Aeromexico Crash

[RobertS975]

Originally Posted by malr

Shouldn't a high-speed abort (before V1) leave enough runway to stop without the overrun?

You are making a huge assumption about what transpired. With intact recorders, possible airport vicinity video and hopefully healthy pilots, there will be lots of data to dissect on this accident.

[archae86]

oops

Originally Posted by malr

Shouldn't a high-speed abort (before V1) leave enough runway to stop without the overrun?

My mistake, I guess. I'm not a pilot, and was speaking English, not realizing I had inadvertently employed a reserved term with a formal meaning. I just meant "terminated the takeoff while going pretty darn fast". As distinct from crashing minutes after takeoff, as some early reports had it.

[Two's in]

Originally Posted by archae86

My mistake, I guess. I'm not a pilot, and was speaking English, not realizing I had inadvertently employed a reserved term with a formal meaning. I just meant "terminated the takeoff while going pretty darn fast". As distinct from crashing minutes after takeoff, as some early reports had it.

Not a mistake at all Archae, there are multiple definitions for V speeds but in general, V1 = The speed beyond which the takeoff should no longer be aborted. It's a reasonable assumption that shortly after V1, either aviation is being committed, or you're coming to a halt within the runway length. There are of course all sorts of traps and gotcha's to complicate that assumption, but the very reason for defining V1 in jet aircraft is to avoid high speed landscaping or low speed, single engine, terminal aerobatics. Like all accidents, in this case there will be a series of events that allowed a foolproof preventative measure being anything but foolproof, but in this case it looks like most people survived; which can only be good news.

[rationalfunctions]

Based on the photos from the BBC article, it looks to have come to a rest around 375m beyond the threshold, past the RESA but well within the airport fence.

Fingers crossed that the injured passengers and crew make a recovery

[lomapaseo]

Originally Posted by Sailvi767

Based on no fatalities most likely a overrun.

Agree .. but to get that far from an expected V1 decision point it would seem that he had to be going pretty damn fast as an overrun.

Of course like any accident it doesn't add up until the facts start coming in.

[Airbubba]

Photo by Kevin Alcantar Drones Durango

There seem to be multiple reports that the plane took off into a heavy rainstorm.

[Clandestino]

Avherald has posted a video showing that the poor bird "jettisoned" its engines to the left of the runway and before DER. So far I'd speculate it wasn't ordinary too-high-speed abort messup and that keeping the bird upright throughout the crash sequence required the heavy dose of good luck.

[pattern_is_full]

Aviation Herald report: Accident: Aeromexico Connect E190 at Durango on Jul 31st 2018, veered off and overran runway after rejected takeoff and burst into flames

MMDO 312150Z 12007KT 10SM BKN020CB BKN025 OVC200 22/14 A3023 RMK 8/903 BINOVC=
MMDO 312103Z RTD 28007KT 7SM OVC015CB 17/14 A3024 RMK SLP118 57014 956 8/9// PISTA CERRADA POR ACFT ACCIDENTADA BINOVC=
MMDO 312018Z 07003KT 7SM TSRA BKN020CB 20/13 A3023 RMK 8/900 TSRAB13=
MMDO 311941Z 01005KT 10SM BKN025CB 28/10 A3023 RMK 8/300=
MMDO 311844Z 12003KT 12SM BKN025TCU BKN200 26/11 A3026 RMK 8/201 ISOL CB=

Airport elev. 6102 ft/1860m. Calculated DA (mine, from METAR above) 7934ft/2418m

AH map shows both engines found off left side of runway, between RWY and TWY A, and between TWY A hold point and twy B. My observation (from misc airport photos) is that there appears to be a full-length drainage ditch between runway left side and the parallel taxiway A, in about the lateral location where the engines were found. Rest of aircraft travelled about 250 m/yds past the point the engines were found. Time between the aircraft comes to a stop, and fire ignition, about 3-4 minutes, thus the moderatel casualties.

It appears to me the drainage area is a swale or valley (shallow but not flat - close order of 1.5 m/yds deep?), with the taxiways crossing it on berms to access the runways - just an impression from the look of the ground around the taxiways (google earth) and how far the ditch "tunnels" past the tawiways.

https://www.google.com/maps/place/Ae...4d-104.5338168

My speculation - aircraft departs left side of runway under asymmetric thrust after engine failure, descends into swale, travels along concrete-lined ditch, loses one engine in rough ground, hits berm for TWY A hold position, lose second engine (and perhaps gear) to ground obstruction (berm), slides across TWY A hold point and along concrete ditch lining on belly, until stopping.

Weight (97 seats out of 100 filled), density altitude and minimal wind may explain high true/ground speed required and achieved. Someone with EMB-190 references may be able to figure that out.

Shades of Continental 1404 runway excursion and loss of gear and one engine in rought ground DEN Dec. 2008, and SWA fall into ditch off taxiway at Nashville Dec. 2015.

EDIT - Airbubba added his excellent photo while I was posting. Obviously better info about final aircraft position. Confirms hold point for 21 could have been an obstruction if they got into the weeds - emphasize "could", not "did." That's a nasty ditch. I think I see an S-curved trace through the grass from the top of the image to the taxiway, but that could be "confirmation bias."

[Airbubba]

The weather around the time of departure did not look good:

MMDO 312018Z 07003KT 7SM TSRA BKN020CB 20/13 A3023 RMK 8/900 TSRAB13

[mosquito88]

Originally Posted by RobertS975

You are making a huge assumption about what transpired. With intact recorders, possible airport vicinity video and hopefully healthy pilots, there will be lots of data to dissect on this accident.

He's not making an assumption, he's asking a question.

[KelvinD]

From the BBC News article:

The airport operator, Grupo Aeroportuario Centro Norte, said early data suggests bad weather was the cause, with the plane taking off during a heavy hailstorm before being forced to make an emergency landing.

[PastTense]

Originally Posted by pattern_is_full

Time between the aircraft comes to a stop, and fire ignition, about 3-4 minutes, thus the moderate casualties.

My thought is it would take substantially longer than this to evacuate all the passengers with some injured. [There is also the issue of passengers removing luggage from overhead racks.]

Anyone know?

[slfool]

A more comprehensive report in The Guardian: https://www.theguardian.com/world/20...-crash-durango

Eighty-five people were injured – some seriously – but José Rosas Aispuro, the governor of Durango state, said there were no fatalities among the 97 adults, two children and four crew members on board ... A spokesman for the Durango state health ministry said two of the victims were in critical condition.

Aispuro later said at a press conference that information he had received suggested that “after the plane had taken off, suddenly it was hit by a gust of wind that made it go down briskly and touch the ground with its left wing, detaching its two engines.“The aircraft was projected off of the runway … and fell approximately 300 metres [away].

[pattern_is_full]

Originally Posted by PastTense

My thought is it would take substantially longer than this to evacuate all the passengers with some injured.

The certification requirement is that it can be done (and demonstrated) in 90 seconds. They got 870 people out of an A380 in 77 seconds in its test.

But yes, real-world factors will change the actual performance. Injuries can occur in the evacuation itself, or even post-evacuation (flying blobs of burning fuel, etc.) That'll all come out eventually.

[Lookleft]

From the photo, the marks on the ground go from the aircraft to the end of the runway, it doesn't appear to have become airborne, which is probably why the aircraft remained intact.

[bud leon]

Originally Posted by Lookleft

From the photo, the marks on the ground go from the aircraft to the end of the runway, it doesn't appear to have become airborne, which is probably why the aircraft remained intact.

The aircraft would normally have been airborne well before the end of the runway.

[ONE GREEN AND HOPING]

Have only speed-read all the above, but sometimes it can be a nasty shock at VR to realise something got missed out on the check list....like flaps or reduced thrust settings. A bit early to run out of fuel...We'll just have to wait and see

[Joe_K]

Originally Posted by Lookleft

From the photo, the marks on the ground go from the aircraft to the end of the runway, it doesn't appear to have become airborne

Which seems to be what Mexican media are now reporting: "Luis Gerardo Fonseca, director general de DGAC, señaló que el piloto interrumpió la carrera antes del despegue, lo que provocó que éste saliera de la pista." (from El Financiero | Las noticias de finanzas, economía y política más importantes del país. )

[Sailvi767]

Big thunderstorm, marble sized hail with gusty winds. Sounds a lot like a setup for a classic wind shear or microburst.

[double_barrel]

Originally Posted by Volume

locked bins may...

We now have electric emergency exit locks on some models (no good Idea IMHO) to prevent passengers from opening them if not desired, it would be a piece of cake to have electric locks on the bins. They may actually even prevent them from opening during hard landings if designed accordingly.

I don't think people evaluate the situation and 'form a view', I think it is sheer mindless habit that you get your bag before you get off. I understand that, even in an obviously life threatening situation, many passengers automatically head for the front left because that is how they boarded.

Thus I think that locked overhead bins would make the situation worse as passengers would stand around aimlessly fiddling with the catches and waiting for the bins to be unlocked.