WAAS + Autopilot = higher risk of midairs?

[TangoWhiskey]

Probably not, when flying direct. But what if you're flying airways, at cardinal altitudes, with GPS WAAS guidance and autopilot holding course and altitude (or climbing/descending)?

Seems to me there would be an increased risk of somebody going right through the middle of your cockpit. Faster aircraft overtaking you from behind, same exact altitude and course; another aircraft climbing or descending on the same course as you, autopilot holding them on the same centerline as you.

I guess the G1000 + GFC700 combo got me thinking about this. Seriously thinking that using the "parallel track" option would help alleviate some of the risk--be a little left or right of dead center.

Then again... we're not hearing of mid-airs attributed to this, so maybe its not the issue I'm imagining it might be.

 

[sba55]

I don't think it's an issue if you're with ATC, which, IMO, you should always be if you're on the airways. The 430W has the parallel track option, too, but I don't really see the point. I want the autopilot to make flying more precise, not less, and relying on the parallel track function to help avoid mid-airs seems dangerous.

That aside, WAAS doesn't have that much to do with this. WAAS corrects errors in the GPS signal. Without WAAS, chances are that the person flying right behind me on the airway is getting the same GPS errors, thus he'll be at the same position anyway.

-Felix

 

[Skip Miller]

Seems to me there would be an increased risk of somebody going right through the middle of your cockpit.

Long ago, different technology. In the marine world, the USCG used to have lightships anchored in strategic locations to assist ships to get a positive fix and thereby avoid the reef/rock/obstruction du jour. In addition to the light, the ships broadcast a radio signal. More than one lightship was sunk by a large merchant vessel homing in on its RDF signal in thick fog.

The solution was to have a low power broadcast on the same frequency with a distinctive warble tone, warning the ship that they were very close.

I think that if the question you raise becomes a real problem, that some TCAS-related system would be developed to warn the pilots.

-Skip

 

[poadeleted20]

I saw this thread title and I thought you were talking about how folks with GPS and a/p tend to stare at the TV and not look outside -- now that's where I see the increased risk of midairs!

 

[TangoWhiskey]

I saw this thread title and I thought you were talking about how folks with GPS and a/p tend to stare at the TV and not look outside -- now that's where I see the increased risk of midairs!

I'd agree with that... hopefully, one uses the a/p so one's eyes CAN spend more time outside.

How do you see the fast airplane closing on you from behind? I guess that's where true TCAS comes in, or flight following...

 

[TMetzinger]

Similar problems existed with airways before GPS, when you had autpilots tracking radials with high precision.

 

[gprellwitz]

I'd agree with that... hopefully, one uses the a/p so one's eyes CAN spend more time outside.

How do you see the fast airplane closing on you from behind? I guess that's where true TCAS comes in, or flight following...

That's where you have to rely on the faster ship behind you to be looking straight ahead out their windshield!

 

[poadeleted20]

Strategic Lateral Offset Procedure, or SLOP.

That's a good tactic in the North Atlantic Tracks, but it won't go over well the current National Airspace System.

 

[Dick Madding]

GPS and Midairs

-snip-

Then again... we're not hearing of mid-airs attributed to this, so maybe its not the issue I'm imagining it might be.[/quote]

How soon we forget- Brazil: Gol Airlines' B-737-800 and an Excelaire Legacy 600 over the Amazon jungle last September [2006]
http://www.flttechonline.com/Curren...sion Prompts NTSB Recommendations on TCAS.htm

Germany midair crash kills 70, July 2, 2002 The Boeing 757 cargo plane started to dive when its on-board warning system instructed the pilot to drop altitude to avoid a crash. If the Boeing had maintained its course, “there certainly would not have been a crash”.

Dick says: ATC got most of the blame for this one, and the father of one of the Russian children killed tracked down and murdered the ATC controller blamed, if I remember correctly.

Thursday Sept. 4, 1997: A U.S. Air Force C-141 cargo plane and a German TU-154 collide in mid-air over Namibia killing 33.

In my opinion, the greater track accuracy does take away more of the uncertainty which some call "The Big Sky Theory". Airspace regulations have nearly eliminated it anyway. The hazard exists when there is a lapse in ATC as in the above first two instances. But I feel the biggest threat is the IFR vs. uncontrolled VFR aircraft where one or both is climbing or descending. TCAS catches most of these, but there's always that chance that the VFR vehicle doesn't have a transponder . . .

Then there's the UAV situation. Those aircraft of various sizes and speeds are flying in unrestricted airspace now. Did one already make it's mark?
October 23, 2002:
http://www.wsfa.com/Global/story.asp?S=1888925&nav=0RdENLrd

ADS-B is coming, and along with it Big Brother and the end of aviation freedom as we have known it. It should be safer, but certainly not as much fun.

 

[AdamZ]

I saw this thread title and I thought you were talking about how folks with GPS and a/p tend to stare at the TV and not look outside -- now that's where I see the increased risk of midairs!

Ed Zachary