Posts by user "remi" [Posts: 13 Total up-votes: 23 Page: 1 of 1]¶

The object that is on a collision course with you is stationary or nearly stationary in your field of vision, if you can see it at all. It may or may not be moving noticeably against the background. The objects that are obviously moving are highly unlikely to be of any concern. It's been demonstrated through decades of experience with midair collisions that see and avoid simply doesn't work. Where avoiding midair collisions depends on see and avoid, midair collisions will happen. Infrequently of course.

Canadian ATC is even more of a "whoa this really is a different country" than a flashing green light.

It will be interesting to see how the balance of fact-finding and fault-finding works out in this new regime. The one thing that people will do with complete reliability is make mistakes.

If you're going to be pedantic ... deionized water is water without ions in it. It's certainly not guaranteed to be free of other things that aren't water, but that also aren't ionized when dissolved in or mixed with water. For example, sugar or ethanol.

Back in the days before RO and cheap purified water, chem labs often had deionization filters attached to their taps. Generally speaking, the impurities in tap water are ionic compounds, so a DI filter can do an excellent job purifying water in some/most cases. DI water is also relatively nonconductive.

There have to be many, many locations where low level urban NVG flight can be practiced/exercised that don't essentially graze the end of an active runway. If nothing else, exercises could be suspended when certain runways are in use. Or conducted after airport curfew. Etc.

See and avoid will always eventually produce midair collisions because physics, geometry, and humans don't permit see and avoid to work flawlessly.

This incident follows the same script as decades of others where ATC verifies that a pilot has the (incorrect) traffic in sight and shortly afterward there is a midair.

But I don't think this is a scenario that suffers from a lack of data. Near misses and incursions are frequent enough that they are well characterized. Nor is it that difficult to project risk from repetitive danger. The risk, in this case, and in many other cases, is known and has been accepted.

I think that anyone who spends a few hours reading the rather large collection of runway incursion and near miss events that have accumulated in the past couple of decades of US aviation will be left with the feeling that we have been not just lucky but incredibly lucky.

The fact that it seems to have become acceptable to erase or overwrite or "forget" to preserve CVR following a near miss or incursion suggests problems deep within regulators and carriers. Fortunately, through completely unrelated activity, 25 hour recorders should mostly resolve this, as long as aircrews don't continue to religiously combine the parking brake and erase buttons. Unfortunately, for now, the only sure means of preserving a CVR is the expiration of the crew and/or loss of the hull.
We've been fortunate and simultaneously unfortunate that 1000+ runway incursions per year and an increasing number of near misses has resulted in zero passenger deaths until now.

Why, though, is depth perception even an issue? Is it hard to distinguish between objects inside and outside the cockpit while wearing NVG? Stereopsis certainly isn't going to tell you whether something is 200m or 2000m distant, it'll be parallax from motion that tells you that, especially at night. I'm just curious what an aviator might be "deceived" by, relating to depth perception.

It does. I've been visiting a friend in Reston for 30 years and one day, quite recently, Metro was just "there."
Avoiding the partisan finger-pointing, I'm going to generally agree here.

We all know there are issues with American ATC. But primarily, they are ordinary problems that don't need radical solutions. The solutions are generally more resources and more rigorous enforcement.

* One of my go-to complaints: Pilots not disciplined for erasing or overwriting CVRs following runway incursions and near misses. No blowback for aircrews refusing to meet with NTSB following incursions/near misses. I mentioned this earlier; hopefully 25 hr recorders will fix the overwrite part of this. Ideally the "erase" button would be removed in all cockpits where it still remains. I understand aircrews wanting to erase their CVRs and avoid meetings with investigators after doing something careless (or straight up idiotic) with a plane full of people, but, folks, how can coming to Jesus *not* be part of the job? We are blessed to live in a country where fatal transportation accidents are not presumed to be criminal (unlike most every other non-Commonwealth nation), and aircrews hardly ever have personal liability for damages. Yes a career might take a hit. That's careers for ya.
* Runway incursions in general: Over 1k per year for many years ... we have systems to manage this but they need to be continually funded, resourced, and improved ... HNL, MDW, LAX need to be sorted out aggressively (LAX is no longer the poster child for incursions, good work there, it's HNL now)
* See-and-avoid: It works as well as it does because of the very high standard of air"person"ship prevalent in the US, but it is absolutely guaranteed that see-and-avoid is insufficient to avoid midair collisions, as it is impossible to see all potential collision aircraft even in broad daylight
* Manufacturer quality: Until MCAS I'd have never thought that US manufacturing processes would (once again) become a significant safety risk, but, here we are, with no indication that the trend has been reversed (it's fair to say that there is some promise that there has been a reversal at the top of Boeing management, but effects haven't appeared at this early date)
* ATC hiring: Pay more, hire more, create alternative career structures that allow qualified "old" people in their 30s to start jobs at ATC while giving them a fair framework for retirement

None of this needs "AI" or "satellites" or "complete rework" or "woodchipper" to fix. It just needs money and constant re-commitment to safety, and commitment to compromising in favor of safety when a decision of "revenue vs safety" arises. Honestly I think it's mostly about money. Perhaps 99% about money. Perhaps 100%.

Perfectly vigilant pilots with perfect eyesight can't prevent all see-and-avoid midairs, as there are midair scenarios (like the ones mentioned) where it is literally impossible for the pilots to see the aircraft on collision course in time to avoid the collision.

The catch here is that we have had roughly two decades of (to my mind) inexplicable fatality-free aviation safety bliss in the US despite significant and slowly rising rates of runway incursions and near misses, and although it's great that everyone except for one Southwest passenger survived all of that, the good fortune has, I think, been mistaken for validation of procedures.