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Pellegrine
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 4:38 am

Let me guess what the final cause is   :

Pilot Error

And as we already know - and have found out - there's scores of pilots who either think they are immune to making errors, that their training is adequate, they very well might have personality traits bordering neophilism, and they are averse to outside criticism.   Not much will be learned, and even less will be changed.
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Starlionblue
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 4:42 am

Quoting AirPacific747 (Reply 6):
I just saw a reportage on Russia Today how they focus on the working environment in Emirates and FlyDubai. Both airlines facing heavy criticism. It's a little bit odd because they are just doing what everyone else in the industry is doing. Most airlines in Europe push their pilots to the limit now and it's not yet being mentioned. 900 hours a year with very little time off is becoming normal.

There are 900 hours and 900 hours. If you fly all those between 0800 and 2200 within a couple of time zones, you're fine. If you're continually changing time zones and have to fly day flights and night flights on a regular basis, you're probably fatigued. Flight duty limits try to account for fatigue, but pilots aren't machines. For example I can go for my rest but that is no guarantee that I will actually be able to rest. It might be the middle of my day, or there might be some hefty turbulence, or the service might be going on around me. And then I'm fatigued because it's my 0400 and I didn't get my rest, even though for duty limits purposes it is counted as rest.

Quoting lightsaber (Reply 14):

Quoting galleypower (Reply 7):
(3) 190 hours in any 4 consecutive weeks.

What?!? Too much for a pilot. Unless they only fly 7am to 7pm. Any off natural sleep pattern flying.... Cut that quantity.

IMHO, every flight that crosses 2am to 5am, home base time, should add 3 hours to the effective weekly/monthly/year duty time. (Ok for daily limits to stay as is). For flights that cross 10pm to 2am, add an hour.

Yea, I have 'butted heads' with pilots on this forum, but not adding rules that reflect natural sleep patterns is silly.

Also add hours if the sleep period shifts more than say 3 hours...

Totally agree, and our flight duty limits do account for time zone changes and length of sector. However as mentioned above we humans don't always comply. I can't always sleep on command and even if I have 0300 is still 0300.

Quoting peanuts (Reply 39):
Do pilots even have a decent situational awareness (including clear visual of instruments) when turbulence and attitude "shakes" them around?

Up to a point, yes. It takes pretty bad turbulence for us not to be able to interpret the instruments.

Quoting hivue (Reply 47):
Quoting zeke (Reply 46):
and trimmed to the full trim movement available to the point where the autopilot disengaged.

So there are situations where the autopilot can disengage and dump the airplane in the pilots' laps with full nose-down (or -up) trim?

As Zeke says, no. The certification requirement is that the autopilot when disconnected must "deliver" the aircarft in trim to the pilot.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
barney captain
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 6:20 am

Quoting Pellegrine (Reply 50):
And as we already know - and have found out - there's scores of pilots who either think they are immune to making errors, that their training is adequate, they very well might have personality traits bordering neophilism, and they are averse to outside criticism.   Not much will be learned, and even less will be changed.

I have no idea where any of that is coming from.
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ThrottleHold
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 7:54 am

Quoting barney captain (Reply 52):

Quoting Pellegrine (Reply 50):
And as we already know - and have found out - there's scores of pilots who either think they are immune to making errors, that their training is adequate, they very well might have personality traits bordering neophilism, and they are averse to outside criticism.   Not much will be learned, and even less will be changed.

I have no idea where any of that is coming from.

From a small man with adequacy issues and a very big chip on his shoulder.
Maybe his mother ran off with a pilot when he was small and didn't love him enough. Who knows?
 
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 10:29 am

Russian TV broadcasts final words of Flydubai pilots before crash

"The unofficial transcript, which had been translated into Russian, suggested that an error by a crew member could have been responsible for the crash, which occurred when the Boeing 737 attempted to land for the second time during difficult weather conditions.
The report suggested that the crew of the aircraft had attempted to pull up and try again after the second landing attempt, but that one of the pilots turned off the autopilot, possibly due to sudden turbulence. Shortly after that, the plane nose-dived to the ground."

from the article:

"The transcript recorded that one of the pilots had said “Don’t worry,” just before saying, “Don’t do that”. The last words recorded were repeated calls to “Pull up,” before only “inhuman screams” could be heard for the last six seconds."


source: arabianbusiness.com
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zeke
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 10:38 am

Quoting 7BOEING7 (Reply 49):
To my knowledge the autopilots will not disengage when full autopilot trim limit is encountered.

That is not my understanding, and I recall only reading this in another 737 accident report last year where the autopilot disconnected when the autopilot maximum authority is exceeded.

If you are saying this does not happen, care to tell us all what if your understanding when the autopilot reaches its maximum authority ?

Quoting 7BOEING7 (Reply 49):
As for the Tartarstan 737 accident, they were operating with only one autopilot engaged prior to the go-around and if you push the TO/GA switch with a single autopilot engaged it will disengage.

I was of the understanding this was a NPA for this accident, thus also single channel.

Quoting Starlionblue (Reply 51):
As Zeke says, no. The certification requirement is that the autopilot when disconnected must "deliver" the aircarft in trim to the pilot.

The 737 actually has a "STAB OUT OF TRIM" indicator to show when it is out of trim with the A/P engaged.
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 11:00 am

Quoting dubaiamman243 (Reply 54):
"The transcript recorded that one of the pilots had said “Don’t worry,” just before saying, “Don’t do that”. The last words recorded were repeated calls to “Pull up,” before only “inhuman screams” could be heard for the last six seconds."

Is there any possible way that the AP was disconnected intentionally and the yoke pushed forward violently causing the dive? The final words of both pilots would feed into this..
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AirPacific747
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 11:34 am

Quoting Starlionblue (Reply 51):
There are 900 hours and 900 hours. If you fly all those between 0800 and 2200 within a couple of time zones, you're fine. If you're continually changing time zones and have to fly day flights and night flights on a regular basis, you're probably fatigued. Flight duty limits try to account for fatigue, but pilots aren't machines. For example I can go for my rest but that is no guarantee that I will actually be able to rest. It might be the middle of my day, or there might be some hefty turbulence, or the service might be going on around me. And then I'm fatigued because it's my 0400 and I didn't get my rest, even though for duty limits purposes it is counted as rest.

I completely agree. The regulation needs to change to favor the pilots' working conditions more than it does now.
 
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 11:35 am

Quoting CF-CPI (Reply 44):
We started all this with the idea of disorientation, but this all happened so fast, as you said, and was so violent, that it must have involved deliberate activation of control systems through PF command...

(The quote is unfinished, hints at mechanical malfunction...)
The idea of disorientation is very much still in thought ( mine, at least...) as, so far all the mechanical dysfunction theories can't match the severity / speed of change of the pitch angle...

There are,though quite a few areas of uncertainty :
- Auto-pilot or not, and how many initially ? The airline SOPs seem strict : just one A/P, whatever the approach, which means that this GA was manual.
- These 738s are HUD-equipped : was it in use during the approach AND the overshoot itself ( in which case the disorientation could be stronger ( as I personally vouch with my HUD experience )


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Photo © Farzad Farajpour - Iranian Spotters



- I would really like to know the weight and balance of that airplane at that moment.
Quoting zeke (Reply 46):
Food for thought

This particular accident comes into my list of those in which the investigators had refrained from "discovering" somatogravic illusion... but they are running very tight circles around it :
"On 24 December 2015, the Interstate Aviation Committee released their final report stating that the crash was caused by an under-qualified crew who lacked the skills to recover from an excessive nose up attitude during a go-around procedure...
- ... the crew initiated a go-around, but being under high workload, which possibly caused a "tunnel vision effect"...
- ...they did not perceive warning messages related to auto-pilot disconnection...
- ... the captain, who never performed a go-around before, apart from the training, moved the yoke, pitching nose down, which led to stopping climb and started descent and increase of the aircraft's airspeed...."


Please compare to what I initially wrote on the mechanism of a spatial disorientation...in this case.
May I add that good as simulators are, they can't reproduce the accelerations during a TO/GA go-around, hence no disorientation... and hence no experience.


[Edited 2016-03-27 05:20:42]
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 11:44 am

Quoting captainmeeerkat (Reply 56):

Quoting dubaiamman243 (Reply 54):
"The transcript recorded that one of the pilots had said “Don’t worry,” just before saying, “Don’t do that”. The last words recorded were repeated calls to “Pull up,” before only “inhuman screams” could be heard for the last six seconds."

Is there any possible way that the AP was disconnected intentionally and the yoke pushed forward violently causing the dive? The final words of both pilots would feed into this..

If nothing else, AFAIK pushing the yoke forward violently would disconnect the AP.
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 12:40 pm

Quoting ThrottleHold (Reply 53):
From a small man with adequacy issues and a very big chip on his shoulder.
Maybe his mother ran off with a pilot when he was small and didn't love him enough. Who knows?

I don't get the hate, the taking of general comments overly personal, et.al., but I don't really care. Again, this is an internet forum. The issues I raised are pertinent. It seems to me like a lot of commercial pilots simply don't want to address these things which could reflect badly on themselves or their training. For shame.

The traveling public puts their lives in your collective hands. We deserve better.
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Pihero
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 12:46 pm

Quoting Starlionblue (Reply 59):
f nothing else, AFAIK pushing the yoke forward violently would disconnect the AP.

Aren't you still in a 'Bus ?
This doesn't exist on a 737... Not to my knowledge anyway.

Quoting Pellegrine (Reply 60):
but I don't really care

Then everybody is content.
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 1:04 pm

Quoting Pellegrine (Reply 60):
, but I don't really care.

That's OK then. I don't really care for your uninformed, uneducated, unsupported, amateur opinion either.
 
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 1:15 pm

Quoting Pihero (Reply 61):

Quoting Starlionblue (Reply 59):
f nothing else, AFAIK pushing the yoke forward violently would disconnect the AP.

Aren't you still in a 'Bus ?
This doesn't exist on a 737... Not to my knowledge anyway.

I stand corrected.

So the AP would stay in even with strong forces applied to the yoke?
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 1:44 pm

Quoting Pellegrine (Reply 60):
but I don't really care
Quoting Pellegrine (Reply 60):
The traveling public puts their lives in your collective hands. We deserve better.

Flying is still the safest way to travel but you are welcomed to use other methods, being in an island may i suggest swimming?
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 2:14 pm

Quoting captainmeeerkat (Reply 56):
Is there any possible way that the AP was disconnected intentionally and the yoke pushed forward violently causing the dive? The final words of both pilots would feed into this..

Intentionally, I doubt very much. Your answer lies in their "Inhuman scrams". Previous incidents of heading the plane into the ground have the pilots executing it in silence, not screaming. Germanwings, Egyptair....
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 3:49 pm

Quoting zeke (Reply 55):
at is not my understanding, and I recall only reading this in another 737 accident report last year where the autopilot disconnected when the autopilot maximum authority is exceeded.

Which accident was that?

Quoting zeke (Reply 55):
I was of the understanding this was a NPA for this accident, thus also single channel.

Then if they did a go-around using the TO/GA switch the autopilot disconnected due to that not running out of trim. If they did a go-around with the autopilot connected using V/S or LVL CHG there shouldn't have been an issue unless they jammed the throttle to the stop.

Quoting zeke (Reply 55):
The 737 actually has a "STAB OUT OF TRIM" indicator to show when it is out of trim with the A/P engaged.

The "STAB OUT OF TRIM" light means the autopilot is not setting the trim properly -- it is not necessarily at it's limit. As far as limits are concerned, I've done multiple A/P go-arounds in extremely light airplanes (empty BBJ's prior to interior installation) and never reached the limit. However in the 737-200 I have done several single channel go-arounds back when it wouldn't disconnect and the "STAB OUT OF TRIM" light would intermittently illuminate. We stopped doing that when we found out a single channel wasn't meant to do an autoland or go-around (it's a long story).
 
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 3:54 pm

Quoting Starlionblue (Reply 63):
So the AP would stay in even with strong forces applied to the yoke?

With the AP on, a manual intervention on the control column will disengage the selected AP mode and make the system revert to CWS - control wheel steering. But the force needed is not very important... not comparable to the ~ 8lbs you'd require on the side-stick to disconnect a 'Bus A/P.
( That's old memory of the 73 )
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zeke
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 4:53 pm

Quoting 7BOEING7 (Reply 66):
Which accident was that?

There has been over 40 accidents and incident reports on 737s in the last few years. I will need to go back and see which one it was. I read it last year, so probably looking at an accident/incident 3-5 years ago as it would take around 2 years to publish a final report.

Quoting 7BOEING7 (Reply 66):
Then if they did a go-around using the TO/GA switch the autopilot disconnected due to that not running out of trim. If they did a go-around with the autopilot connected using V/S or LVL CHG there shouldn't have been an issue unless they jammed the throttle to the stop.

What exactly are you trying to say with that sentance it is poorly worded.

As far as I am aware they were doing a NPA therefore single channel only (unless they tired to put both on where they could have disconnected both by doing so). Doing a single channel approach, press TOGA, what happens to the autopilot ?

I see you avoided the specific question I asked you "care to tell us all what if your understanding when the autopilot reaches its maximum authority ?"

Also care to tell me if you try and engage the autopilot when the autopilot maximum authority is exceeded does that still satisfy the autopilot arming conditions ?

What happens to an autopilot when engaged when the autopilot arming conditions are no longer satisfied ?

Boeing manuals are rubbish when looking for this level of detail.

Quoting 7BOEING7 (Reply 66):
The "STAB OUT OF TRIM" light means the autopilot is not setting the trim properly -- it is not necessarily at it's limit.

I replied to the comment "the certification requirement is that the autopilot when disconnected must "deliver" the aircarft in trim " when the 737 can actually have the autopilot out of trim, hence the "STAB OUT OF TRIM" light that only comes on if the A/P is engaged.

I dont know how your post is relevant to the text you quoted.
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 5:23 pm

Quoting flightsimboy (Reply 65):
Your answer lies in their "Inhuman scrams". Previous incidents of heading the plane into the ground have the pilots executing it in silence, not screaming. Germanwings, Egyptair....

In both cases that you cite, there was only one pilot in the cockpit whereas here there were two. Also passengers screaming could account for the noises.

I don't think it was intentional but it just crossed my mind when someone posted the CVR extract above.

Can it definitely be ruled out?

Edit: spelling

[Edited 2016-03-27 10:25:25]
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 5:46 pm

Quoting zeke (Reply 68):
There has been over 40 accidents and incident reports on 737s in the last few years. I will need to go back and see which one it was.

In other words I can't expect an answer, buy I'll wait.

Quoting zeke (Reply 68):
What exactly are you trying to say with that sentance it is poorly worded.

Sorry, English is my primary language.

What I was trying to say is that the A/P didn't disengage because it reached it's stab limit (as some people are insinuating) but either because they hit the G/A switch or manually disconnected it. If they chose to leave the autopilot connected and were using V/S or LVL CHG to climb there would not be a pitch up issue unless they manually pushed the throttle to the stop.

Quoting zeke (Reply 68):
Doing a single channel approach, press TOGA, what happens to the autopilot ?

It disconnects.

Quoting zeke (Reply 68):
I see you avoided the specific question I asked you "care to tell us all what if your understanding when the autopilot reaches its maximum authority ?"

It won't disconnect.

Quoting zeke (Reply 68):
Also care to tell me if you try and engage the autopilot when the autopilot maximum authority is exceeded does that still satisfy the autopilot arming conditions ?

It won't connect because to exceed it's maximum authority you'll need some force on the control wheel.

Quoting zeke (Reply 68):
What happens to an autopilot when engaged when the autopilot arming conditions are no longer satisfied ?

If you press on the control wheel gently nothing. If you disconnect the STAB TRIM AUTOPILOT cutout switch it disconnects.
 
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zeke
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 6:02 pm

Quoting 7BOEING7 (Reply 70):
In other words I can't expect an answer, buy I'll wait.

2.1.163 Both autopilot channels got disconnected at around 18:39:33 hrs and the subsequent FDR data is consistent with the aircraft being flown under manual control, however, the auto-throttle remained engaged in IAS Speed mode. Therefore, the auto-throttle continued to command thrust to track the airspeed selected on the MCP, but the autopilot stopped commands to the flight control surfaces. Probably the autopilot channels got disconnected due to the aircraft deviation beyond the autopilot maximum authority limits.

from http://aviation-safety.net/database/record.php?id=20120420-0

Quoting 7BOEING7 (Reply 70):
Sorry, English is my primary language.

American is a subset of English.

Quoting 7BOEING7 (Reply 70):
It won't disconnect.

Where is that documented ?

Quoting 7BOEING7 (Reply 70):
It won't connect because to exceed it's maximum authority you'll need some force on the control wheel.

Where is that documented ?

Quoting 7BOEING7 (Reply 70):
If you press on the control wheel gently nothing. If you disconnect the STAB TRIM AUTOPILOT cutout switch it disconnects.

Again, read the question. There are multiple arming conditions.
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Boeing12345
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 7:05 pm

On the NG's Boeing tried to go with a 4 tab elevator trim tab. Folks might recall that this lead to an alert bulletin and AD going back to a 6 tab hinge. Early symptoms were airframe vibration in flight. I believe the elevator and tab has had a couple superseded AD's for repeat inspections and then a final fix. Do not know the build date or if AD is relevant or applicable this airframe. Just food for thought.
 
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 8:15 pm

Quoting Pihero (Reply 67):
With the AP on, a manual intervention on the control column will disengage the selected AP mode and make the system revert to CWS - control wheel steering. But the force needed is not very important... not comparable to the ~ 8lbs you'd require on the side-stick to disconnect a 'Bus A/P.
( That's old memory of the 73 )

  

You'll end up in either CWS pitch, CWS roll or both depending on whether you override with a pitch maneuver, roll maneuver or both.

Quoting zeke (Reply 71):
2.1.163 Both autopilot channels got disconnected at around 18:39:33 hrs and the subsequent FDR data is consistent with the aircraft being flown under manual control, however, the auto-throttle remained engaged in IAS Speed mode. Therefore, the auto-throttle continued to command thrust to track the airspeed selected on the MCP, but the autopilot stopped commands to the flight control surfaces. Probably the autopilot channels got disconnected due to the aircraft deviation beyond the autopilot maximum authority limits

Touche. That was quick. And in this case it was an angle of bank limitation during coupled approaches not a stab trim pitch issue.

Quoting zeke (Reply 71):
Again, read the question. There are multiple arming conditions.

Which one do you want to discuss that might be relevant to his topic?
 
Mir
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 10:26 pm

Quoting zeke (Reply 46):
What is possible is the aircraft was trimming to maintain speed and vertical speed during the climb, and trimmed to the full trim movement available to the point where the autopilot disengaged. At that point the pilots would have had limited control at the trim was at the stop. That is just speculation on my part to explain what is being reported.

The autopilot can't be trimming to maintain both speed and vertical speed, it can only do one or the other.

It's hard for me to envision a situation where the autopilot would reach the nose-down stop in a climb situation - even if we accept that the thrust line of the engines would create a pitch-up moment that would push the nose further up than what was desired, the autopilot's reaction to that would be to trim nose down to compensate. If that got to a point where full nose-down trim wasn't enough, that would indicate a very serious design flaw with the aircraft, and one that would almost have certainly manifested itself before now since the 737 has been in service for a long time and this isn't the first go-around the aircraft has done.

That doesn't preclude the possibility of the trim running away, but that would be a mechanical issue and simply the crew not being able to cope with an aircraft doing what it's designed to do.

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7BOEING7
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Sun Mar 27, 2016 11:24 pm

Quoting Mir (Reply 74):
The autopilot can't be trimming to maintain both speed and vertical speed, it can only do one or the other.

It's hard for me to envision a situation where the autopilot would reach the nose-down stop in a climb situation - even if we accept that the thrust line of the engines would create a pitch-up moment that would push the nose further up than what was desired, the autopilot's reaction to that would be to trim nose down to compensate. If that got to a point where full nose-down trim wasn't enough, that would indicate a very serious design flaw with the aircraft, and one that would almost have certainly manifested itself before now since the 737 has been in service for a long time and this isn't the first go-around the aircraft has done.

That doesn't preclude the possibility of the trim running away, but that would be a mechanical issue and simply the crew not being able to cope with an aircraft doing what it's designed to do

  

And, as mentioned above, having done hundreds of go-arounds in 737's at lower weights than the Dubai airplane it's a none event.
 
Mir
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 12:20 am

Quoting Mir (Reply 74):
that would be a mechanical issue and simply the crew not being able to cope with an aircraft doing what it's designed to do.

Oops, typo here - should be "and NOT simply the crew not being able to cope with an aircraft doing what it's designed to do".

-Mir
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F9Animal
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 12:32 am

If the CVR reading is correct, I could not imagine how crazy things got in that short time frame. Can we rule out spatial disorientation? Judging by the videos, they had no chance of saving that plane.  
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 1:52 am

Quoting SOBHI51 (Reply 64):
Flying is still the safest way to travel but you are welcomed to use other methods, being in an island may i suggest swimming?

American passenger rail is the safest it has ever been. See the accident in Philadelphia? Oh no, let's not bother making it safer or criticizing anything about it. It's statistically one of the safest modes of transport.   Sounds like a US DOT sound bite on CNN.
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zeke
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 4:53 am

Quoting 7BOEING7 (Reply 73):
Touche. That was quick. And in this case it was an angle of bank limitation during coupled approaches not a stab trim pitch issue.

I asked, "care to tell us all what if your understanding when the autopilot reaches its maximum authority ?"

Your reply was

Quoting 7BOEING7 (Reply 70):

It won't disconnect.

Now you are saying because I have been able to find a reference to it in an accident report that it can.

Quoting 7BOEING7 (Reply 73):
Which one do you want to discuss that might be relevant to his topic?

It was a general question like the previous, "What happens to an autopilot when engaged when the autopilot arming conditions are no longer satisfied ?"

Quoting Mir (Reply 74):
The autopilot can't be trimming to maintain both speed and vertical speed, it can only do one or the other.

You got me scratching my head, why is it you say the 737 unable to say maintain 140 kts and a VS of +2000 fpm with the autopilot ?

How does it do a missed approach at airports that have a speed restriction ?
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
Mir
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 5:32 am

Quoting zeke (Reply 79):
You got me scratching my head, why is it you say the 737 unable to say maintain 140 kts and a VS of +2000 fpm with the autopilot ?

With the autopilot alone it can't. There is no mode that will do both those things. Add the autothrottle, and then the autopilot can maintain the 2000fpm by controlling pitch and the autothrottle can take care of the 140 kts by controlling thrust.

Quoting zeke (Reply 79):
How does it do a missed approach at airports that have a speed restriction ?

Again, in conjunction with the autothrottle. The autopilot can either control the speed with pitch while the autothrottle maintains a specific thrust value, or it can maintain a vertical speed with pitch and the autothrottle will manipulate the thrust to maintain the specific airspeed.

The important point is that while the autopilot and autothrottle can and do work together, they are not the same thing. If you're talking about automatic trim control, that's the autopilot only - the autothrottle can't manipulate the trim - and the autopilot can't control both airspeed and vertical speed at the same time, as you need control over both pitch and thrust in order to do that, and just as the autothrottle can't control pitch the autopilot can't control thrust.

-Mir
7 billion, one nation, imagination...it's a beautiful day
 
Mir
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 8:40 am

Quoting Pellegrine (Reply 81):

It sure is looking like some of these "big swinging dick" pilots owe me an apology. I'm not waiting for it to come.

Check the reports.

Instead of making smug (and unsubstantiated) remarks, why not at least provide a link to whatever it is you're using to base your opinions on?

-Mir
7 billion, one nation, imagination...it's a beautiful day
 
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jumbojim747
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 10:04 am

All this animation and auto pilots is driving me insane.
What ever happenes to flying the plane.
Turn all that stuff off and fly the plane.
On a wing and a prayer
 
LTC8K6
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 10:58 am

http://abcnews.go.com/International/...e-crash-data-satisfactory-37961220

UAE Authority: Russia Plane Crash Data 'Satisfactory'
 
mandala499
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 11:29 am

Quoting 7BOEING7 (Reply 70):
What I was trying to say is that the A/P didn't disengage because it reached it's stab limit (as some people are insinuating) but either because they hit the G/A switch or manually disconnected it. If they chose to leave the autopilot connected and were using V/S or LVL CHG to climb there would not be a pitch up issue unless they manually pushed the throttle to the stop.

Yes, single A/P, hit to TO/GA switch below 2000' RA and A/P will disengage. However, one can always re-engage it as long as no force is applied to the control yokes and the stab cutout switch is at normal.

There seems to be confusion in this forum regarding the stabilizer trim. I've been in situations where translations can cause confusion through the media... so, I remind you all of this version which sounds well translated:
http://sputniknews.com/russia/201603...41/fly-dubai-voice-recordings.html

After the plane's captain decided to attempt a second attempt at landing, the Boeing reached an altitude of 1500 meters.

"Ascent continues automatically for 40 seconds," the source reportedly said. "For unknown reasons, the captain disengaged autopilot before the plane reached that height. Maybe the plane ran into ‘atmospheric scissors' (pilot slang), which could severely shake it. And the moment the autopilot was cut off, the Boeing dives to the ground."

According to the transcripts, one pilot told the other, "Don't worry, pull!" Reporters cited experts who believe that, after the autopilot disconnected, the captain attempted to level the plane, but for some reason the vertical stabilizer was turned on after the nosedive. It is possible that, during turbulence, the captain accidentally pressed the thumb controller as he was cutting off autopilot. He likely didn't notice it because he was extremely exhausted. As a result, he couldn't navigate the plane, and the pilots were unable to determine the problem.


I think this version can lead to the following chain:
1. Go-Around, A/P disconnects.
2. Aircraft climbed for 40 seconds with A/P re-engaged.
3. Someone was not comfortable with the situation.
4. Someone switched A/P off, most likely through the trim thumb switches.
5. That someone gave nose down trim through the trim thumb switches.

Remember the crew requested an altitude quite high as their desired altitude after a go-around, so they wouldn't be in a rush to level the aircraft off. Even at 4000fpm, at 4000' they still had a minute to reach FL80.

I agree with Pihero, that somatogravic illusion is still the "best fit" at the moment. The leaks continue to make this possible. I'd personally rule out runaway stabilizer. There'll be a lot more noise between the pilots if they are tired in such a situation.
When losing situational awareness, pray Cumulus Granitus isn't nearby !
 
LTC8K6
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 11:32 am

http://www.kommersant.ru/doc/2949365

http://www.dni.ru/society/2016/3/28/332211.html

Apparently these articles talk about the pilots disagreeing and "fighting" over control?

But maybe there is translation trouble?

[Edited 2016-03-28 04:33:27]
 
YoungMans
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 11:44 am

On RT (see URL below) there also is a new article on this and from the sound of it, it's all very heart rending and tragic.

One feels sorry for all, the passenger's and the pilot's relatives; and indeed, even for the people who have to do the investigations in the aftermath of this.
The agony they all have to face and go through yet.

https://www.rt.com/news/337400-pilots-conflict-boeing-rostov/
 
spacecookie
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 11:52 am

It's not the moment of the go around the pilot failed (it's obvious an pilot error who caused this crash)
The error is the 2 hour hold pattern, the not getting better weather and then the crew tries to land in bad condition , weather and pilots.

Thata my personal opinion about it.
And it makes me sad, try to save time and people die.
 
Flyglobal
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 12:22 pm

Quoting LTC8K6 (Reply 85):
http://www.kommersant.ru/doc/2949365

http://www.dni.ru/society/2016/3/28/332211.html

Apparently these articles talk about the pilots disagreeing and "fighting" over control?

But maybe there is translation trouble?

Same was in the German news today: Disagreement in Cockpit

http://www.focus.de/panorama/videos/...-flydubai-maschine_id_5388821.html

Flyglobal
 
spacecookie
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 12:42 pm

Quoting flyglobal (Reply 88):

sad if true
 
CF-CPI
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 1:08 pm

https://www.rt.com/news/337400-pilots-conflict-boeing-rostov/

^^^YoungMans link, which is in English, is repeated above.

To quote from that article, one anonymous expert suggests the aircraft did indeed the stall regime:
"Anonymous experts Kommersant talked to believe the pilot did not manage the diving rudder and horizontal stabilizer, which steer the plane in opposite directions – down and up, respectively.

When the pilot pulled up, he put both the rudder and stabilizer in a sharp climb mode, somewhat fighter-jet style, plus enacted the TOGA regime’s retracted flaps, decreasing ascending force. As a result, the aircraft lost speed and got into the beyond-stall angle of approach. All this led to an uncontrollable dive, the experts believe."

The nature of the argument between captain and f/o:
"At that moment, the voice recorder is said to have registered a conflict between pilots. The pilot that tried to force the aircraft to gain altitude apparently turned the engines to powerful take-off mode, forcing the aircraft to continue its climb.

The other pilot believed the situation was dangerous and apparently did the opposite: he pushed his own control over to bring the Boeing’s nose down and prevent the sweeping up, while yelling at his colleague to stop doing it that way.

“Wait! Where are you flying? Stop! Stop!” a voice on the recorder reportedly yelled."
 
hivue
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 2:36 pm

Quoting CF-CPI (Reply 90):
When the pilot pulled up, he put both the rudder and stabilizer in a sharp climb mode,

I assume "rudder" is supposed to read "elevator."
"You're sitting. In a chair. In the SKY!!" ~ Louis C.K.
 
Mir
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 2:56 pm

Quoting CF-CPI (Reply 90):
https://www.rt.com/news/337400-pilots-conflict-boeing-rostov/

Well, I've seen worse pieces of aviation reporting than that, but not many of them. Even disregarding the very poor translation, the technical aspects just don't make sense. There is no such thing as a "diving rudder". The controls that manipulate pitch are the same for going nose-up and nose-down, not separate. The 737's controls are manipulated directly through the yoke, not by a computer. And the investigators should have no problem identifying the voices - they're tagged on the CVR as captain and first officer (or, to be more specific, left seat and right seat).

It would be unwise to draw any conclusions from information of such bad quality.

-Mir
7 billion, one nation, imagination...it's a beautiful day
 
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Starlionblue
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 3:41 pm

Quoting jumbojim747 (Reply 82):

All this animation and auto pilots is driving me insane.
What ever happenes to flying the plane.
Turn all that stuff off and fly the plane.

Many people on this forum seem to make the assumption that turning off the automation will somehow magically ensure the pilots do the right thing and fly out of an issue. This is not a given by any means. Turning off the automation typically increases workload. In fact in many emergencies the manuals highly recommend keeping the autopilot on or engaging it so that you can deal with the bigger picture instead of dealing with directional control that the autopilot can do way better.

There are certainly times when you should disconnect automation, for example if it is malfunctioning or you are not getting the results you want and can't quickly figure out why, but turning "all that stuff off" will most likely just decrease the mental bandwidth you have to deal with a given issue.

It's not a black and white situation. "Appropriate use of automation" is key.

Quoting hivue (Reply 91):

Quoting CF-CPI (Reply 90):
When the pilot pulled up, he put both the rudder and stabilizer in a sharp climb mode,

I assume "rudder" is supposed to read "elevator."

This could be an artifact of translation. In many languages all the primary controls are referred to as "rudder". For example in Swedish the elevator is "höjdroder" (height rudder).
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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N14AZ
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 4:44 pm

Quoting CF-CPI (Reply 90):

“Wait! Where are you flying? Stop! Stop!” a voice on the recorder reportedly yelled.[/quote]
Waow, reminds me somehow of AF447 "but I have been pulling all the time!" ... "pulling?"
 
alfa164
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 5:01 pm

Quoting Mir (Reply 92):
Well, I've seen worse pieces of aviation reporting than that, but not many of them. Even disregarding the very poor translation, the technical aspects just don't make sense.

Yoi must remember that the source is RT "News"; not known for any credibility at all. Hopefully, as the investigation continues, we will get more detailed information, rather than a rush-to-judgement.
I'm going to have a smokin' hot body again!
I have decided to be cremated....
 
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zeke
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 5:10 pm

Quoting spacecookie (Reply 87):
The error is the 2 hour hold pattern, the not getting better weather and then the crew tries to land in bad condition , weather and pilots.

The tower reported conditions prior ro the last approach were not that bad, The surface conditions when they did their second approach seemed reasonable to me, 230 12-18 mps (approx 24-36 kts) just 10 degree of the runway seems reasonable, 3500 m of visibility and scattered cloud at 2000 ft. I dont know what the wind gradient was on approach or for the go-around.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
MD11Engineer
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 6:05 pm

Quoting barney captain (Reply 43):
There is not.

There is on electric trim switch on the yoke that is used to trim the stab when the A/P is off (activating it will also disconnect the A/P).

Actually there are two electric trim switches on each column. Both are wired in series, so that you'll have to press both of them at the same time to have a trim input.

Jan
Je Suis Charlie et je suis Ahmet aussi
 
MD11Engineer
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 6:09 pm

Quoting Boeing12345 (Reply 72):
On the NG's Boeing tried to go with a 4 tab elevator trim tab. Folks might recall that this lead to an alert bulletin and AD going back to a 6 tab hinge. Early symptoms were airframe vibration in flight. I believe the elevator and tab has had a couple superseded AD's for repeat inspections and then a final fix. Do not know the build date or if AD is relevant or applicable this airframe. Just food for thought.

That's not a trim tab, but a servo tab. The main purpose is to act as a servo tab during manual reversion to reduce the control forces for the pilots.
Elevator trim on the 737 goes through the stabilizer trim mechanism and the jack screw.

Jan
Je Suis Charlie et je suis Ahmet aussi
 
MD11Engineer
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RE: FlyDubai B738 Crashes On Approach In Russia Part 3

Mon Mar 28, 2016 6:14 pm

Quoting Starlionblue (Reply 93):
This could be an artifact of translation. In many languages all the primary controls are referred to as "rudder". For example in Swedish the elevator is "höjdroder" (height rudder).

Same in German: "Höhenruder" (height rudder)

Jan

[Edited 2016-03-28 11:15:59]
Je Suis Charlie et je suis Ahmet aussi

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