. But the aircraft did exactly what it was supposed to do. The 320 never "took control" of the pilot's inputs.
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Starlionblue
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RE: If To Ignore Windshear Warning

Thu Feb 11, 2016 8:41 am

Windshear warnings are not all the same. For example, we have predictive windshear and reactive windshear. The actions to follow are not identical.

Quoting sudden (Reply 2):

Thanks for clarification.
It just reminded me of the AF A320 that decided to take control over pilot's input, and we know how that ended. I know that issue was resolved long ago though.

As mentioned above, this crash is no mystery, and certainly the plane didn't take control. If you tried to do the same thing in a new FBW Airbus the outcome would be quite similar.

Find below the text of a very old post of mine that I keep stored for when this comes up.


A320 at Mulhouse was an in service AF aircraft doing a flyby at an airshow. So what went wrong?

Some preliminaries:
- Pre flight briefing was not held.
- Flyby altitude was below French regulatory minimums.
- Flyby altitude was below the level of surrounding obstacles (trees).
- Flyby runway was changed at last minute (when in sight of the airfield).

As the plane flew by, speed and altitude were still both decreasing. Engines were at or near idle. The plane's protection systems were compensating by increasing angle of attack (eventually to maximum). But since the plane was just above stall speed, once it reached the max angle of attack the only way not to stall was to decrease the pitch angle and thus descend.

By the time the pilot saw the approaching trees, it was already too late. No amount of thrust would have allowed the plane to clear the trees. On the video you clearly hear the engines spooling up just in time to become woodchippers.

The pilot flying had overconfidence in the plane's control system allowing him to perform a dramatic low speed flyby. In fact, without the control system and envelope protection, the plane might have stalled (it never did). But not stalling is not enough. You also have to avoid hitting the ground.

Nothing was wrong with the plane, and all components performed according to (or beyond) specs. Airbi may have very cool envelope protection systems, but they can't break the laws of physics.

If the pilot had tried the same stunt in a 737 or any other plane, there would still have been a crash.

Old pilot saying: "Use your superior skills to keep yourself out of situations where you might need to use them".


We now return to your regularly scheduled thread.

[Edited 2016-02-11 01:01:10]
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QFA380
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RE: If To Ignore Windshear Warning

Thu Feb 11, 2016 10:26 am

Quoting Starlionblue (Reply 7):

We now return to your regularly scheduled thread.

Amazingly off topic talking about a crash that had absolutely nothing to do with windshear, windshear warnings or pilot responses to those happenings. Hardly as if there are a shortage of windshear related crashes.


I personally would be interested in the thread topic if anyone has knowledge they'd like to share regarding windshear warnings and procedures. Nuances between predictive and reactive windshear events.
 
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RE: If To Ignore Windshear Warning

Thu Feb 11, 2016 12:52 pm

Quoting QFA380 (Reply 8):

Amazingly off topic talking about a crash that had absolutely nothing to do with windshear, windshear warnings or pilot responses to those happenings. Hardly as if there are a shortage of windshear related crashes.

He was quoting the OP where he stated:

Quoting sudden (Reply 2):

and clarified the misperception about FBW.
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Starlionblue
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RE: If To Ignore Windshear Warning

Fri Feb 12, 2016 2:24 am

Quoting QFA380 (Reply 8):
I personally would be interested in the thread topic if anyone has knowledge they'd like to share regarding windshear warnings and procedures. Nuances between predictive and reactive windshear events.

Predictive windshear warning is when a radar system detects movement patterns in droplets that indicate possible windshear ahead of the aircraft (on the A330, up to 5NM ahead). The aircraft is not in windshear (yet). If this occurs on approach, go around is not mandatory since the pilots can look for other clues (e.g. visual indications) to determine if the warning is spurious. The A330 warning is an aural "Windshear ahead", and an arc appears on the NDs showing the predicted windshear area.

Reactive windshear warning is based on movement of the aircraft (IRS and ADR data) and occurs when the aircraft is already in windshear. It is triggered when the predicted energy level falls below a certain threshold. On approach, go-around is mandatory. The A330 warning is an aural "Windshear! Windshear! Windshear!" and "Windshear" text on the PFDs.
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bueb0g
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RE: If To Ignore Windshear Warning

Fri Feb 12, 2016 2:26 am

Quoting QFA380 (Reply 8):
Amazingly off topic talking about a crash that had absolutely nothing to do with windshear, windshear warnings or pilot responses to those happenings. Hardly as if there are a shortage of windshear related crashes.

Clearly a response to OP bringing his accident up. Starlionblue's comment is entirely warranted given the context.
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sudden
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RE: If To Ignore Windshear Warning

Fri Feb 12, 2016 6:04 pm

Quoting Starlionblue (Reply 10):

Thank you.
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BoeingGuy
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RE: If To Ignore Windshear Warning

Mon Feb 15, 2016 3:01 am

Quoting Starlionblue (Reply 10):

Predictive windshear warning is when a radar system detects movement patterns in droplets that indicate possible windshear ahead of the aircraft (on the A330, up to 5NM ahead). The aircraft is not in windshear (yet). If this occurs on approach, go around is not mandatory since the pilots can look for other clues (e.g. visual indications) to determine if the warning is spurious. The A330 warning is an aural "Windshear ahead", and an arc appears on the NDs showing the predicted windshear area.

Reactive windshear warning is based on movement of the aircraft (IRS and ADR data) and occurs when the aircraft is already in windshear. It is triggered when the predicted energy level falls below a certain threshold. On approach, go-around is mandatory. The A330 warning is an aural "Windshear! Windshear! Windshear!" and "Windshear" text on the PFDs.


What you describe is basically the same as it works on Boeing airplanes. Predictive Windshear caution and Time Critical Warning is generated by the WXR. Reactive Windshear Time Critical Warning is generated by GPWS. Both the Predictive and Reactive Windshear time critical warnings show "WINDSHEAR" on the PFD and illuminate the Master Warning Light, similar to how other Time Critical Warnings (e.g. PULL UP or SPEEDBRAKE) are displayed.

Per Boeing's philosophies, the computer doesn't take over from the pilot during a Windshear alert (or any other kind of alert).
 
Pihero
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RE: If To Ignore Windshear Warning

Mon Feb 15, 2016 11:32 am

Quoting BoeingGuy (Reply 13):
Per Boeing's philosophies, the computer doesn't take over from the pilot during a Windshear alert (or any other kind of alert).

Couldn't help having a snipe at the other brand in a very sneaky way, don't you ?
This time, pretending to know that *the computer* can take oiver from the pilots in a windshear ? ( which is patently untrue for any brand I know )

I hope you're proud yourself.
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RE: If To Ignore Windshear Warning

Mon Feb 15, 2016 9:26 pm

Quoting Pihero (Reply 14):
Quoting BoeingGuy (Reply 13):
Per Boeing's philosophies, the computer doesn't take over from the pilot during a Windshear alert (or any other kind of alert).

Couldn't help having a snipe at the other brand in a very sneaky way, don't you ?
This time, pretending to know that *the computer* can take oiver from the pilots in a windshear ? ( which is patently untrue for any brand I know )

I hope you're proud yourself.

Where did I take a snipe at other models? Where did I say that the computer on an Airbus airplane would automatically take over in a Windshear (which I know it won't)?

I made a statement that Boeing airplanes don't do this per philosophy. You are really making something up to even remotely infer I was taking a stab at another manufacturer. Proud of yourself?
 
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RE: If To Ignore Windshear Warning

Mon Feb 15, 2016 10:47 pm

Quoting BoeingGuy (Reply 15):
Where did I say that the computer on an Airbus airplane would automatically take over in a Windshear (which I know it won't)?

That's called a meaningful omission :
Had you known - and I think you actually do - that there is no airplane that automatiocally takes over in a windshear - or any other emergency, you would have written so.
Just saying "...Per Boeing's philosophies, the computer doesn't take over from the pilot during a Windshear alert (or any other kind of alert)..." amounts to : the other manufacturer -which I won't name- has other philosophies...

Quoting BoeingGuy (Reply 15):
Proud of yourself?

Generally I am, and I love pointing at inaccuracies... or worse.
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RE: If To Ignore Windshear Warning

Mon Feb 15, 2016 11:53 pm

Quoting Pihero (Reply 16):
Quoting BoeingGuy (Reply 15):
Proud of yourself?

Generally I am, and I love pointing at inaccuracies... or worse.

Except your logic is very flawed and unnecessarily confrontational. It's like if I simply said my girlfriend was beautiful, period end of sentence. You'd accuse me of calling your girlfriend ugly.

What is it that you seem to feel you need to defend about verious philosophies.

Quoting Pihero (Reply 16):
Had you known - and I think you actually do - that there is no airplane that automatiocally takes over in a windshear - or any other emergency, you would have written so.

Yes, you are correct. I am well aware that no airplane type automatically takes over in a windshear, especially with the autopilot not engaged. I also know that at least one manufacturer is looking at automating autopilot responses to TCAS RAs (not sure where exactly that is in the development phase though).

You also seem to fail to realize that I don't have enough detailed knowledge of other types of airplanes, that I didn't feel totally quality to state that. I simply said that the one type of airplane I am familiar with, per the design philosophy they don't take control automatically.

You made up an imaginary confrontational issue over it.
 
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flylku
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RE: If To Ignore Windshear Warning

Tue Feb 16, 2016 12:11 am

Quoting Starlionblue (Reply 10):
Predictive windshear warning is when a radar system detects movement patterns in droplets that indicate possible windshear ahead of the aircraft (on the A330, up to 5NM ahead).
Quoting mmo (Reply 1):
If the crew decides to accomplish a go around and hit the TOGA button, the aircraft will fly the missed approach procedure that is loaded into the FMS.

Soooooo, if the missed approach procedure would take the aircraft directly through the area of predicted windshear, will the autopilot still do so or will it deviate around it? I suspect it will not deviate as the decision making algorithm to deviate from the flight path in the FMS truly would take us into the realm of autonomous flight.
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RE: If To Ignore Windshear Warning

Tue Feb 16, 2016 3:22 am

Quoting flylku (Reply 18):

If the autopilot is coupled to LNAV it'll fly whatever course is loaded in the box. That's where us humans would intervene and ask for alternate missed approach instructions (if we have time to ask) to stay away from the area. If there is no time, emergency authority and declare to ATC what we are doing and why.
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mmo
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RE: If To Ignore Windshear Warning

Tue Feb 16, 2016 7:16 am

Quoting flylku (Reply 18):
will the autopilot still do so or will it deviate around it?

Just to set the record straight.....neither Airbus nor Boeing will deviate on their own. The FMS is a very rudimentary system and it has no ability to deviate from what is in the legs page, under the heading bug or from what is set in the MCP!

So to answer your question, the missed approach will be flown as is what is on the legs page of the MFX. If you want to deviate you inform ATC or better yet coordinate missed approach instructions before you begin the approach. After all, you should have some indications on WX radar if the windshear is weather related.
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flylku
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RE: If To Ignore Windshear Warning

Tue Feb 16, 2016 5:44 pm

Quoting mmo (Reply 20):
So to answer your question, the missed approach will be flown as is what is on the legs page of the MFX. If you want to deviate you inform ATC or better yet coordinate missed approach instructions before you begin the approach. After all, you should have some indications on WX radar if the windshear is weather related.

I'd have been shocked if the answer had been yes but without direct knowledge did not want to assume.

So, are there any conditions under which the autopilot will deviate from the procedure loaded in the FMS? For example, a TCAS alert. Again, I do not have TCAS but I believe in some airspace alerts that do not pose imminent danger are common. If an alert is received that requires immediate action will the autopilot deviate from the loaded procedure?
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hivue
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RE: If To Ignore Windshear Warning

Tue Feb 16, 2016 5:54 pm

Quoting flylku (Reply 21):
So, are there any conditions under which the autopilot will deviate from the procedure loaded in the FMS?

I think there is a fundamental misunderstanding here. The active, interventional "protections" that various makes of aircraft can provide are functions of FBW control laws. Autopilots, FMSs, FMCs, etc. don't actively intervene and modify the procedures they have been programmed or set to do.
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RE: If To Ignore Windshear Warning

Tue Feb 16, 2016 6:52 pm

Quoting mmo (Reply 1):
If the crew decides to accomplish a go around and hit the TOGA button, the aircraft will fly the missed approach procedure that is loaded into the FMS.

On Boeing airplanes this is called TO/GA to LNAV. Only the newer models have it. For example the 757 and 767 will stay in the GA roll mode and fly heading hold unless the crew manually selects LNAV (the KC-46 767 does have TO/GA to LNAV). With TO/GA to LNAV, LNAV will automatically become active after TO/GA (200 feet with autopilot and 50 feet without).
 
mmo
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RE: If To Ignore Windshear Warning

Tue Feb 16, 2016 9:57 pm

Quoting BoeingGuy (Reply 23):
On Boeing airplanes this is called TO/GA to LNAV. Only the newer models have it.

I do realize that but see the next line. The question was about the 380, 350 or 787.

Quoting sudden (Thread starter):
Can modern jets as the A380, A350 or 787 actually abort the approach themselves if the pilot were to ignore the warning/advise?
Quoting flylku (Reply 21):

So, are there any conditions under which the autopilot will deviate from the procedure loaded in the FMS?

In a word. No! Again, there are no conditions at all in which the aircraft would do anything other than what is programmed into the FMC.
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BoeingGuy
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RE: If To Ignore Windshear Warning

Tue Feb 16, 2016 10:15 pm

Quoting mmo (Reply 24):

In a word. No! Again, there are no conditions at all in which the aircraft would do anything other than what is programmed into the FMC.

I assume you mean only if LNAV and VNAV were engaged. Obviously if you have another autoflight mode active, it will do something other than what is programmed into the FMC.

But yes, for the original question, not even the 787 will automatically respond to a windshear warning without the pilot taking action. The pilots would have to perform the windshear escape maneuver, or do a normal go around for a Predictive Windshear warning, as conditions warrant.
 
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Starlionblue
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RE: If To Ignore Windshear Warning

Wed Feb 17, 2016 1:47 am

Quoting flylku (Reply 21):
So, are there any conditions under which the autopilot will deviate from the procedure loaded in the FMS? For example, a TCAS alert. Again, I do not have TCAS but I believe in some airspace alerts that do not pose imminent danger are common. If an alert is received that requires immediate action will the autopilot deviate from the loaded procedure?


I know it is not what you mean, but autopilots deviate from FMS/FMC procedures all the time when pilots use the FCU/MCP for input. The FMS/FMC is used as a long term input for the autopilot, but there are other inputs, such as FCU/MCP (used for short term input) and ILS receivers.

The 350 has automatic TCAS RA control. So does the 330 apparently but it is not activated on our planes so I don't know how exactly it functions.

TAs and RAs are inhibited given certain conditions. For example close to the ground. No RA, no signal to the pilots to follow it, and if auto-TCAS RA no signal to the autopilot to climb or descend.

Quoting hivue (Reply 22):
Autopilots, FMSs, FMCs, etc. don't actively intervene and modify the procedures they have been programmed or set to do.


Strictly in FMS/FMC terms that is of course correct. However the autoflight system will in some cases deviate without pilot intervention from what the FMS/FMC is telling it, such as auto-TCAS. There are also cases like automatic activation of an engine out SID which involves the FMS changing a procedure "by itself", though of course this is pre-programmed and based on strictly defined parameters.

[Edited 2016-02-16 17:55:29]

[Edited 2016-02-16 17:56:12]
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flylku
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RE: If To Ignore Windshear Warning

Wed Feb 17, 2016 2:10 am

Quoting hivue (Reply 22):

I think there is a fundamental misunderstanding here. The active, interventional "protections" that various makes of aircraft can provide are functions of FBW control laws. Autopilots, FMSs, FMCs, etc. don't actively intervene and modify the procedures they have been programmed or set to do.

Not a misunderstanding on my part, just testing my assumptions that the autopilot flies the procedure that is loaded. The only autopilot I've ever flown could couple up on the localizer and had a basic altitude hold. Air transport aircraft are so much more sophisticated and from the sound of the reply below, beginning to become more autonomous in some conditions.

Quoting Starlionblue (Reply 26):
However the autoflight system will in some cases deviate without pilot intervention from what the FMS/FMC is telling it, such as auto-TCAS. There are also cases like automatic activation of an engine out SID which involves the FMS changing a procedure "by itself", though of course this is pre-programmed and based on strictly defined parameters.

Hmmm, I think I will start a new thread to learn more about this from others who work with and on these devices.
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BoeingGuy
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RE: If To Ignore Windshear Warning

Wed Feb 17, 2016 3:46 am

Quoting Starlionblue (Reply 26):
The 350 has automatic TCAS RA control. So does the 330 apparently but it is not activated on our planes so I don't know how exactly it functions.

How does it work? It follows the RA guidance comments without pilot input?

Quoting Starlionblue (Reply 26):
TAs and RAs are inhibited given certain conditions.

Takeoff

Traffic Advisory (TA) – Inhibited below 600 feet
Resolution Advisory (RA) – Inhibited below 1000 feet
Descend RA’s – Inhibited below 1200 feet

Landing

Increase Descent RA’s – Inhibited below 1450 feet
Descend RA’s – Inhibited below 1000 feet (these are re-enabled at a higher altitude during go-around than other RA’s, so are shown separately)
TCAS RA’s – Inhibited below 1000 feet
TCAS TA’s – Inhibited below 400 feet
 
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Starlionblue
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RE: If To Ignore Windshear Warning

Wed Feb 17, 2016 4:05 am

Quoting BoeingGuy (Reply 28):
Quoting Starlionblue (Reply 26):
The 350 has automatic TCAS RA control. So does the 330 apparently but it is not activated on our planes so I don't know how exactly it functions.

How does it work? It follows the RA guidance comments without pilot input?

AFAIK that's what it does. However I don't have any details since our planes don't have it activated.

RAs at altitude require very delicate control inputs. Very easy to overcontrol. I imagine an autopilot could be more precise. Also an autopilot can be counted on to actually follow an RA, while a fleshbag pilot may decide to ignore it or do the wrong thing, both of which have happened in the past.

[Edited 2016-02-16 20:53:18]
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bueb0g
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RE: If To Ignore Windshear Warning

Wed Feb 17, 2016 9:41 am

Quoting BoeingGuy (Reply 28):
How does it work? It follows the RA guidance comments without pilot input?

Yep, the FD on the A350 gives guidance for the RA, which the AP will follow if engaged.
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BoeingGuy
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RE: If To Ignore Windshear Warning

Wed Feb 17, 2016 3:45 pm

Quoting Starlionblue (Reply 29):
Also an autopilot can be counted on to actually follow an RA, while a fleshbag pilot may decide to ignore it or do the wrong thing, both of which have happened in the past.

Understood. Current industry guidance is that you follow an RA, period. Doesn't matter what ATC told you to do; doesn't matter if you think you see the other airplane (because it may be a different airplane that you do not see that is giving you the RA). TCAS has become reliable enough that you following the RA without question.
 
bueb0g
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RE: If To Ignore Windshear Warning

Fri Feb 19, 2016 8:11 pm

Quoting BoeingGuy (Reply 31):
Understood. Current industry guidance is that you follow an RA, period. Doesn't matter what ATC told you to do; doesn't matter if you think you see the other airplane (because it may be a different airplane that you do not see that is giving you the RA). TCAS has become reliable enough that you following the RA without question.

Yes, everybody knows this. That doesn't guarantee that a crew in the heat of the moment won't fail to follow the RA properly.

Also there are still some airlines that allow a crew to ignore RA if they have the a/c in sight in VMC.
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Starlionblue
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RE: If To Ignore Windshear Warning

Sat Feb 20, 2016 3:27 am

Quoting bueb0g (Reply 32):
Also there are still some airlines that allow a crew to ignore RA if they have the a/c in sight in VMC.

I have the feeling that this opens up a big can of worms. At low altitudes and low-ish speeds visual identification is pretty reliable, as in you know where the other guy is going relative to you. Being aware of the SIDs and STARs in use in the terminal area helps a lot as well.

At high altitudes and cruise speeds it is very hard to see what relative height difference there is to other traffic until you're just about at closest approach. For example a plane crossing opposite 1000 feet higher typically seems to be lower until disconcertingly close to the encounter.

[Edited 2016-02-19 19:33:06]
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mmo
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RE: If To Ignore Windshear Warning

Sat Feb 20, 2016 8:30 am

Quoting bueb0g (Reply 32):
Also there are still some airlines that allow a crew to ignore RA if they have the a/c in sight in VMC.

Perhaps you could name just one airline.......

The problem with that philosophy is it's the airplane you think you see when there is actually another one you don't see that is causing the RA. I know of no airline that has that philosophy you refer to.
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PGNCS
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RE: If To Ignore Windshear Warning

Tue Feb 23, 2016 7:12 pm

Quoting bueb0g (Reply 32):
Also there are still some airlines that allow a crew to ignore RA if they have the a/c in sight in VMC.

Adding to what mmo said, I would be curious as to which operator allows this. Certainly we cannot and I have asked colleagues at other very large and well-respected airlines about this and they also must comply. I'm not saying you are wrong, but it does cry out for a specific example.

Quoting BoeingGuy (Reply 31):
Current industry guidance is that you follow an RA, period.

Wholly agree.
 
Alias1024
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RE: If To Ignore Windshear Warning

Wed Feb 24, 2016 1:29 am

Direct quote from a large US regional airline's SOP:
"Pilots must follow RA guidance unless or until the intruding aircraft can be positively identified and visual separation maintained."

The best example I can think of where crews quite often ignore RAs (regardless of what their SOP might say) is visual approaches into SFO with traffic over the bay joining final for 28R while traffic over the peninsula joins for 28L. NorCal approach will ask if both aircraft have the opposite in sight before clearing them for the visual approach. Depending on how the pilots maneuver, RAs aren't terribly uncommon and nearly everyone ignores the RA as long as they still have the other aircraft in sight.
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Starlionblue
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RE: If To Ignore Windshear Warning

Wed Feb 24, 2016 2:40 am

Quoting Alias1024 (Reply 36):
The best example I can think of where crews quite often ignore RAs (regardless of what their SOP might say) is visual approaches into SFO with traffic over the bay joining final for 28R while traffic over the peninsula joins for 28L.

Given the RA inhibitions below a certain height, would you even get them in this case?
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
BoeingGuy
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RE: If To Ignore Windshear Warning

Wed Feb 24, 2016 2:50 am

Quoting Starlionblue (Reply 37):
Quoting Alias1024 (Reply 36):
The best example I can think of where crews quite often ignore RAs (regardless of what their SOP might say) is visual approaches into SFO with traffic over the bay joining final for 28R while traffic over the peninsula joins for 28L.

Given the RA inhibitions below a certain height, would you even get them in this case?

You'd get them above 1000 feet.

SFO is also a unique situation. You have ATC telling you what airplanes are near you.

This is guidance from one particular manufacturer:

If maneuvering is needed, disengage
the autopilot and autothrottle.
Smoothly adjust pitch and thrust to
satisfy the RA command. Follow the
planned lateral flight path unless visual
contact with the conflicting traffic
requires other action.
Attempt to establish visual contact. Call out any conflicting traffic

WARNING: Comply with the RA if there is a conflict between the
RA and air traffic control.
 
Alias1024
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RE: If To Ignore Windshear Warning

Wed Feb 24, 2016 3:38 am

Quoting BoeingGuy (Reply 38):
You'd get them above 1000 feet.

  

In my experience, the RAs on approach into SFO are most often between crossing the bridge at roughly 1,800 feet and that 1,000 foot threshold where they are inhibited. The aircraft can be so close together that all it takes is a slight drift or slightly mismatched speed to trigger the RA.
It is a mistake to think you can solve any major problems with just potatoes.
 
PITrules
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RE: If To Ignore Windshear Warning

Wed Feb 24, 2016 1:05 pm

Quoting BoeingGuy (Reply 31):
TCAS has become reliable enough that you following the RA without question.
Quoting bueb0g (Reply 32):
Yes, everybody knows this.

Well no. In addition to what already was stated in the above few posts, there are few other situations in which a TCAS RA is ignored:

- A GPWS warning, in which the GPWS escape maneuver has priority over a conflicting TCAS RA. Ive had both in rapid succession once, while on a circle approach to San Pedro Sula. Responding to the RA lead to the GPWS, which then had priority.
- An engine out, at least in a Boeing. Its been a long time since I've flown one, but IIRC Airbus may have the same philosophy. In fact, the engine failure checklist in the 744 has the Transponder Mode Selector selected to "TA ONLY". So this inhibits RAs altogether.
-Arrival and approach phase at very high elevation airports, such as the old Quito airport. My company's procedures has us select "TA ONLY" while approaching those airports.


Regarding the last two points:

-I suppose you are not 'ignoring' an RA in the literal sense if there is a traffic conflict, but that's because you already disabled the function per procedure.
-This has to do with available aircraft performance under those conditions, vs. a TCAS certified with a healthy aircraft at sea level performance.
FLYi
 
PGNCS
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RE: If To Ignore Windshear Warning

Wed Feb 24, 2016 8:00 pm

Quoting Alias1024 (Reply 36):
Direct quote from a large US regional airline's SOP:"Pilots must follow RA guidance unless or until the intruding aircraft can be positively identified and visual separation maintained."

Interesting and thanks for the post. At most operators those specific airports that have this issue (SFO is certainly one) the airline specifically delineates that the TCAS can be turned to "TA Only" and at what point in the arrival that's allowed and the restrictions associated with it. I have not seen a blanket exception like "...unless or until the intruding aircraft can be positively identified and visual separation maintained" before so that's a surprise. I appreciate your contribution. I take it the intention is specifically like SFO or other airports with closely spaced parallel approaches and isn't meant more generally?

Quoting PITrules (Reply 40):
Well no. In addition to what already was stated in the above few posts, there are few other situations in which a TCAS RA is ignored:- A GPWS warning, in which the GPWS escape maneuver has priority over a conflicting TCAS RA. Ive had both in rapid succession once, while on a circle approach to San Pedro Sula. Responding to the RA lead to the GPWS, which then had priority.- An engine out, at least in a Boeing. Its been a long time since I've flown one, but IIRC Airbus may have the same philosophy. In fact, the engine failure checklist in the 744 has the Transponder Mode Selector selected to "TA ONLY". So this inhibits RAs altogether. -Arrival and approach phase at very high elevation airports, such as the old Quito airport. My company's procedures has us select "TA ONLY" while approaching those airports.

Fair points all. In most procedures there are specific exceptions for each of those type of defined conditions rather than a blanket exception like Alias mentioned...I think that was the intent of the query, but your points are valid. Like you say, in every checklist in which an engine isn't available at full power I think most carriers have a step to turn the transponder to "TA Only", so in theory if you did the checklist correctly you wouldn't get the TCAS anyway. I appreciate your response!
 
BoeingGuy
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RE: If To Ignore Windshear Warning

Thu Feb 25, 2016 12:05 am

Quoting PITrules (Reply 40):
Well no. In addition to what already was stated in the above few posts, there are few other situations in which a TCAS RA is ignored:

- A GPWS warning, in which the GPWS escape maneuver has priority over a conflicting TCAS RA. Ive had both in rapid succession once, while on a circle approach to San Pedro Sula. Responding to the RA lead to the GPWS, which then had priority.
- An engine out, at least in a Boeing. Its been a long time since I've flown one, but IIRC Airbus may have the same philosophy. In fact, the engine failure checklist in the 744 has the Transponder Mode Selector selected to "TA ONLY". So this inhibits RAs altogether.
-Arrival and approach phase at very high elevation airports, such as the old Quito airport. My company's procedures has us select "TA ONLY" while approaching those airports.

You're kind of contracting yourself. In each example you give, RA's won't occur or will be removed, so it's kind of hard to say you can ignore an RA when it doesn't even exist.

1) GPWS alerts have priority over RAs. If a GPWS alert such as PULL UP occurs, it's going to out-prioritize the RA so the RA no longer exists.

2) For Boeing at least, the procedure for Engine Shutdown is to manually select TA ONLY as you state. So again, kind of hard to say it's okay to ingore RAs when they won't actually occur.

3) Same thing. You manually selected TA ONLY. RAs don't exist.

Just out of curiosity, why did you select TA ONLY at the old Quito airport? I just flew to the new UIO airport in December as a passenger. We could see the outline and remnants of the old Quito airport from nearby, but I never got to fly into there.
 
PITrules
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RE: If To Ignore Windshear Warning

Thu Feb 25, 2016 12:33 am

Quoting BoeingGuy (Reply 42):

Just out of curiosity, why did you select TA ONLY at the old Quito airport?

That was our published procedure there (for the 757 anyway). It had to do with the airport's 10,000' elevation. I'm going off memory now but I assume when the aircraft is configured for approach and landing at those altitudes a TCAS climb RA may command a rate of climb the aircraft is not capable of doing safely.
FLYi
 
Alias1024
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RE: If To Ignore Windshear Warning

Thu Feb 25, 2016 1:24 am

Quoting PGNCS (Reply 41):
I take it the intention is specifically like SFO or other airports with closely spaced parallel approaches and isn't meant more generally?

It does not specifically explain the reasoning behind the policy. It may be for airports like SFO, perhaps mountainous airports like SUN where high performance traffic is departing and arriving VFR and can generate RAs as they pass each other in the narrow valley. I genuinely don't know the reasoning for the policy as written. During training it is emphasized that you had better be very sure you've positively identified the conflicting aircraft before disregarding an RA.

I've used the latitude of the policy once before in a non-approach situation. I was in a very slow climbing CRJ-200 (I know, redundant statement) on a warm day at 28,000 feet. The center controller lost situational awareness and we received a climb command RA for an MD-80 climbing toward our current altitude on a crossing path. Even at max thrust it did not appear we could safely maintain the commanded climb rate. I climbed as quickly as I felt was safe until we identified the traffic and once we had, pitched to level to regain the lost airspeed even though the RA had not yet extinguished.
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Starlionblue
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RE: If To Ignore Windshear Warning

Thu Feb 25, 2016 5:55 am

Quoting PITrules (Reply 40):
- An engine out, at least in a Boeing. Its been a long time since I've flown one, but IIRC Airbus may have the same philosophy. In fact, the engine failure checklist in the 744 has the Transponder Mode Selector selected to "TA ONLY". So this inhibits RAs altogether.
Quoting BoeingGuy (Reply 42):
2) For Boeing at least, the procedure for Engine Shutdown is to manually select TA ONLY as you state

Same on the 'bus. Simply a performance issue.
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MPadhi
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RE: If To Ignore Windshear Warning

Tue Mar 01, 2016 4:53 pm

Quoting bueb0g (Reply 30):

Yep, the FD on the A350 gives guidance for the RA, which the AP will follow if engaged.

Does this affect autothrottle in any way, like, would it engage TO/GA power?
 
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Starlionblue
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RE: If To Ignore Windshear Warning

Thu Mar 03, 2016 3:44 pm

Quoting MPadhi (Reply 46):
Quoting bueb0g (Reply 30):

Yep, the FD on the A350 gives guidance for the RA, which the AP will follow if engaged.

Does this affect autothrottle in any way, like, would it engage TO/GA power?

I would think not, but not 100% sure. There's no touching the thrust levers* during a "normal" (i.e. manual) RA procedure on the 330.

*There are no "throttles" on a FBW Airbus.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
MPadhi
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RE: If To Ignore Windshear Warning

Sat Mar 05, 2016 8:34 pm

Quoting Starlionblue (Reply 47):
I would think not, but not 100% sure. There's no touching the thrust levers* during a "normal" (i.e. manual) RA procedure on the 330.

*There are no "throttles" on a FBW Airbus.

What exactly happens during a RA? I was under the impression that TCAS advises a climb/descent, so would the thust not need to be changed at all?

Could you explain the last bit of your post about the throttles too?

-An inquisitive idiot  
 
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Starlionblue
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RE: If To Ignore Windshear Warning

Sun Mar 06, 2016 2:26 am

Quoting MPadhi (Reply 48):
hat exactly happens during a RA? I was under the impression that TCAS advises a climb/descent, so would the thust not need to be changed at all?

The thrust certainly changes, but we don't change it manually. It's handled by autothrust.

The exception would be an RA "climb" or "increase climb" on final. This mandates a go-around so obviously we'd move the thrust levers to TOGA.

Quoting MPadhi (Reply 48):
Could you explain the last bit of your post about the throttles too?

It's just one of those nomenclature things. In AirbusLand the thrust levers are never called throttles, and it is "autothrust", not "autothrottle".

If you think about it the wording makes sense since jet engines don't have butterfly valves to "throttle" intake flow like piston engines.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo

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