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PWS
Originally Posted by hunbet
(Post 10212795)
Looks like a very violent and brief squall with hail and windshear. The predictive windshear would have been inhibited just prior to the time they encountered it . Many warnings are inhibited during T/O until established in climb.
Note that the after crash videos don't show any rain. PWS is available up to 100 kts on most aircraft as that’s the whole point, and the WX radar should have given quite a distinct picture. Having said all that, we don’t know if PWS was fitted on this aircraft. |
:ugh:
Originally Posted by TangoAlphad
(Post 10212808)
While I agree most would of been inhibited by take off it doesn't say much for the system if it didn't pick up a cell capable of putting an aircraft back on the deck during the early roll.. (assuming the cell theory)
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Radar View
The on board radar shows what's ahead in a narrow cone. There's a lot of sky and possible nastiness in the hemisphere surrounding the aircraft that's not in that cone.
If the Mexican government offers weather radar images on the web, the pax might have better SA with their phones (airplane mode off) ;) |
The microburst could have formed directly above the airport just as they were on the takeoff roll.The weather radar would have been incapable of detecting anything close.
Moments later it wasn't even raining at the crash site. |
Watching the LiveLeaks video from the left side, you can hear what sounds like wind whistling right when the aircraft rotated and leaves the ground. Soon after, the wind sounds stops and the plane comes back down sans gear. Reminds me of DAL 191: “you’re gonna lose it all of a sudden” when the L1011 enters the rain shaft and encounters a strong headwind. The headwind shears to a downdraft, and all the airspeed is gone. For both aircraft, the time betweeen headwind and downdraft is quite short. Anyone have the expertise to tell if the rotation point is before what would be expected of a plane at this weight in those conditions? If it rotated too soon, it may be because the pilots got the headwind and thought they got a nice “bonus” on takeoff only to lose it. |
If you can set aside the music and narration and just watch the video, we can see what some (not all) microbursts look like and how they behave.
At the start of the takeoff run the vis is good off to the right, (slightly less so to the left) in these videos, but rain & wind increase just prior to rotation. The aircraft gets briefly airborne and settles back, hard, onto the runway. It is apparent in the video that the leading-edge devices are deployed as expected. Could be classic windshear, or "rain-roughened" wing surfaces or a combination of these factors. Regarding reduced-thrust and assumed temperature power settings, this would have been a full-thrust takeoff given the METARS. But, as always, what we think should be the case doesn't explain the accident, (Sid Dekker, Field Guide to Understanding Human Factors). This aircraft type has very good recorders and the QAR may have an even more detailed set of parameters so determining aircraft energy, system & power settings, control inputs, accelerations and so on will be (or should be!) straightforward. The CVR will be interesting in terms of any discussions regarding awareness of weather and the decision to takeoff. NOTE: Bear in mind that this is time lapse work and the speed with which this "rain bomb" moves may be exaggerated. |
Re the evacuation, what strikes me most about the on-board video/audio is that - admittedly in the absence of pictures after the severe impact - the degree of audible panic among the passengers is much lower than I would have expected in the circumstances.
It will be interesting to find out in due course, perhaps, what the thumping noises were. Sounds as if someone near the camera was trying to fight past or through an obstruction. Was the fuselage breached even before the fire destroyed it? |
Originally Posted by Chris Scott
(Post 10213028)
It will be interesting to find out in due course, perhaps, what the thumping noises were. Sounds as if someone near the camera was trying to fight past or through an obstruction. Was the fuselage breached even before the fire destroyed it?
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Wind shear warnings in the aircraft I fly are prohibited until 15'agl radar altimeter. Why o why they didn't sit at the end of the runway 20 minutes and takeoff in the clear. TEM threat-error-management. |
As a reminder, a microburst after take-off put a Pan Am 727 into the ground from 150 feet altitude (Flt. 759, Kenner (New Orleans), 1982). No survivors. In a weird way, this flight was "lucky" if the microburst (if real - high probability) prevented it from getting significantly airborne, if at all. Of course, 36 years ago we were only just starting to get a handle on detecting and handling microburst threats.
______________________ Any followup on the original reports of engine failure? Was that just "fog of war?" If real, what are the odds it was caused by hail or rain ingestion from the same weather event? cf: take-off video. On the positive side, AvHerald quotes hospital as saying the captain is recovering from spinal surgery and can move arms and legs. :ok: |
..the authorities are already stating it can be a lengthy investigation, depending on the condition of the recorders and that the captain is assisting in the investigation..
..that already sounds like the recorders are good enough, but that they are now preparing the "actual happening" of the accident to hold water reg. insurance and upcoming passenger law suits.. ..lure me - if indeed it was a windshear - that they are already preparing to put all blame on the captain for a takeoff into a windshear "which he is expected to be able to predict from the current WX situation based on education, experience and good judgement" ..just my guess - we've seen it all before.. |
Originally Posted by er340790
(Post 10212210)
True... though most incidents I have seen over the last 42 years involved the pushing of that luck.... right up until it ran out. :sad:
It's so nice to hear of a serendipitous outcome in these tines of angst, trouble and strife pretty well everywhere around the world. |
Originally Posted by HarryMann
(Post 10213429)
Same here, very wise words. I know I've had my 9 lives !
It's so nice to hear of a serendipitous outcome in these tines of angst, trouble and strife pretty well everywhere around the world. OAP |
Flex
Originally Posted by TangoAlphad
(Post 10212929)
These days with assumed temp and derates etc etc very hard too tell. Only guide I'd have is if we aren't rotating by the time I'm getting into 900m (alt red white) I'd be getting twitchy.
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Video of takeoff from port side passenger window. Also clearly shows smoke direction after the crash. Audio of distressed victims following the evacuation https://www.buzzfeed.com/briannasack...e9#.yoyMkq37e9 mjb |
Originally Posted by Onceapilot
(Post 10213477)
Yes, less than worst case. :ok: However, this was not serendipitous, if this was primarily caused by downburst, ignoring the adverse conditions and taking-off was pure risk taking. Unfortunately, I have witnessed similar many times from the flightdeck. :oh:
OAP Does Mexico have such a 'blame the crew' culture like 3rd world countries such as Bolivia, Italy and France? |
Originally Posted by daelight
(Post 10214124)
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Does Mexico have such a 'blame the crew' culture like 3rd world countries such as Bolivia, Italy and France? |
Originally Posted by N90-EWR
(Post 10214128)
Taking off under those conditions was an extremely poor judgement call, and as so often I am reminded in these forums, the captain is the ultimate authority in deciding whether to go or not to go, so yes, the blame is on the crew on this one, and the "culture" over there has nothing to do with that.
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Originally Posted by daelight
(Post 10214124)
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Does Mexico have such a 'blame the crew' culture like 3rd world countries such as Bolivia, Italy and France? |
It's way too early to talk of blame and such talk un-nerves future passengers from flying.
As an aviation forum we must be aware that it's corrective actions that count towards calming passengers. Best to concentrate on getting facts and lessons learned |
[QUOTE=Alpine Flyer;10211832]Not wanting to say that can't be a factor but it would require at least a bigger mistake in setting up the take-off in the MCDU as the E-Jets will not accept empty take-off settings (defaulting to max thrust) and warn if the flap setting is different from the one set on the take-off data pages.
On the E170/190s, before takeoff, pressing the take-off config test button (as you enter the runway) will alert you "No Takeoff" if the data is not entered (also alerts you if your flaps setting and the settings input on the MCDU don't match). One possibility I was thinking was that the autothrottles may not have been armed correctly and didn't go into TOGA. Shouldn't have been a problem if the crew caught that early enough but left undetected a lot of runway was like used before the plane accelerated to V1. |
[QUOTE=1.3vso;10214755]
Originally Posted by Alpine Flyer
(Post 10211832)
Not wanting to say that can't be a factor but it would require at least a bigger mistake in setting up the take-off in the MCDU as the E-Jets will not accept empty take-off settings (defaulting to max thrust) and warn if the flap setting is different from the one set on the take-off data pages.
On the E170/190s, before takeoff, pressing the take-off config test button (as you enter the runway) will alert you "No Takeoff" if the data is not entered (also alerts you if your flaps setting and the settings input on the MCDU don't match). One possibility I was thinking was that the autothrottles may not have been armed correctly and didn't go into TOGA. Shouldn't have been a problem if the crew caught that early enough but left undetected a lot of runway was like used before the plane accelerated to V1. I fly the very same aircraft with that airline. Flight deck discipline is very high. From time to time one of us may forget to arm the autothrottle (not part of any checklist) but I have seen this no more than 3 times. I have nearly 2000 hrs in that type. I have been many times in MMDO, Durango, and it is really a treacherous airport to fly in. Usually conditions are VMC but in summer there are a lot of fast moving CBs and thunderstorms. Both Metar and Taf were not showing anyhing unusual but i have seen very sudden gusts and shifts in short final while the tower reported “calm”. The airport is in a flatland surrounded by a very tall montain range. |
Originally Posted by pattern_is_full
(Post 10213062)
As a reminder, a microburst after take-off put a Pan Am 727 into the ground from 150 feet altitude (Flt. 759, Kenner (New Orleans), 1982). No survivors. In a weird way, this flight was "lucky" if the microburst (if real - high probability) prevented it from getting significantly airborne, if at all. Of course, 36 years ago we were only just starting to get a handle on detecting and handling microburst threats.
______________________ Any followup on the original reports of engine failure? Was that just "fog of war?" If real, what are the odds it was caused by hail or rain ingestion from the same weather event? cf: take-off video. On the positive side, AvHerald quotes hospital as saying the captain is recovering from spinal surgery and can move arms and legs. :ok: |
Originally Posted by fisher22
(Post 10215391)
Mexico is still in prehistoric times when it comes to air traffic and weather technology and overall airport infrastructure, in places like Durango (or any other airport for that matter) for ATIS and METARs you'll have a dude looking out the window and guessing what the current conditions are (apart from basic wind/temp/pressure data). In this case I'm sure he saw some rain, estimated the cloud base and put it out on the report, any low level windhsear, microbursts and the like simply can't be detecte
Eveb the smallest airports with airline operations like Matamoros MMMT, Minatitlan MMMT, or Nuevo Laredo MMNL have more than acceptable survelliance equipment. Durango’s weather has always being treacherous. You have no idea and by the way you write, I really doubt you have left your home PC..... |
Originally Posted by Flugjung
(Post 10215592)
stop saying nonsense, I have flown in my airline all over Mexico, US, Central America and the Caribbean Eveb the smallest airports with airline operations like Matamoros MMMT, Minatitlan MMMT, or Nuevo Laredo MMNL have more than acceptable survelliance equipment. Durango’s weather has always being treacherous. You have no idea and by the way you write, I really doubt you have left your home PC..... |
Originally Posted by aterpster
(Post 10215640)
You airline pilots in Mexico and the Mexico ATC system are first rate with, of course, some exceptions. Having said that, as a "gringo" who lives in Southern California, I am afraid to go to Mexico for my safety, your first-rate pilots and ATC notwithstanding.
Back to Mexico's setup....suggest we await the investigation preliminary report to see what factors were found that need to be considered when analysing the outcome of this event. |
Originally Posted by Flugjung
(Post 10215592)
stop saying nonsense, I have flown in my airline all over Mexico, US, Central America and the Caribbean Eveb the smallest airports with airline operations like Matamoros MMMT, Minatitlan MMMT, or Nuevo Laredo MMNL have more than acceptable survelliance equipment. Durango’s weather has always being treacherous. You have no idea and by the way you write, I really doubt you have left your home PC..... I wrote what I wrote because I've seen it first hand, or are any of the airports you mentioned equipped with LLWAS? A microburst alert system? Terminal Doppler radar? What about AWOS, RVR measuring systems? Don't take it personal, but with the technology that exists today maybe the Mexican government should look into investing into better equipment so pilots and controllers are more aware of what's going on around them to keep accidents like this from happening. To say Mexican airports are equipped with state of the art weather measuring systems is just kidding ourselves. |
Originally Posted by fisher22
(Post 10215671)
Are we supposed to be impressed that you've flown to the Caribbean and Central America? Come on man, not on this forum. I wrote what I wrote because I've seen it first hand, or are any of the airports you mentioned equipped with LLWAS? A microburst alert system? Terminal Doppler radar? What about AWOS, RVR measuring systems? Don't take it personal, but with the technology that exists today maybe the Mexican government should look into investing into better equipment so pilots and controllers are more aware of what's going on around them to keep accidents like this from happening. To say Mexican airports are equipped with state of the art weather measuring systems is just kidding ourselves. I’m not trying to impress anybody, simply STOP writing NONSENSE. Saying facilities in Mexico are “prehistoric”, is one. Durango is a small airport with its most impirtant routes being to MEX and TIJ with Volaris and Aeromexico. BTW, ONLY the most important airports in the US have LLWAS , RVR, or Doppler radar. Those systems are expensive and are NOT worth the expense in arports with low traffic. |
Originally Posted by Willoz269
(Post 10215644)
Not sure that was necessary....as a foreigner, I and a few people are actually afraid to visit California or anywhere in the US for our safety. Back to Mexico's setup....suggest we await the investigation preliminary report to see what factors were found that need to be considered when analysing the outcome of this event.
@FlugJung: thanks for your experienced-based points regarding why that particular airport was not set up with LLWAS. @fisher: making a broad brush assertion like that is going to get a pointed response; not sure why you chose to stir the pot, but to each his own I guess. I'm just glad they all got out. |
Originally Posted by aterpster
(Post 10215640)
You airline pilots in Mexico and the Mexico ATC system are first rate with, of course, some exceptions. Having said that, as a "gringo" who lives in Southern California, I am afraid to go to Mexico for my safety, your first-rate pilots and ATC notwithstanding.
Willoz. I’ve visited your nation a number of times and never had an issue, but I knew where to avoid to stay out of trouble. There’s areas of Sydney that I’d avoid for my safety, doesn’t mean the whole nation is off limits. You might want to consider a similar approach to the US. |
Just because the airport has LLWAS , RVR, and Doppler radar it still won't stop stupid pilots from doing stupid stuff.
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Originally Posted by Halfnut
(Post 10217967)
Just because the airport has LLWAS , RVR, and Doppler radar it still won't stop stupid pilots from doing stupid stuff.
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Update from DGAC
Bad weather caused Aeromexico crash in July, investigators say September 5, 2018 / 10:25 PM MEXICO CITY (Reuters) - An Aeromexico plane crash in July that injured dozens of people in northern Mexico was likely caused by bad weather, authorities investigating the accident said on Wednesday. Jose Armando Constantino, the director of analysis of accidents and incidents for Mexico’s civil aviation agency, said there was no evidence of human error or mechanical failures. "There is no evidence that the motors had a mechanical or technical problem," he told a news conference. "The air speed indicates there were many fluctuations, there was an external factor. The external factor is a microburst, the probable cause (of the accident) was due to meteorological factors," he said. * * * * * * * * Investigators have found no evidence indicating that the crew should have known not to take off, Constantino said. A pilot in training served as copilot while the plane was taking off, he said. The agency will later present a final report detailing its findings about the accident. |
It's interesting that, more than a month after the event, we are still seeing reports that it was an RTO gone wrong, despite there being no evidence to support that assertion.
Accident: Aeromexico Connect E190 at Durango on Jul 31st 2018, veered off and overran runway after rejected takeoff and burst into flames Link to Reuters/DGAC article quoted above: Reuters: Bad weather caused Aeromexico crash in July, investigators say |
It's interesting that, more than a month after the event, we are still seeing reports that it was an RTO gone wrong, despite there being no evidence to support that assertion. |
The evidence does support RTO somewhat. Once through the hail, the aircraft settled back onto the runway, without rolling pitching or yawing. Engine noise is gone, and the screams do not start until we see debris flying past the window frame. No “rotation”. The slog through the overrun was the gear snagging on irregular surface and planted soil, gravel? |
Originally Posted by Concours77
(Post 10242826)
The evidence does support RTO somewhat. Once through the hail, the aircraft settled back onto the runway, without rolling pitching or yawing. Engine noise is gone,
Given that the intact, detached engines have been available to investigators for several weeks, I think we'd know by now if a reverser had been deployed on either/both before they departed the wing. |
In the preliminary report on page 39 it shows 91% N1 and 95% N2, is that maximum for the conditions (28 C at 6600ft) or was this a reduced thrust takeoff?
There is also 75.0 and 75.3 printed on the throttles in the bottom right of the picture. http://avherald.com/files/aeromexico...ary_report.pdf |
Third crew member in cockpit
On page 41 of the preliminary report (pdf), third paragraph, begins with "se detectó...", says "there was detected a non-authorized en-route habilitation session. One "crew member" acted as co-pilot, with Commander's surveillance until he (the Commander) asked for the control. The aeronautical authorities were given word of this".
This means a THIRD CREW member was in the cockpit at the moment of the TO procedure, acting as co-pilot and made the TO procedure actions until the PIC asked for the controls of the AC. This was confirmed in a press conference in Mexico and is published in several media: https://elpais.com/internacional/201...32_422381.html http://www.eluniversal.com.mx/carter...-de-aeromexico |
Given the impact, belly first, the engines were gone immediately. The lack of noise starts whilst still airborne, due to retarded throttles.... just a theory, I’ll push it until I see the final. Meanwhile, thanks for the reply:ok: |
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