FlyDubai 737-800 down in Russia
Discussion
essayer said:
Is this similar to the Bournemouth incident ? 737 and a stall after go around..
pitch up stallhttps://www.gov.uk/aaib-reports/aar-3-2009-boeing-...
not same?
k me sideways at that approach 
It's worth remembering that the 737-300 incident in Bournemouth didn't start at the go-around. The autothrottle dropped out on the approach and the pilots didn't notice: this was the cause of the incident. All of the events afterwards were an attempt at recovery including the 'go around'(GA).
The aircraft was following the glideslope (GS) with the engines at idle, for around 45 seconds, if I recall correctly. In order to maintain the GS the aircraft, and so, the autopilot had to trade speed for height; hence the it was decelerating all the way down the approach - to around 110kts ish. It continued to pitch up to maintain the GS right until the first stick shaker activated. No hint of a GA at this point, but a whole load of trouble. The correct action at this point is to perform a stall recovery whilst minimising height loss. Simply put, this involves a large push on the control column to hold the aircraft pitch around zero degrees and as much power as you've got to accelerate. In this case they'd also have needed to trim forward to overcome significant aft control column forces (more below). Once you've accelerated to a safe speed you'd perform a standard GA.
For whatever reasons, the crew elected to go around from a very low energy state and an already high pitch attitude. This only compounded their problems, but the incident wasn't caused by the pitch/power couple on the 737 during the go around. The further high pitch attitudes and low speeds on the GA were exacerbated by the autopilot having wound the elevator trim fully back in an attempt to reduce the aft control force required to maintain the GS with no thrust. Furthermore, the crew made no attempt to manually trim forward, and so ease the aft control column forces, helping to get the aircraft's nose down and aid acceleration.
The crew were effectively passengers from the point they elected to GA rather than perform a stall recovery. I think the speed dropped as low as 90kts or so during this manoeuvre. With no forward elevator trim being applied it was actually the selection of Flaps to 15 degrees from the approach setting which, luckily, produced a slight nose down motion and allowed the aircraft to begin accelerating.
There are a few posts on the 'other site' suggesting that the Bournemouth incident was caused by the 737's pitch/power couple. It wasn't. Any similarities between Bournemouth and this Fly Dubai event would have to start by looking at very low speed on the approach.
The aircraft was following the glideslope (GS) with the engines at idle, for around 45 seconds, if I recall correctly. In order to maintain the GS the aircraft, and so, the autopilot had to trade speed for height; hence the it was decelerating all the way down the approach - to around 110kts ish. It continued to pitch up to maintain the GS right until the first stick shaker activated. No hint of a GA at this point, but a whole load of trouble. The correct action at this point is to perform a stall recovery whilst minimising height loss. Simply put, this involves a large push on the control column to hold the aircraft pitch around zero degrees and as much power as you've got to accelerate. In this case they'd also have needed to trim forward to overcome significant aft control column forces (more below). Once you've accelerated to a safe speed you'd perform a standard GA.
For whatever reasons, the crew elected to go around from a very low energy state and an already high pitch attitude. This only compounded their problems, but the incident wasn't caused by the pitch/power couple on the 737 during the go around. The further high pitch attitudes and low speeds on the GA were exacerbated by the autopilot having wound the elevator trim fully back in an attempt to reduce the aft control force required to maintain the GS with no thrust. Furthermore, the crew made no attempt to manually trim forward, and so ease the aft control column forces, helping to get the aircraft's nose down and aid acceleration.
The crew were effectively passengers from the point they elected to GA rather than perform a stall recovery. I think the speed dropped as low as 90kts or so during this manoeuvre. With no forward elevator trim being applied it was actually the selection of Flaps to 15 degrees from the approach setting which, luckily, produced a slight nose down motion and allowed the aircraft to begin accelerating.
There are a few posts on the 'other site' suggesting that the Bournemouth incident was caused by the 737's pitch/power couple. It wasn't. Any similarities between Bournemouth and this Fly Dubai event would have to start by looking at very low speed on the approach.
Edited by pushthebutton on Saturday 19th March 21:57
There's been a few incidents where the 737 autothrottle has failed on approach and nobody has noticed (or the resultant speed decay) that plane is full of gotchas.
For people that might not know. If the aircraft starts to stall, you must obviously follow the stall recovery which involves not raising the flaps. If you don't know what's going on and do a go around by mistake, that involves raising some flaps and the gear and making the event much much worse.
For people that might not know. If the aircraft starts to stall, you must obviously follow the stall recovery which involves not raising the flaps. If you don't know what's going on and do a go around by mistake, that involves raising some flaps and the gear and making the event much much worse.
That doesn't look like a wing strike on landing, more like a fall out of the sky! Hard to tell angle as its not clear where the cctv camera is located in relation. But there is no mistaking that descent speed. It appears to be real time too given the passing cars in the footage.
There's more to this than the authorities have released to the media.. The circling for 2 hours due to weather makes no sense when others diverted no problem, then that crazy descent was more like a lawn dart.
Perhaps ran out of fuel on final approach followed by a catastrophic stall?
Tragic, whatever.
There's more to this than the authorities have released to the media.. The circling for 2 hours due to weather makes no sense when others diverted no problem, then that crazy descent was more like a lawn dart.
Perhaps ran out of fuel on final approach followed by a catastrophic stall?
Tragic, whatever.
dvs_dave said:
There's more to this than the authorities have released to the media.. The circling for 2 hours due to weather makes no sense when others diverted no problem, then that crazy descent was more like a lawn dart.
Perhaps ran out of fuel on final approach followed by a catastrophic stall?
ETA: More info available here:Perhaps ran out of fuel on final approach followed by a catastrophic stall?
http://www.pprune.org/rumours-news/576325-b-738-cr...
Post retracted.
Edited by Pennyroyal Tea on Sunday 20th March 05:37
Hmmm. New footage and speculation that it's on fire during the descent.
http://www.dailymail.co.uk/news/article-3500756/Ne...
http://www.dailymail.co.uk/news/article-3500756/Ne...
hornetrider said:
Hmmm. New footage and speculation that it's on fire during the descent.
http://www.dailymail.co.uk/news/article-3500756/Ne...
Head on view of landing lights in misty weather?http://www.dailymail.co.uk/news/article-3500756/Ne...
I was going to post yesterday saying I wonder if they did some damage on the first go but looking at the data they never got near the ground so I did not bother but I wonder if something did in fact happen on finals on the first go and they spent the next 2 hours trying to manage the problem?
Either way that went in nose down like a brick.
Either way that went in nose down like a brick.
Pennyroyal Tea said:
ATC recording points to all being well: pilots are calm and relaxed even during the 2nd approach.
It clearly appears to be out of control though, odd.Those poor people. Circling for two hours is ridiculous, and this incident won't do much for my dislike of flying. A couple of years ago I was on a Ryanair flight to Rhodes - I had looked at the weather in the morning, which suggested 60 mph winds in a direction which would have meant crosswinds, and I didn't think there was much chance of us going. However we took off on time, and yes, I was right as we started circling and the pilot said we would see if the weather improves. It wasn't two hours though - we diverted to Crete, refuelled and flew straight back to the UK (a soul destroying experience).
My point is are these budget airlines under pressure to maintain their schedules and have planes in the right places? They could have diverted in this situation, but didn't for some reason and thought they needed to have a go/take a risk with terrible consequences. I don't know if any other planes were landing or if they all diverted though.
Honeywell said:
Windshear/Turbulence on approach put them in a low energy state, they went around and they got the nose too high and stalled it.
Just after midnight, two Captains flying together and they'd been airborne for six hours. Crap handling happens.
That's my guess right now.
The 245knt vertical descent speed from an altitude of 3500ft into the tarmac suggests otherwise, though. That's not a stall.Just after midnight, two Captains flying together and they'd been airborne for six hours. Crap handling happens.
That's my guess right now.
ETA: And the fact that the nose was pitched down on impact.
Edited by Pennyroyal Tea on Sunday 20th March 10:55
Pennyroyal Tea said:
But an 800 series?? The plane was only 5yrs old.
It just doesn't make sense.
Age isn't as relevant as you'd think. I'm sure they exist, but I can't recall the last accident investigation that concluded that the cause was the age of the aircraft. Generally, they are at their most unreliable when they are brand new or getting to the end of their service life, but regular, targeted maintenance can overcome the latter. The autothrottle failing is a catch all phrase; it generally means not operating as intended. The Turkish 737-800 incident at Amsterdam could be described as an autothrottle failure, but was caused by a faulty left side radio altimeter input into the autothrottle control software. It was also a new aircraft.It just doesn't make sense.
If I had to recall the number of times the autothrottle dropped out on me I'd lose count after running out of fingers and toes. Such issues are relatively common and dealt with as a matter of course but, if they're not, you read about it for years to come.
pushthebutton said:
If I had to recall the number of times the autothrottle dropped out on me I'd lose count after running out of fingers and toes. Such issues are relatively common and dealt with as a matter of course but, if they're not, you read about it for years to come.
Interesting, on what types did you get the A/T failing on you. 2000 hrs on the 738 and not one failure for me.Gassing Station | Boats, Planes & Trains | Top of Page | What's New | My Stuff