Emirates B777 gear collapse @ DXB?
Join Date: Apr 2015
Location: Earth
Posts: 82
Likes: 0
Received 0 Likes
on
0 Posts
We are not even sure whether there was an aircraft immediately ahead of 521 who had to clear the runway before Twr could issue landing clearance to 521.
ATC wasnt too busy to see something that caused them to issue climb instruction. Lets stop the ridiculous rebuttals shall we?
Dubai Tower doesn't always have to wait for the aircraft to clear the runway before giving clearance to land to the following aircraft. At times when Local Reduced Separation procedures are in force this is what occurs. I don't know if they were at the time, or not.
Likewise, you don't know whether the Tower instructions for the missed approach were given in response to EK521 informing them that they were conducting a missed approach. The transmission are clipped, and not all have been caught.
Last edited by keepitrealok; 6th Aug 2016 at 17:08.
Join Date: Dec 1998
Location: UK
Posts: 293
Likes: 0
Received 0 Likes
on
0 Posts
Yes, the 777 TOGA system is very similar to 737. It is possible to only half press, or miss, the TOGA button which doesn't then engage the A/T. Some pilots have a habit of immediately taking their hand off the thrust lever and pulling back with 2 hands without checking the thrust levers have advanced. The other pilot could be on the radio. You could get a positive rate momentarily, before the speed decay results in a loss of altitude.
Join Date: Jun 2001
Location: Somewhere on the warm side!
Posts: 70
Likes: 0
Received 0 Likes
on
0 Posts
Met equipment at DXB
Most of the ground-based windshear detection systems used around the world employ doppler radar that relies on the reflectivity of water droplets in the air. They're not much good in dry conditions. Hong Kong has a LIDAR system to complement its Terminal Doppler Weather Radar (TDWR). The LIDAR uses an infrared laser to detect the movement of dust particles or aerosols in dry conditions. I don't know what type of equipment they have in Dubai.
Join Date: Jun 2009
Location: San Clemente, CA
Posts: 36
Likes: 0
Received 0 Likes
on
0 Posts
Obviously, too early to jump into any conclusions and I hate to speculate.
Heard from a former EK Pilot, this particular tail number was known as the "pig!"
(An old and heavy -300 with the -200 engines!)
Add the very high density altitude (49C and low QNH) with the possibility of tail wind and windshear. Making a lethal combination with a possible pilot fatigue!
Like the FlyDubai crash in Russia, there is an absolute news silence here in America!
Well, we have more important news here, like Trump's Tweets. Besides, Richard Quest and Marry Schiavo already solved the mystery on CNN. So, there is nothing left to talk about! :-)
Heard from a former EK Pilot, this particular tail number was known as the "pig!"
(An old and heavy -300 with the -200 engines!)
Add the very high density altitude (49C and low QNH) with the possibility of tail wind and windshear. Making a lethal combination with a possible pilot fatigue!
Like the FlyDubai crash in Russia, there is an absolute news silence here in America!
Well, we have more important news here, like Trump's Tweets. Besides, Richard Quest and Marry Schiavo already solved the mystery on CNN. So, there is nothing left to talk about! :-)
Join Date: Jun 2001
Location: Rockytop, Tennessee, USA
Posts: 5,898
Likes: 0
Received 1 Like
on
1 Post
Sometimes you can infer who was on the plane from schedule line awards but often trips are traded. The captain on the Pan Am Lockerbie crash had swapped the trip for example. And I can still remember watching the crew names for PA103 come off the printer before the flight was locked out of the schedule viewer.
Can anyone tell me at what point the EECs go from approach to intermediate or minimum idle as all my FCOM says is "after touchdown"? If the engines had gone to a lower idle the difficulty could be greatly exacerbated.
It's standard Boeing design practice to hold the engines at approach idle for 5 seconds after the air/ground transition, although the specific implementation varies with the different aircraft models. The older aircraft (e.g. 747-400 and 767) do it with time delay relays, newer models do it in software.
Join Date: Dec 2007
Location: snu
Posts: 11
Likes: 0
Received 0 Likes
on
0 Posts
Some points which haven't eben discussed
1. flap Setting seems to be 15! Why this??
2. the tail has traces from a tailstrike.
3. speedbrakes not extended!
there has To ne more than simple pilots error
1. flap Setting seems to be 15! Why this??
2. the tail has traces from a tailstrike.
3. speedbrakes not extended!
there has To ne more than simple pilots error
Join Date: Aug 2002
Location: Zone of Alienation
Age: 79
Posts: 9
Likes: 0
Received 0 Likes
on
0 Posts
1. Maybe the flaps only appear to be at 15.
2. Perhaps there was a tail strike.
3. Spoilers would not deploy if the gear were not down and conditions met.
4. Don't know of any generic malfunction that would lead to all the above.
2. Perhaps there was a tail strike.
3. Spoilers would not deploy if the gear were not down and conditions met.
4. Don't know of any generic malfunction that would lead to all the above.
Join Date: Aug 2002
Location: south england
Posts: 393
Likes: 0
Received 0 Likes
on
0 Posts
I truly feel for the moderators, they must be sorely tempted to shut this thread down. Please think before you post.......treat your post like a rant to your boss....sleep on it, read it again in the morning and then send it if you think it makes sense.
Join Date: Dec 2014
Location: Schiphol
Posts: 475
Likes: 0
Received 0 Likes
on
0 Posts
Impressions based on available video and photo material:
A. Righthandwing top panel:
At one stage in the video’s there is a major explosion on the right hand wing side. A large dark object is seen flying/blasted away. Some suggested that this was an escape slide.
Looking at the present state of photo and video material, my impression is that it is far more likely that it is a significant ‘part’ of the ‘top panel’ of the righthand wing. This ‘part’ roughly running outward from the wing root in spanwisedirection upto the middle of the second slat right from the right-hand engine. Fuselage-lengthwise this ‘top panel part’ running roughly between rear and front spar. The outer slats probably not even ‘hit’ during the explosion. So all in all a very large ‘toppanel’ (meaning top skin(s) sections with stiffeners and other attached systems and structural materials).
From the photos you expect the panel tearing near the wing root and rotating up from that root with a ‘hinge’ line roughly running through the end of the second outer slat position. You can see an upward bent top panel edge, still attached to the‘outer’ wing, at that line.
On one of the photos taken from above you see a large top (black) section missing from the wing.
During the explosion you see the flames ‘following’ and ‘shielded by’ the dark object. Which I would not expect if it was an escape slide.
There is a photo of a large piece of flat panel lying topside down on the runway/taxiway area, with what may be yellow tape/hose draped round it. Striking that it is not covered in soot or burned.
B. Enginebreak away:
For this item the video material is incomplete. Of low quality and dynamic. And starts only when a crash situation was clear. But to try to figure out what happened ...with what we have ... the plane rotates around the right hand engine so to speak, after it broke away. This happened in such a manner that it cut fuellines and (partially) ruptured fuel tanks. With probably the fire running from the engine to that fuel pool. Fire in the engine is visible at the start of the break away video segments.
A+B =combining these two items:
If the initial fire started around the righthand engine, which was away from the centertank. And assuming that the center tanks content had been consumed first during the trip, giving them a more explosion prone gas/fuel mixture (at least compared to that of a fuel filled tank). Next, the fuel pool fire may have heated up that center tank volume from the outside, leading up to the explosion that we discussed under item A. This explosion (further) opening up the righthand center upper fuselage. Which would explain the fact that the right hand side fuselage shows far more damage than the left. While cargo holds appear to show minimal soot. And maybe also offer some explanation of why most slides were initially deployed on the right hand side at the start of the evacuation. And passengers later escaping via the left hand slide aft.
I am not familiar with the engine break away design scenario’s of the 777. But this case will surely be used to review them. I wonder if the sequence of events of this accident will turn out to be one of the 'foreseen' scenario's, either a design one or even a certification one.
Sorry for the long post.
A. Righthandwing top panel:
At one stage in the video’s there is a major explosion on the right hand wing side. A large dark object is seen flying/blasted away. Some suggested that this was an escape slide.
Looking at the present state of photo and video material, my impression is that it is far more likely that it is a significant ‘part’ of the ‘top panel’ of the righthand wing. This ‘part’ roughly running outward from the wing root in spanwisedirection upto the middle of the second slat right from the right-hand engine. Fuselage-lengthwise this ‘top panel part’ running roughly between rear and front spar. The outer slats probably not even ‘hit’ during the explosion. So all in all a very large ‘toppanel’ (meaning top skin(s) sections with stiffeners and other attached systems and structural materials).
From the photos you expect the panel tearing near the wing root and rotating up from that root with a ‘hinge’ line roughly running through the end of the second outer slat position. You can see an upward bent top panel edge, still attached to the‘outer’ wing, at that line.
On one of the photos taken from above you see a large top (black) section missing from the wing.
During the explosion you see the flames ‘following’ and ‘shielded by’ the dark object. Which I would not expect if it was an escape slide.
There is a photo of a large piece of flat panel lying topside down on the runway/taxiway area, with what may be yellow tape/hose draped round it. Striking that it is not covered in soot or burned.
B. Enginebreak away:
For this item the video material is incomplete. Of low quality and dynamic. And starts only when a crash situation was clear. But to try to figure out what happened ...with what we have ... the plane rotates around the right hand engine so to speak, after it broke away. This happened in such a manner that it cut fuellines and (partially) ruptured fuel tanks. With probably the fire running from the engine to that fuel pool. Fire in the engine is visible at the start of the break away video segments.
A+B =combining these two items:
If the initial fire started around the righthand engine, which was away from the centertank. And assuming that the center tanks content had been consumed first during the trip, giving them a more explosion prone gas/fuel mixture (at least compared to that of a fuel filled tank). Next, the fuel pool fire may have heated up that center tank volume from the outside, leading up to the explosion that we discussed under item A. This explosion (further) opening up the righthand center upper fuselage. Which would explain the fact that the right hand side fuselage shows far more damage than the left. While cargo holds appear to show minimal soot. And maybe also offer some explanation of why most slides were initially deployed on the right hand side at the start of the evacuation. And passengers later escaping via the left hand slide aft.
I am not familiar with the engine break away design scenario’s of the 777. But this case will surely be used to review them. I wonder if the sequence of events of this accident will turn out to be one of the 'foreseen' scenario's, either a design one or even a certification one.
Sorry for the long post.
Join Date: Feb 2005
Location: Blingland
Age: 56
Posts: 329
Likes: 0
Received 0 Likes
on
0 Posts
Heard from a former EK Pilot, this particular tail number was known as the "pig!"
(An old and heavy -300 with the -200 engines!)
Complete and utter drivel. Never heard that about any plane at EK. -200 engines, it would never get off ground.... Utter tosh.
SyB
(An old and heavy -300 with the -200 engines!)
Complete and utter drivel. Never heard that about any plane at EK. -200 engines, it would never get off ground.... Utter tosh.
SyB
Join Date: Mar 2011
Location: Reup
Posts: 129
Likes: 0
Received 0 Likes
on
0 Posts
Best post ever on pprune or aviation forums in general
climb requirements are pretty simple.
14 cfr part 25.121(d) requires the plane to be able to achieve 2.1% gradient in the conditions, with a critical engine failed, with the gear retracted.
Part 25.119 covers landing climb, all engines operating. Gradient requirement of 3.2%. That is in landing config, e.g., f30, gear down. The sub para (a) is pertinent on some aircraft, (the pw4098 was one that could be a long time between wanting and getting, but well within the required periods).
The gradients for the aircraft cover therefore approach configuration engine out, and all engines in full landing configuration. That is rational and works well.
Any assumption that after some millions of hours of operating we suddenly get a plane that cannot achieve a gradient would have to assume some extenuating circumstance well outside of normal operations. High temps are an issue, the reported temp and local temp of an airmass that the aircraft passes by are different, but you will likely find that that is not a big issue in this case. Wind shear equates directly to a change in the cas as the energy state of the aircraft alters with a time domain delay due to inertia, either increasing it or reducing it depending on the sequence of encounter. In these conditions, again they would have to be rather severe to critically affect the energy state of the aircraft. Increasing tailwind, or reducing headwind result in loss of cas. Modest shear will alter the performance outcome from an expected outcome such as a pitch attitude that is selected, the flight path then is reduced where cas is lower than expected. That may seem pretty obvious, but when you rotate you are not necessarily looking at pertinent data, and routine standards evals show that the same is true for the pm case, what they are looking at during the change in flight path is not necessarily what you may expect. Bottom line, pitching up and assuming that the plane will achieve a certain performance is human nature, reinforced by the routine expectancy being matched by reinforcing outcomes, (we don't get surprises that often, fortunately).
On any day, proceduralizing of our processes in the cockpit act as much as a threat to the operation as an enhancement. How often is a checklist item answered without the actual condition being confirmed... "clear left/right!... Without anyone looking, standard callouts being made without the requisite action being taken that is supposed to be verified/reinforced by the callout. Sucks to be human, but then humans also can do things that computers cannot do, so it really sucks to be walk-on freight. You get what you pay for...
Emirates is a compliant airline; look at any iosa audit and you will find that in fact most are. (in fact, almost all are, and that should make one ponder for a moment, and then the moment will be lost in time). Emirates has a public image that is one of competence. Airlines are obliged to balance safety and economics, no matter what pr may say, that is not just the air transport industry, that is every human endeavour, in fact every system in nature that has a choice of actions. We are likely to find not very much was out of the ordinary here; we tend to forget due to the amazing reliability of the global air transport system that very flight involves an extraordinary confluence of things going right, with great demands for perfection. A failure can occur when a number of conditions are just sufficiently outside of normal to act together in concert to result in an unanticipated outcome. Such a failure mode comes from the reality of complex systems having potential for resonance to occur, where stochastic system behaviour of various inputs results in something that is outside of the expected occurring. Such a failure doesn't need active failures, it can occur with a number of within limit conditions just ending up at the wrong place at the wrong time. Sometimes, it just sucks. If that sounds depressing to people that may gain succour from linear or quasi linear causation, it need not be. It indicates that the most important thing we can have in operations is situational awareness, and that means, knowing when it likely to be compromised hints at how to get serious about maintaining system integrity. But, it is much easier to shoot the messenger, that cures the problem immediately, and everyone is satisfied that both justice, and system safety has been satisfied. Unfortunately, the world is not linear, nor quasi linear, and so a similar event will not be avoided.
Wonder how the emirates management will respond, insight or pavlovian responses.
If resonance appears a strange concept, one should consider their daily experience, or read up on complex systems failures as ladkin or hollnagel consider. Aircraft losses are brutal, so is a nuclear power station loss, and similar critical coupled systems.
Flight crew are not served well by rigid sops that end up affecting sa. Losing sa is just being human, yet our systems tend to belt the stuffing out of our crews for merely being so.
Never dull
14 cfr part 25.121(d) requires the plane to be able to achieve 2.1% gradient in the conditions, with a critical engine failed, with the gear retracted.
Part 25.119 covers landing climb, all engines operating. Gradient requirement of 3.2%. That is in landing config, e.g., f30, gear down. The sub para (a) is pertinent on some aircraft, (the pw4098 was one that could be a long time between wanting and getting, but well within the required periods).
The gradients for the aircraft cover therefore approach configuration engine out, and all engines in full landing configuration. That is rational and works well.
Any assumption that after some millions of hours of operating we suddenly get a plane that cannot achieve a gradient would have to assume some extenuating circumstance well outside of normal operations. High temps are an issue, the reported temp and local temp of an airmass that the aircraft passes by are different, but you will likely find that that is not a big issue in this case. Wind shear equates directly to a change in the cas as the energy state of the aircraft alters with a time domain delay due to inertia, either increasing it or reducing it depending on the sequence of encounter. In these conditions, again they would have to be rather severe to critically affect the energy state of the aircraft. Increasing tailwind, or reducing headwind result in loss of cas. Modest shear will alter the performance outcome from an expected outcome such as a pitch attitude that is selected, the flight path then is reduced where cas is lower than expected. That may seem pretty obvious, but when you rotate you are not necessarily looking at pertinent data, and routine standards evals show that the same is true for the pm case, what they are looking at during the change in flight path is not necessarily what you may expect. Bottom line, pitching up and assuming that the plane will achieve a certain performance is human nature, reinforced by the routine expectancy being matched by reinforcing outcomes, (we don't get surprises that often, fortunately).
On any day, proceduralizing of our processes in the cockpit act as much as a threat to the operation as an enhancement. How often is a checklist item answered without the actual condition being confirmed... "clear left/right!... Without anyone looking, standard callouts being made without the requisite action being taken that is supposed to be verified/reinforced by the callout. Sucks to be human, but then humans also can do things that computers cannot do, so it really sucks to be walk-on freight. You get what you pay for...
Emirates is a compliant airline; look at any iosa audit and you will find that in fact most are. (in fact, almost all are, and that should make one ponder for a moment, and then the moment will be lost in time). Emirates has a public image that is one of competence. Airlines are obliged to balance safety and economics, no matter what pr may say, that is not just the air transport industry, that is every human endeavour, in fact every system in nature that has a choice of actions. We are likely to find not very much was out of the ordinary here; we tend to forget due to the amazing reliability of the global air transport system that very flight involves an extraordinary confluence of things going right, with great demands for perfection. A failure can occur when a number of conditions are just sufficiently outside of normal to act together in concert to result in an unanticipated outcome. Such a failure mode comes from the reality of complex systems having potential for resonance to occur, where stochastic system behaviour of various inputs results in something that is outside of the expected occurring. Such a failure doesn't need active failures, it can occur with a number of within limit conditions just ending up at the wrong place at the wrong time. Sometimes, it just sucks. If that sounds depressing to people that may gain succour from linear or quasi linear causation, it need not be. It indicates that the most important thing we can have in operations is situational awareness, and that means, knowing when it likely to be compromised hints at how to get serious about maintaining system integrity. But, it is much easier to shoot the messenger, that cures the problem immediately, and everyone is satisfied that both justice, and system safety has been satisfied. Unfortunately, the world is not linear, nor quasi linear, and so a similar event will not be avoided.
Wonder how the emirates management will respond, insight or pavlovian responses.
If resonance appears a strange concept, one should consider their daily experience, or read up on complex systems failures as ladkin or hollnagel consider. Aircraft losses are brutal, so is a nuclear power station loss, and similar critical coupled systems.
Flight crew are not served well by rigid sops that end up affecting sa. Losing sa is just being human, yet our systems tend to belt the stuffing out of our crews for merely being so.
Never dull
Join Date: Jun 2016
Location: Singapore
Posts: 72
Likes: 0
Received 0 Likes
on
0 Posts
Or stalled in to the ground
Either way, the crux of this fortunate (barring the fire fighter who died, may he RIP) was the wheels up decision. Not good. Alas some poor sod pushed the lever...
Join Date: Mar 2014
Location: WA STATE
Age: 78
Posts: 0
Likes: 0
Received 0 Likes
on
0 Posts
This typer of designRE AO283 POST 531 "
SUGGEST you take a look at posts 260 thru 290 around page 14 re a short discussion and response re strut design parameters started by myself ( CONSO ) short version is the strut system is designed to fail such that engine pivots up over the wing to protect frontspar etc. Also dry bay on each side of strut assembly. Normally for a straight ahead landing failure or in air failure. What happens with side loads as shown by video becomes a bit more problamatical.
This type of design parameter has been standard for decades at least at Boeing
I am not familiar with the engine break away design scenario’s of the 777. But this case will surely be used to review them. I wonder if the sequence of events of this accident will turn out to be one of the 'foreseen' scenario's, either a design one or even a certification one.
This type of design parameter has been standard for decades at least at Boeing
Last edited by CONSO; 6th Aug 2016 at 21:55. Reason: correct post number- added parameter comment
what conso said. The engine and pylon assembly is designed to come off on impact without compromising wing box/fuel tank integrity. by that I don't mean damage or leaks, but without catastrophic failure of the wing primary structure.
To my mind the first thing that needs to be ruled out as the cause of the "explosion" are the right MLG wheels and tyres, assuming the gear was still roughly somewhere between rear spar and LG beam after the aircraft stopped. They are a known explosion hazard and the fusible plugs may not have popped in time.
To my mind the first thing that needs to be ruled out as the cause of the "explosion" are the right MLG wheels and tyres, assuming the gear was still roughly somewhere between rear spar and LG beam after the aircraft stopped. They are a known explosion hazard and the fusible plugs may not have popped in time.
Join Date: Jan 2008
Location: Dxb 30L
Posts: 53
Likes: 0
Received 0 Likes
on
0 Posts
Taken from FAA Certification Data Sheet
B777-200
2 Rolls-Royce Turbofan Model: RB211-Trent 875-17, RB211-Trent, 877-17, RB211-Trent 884-17, RB211-Trent 892-17, or RB211 Trent 892B-17, RB211 Trent 895-17
777-300
2 Rolls-Royce Turbofan Model: RB211-Trent 884-17, RB211-Trent 884B-17, or RB211-Trent 892-17
========================
777-31H 28680, 28687, 29062-29064, 29067, 29395-29397, 32699, 32700, 32702
A6-EMW Serial # 32700
Not so sure what to say more....
Join Date: May 2007
Location: Western Pacific
Posts: 721
Likes: 0
Received 0 Likes
on
0 Posts
Looking at the video of the removal of the aircraft, it appears that the nose gear is not fully retracted (or extended for that matter). I know that aircraft with gear doors on the main gear suffer from increased drag during the gear cycle, so perhaps they were climbing when the gear was selected up & the extra drag, coupled with other factors, caused it to lose altitude & settle back onto the runway.
If the PF was increasing attitude in order to try & prevent the altitude loss, the aircraft may have struck tail first, explaining the damage to the underside of the rear fuselage. The aircraft would then rapidly pitch nose down. If the right wing was slightly down, then most of this force would be brought to bear on the right engine nacelle & may have exceeded the design strength of the engine mounts & pylon, causing the right engine to separate, different to what happened with the BA & LOT crashes.
Lots of speculation. The final report, if we ever get to see it, will make for interesting reading.
If the PF was increasing attitude in order to try & prevent the altitude loss, the aircraft may have struck tail first, explaining the damage to the underside of the rear fuselage. The aircraft would then rapidly pitch nose down. If the right wing was slightly down, then most of this force would be brought to bear on the right engine nacelle & may have exceeded the design strength of the engine mounts & pylon, causing the right engine to separate, different to what happened with the BA & LOT crashes.
Lots of speculation. The final report, if we ever get to see it, will make for interesting reading.
Join Date: May 2005
Location: On a good day - at sea
Posts: 263
Likes: 0
Received 0 Likes
on
0 Posts
In the EVAC video I distinctly heard a PA call - "CABIN CREW.......unintelligible".
Presuming the video was only started after some time had passed following the stop (everybody was already in the aisles and grabbing bags) it strikes me as odd that the F/D crew would wait so long to make the PA if indeed it was the F/D crew. If it was the cabin crew making the PA then it seems even more odd. I'm especially bothered that I did not hear any non PA cabin crew voices until well into the video, very near the end. Perhaps those voices were in fact there but not in English so I missed them? If they were only communicating in English then that obviously is a problem in itself , not to mention that those voices should have been heard loud and clear much sooner.
Presuming the video was only started after some time had passed following the stop (everybody was already in the aisles and grabbing bags) it strikes me as odd that the F/D crew would wait so long to make the PA if indeed it was the F/D crew. If it was the cabin crew making the PA then it seems even more odd. I'm especially bothered that I did not hear any non PA cabin crew voices until well into the video, very near the end. Perhaps those voices were in fact there but not in English so I missed them? If they were only communicating in English then that obviously is a problem in itself , not to mention that those voices should have been heard loud and clear much sooner.
Last edited by nnc0; 7th Aug 2016 at 01:50.
Join Date: Mar 2008
Location: cloudcuckooland
Posts: 191
Likes: 0
Received 0 Likes
on
0 Posts
I once did a go-round where the moment I pushed the TOGA switches the Autothrottle dropped out. You then have to firewall the thrust levers manually. Possible scenario here?