Close encounter

lol i have had closer, but yea, they should.

Oh, yeah, I've had closer. I had a Dash-8 pass me so close I think our wings must have crossed while we were both on short final.

Did you have flight following? Did they warn you?

Ed

OK ladies and genrlemen, it's time for your quiz. These questions apply to the US-regulations may vary in other countries.

In the screen shot depicted in the original post,

1. Who is responsible for keeping these aircraft safely separated?
2. Assuming that they are flying legally, how much minimum physical
separation do regulations require?
3. These aircraft do not appear from the screen shot to be close
enough to pose a danger to each other on their current courses. In
a situation where the faster aricraft is descending and overtaking
the smaller aircraft, which aircraft has the right-of-way?

Interesting

1. Who is responsible for keeping these aircraft safely separated?

It depends. If IFR, separation is the responsibility of ATC. If VFR, separation is the responsibility of the pilot. Even here there are exceptions, B airspace comes to mind, collision warnings and of course ATC has to issue traffic advisories to IFR flights about VFR traffic nearby.

2. Assuming that they are flying legally, how much minimum physical
separation do regulations require?

Unless I don't remember it correctly (quite possible) 1000 ft vertical or 3 nm lateral separation.

3. These aircraft do not appear from the screen shot to be close
enough to pose a danger to each other on their current courses. In
a situation where the faster aricraft is descending and overtaking
the smaller aircraft, which aircraft has the right-of-way?

And this is the winner. ATC put faster before slower, but if this is a VFR situation, I don't know. Probably the same.

Don Wood wrote:

OK ladies and genrlemen, it's time for your quiz. These questions apply to the US-regulations may vary in other countries.

In the screen shot depicted in the original post,

1. Who is responsible for keeping these aircraft safely separated?

The Pilot of each aircraft.

2. Assuming that they are flying legally, how much minimum physical
separation do regulations require?

No minimum other than maintaining visual separation including allowing for wake turbulence.

3. These aircraft do not appear from the screen shot to be close
enough to pose a danger to each other on their current courses. In
a situation where the faster aricraft is descending and overtaking
the smaller aircraft, which aircraft has the right-of-way?

The aircraft being overtaken has right of way.

1. The pilot of each aircraft.

2. No minimum other than maintaining visual separation including allowing for wake turbulence.

3. The aircraft being overtaken has right of way.

And the Answers are:

1. The pilots. Even if they are both on IFR flight plans, in visual conditons, the pilots have the responsibility to "see and avoid" other traffic.
2. It is difficult to tell their altitude from the screen shot so there may be two different answers. If they are above 3,000 feet AGL, then they are obligated to maintain IFR or VFR altitude requirements. Thus, the minimum separation they might legally have is 500 feet. (IFR at thousand foot steps (4,000-5,000,6,000 etc); VFR at thousand foot plus 500 foot steps (3,500-4,500-5,500 etc)). If they are below 3000 feet AGL, the only minimum separation if both are VFR is "see and avoid".
3. The two posters who said the aircraft being overtaken has the right-of-way were correct. Faster or slower are not factors.

The reason I posted this quiz based on the photo in the original post is that these are exactly the factors that led to the 1978 collision between a PSA inbound B-727 and a C-172 flying a VFR practice IFR approach to Lindberg-San Diego that resulted in massive loss of life, total destruction of both aircraft, and tremendous damage on the ground.

The Cessna was straight and level being vectored by ATC for a practice ILS approach at Lindberg. PSA was inbound from the north with the field in sight on an IFR flight plan but had been cleared for a visual approach. Both PSA and the Cessna had been advised by ATC of the traffic. PSA acknowledged and advised ATC they had the Cessna in sight. PSA was behind and above the Cessna which had no capability to see the 727. Despite having acknowledged the traffic was in sight, PSA overan the Cessna, mortalling wounding both aircraft.

The resulting accident probable cause report laid the blame on the PSA aircrew for failure to maintain visual contact with the traffic and for failing to avoid the Cessna, which had the right-of-way. A contributing factor was ATC's failure to provide additional information but the report specifically stated that, once the PSA aircrew had called the traffic in sight, ATC no longer had any responsibility for maintaining separation. It was pointed out that ATC radar did not have the capability to determine whether or not close traffic posed an imminent hazard to each other. It could only determine they were close and in VFR conditions, it was up to the pilots to maintain separation.

I still disagree with part of the answer, I'll have to look it up I suppose. When under radar control (assigned a squawk code, radar identified and accepting vectors from a center or approach or even tower) it is the responsibility of the ATC to provide separation. VFR flights (or visual approaches, that are for all practical purposes VFR), maintain own separation. Ultimately, in a crisis, TCAS overrides ATC, but nothing else.

Bindolaf: If both flights are under IFR control, ATC has a resposibility for separation, however, in VFR conditions it does not override the pilot's responsibility to "see and avoid". Pilots also have the responsibility to refuse an ATC clearance or instruction if they are aware it puts the safety of flight at risk.

In the case stated, both aircraft are in VFR conditions and there is no information to suggest either or both are in contact with ATC or being painted by ATC radar. There are still many light aircraft that do not have radar transponders and ATC radar may or may not see them depending on their size and location from the radar transmitter. It remains the pilot's responsibility to "see and avoid".

The point of this entire set of messages, in my opinion, was to emphasize that pilots and not ATC are primarily responsible for the safety of their aircraft. ATC is simply one tool they have available to help meet that responsibility.

Very true, Don.