En route wake avoidance

Wardogg

Meat Popsicle
Almost all the FAA guidance about en route wake avoidance is information about head-on or same direction flight paths. What about perpendicular courses?

At FL400 ATC advises of a A380 11'oclock 7 miles 1000 above us "caution wake turbulence." At the time our flightpath would have us passing 3-5 miles behind it perpendicular to his track. What is the best course of action here? Maintain course and take the wake on directly? Take a turn to hit it at a 30 degree offset of its path? Being only a few miles away would it be better to turn towards the direction of the crossing aircraft path or away from its direction of flight putting you further behind the aircraft?

My current knowledge of wake vortices are 3-500 fpm decent up to about 1500ft. Then it stops descending and just spins itself out. We made a call that, looking back on it now, I think was the wrong call. However, we passed through the flight path of the aircraft without incident and did not encounter the wake. But I believe it was luck rather than "our"/"PF's" decision. So with that being said, what is the consensus here? I don't remember any guidance or procedures from my time at the regional level. And we haven't discussed it at during any of my biz-jet training. Can I not find any FAA information on it because it's a non-issue?
 
I was 20 miles in trail of a 767 when cleared to the same altitude (in the flight levels) on the same course. Was cautioned about wake turbulence and proceeded to climb thinking it wouldn’t be an issue that far in trail. About 1000 feet to hit the worst wake I’ve ever experienced. Rolled us smoothly almost 90 degrees to the right before able to recover. I would have never thought it could be that bad at 20 miles, but definitely lesson learned. No rhyme or reason to when you experience it, because I’ve been much closer and in situations where wake was supposed to be greater but it was either nothing or just a little bump.
I’m much more cautious now. In your scenario I would’ve probably asked for lower than 1000 feet separation.
 
Almost all the FAA guidance about en route wake avoidance is information about head-on or same direction flight paths. What about perpendicular courses?

At FL400 ATC advises of a A380 11'oclock 7 miles 1000 above us "caution wake turbulence." At the time our flightpath would have us passing 3-5 miles behind it perpendicular to his track. What is the best course of action here? Maintain course and take the wake on directly? Take a turn to hit it at a 30 degree offset of its path? Being only a few miles away would it be better to turn towards the direction of the crossing aircraft path or away from its direction of flight putting you further behind the aircraft?

My current knowledge of wake vortices are 3-500 fpm decent up to about 1500ft. Then it stops descending and just spins itself out. We made a call that, looking back on it now, I think was the wrong call. However, we passed through the flight path of the aircraft without incident and did not encounter the wake. But I believe it was luck rather than "our"/"PF's" decision. So with that being said, what is the consensus here? I don't remember any guidance or procedures from my time at the regional level. And we haven't discussed it at during any of my biz-jet training. Can I not find any FAA information on it because it's a non-issue?
I don’t know what the rate of descent of a wake vortex is in the flight levels (which itself is a really interesting question), but if the jet is perpendicular to you and 3-5 miles you would be fine - the wake couldn’t have gotten to you if the 300-500fpm rule holds.

Even if thejet making the wake was only doing 180kts (or 3 NM per minute) the vortex should still be above you.

If - for whatever reason - vortices descend faster in the flight levels you could have an issue, but they would have to descend a lot faster. Realistically a vortex would have to descend at the perfect speed to match your flight path, otherwise it would best you down or miss you.

Also, I’m unsure if a vortex in such thin air would be as forceful as it is down lower… but a A380 is loving a ton of air.
 
I was on a Emirates A380 and we flew through another A380 wake. And boy was that a fun ride. Most of the glasses at the lounge fell and broke.
 
I don’t know what the rate of descent of a wake vortex is in the flight levels (which itself is a really interesting question), but if the jet is perpendicular to you and 3-5 miles you would be fine - the wake couldn’t have gotten to you if the 300-500fpm rule holds.

Even if thejet making the wake was only doing 180kts (or 3 NM per minute) the vortex should still be above you.

If - for whatever reason - vortices descend faster in the flight levels you could have an issue, but they would have to descend a lot faster. Realistically a vortex would have to descend at the perfect speed to match your flight path, otherwise it would best you down or miss you.

Also, I’m unsure if a vortex in such thin air would be as forceful as it is down lower… but a A380 is loving a ton of air.
Being in a medium rated bizjet as soon as I heard A380 immediately thought of this incident.



Different encounter. They were head on. I was not. But I wonder if the encounter would be different hitting it from the side. So to speak instead of being rolled in it like a barrel.
 
Being in a medium rated bizjet as soon as I heard A380 immediately thought of this incident.



Different encounter. They were head on. I was not. But I wonder if the encounter would be different hitting it from the side. So to speak instead of being rolled in it like a barrel.
first place my mind went as well. I’d have changed course just because of that, LOL! hearing @SFCC/UND tell of the wake rocking another A380 has fully convinced me to avoid close proximity at all costs.
 
Wake turb moves with the wind, at least left or right, so if your were in a strong headwind it might have made that 3 min in trail actually 90 seconds from the wake. I don’t know if wind has an effect on it like that though or not. I do know in a briefing we had a couple years ago it was discovered that time has more to do with it than distance, and that 2 min seemed to be the magic number.
 
Worst wake I’ve ever had was when SoCal ran an A321 1000’ over the top of me on a SID. Had the new winglets (got a good view of them before getting slammed into a 60ish degree bank) and I’m guessing was at climb thrust. Found out after getting a callback from my ASRS that there’s no wake turbulence separation standards if you’re talking to center. Not sure if that’s still the case.
 
Worst wake I’ve ever had was when SoCal ran an A321 1000’ over the top of me on a SID. Had the new winglets (got a good view of them before getting slammed into a 60ish degree bank) and I’m guessing was at climb thrust. Found out after getting a callback from my ASRS that there’s no wake turbulence separation standards if you’re talking to center. Not sure if that’s still the case.
What were you in?
 
Being in a medium rated bizjet as soon as I heard A380 immediately thought of this incident.



Different encounter. They were head on. I was not. But I wonder if the encounter would be different hitting it from the side. So to speak instead of being rolled in it like a barrel.
I hit a 737’s wake perpendicularly in a 207 many moons ago, it hurt, but thankfully didn’t kill me.

Was more like hitting a wall than air lol - can’t sayI would enjoy that in in the flight levels. Still I reckon you are alright.

What were you in?
the international space station.
 
Worst wake I’ve ever had was when SoCal ran an A321 1000’ over the top of me on a SID. Had the new winglets (got a good view of them before getting slammed into a 60ish degree bank) and I’m guessing was at climb thrust. Found out after getting a callback from my ASRS that there’s no wake turbulence separation standards if you’re talking to center. Not sure if that’s still the case.
If it's not in CLB thrust 99 percent of the flight, things have gone wrong.
 
I hit a 737’s wake perpendicularly in a 207 many moons ago, it hurt, but thankfully didn’t kill me.

Was more like hitting a wall than air lol - can’t sayI would enjoy that in in the flight levels. Still I reckon you are alright.
The only other report I can find about an en route perpendicular encounter at altitude was from a GIV and a 747. Their report described it exactly as you did. "Hitting a wall" In our case I was flying with a contractor that I had never met before and it was only our 2nd leg together. He made the call to take a 30 degree cut to the left so as "not to hit the wake perpendicular." I wasn't sure that was the correct call, but in my mind I justified it as we may pass far enough behind the aircraft that we would miss it altogether. I was right. But I don't know if we were above it or below it. Hitting it at an angle to the direction of flight seems to me to be a worse option than taking it head on perpendicular.

Looking back on it now I think @averettpilot has it right. We should have asked for an immediate short term descent. If that wasn't possible then at best we should have asked for a 30 degree cut to the right to put us closer to being directly under the crossing aircraft. In the case of the Challenger/vs/A380 the wake encounter occurred 48 seconds after the cross – when the two aircraft were 15nm part. So in my eyes, underneath him, the closer I can get the better.
 
The only other report I can find about an en route perpendicular encounter at altitude was from a GIV and a 747. Their report described it exactly as you did. "Hitting a wall" In our case I was flying with a contractor that I had never met before and it was only our 2nd leg together. He made the call to take a 30 degree cut to the left so as "not to hit the wake perpendicular." I wasn't sure that was the correct call, but in my mind I justified it as we may pass far enough behind the aircraft that we would miss it altogether. I was right. But I don't know if we were above it or below it. Hitting it at an angle to the direction of flight seems to me to be a worse option than taking it head on perpendicular.

Looking back on it now I think @averettpilot has it right. We should have asked for an immediate short term descent. If that wasn't possible then at best we should have asked for a 30 degree cut to the right to put us closer to being directly under the crossing aircraft. In the case of the Challenger/vs/A380 the wake encounter occurred 48 seconds after the cross – when the two aircraft were 15nm part. So in my eyes, underneath him, the closer I can get the better.
Climbing above it would be my first choice if possible.
 
Climb? Descend? Turn? Naw, just buckle up and send it

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Climb? Descend? Turn? Naw, just buckle up and send it

sendittt.gif
Dollars to donuts you either fly freight or fly to JNU regularly.

I remember flying into JNU in the winter, and it was crazy rough - like the oxygen masks came out of the overhead, no drink service etc. I flew little airplanes in J-town at the time and I was even uncomfortable lol.

Literally none of the pax seemed phased in the least and a guy started playing a harmonica somewhere before BARLO. Was wild.
 
Not in the flight levels, but I was once tossed around in a 152 doing pattern work at KVNY by an MD-80 on approach to KBUR. My flight instructor thought it was one of the best real world learning experiences possible, he was right.
 
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