Now you are getting into my professional field. Let me offer a few comments.

The problem in Austria appears to be with a loss of transponder info in the ground station. There are a number of possible causes of this, both in the ground stations and in the transmission of the transponder info, but it should be remembered that there are other ways of separating traffic that remain effective:

1. "Block airspace" reserves a volume of airspace for each plane, based on its departure time and assumed speed and directions. Flight plans are not allowed that would result in blocks overlapping. These blocks would be updated over the span of a flight, based on radar data or information transmitted from the aircraft, such as when an aircraft descends and starts a landing approach for example.

2. TCAS, as an earlier poster noted, uses transponder info transmitted from each aircraft to detect upcoming collisions, and calculate avoidance maneuvers and alert the aircrew as required. No involvement from any ground station is required.

All this explains why the Austrian official said no aircraft were ever at risk.

About air to air radar, getting useful information from this requires very large and powerful (and therefore expensive) radars, and well trained aircrew. The required radar power actually becomes a health hazard to those outside the aircraft, leading to detailed operating procedures at military airports to prevent frying your ground crew. Imagine an airliner approaching the gate, having forgot to switch off the air to air mode! TCAS provides the same level of protection, with very little extra gear or extra training and without the health hazards.

Chris, your example of large ships in the Channel requires much less radar energy and sophistication for three main reasons. The targets are really big, they move slowly, and the problem is 2D (all the ships remain on the surface of the Channel). Detecting the other target at 2 miles range gives you lots of time to react. Two airliners in a head on approach at cruising speed would collide less than one minute after detecting each other at a 2 mile range. In that few seconds you have to determine if the 3D flight paths will cross (much number crunching, requiring multiple sets of data on relative locations and how they are changing over time), and then select and implement a corrective action (again, more number crunching, plus human reaction time). As a result, radars on commercial aircraft are useful for seeing weather, and maybe for ground mapping for navigation, but are not designed to be useful in detecting airborne targets.

Obviously, there are still possible flaws and mistakes we need to worry about, but a few minutes drop out in a European ground station doesn't worry me too much. Here is some of what does worry me when flying on airlines (nervous fliers may skip over this bit.)

TCAS relies on each aircraft having a functioning transponder. Over Europe and North America and some other parts of the world this does not worry me at all. Enforcement is very strict. Where it does worry me is over other parts of the world, where enforcement may be lax and equipment may be older and less well maintained, or near conflict zones, where high performance aircraft may be operating without transponders, or with misleading transponders, for tactical reasons. I will not be flying near the Ukraine/Russia border in the near future.

The various versions of block airspace require aircrews and ground staff to follow procedures. Again, this is very likely over some places like Europe and North America, and less likely in other places. I am very careful flying in some parts of the world, and will only fly on reliable airlines in these regions.

I believe that your times are a bit wrong. At 2 miles distance, the airplanes will collide in about 6 seconds. This assumes a flight speed for each aircraft of 600MpH, so head on that would be 1200 MpH. This is 20 miles per minute or 3 seconds per mile. That is clearly not enough time to do anything. 20 miles gives you a minute to do something to miss the other aircraft. TCAS is designed to tell the two aircraft to both do things that will help avoid the collision. BTW, if your TCAS tells you to do one thing, and ATC is telling you something else, you are supposed to believe TCAS. There was a collision over, I believe, Switzerland that was caused when one aircraft believed TCAS, and the other believed ATC.

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BOINC WIKI

John is right. That is what I get for doing math in my head. The point still remains: in order for air to air radar to be useful, very high radar powers are needed, in order detect small targets at useful ranges. That results in high weight, high cost, and health hazards.

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Para-glider crash in Illinois.

Irrelevant grammar rant: "Rescue workers spent hours trying to reach the aircraft, which was lodged against a log 500 feet from each shore of the river in waist-high, fast-moving water 50 yards south of the damn, Marseilles Fire Chief Mick Garrison told WGN-TV."

(Okay, they did get it right at least two other times.)

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David
Sitting on my butt while others boldly go,
Waiting for a message from a small furry creature from Alpha Centauri.

Thanks Bill for an interesting post.

However, that's okay as long as your instruments are working & calibrated correctly...

Plane diverted due to faulty fuel gauge

Edit: -

As for your remarks about certain parts of the world, maybe this will cheer you up :-)

Plane lands at wrong airport

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Both are very regular events. You don't have to go to the third world to find planes landing at the wrong airport. The important message in both those stories is that nobody and nothing was hurt. They erred, but on the side of safety.

Maybe we need a thread about "transportation inconvenience". I could tell you so many stories....

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Heh. "Transportation inconvenience."

Last week, Amtrak 7 The Empire Builder left Chicago with 3 private cars right behind the engines, and 2 BNSF business cars and 4 Amtrak business cars at the end. The purpose for all the business cars was for BNSF and Amtrak executives to work out just why the train is so late every day and what they can do about it.

However, it left Chicago 4 hours late. Why? Because the previous day's #8 arrived 17 hours late and they couldn't service the train that fast.

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David
Sitting on my butt while others boldly go,
Waiting for a message from a small furry creature from Alpha Centauri.

Lorry driver from Bridgend - You canna be Sirius

Lovely photo's though :-)

What's the best joke about women drivers?

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oops...

Sorry folks, got out of bed on the wrong side this morning

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Barcelona near miss

Glad the pilot of the aircraft that was landing could go around...

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BOINC WIKI

Looks like it's going to be a week of...

Oops

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Looks like it's going to be a week of...

Oops

I admit I'm not an expert on that kind of design engineering, but it seems to me it might be better to have a rail on the ceiling instead of a wire like outside.

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David
Sitting on my butt while others boldly go,
Waiting for a message from a small furry creature from Alpha Centauri.

The reason for overhead wire supply is that it gives better contact at high speed with less wear on the collection equipment. It also allows a higher voltage (25kV is used) against a maximum of about 2kv with a "live rail" system and given that the trains running through the tunnel draw between 6 and 12 MW from the supply on the way up which is about 500A at 25kV, or about 6,000A at 2000V...

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Bob Smith
Member of Seti PIPPS (Pluto is a Planet Protest Society)
Somewhere in the (un)known Universe?

With the length of the tunnel, I'm surprised they went with cable in the first place. What would have made more sense was rails a la London Underground.

At least with power rails & shoes underneath the carriages, the train wouldn't have been stuck for several hours entangled in cable.

I've never took note of how many pantographs on a train, but with four shoes per carriage, it would not make any difference should a carriage or two fail, however with pantographs, wondering how many have to fail before the train loses all power...

Edit: - Rob posted before I could finish my post.

But wouldn't it be much safer & more profitable to use rails?

Edit 2: -

This wasn't the first issue the Eurotunnel has had with overhead cabling. At least with rails the prospect of fire is greatly reduced.

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The reason for overhead wire supply is that it gives better contact at high speed with less wear on the collection equipment. It also allows a higher voltage (25kV is used) against a maximum of about 2kv with a "live rail" system and given that the trains running through the tunnel draw between 6 and 12 MW from the supply on the way up which is about 500A at 25kV, or about 6,000A at 2000V...

I understand the reason for using a wire in general. I'm just saying that within the tunnel, a rigid rail might work better than a flexible wire. It would be less likely to have this exact problem.

[edit]
But I suppose if it was a good idea, someone would have thought of it already.

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David
Sitting on my butt while others boldly go,
Waiting for a message from a small furry creature from Alpha Centauri.

Couldn't think where else to post this, so put it here as a bit of light relief...

Lucky bugger

...well it is about the Eurotunnel :-)

Edit: -

Can't wait for Jaguar to release the video.

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The reason for overhead wire supply is that it gives better contact at high speed with less wear on the collection equipment. It also allows a higher voltage (25kV is used) against a maximum of about 2kv with a "live rail" system and given that the trains running through the tunnel draw between 6 and 12 MW from the supply on the way up which is about 500A at 25kV, or about 6,000A at 2000V...

I understand the reason for using a wire in general. I'm just saying that within the tunnel, a rigid rail might work better than a flexible wire. It would be less likely to have this exact problem.

[edit]
But I suppose if it was a good idea, someone would have thought of it already.

A copper rail would be extremely heavy and costly, so catenary is preferred, copper last I looked is right up there in weight, near gold, lead and uranium.

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The T1 Trust, PRR T1 Class 4-4-4-4 #5550, 1 of America's First HST's

Why a copper rail?

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Why a copper rail?

Copper conducts electricity well, aluminum does too for a bit, but gets a white oxidizing layer and iron/steel conducts poorly, hence only 2kv on rails.

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The T1 Trust, PRR T1 Class 4-4-4-4 #5550, 1 of America's First HST's

True but as you stated, copper is expensive, now take into account the length of the tunnel.

That's one hell of lot of copper.

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