If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.
Announcement
Collapse
No announcement yet.
Emirates EK-231 Report Out - Slave to the Flight Director
But again, you are talking about a damaged (flawed in some way) wing. Such an airplane is no longer airworthy.
And again, in this case, the airplane was nowhere near stalling,
Sigh, that's not damage, and certainly not not airworthy.
Thats how a plane/wing looks like a few years and what do you do with different AoA indications?
Isn't the plane airworthy if it's e.g. flying with a tiny amount of sideslip?
I never said that. Never. I said that if in doubt, it's better to fly too fast than too slow.
Sigh, that's not damage, and certainly not not airworthy.
Thats how a plane/wing looks like a few years and what do you do with different AoA indications?
Isn't the plane airworthy if it's e.g. flying with a tiny amount of sideslip?
The stall warning margin is a certification requirement and, once certified, if that margin is allowed to change in any significant way—due to the physical condition of the wing—that might lead to a sudden stall without warning, I give up. I simply don’t believe that a commercial airplane would be considered airworthy in that state. It goes against logic.
I said that if in doubt, it's better to fly too fast than too slow.
Its the doubt itself that concerns me here. I don’t see valid cause for doubt. And I would say it’s better to fly at the low end of the envelope than to fly too low. But this also isn’t relevant, as they were well inside the envelope before reducing pitch.
I simply don’t believe that a commercial airplane would be considered airworthy in that state.
Why without warning? Where did you get this new idea from?
That's the way it apparently is and it looks like you have to accept it.
How should a change be detected? Re-certification flights every month for every single plane to check if the stall speed has increased?
If yes, rewrite the whole takeoff and landing performance section for each individual plane?
Again, simply stay away from the stall regime as much as possible (except in the sim of course)
Why without warning? Where did you get this new idea from?
We have to stay focused on what we are discussing. You have implied (twice) that there is justification for following the FD's in this incident because "it's better to fly too fast than too slow". When I pointed out that there was no stall warning or any warning on the speed tape, you replied that stall can occur before or just beyond the stall warning due to flaws in the wing. That's where I get this idea from.
Even if that were the case, if the stall warning system isn't aware of the flaws and a lowered stall threshold, why would the FD's be aware of it? It isn't logical.
They were at a phase of flight where the primary objective is to reach a safe minimum altitude. I'm not discounting the confusion factor she faced, but any competent commercial pilot at the helm of a B777 should instinctively think "there's something wrong with the flight director" in that situation, NOT "I am climbing too steeply and must reduce my current pitch by up to half", and certainly not "stall is imminent".
Look, what you are bringing up here is interesting and I would like to learn more about it. Start a new thread with it. Gabriel will have a ball.
How should a change be detected? Re-certification flights every month for every single plane to check if the stall speed has increased?
Every walk around should include a careful look for obvious leading edge damage. Periodic inspections should be more scrutinous. Small variations in the actual stall speed are tolerable but anything that renders the stall warning ineffective in definitely not going to fly.
You have implied (twice) that there is justification for following the FD's in this incident because "it's better to fly too fast than too slow".
...if the stall warning system isn't aware of the flaws and a lowered stall threshold, why would the FD's be aware of it? It isn't logical.
They were at a phase of flight where the primary objective is to reach a safe minimum altitude.
I'm not discounting the confusion factor she faced, but any competent commercial pilot at the helm of a B777 should instinctively think "there's something wrong with the flight director" in that situation..."
Every walk around should include a careful look for obvious leading edge damage. Periodic inspections should be more scrutinous. Small variations in the actual stall speed are tolerable but anything that renders the stall warning ineffective in definitely not going to fly.
Again, I never wrote that. We are going in circles since you can't accept that I didn't write that there was any reason to follow the FD.
Of course it's not logical because the FD isn't aware of it. You are trying to connect items which can't be connected.
Minimum safe altitude? You know DXB and the area around the airport? I'm pretty sure that the response at MXP would have been different.
And again, instinctively she initially didn't reduce the pitch to the FD commanded attitude.
And on which plane, except e.g. the CRJ, can you get close enough to the LE to detect a tenth of an inch 'damage'. Let alone the fact that I doubt that any pilot knows if the plane has been manufactured that way.
And you are conveniently leaving out the much more important differences in AoA indications which are 100% impossible to detect during preflight.
This is going (as expected) nowhere, so I'm planning not to reply to you in this thread anymore.
Minimum safe altitude? You know DXB and the area around the airport? I'm pretty sure that the response at MXP would have been different.
Not the published MSA. I mean a universal minimum safe altitude (including a margin) to not hit terrain, trees, common structures, etc. in a large passenger jet. This is not 100ft AGL.
As I suggested, post a new thread about the variable stall AoA issue.
I mean the universal minimum safe altitude (including a margin) to not hit trees, common structures, etc. in a large passenger jet. This is not 100ft AGL.
As I suggested, post a new thread about the variable stall AoA issue.
And where did you get the 100ft from? The report says that the roll input started at 160ft with a ROC of 255ft/min and at a pitch attitude of +7.7°.
The actual pitch down comes around 120ft. My bad. That's splitting some hairs though.
The altitude remained below 200 AGL until TO/GA was selected. That's not good either. The rate of climb dropped to 64 fpm.
At 2311:00, the climb rate was about 64 feet per minute.
That's roughly one foot per second.
According to the DFDR plot, pitch reached around 3 deg ANU before TO/GA was selected.
Not healthy behavior for a triple-7 full of souls on board.
I genuinely didn’t know what FMA stood for, but if Evan can drop an acronym, we better expound upon how the pilots screwed it up.
Not knowing what it was, I didn’t see it.
I was seriously noting that the attitude looked pretty OK, but the airspeed was problematic for a 777.
I think that might be important.
But since I don’t know my acronyms and only have familiarity with several TYPES of 172s, I’m not qualified to comment on 777 airspeeds.
Thanx for the explanation. The screenshot isn't from this incident, it's from a GA plane, e.g. a 172.
At 90kts no airliner would be able to fly. They got airborne at >190kts.
It was only an example because Evan didn't even know that GA planes have FMAs. FlightModeAnnounciator. It shows the active (green) and armed (white) FD modes. In this case the lateral modes GPS and ROL, AP, vertical modes VS and ALTS.
The actual pitch down comes around 120ft. My bad. That's splitting some hairs though.
According to the DFDR plot, pitch reached around 3 deg ANU before TO/GA was selected.
Not healthy behavior for a triple-7 full of souls on board.
Well, if you are looking for errors you have to be precise with your accusations and observations.
And? The never flew level let alone descended.
Why? If the situation would have become dangerous, e.g. if they would have started descending, they would have received a DON'T SINK and/or PULL UP warning.
In both cases this would have led to an immediate TOGA selection and pull up.
Well, if you are looking for errors you have to be precise with your accusations and observations.
And? The never flew level let alone descended.
Why? If the situation would have become dangerous, e.g. if they would have started descending, they would have received a DON'T SINK and/or PULL UP warning.
In both cases this would have led to an immediate TOGA selection and pull up.
Immediate or after a second or two of reaction time (or fifteen in this case)? You don’t seem to grasp the core aviation safety principal of ‘safe margin’. Where is the safe margin when flying well under 200ft, while reducing climb to nearly level (trending downward) with takeoff thrust? I can’t believe I’m having to even ask you that?
The most concerning aspect of this for me is that the pilot seemed to have concentrated ONLY on the flight director, probably from habit as SOP is to follow it up to AP engagement height, while being unaware of every other indication, let alone the illogical—and dangerous—nature of the pitch order it was giving. When I mention betrayal of trust, this is what I’m talking about. Complacency. This is a critical phase of flight where you want your pilots to be most vigilant, monitoring every important parameter, ready for the unexpected with the basic airmanship training and instincts to properly react.
Immediate or after a second or two of reaction time (or fifteen in this case)?
When I mention betrayal of trust, this is what I’m talking about. Complacency.
This is a critical phase of flight where you want your pilots to be most vigilant, monitoring every important parameter, ready for the unexpected with the basic airmanship training and instincts to properly react.
A second or two? Fifteen? No way she reacted that slow, Oh my gosh! That's hard to believe.
You really have zero knowledge of what's going on in an airliner cockpit.
Betrayal of thrust and complacency. It's truly amazing how much crap you can pack into your short posts.
I fully agree. If decision making in an airliner is so easy, explain to me why they didn't immediately fire the crew from US 1549 or even better sue them because they have violated all the basic airmanship etc. Evan rules.
Both engines failed at a speed of 219kts at 2747ft and it took them 20sec to lower the nose to regain some speed because it had dropped to 183kts while climbing more than 300ft without any thrust.
Thank you. I went to Google and figured out what it meant.
I think differently from Evan. I can see a little insidiousness in the FD operation, but I am disturbed that an ATP would strongly tunnel-vision on the FD while maintaining crummy climb attitudes and high airspeeds vs typical values.
Yes, autopilots and FDs need to display what they are doing/modes.
As to the multiple pages of discussion, I’m not sure what Evan expects the industry to do. It’s fun to play coulda woulda shoulda, but conversely we need to be careful on dispensing free advice.
Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.
A second or two? Fifteen? No way she reacted that slow, Oh my gosh! That's hard to believe.
It took her 15 seconds to gain situational awareness and apply TO/GA.
She lowered the pitch to a level that she deemed reasonable (from her perspective) within the range of 5 to 7.7 degrees and maintained it for about 15 seconds in order to better understand the situation. This occurred despite the low rate of climb, increasing airspeed, and directive voice interventions from the Copilot and the augmenting pilots.
The intention to rotate the Aircraft towards 15 degrees was disrupted by the habit-based inclination to follow the flight director.
The Commander reduced the pitch attitude abruptly from about 7.7 to 3 degrees nose-up. It was noted that the nose-down control inputs made by the Commander required a large amount of force on the control column.
But I'm speaking generally about margins. For example, ASDA includes margin for a one-second delayed reaction time. I don't believe that GWPS warnings in this scenario are going to allow an acceptable safety margin in terms of delayed reaction time.
The rest of your last post isn't worthy of a response.
We process personal data about users of our site, through the use of cookies and other technologies, to deliver our services, personalize advertising, and to analyze site activity. We may share certain information about our users with our advertising and analytics partners. For additional details, refer to our Privacy Policy.
By clicking "I AGREE" below, you agree to our Privacy Policy and our personal data processing and cookie practices as described therein. You also acknowledge that this forum may be hosted outside your country and you consent to the collection, storage, and processing of your data in the country where this forum is hosted.
Tweet
Comment