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by jedmeyers 3568 days ago
TCAS Resolution Advisory will give an attentive pilot a good 5 seconds to react in the worst case. How much time does a Tesla 'pilot' have in case of "oh, crap, there is a truck stopped 20 feet in front of you that I failed to detect at highway speed. Now you drive!"?
2 comments
smileysteve 3568 days ago
> TCAS Resolution Advisory will give an attentive pilot a good 5 seconds

> "oh, crap, there is a truck stopped 20 feet in front of you that I failed to detect at highway speed.

To appreciate your differences in measurement. 5 seconds in a plane is something about a mile away. A high performance car can still stop from 60-0 at 110ft; which is about 1 second. In context of time; it takes at least .7 second for the human to respond.

(The car or terrain monitoring autopilot can react in <.1 s; which means if the car sees the obstacle at 110 feet away it can stop in time, while, if a car pulls out in the highway in front of a human it would take closer to 200ft to stop.)

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jedmeyers 3568 days ago
> The car or terrain monitoring autopilot can react in <.1 s; which means if the car sees the obstacle at 110 feet away it can stop in time

What happens if the driver expects the car to react upon seeing the obstacle but it fails to do so? Will the driver have enough of the remaining time to react?

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smileysteve 3567 days ago
Nope. And in the case of terrain following airplane algorithms, it's practically impossible to maintain minimum clearance AND allow for any expectation of pilot override.

The >=.7 second human reaction time (with a planned/known reaction such as brakes or jerking steering wheel) is the very reason why Autopilots are safer.

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throwaway729 3567 days ago
The differences between TCAS and Tesla are even more extreme.

> TCAS Resolution Advisory will give an attentive pilot a good 5 seconds to react in the worst case

5 seconds in order to avoid violating intruder's airspace, not to avoid actually hitting the intruder. AFAIK there's even then some additional buffer zone.

Also, reading the list of actual TCAS advisories sheds additional light of the substantial differences:

https://en.wikipedia.org/wiki/Traffic_collision_avoidance_sy...

Differences from Tesla / cars:

1. Almost all advisories actually tell the pilot what the problem is and what to do, not just that there's a problem. Tesla Autopilot basically has one advisory: "TA".

2. Almost all of the advisories resolve collisions by making one-dimensional maneuvers. Having an extra dimension allows you to substantially simplify the collision avoidance problem.

3. It's a safe bet (although not assumed) that both planes involved in a TCAS event are receiving advisories and cooperating with ground ATC.

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