An interesting situation

Aztec Driver

Aztec Driver

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Bryon
I did a multiple leg charter today. On the one leg around Philadelphia, while on VFR flight following, I had an airliner get annoyed with me. The controller told me to fly 120 and descend to 2500, before turning south on course, which I did. As I reached 2500 and started to turn on course, the controller reconfirms that I am free to turn on course. As I round out from my turn, above and to the right, 2-3 miles away is a 777 heading east and crossing my path, at what looked like 300-500 feet above. He stayed ahead of me, I constantly had him in sight, and there was no danger, however, it must have set off his TCAS, because, as the controller called out traffic to the airliner, the pilot radioed back that he has it on TCAS and has to climb immediately. I was still at 2500. The pilot then radios back that "that guy was only 300 feet below me, what is he doing that close to me?"

The controller replied that "he is flying around VFR." He then verified my altitude at 2500.

I am wondering if the controller was expecting me to continue my descent, or if, possibly, my transponder or altimeter are off enough to give that much of an error on altitude reporting. This seems to be a situation where the controller got us too close together, or am I missing something that I should have done better.

All in all, it was a grueling early morning constantly moving charter.
 
I think I'd be more worried about flying under his wake. If he'd been cleared for a visual approach and you were VFR, I think it was none issue. We had a similar but opposite thing last weekend. Had a Piaggio drop 200- 300 ft and cross in front of us and then climb back and fly his approach into DTW. No complaints no problems, we both went peacefully on our way. I'm betting he had us on his TCAS. We had him in our windscreen.
 
I believe the response to a TCAS RA is to follow it first, and tell ATC second. So if you didn't see him climb, I doubt his TCAS told him to do so.
 
TMetzinger said:
I believe the response to a TCAS RA is to follow it first, and tell ATC second. So if you didn't see him climb, I doubt his TCAS told him to do so.
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I definetely saw him climb. And he also circled back around in front of me, crossing my path a second time.
 
Well if you were at 2500 it was his issue perhaps he was 200 ft. low. I 'd have replied to ATC tha.t 123X was at 2500
 
I'd be very concerned about flying 300' below a 777. What is the wake turbulence likely to be like in that situation?
 
qbynewbie said:
I'd be very concerned about flying 300' below a 777. What is the wake turbulence likely to be like in that situation?
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Wake turbulence is worst when the airplane is heavy, slow, and at high angle of attack. So it would depend on the phase of flight how bad the wake turbulence would be.

300' sounds awfully close. The closest I've been is 1000' below a 757 and I felt nary a bump.
 
Where were you? On the Jersey side of the Delaware? I've noticed that the controllers let folks get (seemingly) close over there. I've had some mighty big birds above me inbound on my usual PNE to LOM route across Jersey at the same altitude.
 
dmccormack said:
Wake turbulence is worst when the airplane is heavy, slow, and at high angle of attack. So it would depend on the phase of flight how bad the wake turbulence would be.

300' sounds awfully close. The closest I've been is 1000' below a 757 and I felt nary a bump.
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Makes sense. Thanks.
 
Sounds like both of you were just doing what you were told... another strike against the controller, from where I sit, is his comment that you were "flying around VFR", as if he had no idea what you were up to and had no say in it. :mad:
 
Controllers are not permitted to allow VFR traffic they are working to cross within 500 feet vertically of IFR traffic unless the VFR traffic calls the IFR traffic in sight and agrees to maintain visual separation. Unfortunately, TCAS doesn't know when the VFR pilot sees the IFR aircraft or that s/he is maintaining visual separation, and reacts whenever its programmed separation criteria are violated. Further, crews of TCAS aircraft are required by regulation to follow TCAS avoidance maneuvers. This combination of rules created the situation described, in which all three parties (VFR pilot, 777 pilot, and controller) did what they were supposed to do, and it still got crazy. That's the way it is, and the 777 pilot and controller should both understand it.
 
If I were flying a big bird, and ATC told me some bugsmasher was close, not illegally close but close enough to set off the bright flashing lights, I'd get nervous too. Too many bozos with PPLs flying around out there.
 
Aztec Driver said:
I did a multiple leg charter today. On the one leg around Philadelphia, while on VFR flight following, I had an airliner get annoyed with me. The controller told me to fly 120 and descend to 2500, before turning south on course, which I did. As I reached 2500 and started to turn on course, the controller reconfirms that I am free to turn on course. As I round out from my turn, above and to the right, 2-3 miles away is a 777 heading east and crossing my path, at what looked like 300-500 feet above. He stayed ahead of me, I constantly had him in sight, and there was no danger, however, it must have set off his TCAS, because, as the controller called out traffic to the airliner, the pilot radioed back that he has it on TCAS and has to climb immediately. I was still at 2500. The pilot then radios back that "that guy was only 300 feet below me, what is he doing that close to me?"
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I had the very same thing happen to me once. Class C, following controllers vectors, stated I had the aircraft in sight at the altitude they instructed me to remain at... All the sudden I see the airliner start climbing and cleaning up their plane. Airliner pilot tells ATC that we setoff TCAS and per company policy they had to climb. They weren't happy about it--as it messed up their whole approach. **** happens.

The closest I've ever been to an airliner scared the crap out of me. I had about 70 hours and was under a class bravo clearance following their vectors. All of the sudden they told me a Boeing 747 would be passing behind me and to REMAIN AT ASSIGNED altitude. I remained at my altitude and a moment later the Boeing passed in front of me slightly above me. It was close enough that I could see individual faces on the 747...and the sunglasses of the pilot. My passenger, first time in an airplane, proceeds to give the Boeing the finger for "following to close" which I thought was funny as hell.
 
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Personally I think it's a very good idea to maintain at least 500 ft vertical separation from any traffic who's path converges with yours whether or not it's a big airliner. And technically since he was on your right you were the one that was supposed to maneuver to avoid the conflict. Now given that he was descending and you were maintaining altitude, keeping that separation could be a bit tricky and I probably would have queried the controller as to the expected altitude of the big bogey. Judging altitude separation from something that big seems pretty tough to me.

As to the wake issue, if you pass directly under the airplane (not just the airplane's path) with any reasonable separation you will not encounter a wake. It's when you pass behind at or below an airplane that you will get tossed around. That says to me that you'd have been better off going behind the jet at or above his altitude (at the point where his path crossed yours).
 
dmccormack said:
Wake turbulence is worst when the airplane is heavy, slow, and at high angle of attack. So it would depend on the phase of flight how bad the wake turbulence would be.

300' sounds awfully close. The closest I've been is 1000' below a 757 and I felt nary a bump.
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You didn't feel a bump because you were LUCKY and completely missed his wake.

I drive home, north from my flying job at Boeing Field. One day I was sitting at a traffic light at Lucille St. when a 757 flew overhead, on final to 13R at Boeing. A moment later his wake, travelling downward and outward, hit the street. It was violent even in my CAR! The traffic signal bounced wildly from its overhead wiring. A huge cloud of dust spun and flung street garbage everywhere.

That incident has stuck in my mind ever since. You don't want to mess with a big airplane, and ESPECIALLY a 757, which has the worst wake of all.
 
Ron Levy said:
...Further, crews of TCAS aircraft are required by regulation to follow TCAS avoidance maneuvers.
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Got a regulatory reference for that, Ron? All I can find is
§ 91.221 Traffic alert and collision avoidance system equipment and use.

(a) All airspace: U.S.-registered civil aircraft. Any traffic alert and collision avoidance system installed in a U.S.-registered civil aircraft must be approved by the Administrator.
(b) Traffic alert and collision avoidance system, operation required. Each person operating an aircraft equipped with an operable traffic alert and collision avoidance system shall have that system on and operating.
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and
§ 121.356 Collision avoidance system.

Effective January 1, 2005, any airplane you operate under this part must be equipped and operated according to the following table:
Collision Avoidance Systems

If you operate any—Then you must operate that airplane with—(a) Turbine-powered airplane of more than 33,000 pounds maximum certificated takeoff weight(1) An appropriate class of Mode S transponder that meets Technical Standard Order (TSO) C–112, or a later version, and one of the following approved units:
(i) TCAS II that meets TSO C–119b (version 7.0), or takeoff weight a later version. (ii) TCAS II that meets TSO C–119a (version 6.04A Enhanced) that was installed in that airplane before May 1, 2003. If that TCAS II version 6.04A Enhanced no longer can be repaired to TSO C–119a standards, it must be replaced with a TCAS II that meets TSO C–119b (version 7.0), or a later version.
(iii) A collision avoidance system equivalent to TSO C–119b (version 7.0), or a later version, capable of coordinating with units that meet TSO C–119a (version 6.04A Enhanced), or a later version.(b) Passenger or combination cargo/passenger (combi) airplane that has a passenger seat configuration of 10–30 seats(1) TCAS I that meets TSO C–118, or a later version, or
(2) A collision avoidance system equivalent to has a TSO C–118, or a later version, or
(3) A collision avoidance system and Mode S transponder that meet paragraph (a)(1) of this section.(c) Piston-powered airplane of more than 33,000 pounds maximum certificated takeoff weight(1) TCAS I that meets TSO C–118, or a later version, or
(2) A collision avoidance system equivalent to maximum TSO C–118, or a later version, or
(3) A collision avoidance system and Mode S transponder that meet paragraph (a)(1) of this section.
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...which doesn't require flight crews to follow TCAS avoidance maneuvers.

My understanding is that it's the company manual that addresses how TCAS commands are dealt with. (Which is, technically, regulatory as well, since regulations require compliance with company procedures, but still not necessarily requiring the crew to follow TCAS commands.)

Fly safe!

David
 
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kgruber said:
You didn't feel a bump because you were LUCKY and completely missed his wake.

I drive home, north from my flying job at Boeing Field. One day I was sitting at a traffic light at Lucille St. when a 757 flew overhead, on final to 13R at Boeing. A moment later his wake, travelling downward and outward, hit the street. It was violent even in my CAR! The traffic signal bounced wildly from its overhead wiring. A huge cloud of dust spun and flung street garbage everywhere.

That incident has stuck in my mind ever since. You don't want to mess with a big airplane, and ESPECIALLY a 757, which has the worst wake of all.
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Read again -- you felt that wake turbulence because --on final -- the 757 was low and slow, in a high angle of attack/high drag configuration.

I did not because I crossed directly beneath and the a/c was climbing -- therefore faster, with a lower AoA, and in a low drag configuration.
 
barney said:
I wouldn't make a habit of that. ATC is required to keep a 757 4 miles in trail of another 757 even if they are at the same alt. Personal experience in aircraft of some significance themselves has told me you can have your world rocked by any type aircraft at any speed and in any configuration. Be careful out there.
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One more time. There is no wake a hundred feet below any airplane in flight (let's exclude any VTOLs). The wake appears at and below the airplane's path. If you crossed the airplane's path behind the airplane itself you could encounter a wake, but if you pass directly below the airplane you won't have to worry about worlds rocking (assuming you're low enough to miss the airplane!).
 
Whoa, here. The VFR guy is on FF, and follows ATC instructions to the letter. If that puts him near a deal, that's not the VFR pilots fault. Gee, I'm sorry it set of his bell, but that's not the VFR guys problem. Suppose our VFR guy DIDN'T follow directions?

I say the pilot did everything right, and it's ATC and the 777 to get things sorted out. Share the air.
 
lancefisher said:
One more time. There is no wake a hundred feet below any airplane in flight (let's exclude any VTOLs). The wake appears at and below the airplane's path. If you crossed the airplane's path behind the airplane itself you could encounter a wake, but if you pass directly below the airplane you won't have to worry about worlds rocking (assuming you're low enough to miss the airplane!).
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:yes::yes::yes:
 
Company policies often require response to Resolution Advisories. But, outside of an RA, if a pilot sees traffic on TCAS, he can individually determine if he thinks there is a threat.
With the price of AVgas, there are fewer situations where the big boys see VFRs. The pilot of the VFR aircraft did nothing wrong. The controller said you were "VFR." It wasn't an insult, it was a statement that you were following "Visual Flight Rules."
In the flight levels, there are no VFRs (okay, not counting U-2s above FL600). So our jumpy carrier pilot got a little excited when he saw an aircraft near him on a diverging flight path.
He was a little careful. I am not sure what he said, but, by his view, his concern was warrented.
His understanding of VFR could use a little sprucing up. But you did nothing wrong. I do not think the controller did anything wrong.
But you should understand that his statement that you were VFR was not a cut-down. I suspect that, by his reckoning, you had every right to proceed VFR on the course that you had. He was kind of sticking up for you (I think).:blueplane:
 
ApacheBob said:
Company policies often require response to Resolution Advisories. But, outside of an RA, if a pilot sees traffic on TCAS, he can individually determine if he thinks there is a threat.
With the price of AVgas, there are fewer situations where the big boys see VFRs. The pilot of the VFR aircraft did nothing wrong. The controller said you were "VFR." It wasn't an insult, it was a statement that you were following "Visual Flight Rules."
In the flight levels, there are no VFRs (okay, not counting U-2s above FL600). So our jumpy carrier pilot got a little excited when he saw an aircraft near him on a diverging flight path.
He was a little careful. I am not sure what he said, but, by his view, his concern was warrented.
His understanding of VFR could use a little sprucing up. But you did nothing wrong. I do not think the controller did anything wrong.
But you should understand that his statement that you were VFR was not a cut-down. I suspect that, by his reckoning, you had every right to proceed VFR on the course that you had. He was kind of sticking up for you (I think).:blueplane:
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I did not believe the controller was cutting me down. Moreso, it sounded like he was berating the airliner pilot for not knowing that we could be flying VFR near him. I believe the other pilot believed that all traffic was being given his minimum separation and he shouldn't have to worry about it, and was miffed at both the controller and myself because his TCAS went off and he had to make an abrupt climb unexpectedly.

I will say that the controllers around Philly are usually very busy and don't take kindly to VFR flight following much. I was flying close to their airspace and fitting in between Class B and Class D at PNE, so I wanted to make sure they knew I was there, and what to expect from me. Everything worked out fine, it just wasn't pleasant or professional to have a 777 pilot get irritated at me. It certainly wasn't my intention to set off his TCAS. There was no danger, but I can see his dilemma.

Is this a good scenarion for sending in an ASRS?
 
Aztec Driver said:
Is this a good scenarion for sending in an ASRS?
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Yes! Not because you need any sort of keep-out-of-jail card, but because it helps point out a potential flaw in the system that can be studied and perhaps rectified for greater safety.
 
gprellwitz said:
Yes! Not because you need any sort of keep-out-of-jail card, but because it helps point out a potential flaw in the system that can be studied and perhaps rectified for greater safety.
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Which might mean "Don't let those VFR guys inside the airspace with the big boys" a la Chicago. :(

barney said:
What can I say? My experiences with wake turbulence in three plus decades of pushing iron for a living has been trumped yet once again. Hell, I've hit my own wake during a perfectly executed steep turn. Heres wishing you continued good fortune. :cheerswine:
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Ummm... Explain to me how wake turbulence can go STRAIGHT DOWN from an airplane? It goes down BEHIND the airplane. If you go directly below the airplane, and not behind it at all (the scenario Lance described), you will not encounter wake turbulence. It's just not possible, as the wake would have to have an infinite rate of descent... I'd love to hear any explanation otherwise. :dunno:
 
Ron Levy said:
Controllers are not permitted to allow VFR traffic they are working to cross within 500 feet vertically of IFR traffic unless the VFR traffic calls the IFR traffic in sight and agrees to maintain visual separation.
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Flying on an IFR flight plan in VFR conditions does not absolve the IFR pilot from maintaining a lookout for other aircraft.
 
john smith said:
Flying on an IFR flight plan in VFR conditions does not absolve the IFR pilot from maintaining a lookout for other aircraft.
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True, but not relevant to the issue of the controller's obligation to separate known VFR traffic from IFR traffic.
 
Ron Levy said:
Controllers are not permitted to allow VFR traffic they are working to cross within 500 feet vertically of IFR traffic unless the VFR traffic calls the IFR traffic in sight and agrees to maintain visual separation....
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True in Class B; but, I'm not aware of any separation requirement between IFR and VFR in Class E airspace. Issue traffic, yes. Issue a safety alert, yes. Separate, no.
 
kkoran said:
True in Class B; but, I'm not aware of any separation requirement between IFR and VFR in Class E airspace. Issue traffic, yes. Issue a safety alert, yes. Separate, no.
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FAA Order 7110.65 does not make any differentiation between IFR and VFR aircraft in the chapter on Radar operations where it discusses identified targets.
 
Ron Levy said:
FAA Order 7110.65 does not make any differentiation between IFR and VFR aircraft in the chapter on Radar operations where it discusses identified targets.
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Ron,

I disagree (respectfully, since you are almost always right) with your interpretation of 7110.65. I reviewed Chapter 5, Section 5 (Radar Separation) before making my first post. While it doesn't make a distinction between IFR and VFR, it does not set a requirement for separating IFR and VFR or VFR and VFR aircraft. Para 5-5-1b says that Radar separation may be applied between radar identified aircraft. This isn't a requirement (shall), but, rather, a restriction on when a controller can use radar to separate aircraft.

The only references to 500 ft vertical separation between IFR and VFR aircraft I can find are: Para 7-7-3 (TRSA), Para 7-8-3 (Class C), and Para 7-9-4 (Class B). If 500 ft was a general requirement, there wouldn't be a need to specify the requirement for each of these airspace types.



 
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