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YYZYYT
Posts: 1136
Joined: Tue Apr 05, 2005 12:41 am

Re: LATAM A20N ground collision during takeoff run at LIM

Thu Nov 24, 2022 5:45 pm

CrewBunk wrote:

Using this incident as an example. One would have to look at the FDR, but let’s say they were below V1, but at a possible flying speed. Detecting the obstacle, an emergency system might reject the takeoff, but the Captain might have already decided to rotate early, clear the obstacle and stagger into the air.

Granted it puts the aircraft into a vulnerable position, should an engine (for example) fail. Second segment climb performance is now poorer. But …. the ground collision would have been avoided.

Looking at your example though: “it’s well established that no plane is supposed to be equipped with the tech to independently reject the takeoff”.


If the aircraft is below v1, is there any scenario where it has enough speed to become airborne?

Also, isn't 'try to struggle into the air" (aka, pull up in a desperate attempt to get the aircraft airborne before you should) the last thing a pilot should do? It could easily take an unfortunate but survivable crash (Lima) and turn it into an unsurvivable one (like Linate)

Not a pilot, would love to hear some thoughts from those who are.
 
GalaxyFlyer
Posts: 10319
Joined: Fri Jan 01, 2016 4:44 am

Re: LATAM A20N ground collision during takeoff run at LIM

Thu Nov 24, 2022 6:01 pm

The data doesn’t provide any information on whether the crew could get it airborne at or below V1. Very risky call to try to get airborne, if you do make contact with the obstacle, it’s gonna be Linate again.
 
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CrewBunk
Posts: 688
Joined: Sat Nov 18, 2017 3:12 am

Re: LATAM A20N ground collision during takeoff run at LIM

Thu Nov 24, 2022 6:33 pm

YYZYYT wrote:
If the aircraft is below v1, is there any scenario where it has enough speed to become airborne?


Yes. But that’s not really the point I was trying to make. I was suggesting the decision to continue/reject should be made by the Captain, not the aircraft automation.

For the record and because you asked, if V1 is set as it can not be above Vr, (so they will be the same) then in theory, a flying speed could be achieved before V1. This is common on longer runways, not contamination restricted.

But I agree with the above sentiment, attempting to rotate early to avoid an obstacle is not a good idea. I just used it as an example where the Captain’s intent and the automation of the aircraft (if it were ever designed) may not be the same.
 
889091
Posts: 1000
Joined: Sat Apr 06, 2019 7:56 pm

Re: LATAM A20N ground collision during takeoff run at LIM

Thu Nov 24, 2022 6:59 pm

GalaxyFlyer wrote:
889091 wrote:
Perhaps it is time to develop Autonomous Emergency Braking (AEB) for planes if speed is below V1?


Why? What would it have done here? AEB would create another layer of both benefit and hazard. An impeding collision would have to detected looking only at the active runway surface, not looking that taxiways,p where planes are frequently holding while the departing plane goes by. The hazard, of course, a false positive resulting in a needless high speed abort which isn’t an entirely safe evolution.

BTW, these collisions are pretty rare, the last one was a snow plow in Moscow. This scenario is mostly a sim treat.


For this particular scenario, we are still unsure if the pilots did actually see the fire truck or not. We will find out in due course after the investigation is completed.

Aviation technology normally finds its way into the automotive industry after a few years/decades (cue ABS). For once maybe this technology within the automotive sector will find its way into the aviation sector. This accident occurred during the day, with clear visibility. Perhaps it would have been helpful in the event of SQ006 (dark, moonless rainy night with approaching storm), NW1482 (fog) and the obvious one, PanAm and KLM in Tenerife.

Yes, I appreciate that there are challenges in terms of fine tuning the tech, but most of the legwork has already been done by the auto industry.

Just throwing it out there for discussion.
 
GalaxyFlyer
Posts: 10319
Joined: Fri Jan 01, 2016 4:44 am

Re: LATAM A20N ground collision during takeoff run at LIM

Thu Nov 24, 2022 7:29 pm

889091 wrote:
GalaxyFlyer wrote:
889091 wrote:
Perhaps it is time to develop Autonomous Emergency Braking (AEB) for planes if speed is below V1?


Why? What would it have done here? AEB would create another layer of both benefit and hazard. An impeding collision would have to detected looking only at the active runway surface, not looking that taxiways,p where planes are frequently holding while the departing plane goes by. The hazard, of course, a false positive resulting in a needless high speed abort which isn’t an entirely safe evolution.

BTW, these collisions are pretty rare, the last one was a snow plow in Moscow. This scenario is mostly a sim treat.


For this particular scenario, we are still unsure if the pilots did actually see the fire truck or not. We will find out in due course after the investigation is completed.

Aviation technology normally finds its way into the automotive industry after a few years/decades (cue ABS). For once maybe this technology within the automotive sector will find its way into the aviation sector. This accident occurred during the day, with clear visibility. Perhaps it would have been helpful in the event of SQ006 (dark, moonless rainy night with approaching storm), NW1482 (fog) and the obvious one, PanAm and KLM in Tenerife.

Yes, I appreciate that there are challenges in terms of fine tuning the tech, but most of the legwork has already been done by the auto industry.

Just throwing it out there for discussion.


The risk analysis for in a commercial aviation setting is vastly different than in automotive industry. The AEB false positive rate in ground vehicles would be totally unacceptable in aviation. The margins are much tighter. Look at this case, the AEB would have to see the fire apparatus, calculate its movement and compute the point of impact, notify the crew and apply the stopping devices. We’re never going to take that ultimate authority away from the crew. We do have surface manage to systems that shows all the equipment moving on the surfaces.

I can’t accept AEB in a car due to the possibility of a false positive which has been a non-zero event
 
kraz911
Posts: 207
Joined: Sat May 03, 2014 5:21 am

Re: LATAM A20N ground collision during takeoff run at LIM

Thu Nov 24, 2022 11:10 pm

Hello all,
Watching the videos and looking at the pictures, it could have been much worse. Condolences to the family and friends of the fire truck firefighters. Looking at the video, the driver of the truck tried to veer right to avoid collision with the aircraft. Unfortunately he was seconds too late. In a still from that video, it seems the aircraft struck the fire truck by the engine striking the truck in a t-bone fashion in the middle of the fire truck. Sadly the starboard main landing gear went through the fire truck cab, all this at 130 knots. The flight crew probably saw the trucks coming from the right but couldn’t have done anything to avoid the collision. The captain did a great job maintaining some control keeping on the runway. Now we have to see if clearance was given to cross the runway. Regarding if the aircraft will be a write off. I was wrong with the BA 777 at LAS so I’ll just guess that if the starboard wing isn’t tweeked or the spars aren’t bent and if the structure around the starboard main gear isn’t too bad, they’ll probably fix it. The aircraft’s only saving grace is it’s age. The insurance under writer will decide if if fixed or parted...
 
pugman211
Posts: 652
Joined: Thu Dec 20, 2012 1:55 pm

Re: LATAM A20N ground collision during takeoff run at LIM

Fri Nov 25, 2022 2:29 am

Nope, this a/c is done. Not only did the engine and gear get ripped off, the entire engine pylon is also missing. And to me the front of the wing in that area looks ruptured.
 
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AirKevin
Posts: 1371
Joined: Wed Apr 26, 2017 2:18 am

Re: LATAM A20N ground collision during takeoff run at LIM

Sat Nov 26, 2022 5:03 pm

kraz911 wrote:
I’ll just guess that if the starboard wing isn’t tweeked or the spars aren’t bent and if the structure around the starboard main gear isn’t too bad, they’ll probably fix it.

Looking at the pictures of the damage, I would be surprised if all of those things didn't happen.
 
Heinkel
Posts: 421
Joined: Sun Sep 08, 2013 6:15 pm

Re: LATAM A20N ground collision during takeoff run at LIM

Sat Nov 26, 2022 9:01 pm

AirKevin wrote:
kraz911 wrote:
I’ll just guess that if the starboard wing isn’t tweeked or the spars aren’t bent and if the structure around the starboard main gear isn’t too bad, they’ll probably fix it.

Looking at the pictures of the damage, I would be surprised if all of those things didn't happen.


And don't forget the fire damage.

An A320neo is much cheaper than a 777. So it comes much faster to an economical write-off.
 
First300
Posts: 56
Joined: Sun Sep 25, 2022 11:52 am

Re: LATAM A20N ground collision during takeoff run at LIM

Sat Nov 26, 2022 9:37 pm

Heinkel wrote:
AirKevin wrote:
kraz911 wrote:
I’ll just guess that if the starboard wing isn’t tweeked or the spars aren’t bent and if the structure around the starboard main gear isn’t too bad, they’ll probably fix it.

Looking at the pictures of the damage, I would be surprised if all of those things didn't happen.


And don't forget the fire damage.

An A320neo is much cheaper than a 777. So it comes much faster to an economical write-off.


That 777 was more than 20 years old? I doubt that there is so much difference in value.
 
gzm
Posts: 404
Joined: Thu Aug 21, 2014 1:52 pm

Re: LATAM A20N ground collision during takeoff run at LIM

Sun Nov 27, 2022 9:03 am

kraz911 wrote:
I’ll just guess that if the starboard wing isn’t tweaked or the spars aren’t bent and if the structure around the starboard main gear isn’t too bad, they’ll probably fix it. The aircraft’s only saving grace is its age.

Not only its age, there is another factor: Availability of the model. If they have to wait say, two years to receive a replacement, chances are they will repair it. For example, in 1976 TMA (at ATH) and JAL (at ANC) each decided to have a badly damaged B747 repaired instead of having to wait for two years to receive a new aircraft from the factory. The insurance, at least in the TMA incident, had to pay a little less than the total amount the plane was insured.
 
Cubsrule
Posts: 15908
Joined: Sat May 15, 2004 12:13 pm

Re: LATAM A20N ground collision during takeoff run at LIM

Sun Nov 27, 2022 10:35 am

GalaxyFlyer wrote:
889091 wrote:
GalaxyFlyer wrote:

Why? What would it have done here? AEB would create another layer of both benefit and hazard. An impeding collision would have to detected looking only at the active runway surface, not looking that taxiways,p where planes are frequently holding while the departing plane goes by. The hazard, of course, a false positive resulting in a needless high speed abort which isn’t an entirely safe evolution.

BTW, these collisions are pretty rare, the last one was a snow plow in Moscow. This scenario is mostly a sim treat.


For this particular scenario, we are still unsure if the pilots did actually see the fire truck or not. We will find out in due course after the investigation is completed.

Aviation technology normally finds its way into the automotive industry after a few years/decades (cue ABS). For once maybe this technology within the automotive sector will find its way into the aviation sector. This accident occurred during the day, with clear visibility. Perhaps it would have been helpful in the event of SQ006 (dark, moonless rainy night with approaching storm), NW1482 (fog) and the obvious one, PanAm and KLM in Tenerife.

Yes, I appreciate that there are challenges in terms of fine tuning the tech, but most of the legwork has already been done by the auto industry.

Just throwing it out there for discussion.


The risk analysis for in a commercial aviation setting is vastly different than in automotive industry. The AEB false positive rate in ground vehicles would be totally unacceptable in aviation. The margins are much tighter. Look at this case, the AEB would have to see the fire apparatus, calculate its movement and compute the point of impact, notify the crew and apply the stopping devices. We’re never going to take that ultimate authority away from the crew. We do have surface manage to systems that shows all the equipment moving on the surfaces.

I can’t accept AEB in a car due to the possibility of a false positive which has been a non-zero event


Let’s pretend (counterfactually) that there were some sort of AEB system that were sufficiently reliable for air carrier operations and (also counterfactually) that it were economical to certify it.

AEB isn’t designed for, and does not do well in, very unusual crash scenarios. It does not/would not prevent a collision where the precipitating conflict occurs at high speeds. At best it reduces the closing speed of the striking vehicle. Given the mass delta between the aircraft and the fire apparatus, even at a somewhat lower speed the occupants of the fire apparatus would have had a very bad day and as we saw the crash as it happened was survivable for the aircraft occupants. As others have pointed out, Airbus deserves at least some credit for that but the physics of the crash didn’t hurt.
 
pugman211
Posts: 652
Joined: Thu Dec 20, 2012 1:55 pm

Re: LATAM A20N ground collision during takeoff run at LIM

Sun Nov 27, 2022 11:02 am

Another thing to consider, if they were able to emergency brake, that would point the nose down which in turn would of made the wing a bit lower possibly causing a worse overall outcome.

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