Flydubai Flight 981, 737, Rostov-on-Don, Russia

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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby 3WE » Mon Mar 28, 2016 2:46 pm

some stuff but did not use the word "crosswind"
...looking for some confirmation that the crosswinds were probably not that excessive while neither making the absolute statement that there's no way at all whatsoever that crosswinds were a contributing factor...
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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby 3WE » Mon Mar 28, 2016 3:00 pm

Via Gabriel:

- Upon deciding on going around, PF turned AP off and executed the procedure manually Here's where Evan starts spouting the word "Cowboy" and irritating me.

- PF did not account for the different GA behavior of the aircraft with AP off and the aircraft began climbing "like a jetfighter" Ok...I've read that can happen with the underslung engines.

- The aircraft reached a "critical climb angle" and its speed started to decay Ummm, fly the plane...LOOK AT THE EXPELETIVE FD/AI...right???

- A disagreement emerged between PF and PNF Cue Evan CRM rant...yes, CRM is important

- PF continued to pull on the control column [UGH...PLEASE, NO...NOT ANOTHER RELENTLESS PULL UP] , while the PNF started to push it forward and shout something on the lines of "Stop. What are you doing?" @#%@! If the nose is too high, push...if the nose is too low, pull (with care and within the limits of Gabriel stall rants)

- The two pilots did not seem able to understand each other, and as the plane began plunging towards the ground, there were mostly desperate screams of terror Cue Evan CRM rant...yes, CRM is important

- It is difficult to determine who was flying the plane at that moment. Bad sarcasm...when a plane is stalling it is not flying, therefore, no one was flying including the plane
It bothers me that I am not surprised and somehow expected to see something like this.
I sometimes have sympathy for Colgan...DOG tired and suddenly the plane goes bezerk bitching at you...a rude awakening, a reflexive response (with your brain kind of foggy) with a matter of seconds to recover...I'll also re-offer an opinion...hand flying a go-around, the PF turns his attention to the FMS (maybe just watching the PNF messing with it) while the PNF is also focused on the FMS and NOT watching the PF's attitude...yes, a CRM breakdown along with being DOG tired...just speculating...
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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby flyboy2548m » Mon Mar 28, 2016 11:48 pm

...I'll also re-offer an opinion...hand flying a go-around, the PF turns his attention to the FMS (maybe just watching the PNF messing with it) while the PNF is also focused on the FMS and NOT watching the PF's attitude...
There is really no reason for EITHER pilot to be looking at the FMS during a G/A.
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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby 3WE » Tue Mar 29, 2016 2:22 pm

...I'll also re-offer an opinion...hand flying a go-around, the PF turns his attention to the FMS (maybe just watching the PNF messing with it) while the PNF is also focused on the FMS and NOT watching the PF's attitude...
There is really no reason for EITHER pilot to be looking at the FMS during a G/A.
Hmmm...Not sure what to say...I think the short answer is that I didn't necessarily mean THE FMS, but I DO think the PNF has some "office duties" to do during a go-around.

On a go-around (Fundamental rules, not 737-800 QRH), Yes, big #1 is coal levers forward, attitude, airspeed, climb, etc are good, gear up, flaps to a go-around setting and establish a stable climb* whether it's Otto or Anatoly working the control column...

(Power up, clean up, establish a good climb takes, what, 15 seconds?)

But after that climb is established (and in less than a minute) ATC is going to give you a departure frequency and heading and altitude assignment- AND you need to be executing a missed-approach procedure...

So, my ass hat vision is that (after the nice climb is established/15 seconds) PNF has some frequencies to tune, an altitude to punch in, maybe a heading to check or adjust, and run a memory checklist.

Take all of that and factor in the fatigue...

My thought [pure ass hat speculation] was that PNF is doing his job of twisting knobs, but is tired tonight so he doesn't monitor his instruments for 15/whatever seconds. PF is tired and glances over to PNF doing something and (unfortunately and in violation of Evan procedure) fixates and zones out for 15 whatever seconds while pulling a bit too much or punching nose up trim a bit too much or just not watching as the plane accelerates into a steeper climb...

By the time they wake up (or look at the flight instruments), things are FUBAR'd (R = recovery)...

I'm grasping to come up with some sort of situation where fairly well trained guys who had never before crashed a plane would go way nose up and fight over lowering the nose...that's all, and yes it's a stretch of the imagination and purely speculative and involves deviations from procedure.
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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby ocelot » Thu Mar 31, 2016 4:59 am

I admit my thought when I saw the press reports was to wonder if the rudder hard-over problem's come back, but sounds like not.

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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby Gabriel » Wed Apr 06, 2016 3:30 am

http://avherald.com/h?article=495997e2&opt=0
On Apr 5th 2016 Russia's Ministry of Transport reported that on first approach to runway 22 the aircraft went around, the crew reported a wind shear on final approach, climbed to FL050 then FL080 and entered a hold to wait for improvement of weather. The crew subsequently requested and was cleared to FL150 in the hold. When air traffic control provided information that the visibility was 5000 meters, cloud ceiling at 630 meters/2000 feet, winds from 230 degrees at 13m/s gusting 18m/s (25 knots gusting 35 knots), no wind shear, the crew requested another approach clearance. On final approach at about 220 meters/720 feet the crew went around again and climbed, at 900 meters/3000 feet the stabilizer moved nose down causing the aircraft to stop climbing at about 1000 meters/3330 feet and entering a descent. The aircraft impacted ground about 120 meters from the runway threshold. Preliminary examination results of flight data and cockpit voice recorder do not reveal any evidence of a technical malfunction of engines or aircraft systems or any evidence of an explosion. The investigation is focusing on how the pitch control system works and crew actions during the go around. The captain (ATPL, 5,965 hours total, 2,597 hours on type) was certified for CATIIIa approaches.
All seems perfectly normal until the underlined part.
So say they they wanted to level off at 3000ft, they applied nose-down trim to level off and ___________________.

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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby 3WE » Wed Apr 06, 2016 11:06 am

If you go around at 720 feet, and reach 3000 feet near the runway threshold...that climb seems kind of extreme and or the 720 feet seems likely well out and well below the ideal glide path.
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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby Gabriel » Sat Apr 09, 2016 5:34 am

http://avherald.com/h?article=495997e2&opt=0
On Apr 8th 2016 the MAK reported in Russian, that the actual weather conditions were as forecast and reported by the weather systems, all weather instruments were working normally. According to flight data recorder the first approach was performed in manual control in adverse weather conditions with winds from 230 degrees at 13m/s gusting 18m/s (25 knots gusting 35 knots), light rain, mist and light to moderate windshear. At an altitude of 340 meters/1100 feet the crew initated a go around due to a sudden change of direction and strength of wind and entered a hold to wait for improvement of weather conditions. The second approach was also flown in manual control, at a height of 220 meters/720 feet about 4km/2.2nm from the runway threshold the crew initiated a go around again selecting TOGA on the engines. At an altitude of 900 meters/2950 feet there were simultaneous actions, the crew returned the flight controls to neutral and the pitch trim moved 5 degrees nose down causing a rapid nose down movement of the aircraft resulting in -1G of vertical acceleration. The subsequent crew actions did not permit to pull the aircraft out of the resulting nose dive, the aircraft impacted ground at a speed of about 600kph/325 knots with the nose more than 50 degrees below the horizont.
The MAK doesn't mention anything special between the initiation of the go-around at 720ft and the start of the upset at 2950 ft. Which doesn't necessarily mean that there wasn't anything special.

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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby 3WE » Sat Apr 09, 2016 12:38 pm

I won't redo my math, but now they have them going around sooner and leveling sooner for ~900 feet less climb, so no more arguments that the climb might have had to be extreme..../ardvark2zz
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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby Gabriel » Sat Apr 09, 2016 6:26 pm

They went from say 15 degrees nose up to more than 50 degrees nose down in a bunch of seconds. They went from +1G to -1G probably a much smaler bunch of seconds. There is no way to miss that. Spatial disorientation, somatogravic or somatogyral illusions, fatigue, and what not may help explain why this was caused in the first place and maybe why they could not recover, but they immediately knew that there was something very very bad going on.

This is very speculative and fuzzy, but it looks that something wrong happened with the trim (runaway or unintentional command in the AND direction) and that they could not recover from the subsequent pitch-down (and then dive) be it because they didn't recognize the trim issue or because they could not correct it, and elevator alone was not enough.

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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby flyboy2548m » Sat Apr 09, 2016 7:07 pm

They went from say 15 degrees nose up to more than 50 degrees nose down in a bunch of seconds. They went from +1G to -1G probably a much smaler bunch of seconds. There is no way to miss that. Spatial disorientation, somatogravic or somatogyral illusions, fatigue, and what not may help explain why this was caused in the first place and maybe why they could not recover, but they immediately knew that there was something very very bad going on.

This is very speculative and fuzzy, but it looks that something wrong happened with the trim (runaway or unintentional command in the AND direction) and that they could not recover from the subsequent pitch-down (and then dive) be it because they didn't recognize the trim issue or because they could not correct it, and elevator alone was not enough.
How many forums do you plan on posting the same shit on?
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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby Not_Karl » Sat Apr 09, 2016 7:44 pm

How many forums do you plan on posting the same shit on?
Hey! I'm reading it.
And I much prefer to do it here than on a "more photography than aviation oriented" forum....
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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby 3WE » Sun Apr 10, 2016 12:45 am

They went from say 15 degrees nose up to more than 50 degrees nose down in a bunch of seconds. They went from +1G to -1G probably a much smaler bunch of seconds. There is no way to miss that. Spatial disorientation, somatogravic or somatogyral illusions, fatigue, and what not may help explain why this was caused in the first place and maybe why they could not recover, but they immediately knew that there was something very very bad going on.

This is very speculative and fuzzy, but it looks that something wrong happened with the trim (runaway or unintentional command in the AND direction) and that they could not recover from the subsequent pitch-down (and then dive) be it because they didn't recognize the trim issue or because they could not correct it, and elevator alone was not enough.
How many forums do you plan on posting the same shit on?
Let me try for a middle ground here...I like to think we're different here- with a little more understanding...thus maybe not an exact copy paste...(not that I'm not guilty of that sometimes.)
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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby Gabriel » Sun Apr 10, 2016 6:35 am

How many forums do you plan on posting the same shit on?
That's none of your business.

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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby 3WE » Sun Apr 10, 2016 12:55 pm

....something wrong happened with the trim...and elevator alone was not enough.
The response of the plane seems way too much for it being trim (trim = the system to neutralize control forces)

Unless you meant trim as the "sum of all airfoils"...

I'm saying something bigger (a lot bigger) probably broke to achieve that kind of dive.
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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby Gabriel » Sun Apr 10, 2016 4:51 pm

....something wrong happened with the trim...and elevator alone was not enough.
The response of the plane seems way too much for it being trim (trim = the system to neutralize control forces)

Unless you meant trim as the "sum of all airfoils"...

I'm saying something bigger (a lot bigger) probably broke to achieve that kind of dive.
Trim in a 737 is a completely different animal than in a 172 or Tomahawk, where you can easily overpower it (ok, or with some effort and sometimes some disorientation, because it feels like you are pulling up like hell and about to stall or break the plane when you are just compensating for a full nose-down trim). Now, a 172 flies at between 60 and 90 kts (1.5 times). The 737 between 130 and 300. (2.5 times). The 172 has powerful flaps that affect the trim a lot, still nothing compared with the 737 flaps and slats, the 172 has a nose mounted engine, 737 has underslung engines, the 172 has a CG range of perhaps 5% of the chord, the 737 perhaps 20%. In the 172, the trim tab moves the elevator (hence you fight with the trim for the control of the same surface), in the 737, the trim mechanism moves the stabilizer that has an area quite bigger than the elevator (hence nothing you do with the elevator wwill change the stabilizer position). In a 172 you can overpower the trim. In a 737, it can be impossible.

No certification standard requires that the elevator must have enough authority to overpower a runaway trim.

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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby Gabriel » Sun Apr 10, 2016 4:58 pm

How many forums do you plan on posting the same shit on?
Let me give you a less flyboyish, and hence more constructive, answer.

My opinions, analysis, information, and even random thoughts about an airplane accident tend to be quite independent of the forum where I am posting, hence there is no reason why I would not share the same idea with as many forums as I am participating and feel like sharing.

Instead, when I reply to specific posts in one given forum, I typically don't go about copy-pasting in the others (although in specific circumstances I might just do that too).

Whether you consider what I have to say a shit is irrelevant to the all of the above. Some don't consider it a shit.

And 3we, I posted that comment here first, and then copied-pasted it in the other forum. So let them, if any, be the offended ones.

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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby 3WE » Sun Apr 10, 2016 5:08 pm

...Trim in a 737 is a completely different animal than in a 172 or Tomahawk...No certification standard requires that the elevator must have enough authority to overpower a runaway trim.
Yeah, I know...

...BUT...

...the ability to cause a SUDDEN dive of THAT severity????

Ironingly, I wonder if the trim runaway procedure calls for pulling a circuit breaker.
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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby 3WE » Sun Apr 10, 2016 5:12 pm

If my memory serves, our very own Dummy once had the trim act up.

FWIW, I think he went on to complete the flight...
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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby PurduePilot » Tue Apr 19, 2016 3:43 am

...Trim in a 737 is a completely different animal than in a 172 or Tomahawk...No certification standard requires that the elevator must have enough authority to overpower a runaway trim.
Yeah, I know...

...BUT...

...the ability to cause a SUDDEN dive of THAT severity????

Ironingly, I wonder if the trim runaway procedure calls for pulling a circuit breaker.
Threre is a trim cutout switch located near the bases of the throttles.

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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby flyboy2548m » Tue Apr 19, 2016 2:43 pm

Let me give you a less flyboyish, and hence more constructive, answer.

My opinions, analysis, information, and even random thoughts about an airplane accident tend to be quite independent of the forum where I am posting, hence there is no reason why I would not share the same idea with as many forums as I am participating and feel like sharing.
Of course not. Heaven forbid some forum out there should lose out on some of your wisdom. Indeed, the very sky will fall and the very sun will extinguish.
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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby elaw » Thu Apr 21, 2016 11:56 am

...says the pot to the kettle...
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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby 3WE » Tue Apr 26, 2016 12:25 pm

According to a crappy Internet article, the preliminary report says $20 somatographic disorientation causing the pilots to initiate a 50-degree nose-down dive.

[Redundant mode]

Yeah, sure momentary disorientation- shove the yoke forward...if you really really screw up (fatigue factor), maybe you get light in the seat and the plane levels off or makes a shallow, descent. That [/b]is believable.

But no- now we're doing relentless push overs.

The nice big flat screen display of blue on brown with airspeed on the left provided insufficient feedback to allow the pilots to stabilize things before entering an air-show dive...really?

The flight director thingie that I thought operated just nearly absolutely almost 100% of the hand-flying time provided insufficient feedback to allow the pilots to stabilize things before entering an air-show dive...really?

The general requirement that in IMC that you don't make big sustained control inputs.

Gabe's inference of negative G's...that provided insufficient feedback to allow the pilots to stabilize things before entering an air-show dive...really?

Two pilots and an Otto or two...none of that provided sufficient feedback to allow the pilots to stabilize things before entering an air-show dive...really?

(I know, eye-rolling, seemingly incomprehensible plane crashes have happened many times before). :(
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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby PurduePilot » Sat Apr 30, 2016 3:44 am

I experienced somatogravic issues during my most recent missed approach in IMC in the 182RG. Everything felt and sounded fine while I was fiddling with the radio and when I resumed my scan I was leveled off and accelerating instead of climbing at Vy. Contributing factor was probably that this was the one one with the bigger STC'd engine and has 15% more power than I'm used to. Very real scary phenomenon but I don't think it was the cause of this accident.

More likely, especially with underslung engines, is that they had excessive pitch up due to skill/scan/distraction, and then overreacted.

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Re: Flydubai Flight 981, 737, Rostov-on-Don, Russia

Postby flyboy2548m » Sat Apr 30, 2016 3:26 pm

I experienced somatogravic issues during my most recent missed approach in IMC in the 182RG. Everything felt and sounded fine while I was fiddling with the radio and when I resumed my scan I was leveled off and accelerating instead of climbing at Vy. Contributing factor was probably that this was the one one with the bigger STC'd engine and has 15% more power than I'm used to. Very real scary phenomenon but I don't think it was the cause of this accident.
I just shot like 10 missed approaches in the sim during my recurrent last week. Even with 27,000lbs of underslung might per side, no somatogravic illusions. None! That's how awesome I am.
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