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Blown away by ATC mistake.

Pro Member Captain
Steve (SpiderWings) Captain

Here's something that happened on the very last of 16 legs of my crossing the USA in a Piper J3 Cub. Since I was recreating the 1911 adventure by Calbraith Rogers and trying to feel what it must have been like back then, I wasn't using instruments or maps and I wasn't talking to ATC.

So that explains why I wasn't warned about this 737 coming up behind me. But how about him? I was surprised that he came so close (1/10 mile).

If I've not requested Flight Following, then does that mean I don't show up on the ATC radars?

Just curious. Any insights?

.... oh... after he passed by, the Cub which I had flying nice and straight and level, took a nose dive for the ground and I had a few tense moments before getting it settled down again. My mind is blank... trying to think of the word describing the air behind a passing jetliner. Is that effect broad enough to reach 1/10th of a mile?

Pro Member Chief Captain
Jonathan (99jolegg) Chief Captain

If you don't have a VFR flight following (US) or a Flight Information / Advisory Service (UK) then you will still appear on their radars, because waves are bouncing off your aircraft and are being picked up, just the same as any other aircraft. However, you won't receive any traffic advisories, but other aircraft who are in contact with ATC, will receive warnings like of you "N704FR traffic is at 2 o'clock, at 2000ft, type unknown, report in sight", providing the transponder has Mode C.

Wake turbulence is more of a problem on approach, when flaps are deployed and the aircraft's frame is "dirty" i.e. a lot of induced drag is created. This slow speed and drag causes powerful vortices like horizontal, usually invisible tornadoes. On a 737, they can last up to 3nm behind them. However, fly within 2 metres of a 737 in the sim, and you won't notice a thing - its not replicated in FS9, and I doubt it is in FSX either.

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Bindolaf Captain

When flying VFR, separation is *entirely* the responsibility of the pilot. Of course, I'm sure you had stayed clear of Bravo airspace and kept VFR altitudes? Wink

When an IFR flight approaches a VFR, the controller will notify the IFR of traffic, but probably have no contact with the VFR (unless on approach inside the "B"). So be careful Razz

Don Wood Guest

In real life, that J-3 may or may not have shown up on radar. It appears from the screen picture that it was fairly low and in an area of hilly terrain. The combination of that and the fact that the J-3 is fabric covered makes it a very poor radar target unless equipped with a transponder. ATC radar may or may not be able to get a skin paint on it in those conditions.

I would also guess from the picture the J-3 pilot is violating rules of flight. For the jet liner to be that low indicates it is probably in the landing or take off mode and fairly close to the airport it arrived or departed from. If so, it is very likely controlled airsapce and the J-3 pilot is in violation being there without being in contact with ATC.

Are you sure that's a 737? From the engine nacelles, it looks more like a 757 or 767 to me and wake turbulence would be even more an issue because both those aircraft are much heavier than a 737.

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Steve (SpiderWings) Captain

99jolegg wrote:

...
Wake turbulence is more of a problem on approach, when flaps are deployed and the aircraft's frame is "dirty" i.e. a lot of induced drag is created. This slow speed and drag causes powerful vortices like horizontal, usually invisible tornadoes....

The J3 Cub is slow at its best. Also very light so I wonder if there was some wake turbulence effect or if it was just the software burping.

Bindolaf wrote:

When flying VFR, separation is *entirely* the responsibility of the pilot. Of course, I'm sure you had stayed clear of Bravo airspace and kept VFR altitudes? Wink

When an IFR flight approaches a VFR, the controller will notify the IFR of traffic, but probably have no contact with the VFR (unless on approach inside the "B"). So be careful Razz

You got me thinking... I need to learn more about airspace and things such as VFR altitudes. I just went into the sim and with my log was able to recreate the aircraft position. I was at N34* 29' W117* 38' at or near 10,000 feet which is 60 miles out of LAX. The sim map didn't show any restricted airspace for the area but I do see that I was close to an airway into LAX. The jetliner was probably only 5 minutes out... in the cub I was over an hour out... but he was probably descending for a landing.

Don Wood wrote:

In real life, that J-3 may or may not have shown up on radar. It appears from the screen picture that it was fairly low and in an area of hilly terrain. The combination of that and the fact that the J-3 is fabric covered makes it a very poor radar target unless equipped with a transponder. ATC radar may or may not be able to get a skin paint on it in those conditions.

I would also guess from the picture the J-3 pilot is violating rules of flight. For the jet liner to be that low indicates it is probably in the landing or take off mode and fairly close to the airport it arrived or departed from. If so, it is very likely controlled airsapce and the J-3 pilot is in violation being there without being in contact with ATC.

Are you sure that's a 737? From the engine nacelles, it looks more like a 757 or 767 to me and wake turbulence would be even more an issue because both those aircraft are much heavier than a 737.

Good point about the fabric and the J3 not showing up on radar. However I was up around 10,000 feet. Those "hills" in the screenshot are the San Gabriel Mtns with peaks in the 6,000 foot range - although a bit lower on the east end where the shot is.

I might well have been in violation of VFR altitude and yes for not being in ATC contact. Trying to recreate 1911 flight where such things didn't exist balanced with the current rules was something I battled over in my mindset for the flight. I did however contact ATC as I got closer to LAX.

It may be a 757 or 767 but the note in my log reads 737 so I'm thinking thats what I saw in the identifing tag. However, I may well need a new pair of glasses... it could have been a 757 and I just saw 737 confusing the 5 for a 3.

Anyway, thanks all for your comments and giving me some good things to think about.

Pro Member Chief Captain
Jonathan (99jolegg) Chief Captain

Heres something I wrote for someone else about VFR / IFR altitude selection:

--------------------------------------------------------------------------------------------------------------------

Below FL245 - Quadrantal Rule:

The Quadrantal Rules stipulates that when flying IFR above the transition altitude (outside of controlled airspace) the PIC must select a Flight Level for cruising based on the quadrantal rule.

Excuse my crude demonstration courtesy of MS Paint:

A = An odd flight level between 000 - 089 degrees
B = An odd flight level + 500ft between 090 - 179 degrees
C = Even flight level between 180 - 269 degrees
D = Even flight level + 500ft between 270 - 359 degrees

For example, if you are flying below FL245 and above FL30 in a direction of 156 degrees, then you must fly at an Odd flight level (FL130) + 500ft i.e. fly at an altitude of FL135 or FL155 etc.

Above FL245 - Semi-Circular Rule:

This is slightly more simple. Above FL245, in an Easterly direction, i.e. flying in a direction of 000 to 179 (A and B in the diagram), then you fly at an odd Flight Level, i.e. FL250, FL270, FL290, FL310, FL330, FL350, FL370, FL390 and FL410. After that, you fly at 4000ft above.

In a Westerly direction, i.e. between 180 and 359 degrees (C and D in the diagram), then you fly at even Flight Levels, i.e. FL260, FL280, FL300, FL320, FL340, FL360, FL380, FL400, FL430 (yes, its the exception for some reason) and then 4000ft higher than that if you want to fly higher.

Remember, all of the above is for uncontrolled airspace. If you are in controlled airspace, the Flight Level for cruise is dictated by your flight plan, pertaining restrictions and ATC.

--------------------------------------------------------------------------------------------------------------------

And I'm 99% sure thats a 737, it simply doesn't look like any other aircraft to me.

Also, I find this link quite good for going through the details of airspace, if you're interested:

Arrow http://www.aopa.org/asf/publications/sa02.pdf

Wink

Pro Member Captain
Steve (SpiderWings) Captain

99jolegg wrote:

Heres something I wrote for someone else about VFR / IFR altitude selection:....

..... Arrow http://www.aopa.org/asf/publications/sa02.pdf

Wink

Many thanks 99jolegg! I did know something about odd and even altitudes but really didn't know the details. I've copied your post to my folder for things to study/learn about flying.

I clicked the link before remembering what it is I don't like about pdf files Cool
On my system they don't let me do anything else while the file downloads... so I went a fixed a sandwich... and then it only lets me see the top page and locks up sometimes while scrolling around that.

Anyway, I will go to www.aopa.org and see what I can find none pdf. What I saw looked pretty helpful and interesting before I locked it up. Thanks again for the help.

Pro Member Chief Captain
Jonathan (99jolegg) Chief Captain

Download this, I've put it in a word document:

The link will cease working in 7 days Wink

Don Wood Guest

SpiderWings: The information for altitude usage in the post above may be correct in the UK. It is not correct for the USA. Altitude assignments in the US have nothing to do with quadrants. They depend only on the magnetic direction of flight and the type (IFR vs VFR) of flight.

Above 3,000 feet AGL, VFR flights and IFR on-top flights on a magnetic course of 0 to 189 degrees are required to maintain odd thousands of feet plus 500 when in level flight. Flights from 180 to 359 degrees maintain even thousands of feet plus 500 (i.e., 4,500, 6,500, etc). For IFR flights outside controlled airspace, the rules are the same except that you do not add the 500 feet. For generally westbound flights, flight altitudes assigned would be even 1,000's (i.e., 6,000, 8,000, etc).

In the PCA, (in the US, above 18,000 feet), there are other rules but all flights in this airspace must be IFR so flight levels are always assigned by ATC as they are in lower controlled airspace.

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Solotwo Chief Captain

The title of this thread just makes me laugh.

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Steve (SpiderWings) Captain

Thanks Don.

So its like the semi circle that 99jolegg showed for FL245 and above except for VFR between 3,000 and 18,000.

I got some practice wht FL's flying from Honolulu to Denver yesterday and this would explain why I some some aircraft flying somewhat perpendicular to my heading at what I thought were incorrect levels.

Learning bit by bit here. Thanks all. I may never run out of questions though.

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Jonathan (99jolegg) Chief Captain

From what Don says, then yes it is, except, you add 500ft to the thousands of feet to get your cruising altitude.

Sorry for the misleading information - I was under the impression that, that was something the unified between the US and UK.

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Manuel Agustin Clausse (Agus0404) Chief Captain

That varies for country to country. In Portugal is different than the US system and the UK system. But it is somewhat similar.

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Jonathan (99jolegg) Chief Captain

Agus0404 wrote:

That varies for country to country. In Portugal is different than the US system and the UK system. But it is somewhat similar.

Interesting. I'd have thought with the JAA, it'd be the same in Europe.

Pro Member Chief Captain
Manuel Agustin Clausse (Agus0404) Chief Captain

It would have to be the same, but some countries have their own. The same happens with the Transition Altitude. Countries in Europe have different Transition Altitudes.

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Bindolaf Captain

Don Wood is right - I'd never heard of the quadrants.

Check this out: http://en.wikipedia.org/wiki/RVSM

Not all countries are RVSM, but I think most of Europe is.

Don Wood Guest

Just to clarify, you add the 500 feet if you are a VFR flight or if you IFR on-top (not available in all countries). You do not add the 500 feet if you are on an IFR flight.

To avoid another question, in the US, IFR on-top is an IFR flight plan that allows you to climb through an overcast and once you are above the clouds, allows you to fly with the freedom of a VFR flight. The pilot must be IFR rated and the aircraft must meet the minimum equipment requirements for IFR flight but, once above the clouds, you do not have to follow IFR flight rules.

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