Anatomy of a Near Midair Collision

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SportPilot
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Re: Anatomy of a Near Midair Collision

Postby SportPilot » Thu May 12, 2016 8:04 pm

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Last edited by SportPilot on Sun May 15, 2016 2:41 am, edited 1 time in total.

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Re: Anatomy of a Near Midair Collision

Postby drseti » Thu May 12, 2016 8:22 pm

That's a distinct possibility.
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
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Re: Anatomy of a Near Midair Collision

Postby dstclair » Thu May 12, 2016 8:28 pm

FastEddieB wrote:In the training, it was emphasized never to maneuver the aircraft solely on the basis of a traffic warning. You touched upon the reason - pressure altitude is only broadcast in hundreds of feet, so its possible that if your aircraft is off by only one "tick" and the other aircraft by one "tick" in the opposite direction, you might both be getting warnings of an aircraft at the same altitude when in fact you might have up to 200' of separation. For a pilot to begin a climb or descent based solely on the traffic warning could actually put aircraft in conflict that would otherwise not have been.

Now some say the limitations are put there by lawyers and it would be foolish to just cruise on without taking some evasive action. I understand that reasoning as well. But waiting for either visual contact or ATC instructions is what we were advised to teach, and I think its the safest option, with anything short of a full TCAS which advises what specific action to take.

Could not agree more with maintaining altitude is the safest option without visual contact or ATC instructions for oncoming traffic. Could not disagree more when it comes to taking lateral action when your traffic system indicates an essentially head-on mid-air collision. Let's play this out in the 6 potential scenarios with Pilot A being the oncoming traffic and Pilot B being the one with his handy ADS-B systems. Both pilots understand the FARs, specifically FAR 91.113:
e) Approaching head-on. When aircraft are approaching each other head-on, or nearly so, each pilot of each aircraft shall alter course to the right.


Pilot B's ADS-B gizmo indicates A is approaching from the opposite direction at the same altitude:

* A sees B, B sees A - both bank right and life is good
* A sees B, B doesn't see A but trusts ADS-B - both bank right and life is good
* A sees B, B doesn't see A and ignores ADS-B - A banks rights, B continues straight and life is good
* A doesn't see B, B sees A - A continues straight, B banks right and life is good
* A doesn't see B, B doesn't see A but trusts ADS-B - A continues straight, B banks right and life is good
* A doesn't see B, B doesn't see A and ignores ADS-B - A and B continue straight and life is not good

Note that the least safe option is to ignore your ADS-B information.
Last edited by dstclair on Fri May 13, 2016 7:50 am, edited 1 time in total.
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Re: Anatomy of a Near Midair Collision

Postby FastEddieB » Thu May 12, 2016 9:02 pm

Dave,

Very well thought out scenarios.

Like I said, Cirrus actually puts it in "Limitations", so its hard to teach actions in violation of that.

Right now I have no traffic, and don't miss it at all. If and when I do have it in the cockpit in the future, I guess I'll have to weigh my options.
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Re: Anatomy of a Near Midair Collision

Postby SportPilot » Thu May 12, 2016 10:39 pm

.......
Last edited by SportPilot on Sun May 15, 2016 2:40 am, edited 1 time in total.

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Re: Anatomy of a Near Midair Collision

Postby SportPilot » Fri May 13, 2016 12:13 am

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Last edited by SportPilot on Sun May 15, 2016 2:39 am, edited 1 time in total.

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Re: Anatomy of a Near Midair Collision

Postby designrs » Fri May 13, 2016 7:45 am

SportPilot wrote:You might miss it more than you know.


+ 1,000

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Re: Anatomy of a Near Midair Collision

Postby designrs » Fri May 13, 2016 8:20 am

>> never to maneuver the aircraft solely on the basis of a traffic warning
Pure legal liability disclaimer.

OVER RELIANCE ON VFR ATC - FALSE SENSE OF SECURITY
In many cases ATC has ZERO obligation for VFR traffic seperation. See-And-Avoid is the regulatory law. While well intended, flight following is severely lacking. It's a false sense of security. I flew with ADS-B and flight following exactly once. There was so much close proximity traffic that was not called out. Sure they called out one or two, but what about the other six??

"CAN'T SEE - CAN'T AVOID"
Even knowing exactly where to look, many times you can't see the threat (glare, haze, obstructions, traffic behind the aircraft, pitch, bank etc.) Get ADS-B In/Out and realize that you will never see 75% of close proximity traffic with your eyeballs.

GPS ALTITUDE vs. PRESSURE ALTITUDE
If you compare your GPS altitude to your altimeter you get a sense of the margin of error on a given day. So yes, 200 feet may not provide adequate seperation. 700+ feet usually does, unless the GPS to Altimiter difference is huge.

LATERAL SEPERATION
Lateral position is accurate for seperation, although altitude seperation can usually be achieved quicker.

THE ADS-B SCAN
Not a substitute for looking outside the aircraft, ADS-B simply becomes part of the scan. Scanning allows for early preemptive traffic avoidance, instead of waiting for the alert.

ADS-B IN CONTROLLED AIRSPACE
ADS-B In/Out will usually alert you of traffic conflict before ATC calls it out... IF they even call it.

EXAMPLE:
Just yesterday I was departing a Class-D airport through a one-mile wide VFR corridor. Just exited the Class-D. ADS-B shows traffic three miles, head-on, +200 feet and descending. I'm climbing so I'm going up while he's going down. I also turned right to provide lateral seperation. Banked and looked over my shoulder, knowing exactly where to look... NEVER SAW HIM!

EXAMPLE 2:
ADS-B shows distant traffic seven miles away. Small modifications to course provide increased seperation and safety.

My Personal Opinions:
1) See-And-Avoid is inadequate 75% of the time except in the pattern.
2) Outside of highly monitored controlled airspace, flight following and ATC VFR seperation is severely lacking, no matter how well intended.
3) Within controlled airspace, ADS-B In/Out will alert you of many close proximity aircraft way before ATC
4) ADS-B In/Out rules! I will not fly without it.
- Richard

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Re: Anatomy of a Near Midair Collision

Postby drseti » Fri May 13, 2016 8:37 am

Just remember that ADS-B only detects transponder-equipped targets. That flock of seagulls Skiles and Sullenberger hit may have been squawking, but they weren't squawking Mode C!
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
Prof H Paul Shuch
PhD CFII DPE LSRM-A/GL/WS/PPC iRMT
AvSport LLC, KLHV
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AvSport.org
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Re: Anatomy of a Near Midair Collision

Postby MrMorden » Fri May 13, 2016 10:00 am

drseti wrote:Just remember that ADS-B only detects transponder-equipped targets. That flock of seagulls Skiles and Sullenberger hit may have been squawking, but they weren't squawking Mode C!


Neither is that hand-propped Cub.

I think for traffic alerts, as stated, you should try to make visual contact. But if the alert shows same altitude and close and decreasing distance to your aircraft and visual contact is still not made, some evasion might be smart. I'd probably opt for a climbing right turn, since I'm in a high wing. In a low wing I'd probably make it a descending right turn.
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Re: Anatomy of a Near Midair Collision

Postby Merlinspop » Fri May 13, 2016 10:17 am

MrMorden wrote:
drseti wrote:Just remember that ADS-B only detects transponder-equipped targets. That flock of seagulls Skiles and Sullenberger hit may have been squawking, but they weren't squawking Mode C!


Neither is that hand-propped Cub.

I think for traffic alerts, as stated, you should try to make visual contact. But if the alert shows same altitude and close and decreasing distance to your aircraft and visual contact is still not made, some evasion might be smart. I'd probably opt for a climbing right turn, since I'm in a high wing. In a low wing I'd probably make it a descending right turn.

Wouldn't you want to climb/descend into airspace you can visually check first? If the high wing blocks your view of the sky above and to your right (and visa versa with a low wing), you might be climbing into exactly the wrong place. Just a thought.
- Bruce

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Re: Anatomy of a Near Midair Collision

Postby dstclair » Fri May 13, 2016 10:18 am

MrMorden wrote:
drseti wrote:Just remember that ADS-B only detects transponder-equipped targets. That flock of seagulls Skiles and Sullenberger hit may have been squawking, but they weren't squawking Mode C!


Neither is that hand-propped Cub.

Not entirely correct. TIS-B shows primary radar for targets where secondary radar (transponder or UAT based) is either missing or was lost. Of course, primary radar is not available in all areas.
dave


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