ATR 72 Crash in Brazil

BobDDuck said:
I've posted about it before, but I got rolled about 90 degrees in a CRJ taking off behind a 330 in PHL. And this was before RECAT so you got even more space back then.

Even now in a heavy, I still drag my feet a bit taxiing into position and putting up the power if we've been cleared to go right behind another big plane.
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I was thinking about your story when I initially saw the video.
 
I've been rolled pretty good by an A320/321 out of SEA on north flow maintaining visual sep. I guess it was startling in the sense that it was rapid and uncommanded, but it didn't get to much more than 30 ish deg AOB.....so not nearly as bad as what some of you describe. It also wasn't at triple digit altitudes.
 
Maximilian_Jenius said:
500 hour pilot question. Don't taze me. But aren't you supposed to take off before or after a heavy jet t/o point, to avoid that? I know that you said that you were heavy, but could you have ran the numbers to takeoff at a higher thrust output, to take off before their rotation and fly above the 767's wake?
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My understanding is those figures you see in the AIM are guidelines for avoidance, but if you’re on an IFR flight plan under positive control by ATC there’s only so much you can do and ATC is responsible for wake turbulence separation via their rules in the 7110.65. I’m not a controller but I think I grabbed the right sections below:

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NOTE-

Aircraft same runway separation (SRS) categories are specified in FAA Order JO 7360.1, Aircraft Type Designators and based upon the following definitions:
CATEGORY I− small single-engine propeller driven aircraft weighing 12,500 lbs. or less, and all helicopters.
CATEGORY II− small twin-engine propeller driven aircraft weighing 12,500 lbs. or less.
CATEGORY III− all other aircraft.
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So in other words, non-heavy vs. non-heavy your same runway separation rules are in feet. But once you start introducing 757s and heavies and supers into the mix it switches to time.

The fact that so many of you guys have gotten rocked by airplanes smaller than a 757 makes me think these rules are a work in progress. I hope you ASAPed it! :)
 
///AMG said:
I've been rolled pretty good by an A320/321 out of SEA on north flow maintaining visual sep. I guess it was startling in the sense that it was rapid and uncommanded, but it didn't get to much more than 30 ish deg AOB.....so not nearly as bad as what some of you describe. It also wasn't at triple digit altitudes.
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We got smacked by some unseen wake of a (supposedly) 320 one day in the Jungle Jet. We weren't even on an arrival yet...just cruising right along and then WHAM! - sudden bank - not a lot - maybe 15-18 degrees - and the whole plane felt like it had been tapped by a hammer. Damndest thing.
 
BobDDuck said:
I've posted about it before, but I got rolled about 90 degrees in a CRJ taking off behind a 330 in PHL. And this was before RECAT so you got even more space back then.

Even now in a heavy, I still drag my feet a bit taxiing into position and putting up the power if we've been cleared to go right behind another big plane.
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I’ve gotten rocked in the 330 a time or two behind a heavy or super. Especially leading up to the tracks, I’m all for asking for an offset to get space, or a slow down to give us more said space.
 
DPApilot said:
I’ve gotten rocked in the 330 a time or two behind a heavy or super. Especially leading up to the tracks, I’m all for asking for an offset to get space, or a slow down to give us more said space.
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Slow motion terror is the ANA 380 Honu 10 miles behind you and 1000 feet higher, doing .3 mach faster than you, with the winds from left to right to SLOP won't help.

We just kept hoping that by the time they caught up to us, we would have diverged off their filed route.
 
inigo88 said:
My understanding is those figures you see in the AIM are guidelines for avoidance, but if you’re on an IFR flight plan under positive control by ATC there’s only so much you can do and ATC is responsible for wake turbulence separation via their rules in the 7110.65. I’m not a controller but I think I grabbed the right sections below:

View attachment 79220



View attachment 79221

View attachment 79222

So in other words, non-heavy vs. non-heavy your same runway separation rules are in feet. But once you start introducing 757s and heavies and supers into the mix it switches to time.

The fact that so many of you guys have gotten rocked by airplanes smaller than a 757 makes me think these rules are a work in progress. I hope you ASAPed it! :)
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This is not the most up-to-date information. Radar separation--not time-- is used as long as radar is available. These rules are what is applied when the new consolidated wake turbulence have not yet been adapted at a particular airport.

Below I will post the CWT chart. A common scenario is an "F" departing behind a "C." An F need 3.5nm of radar spacing behind a C. The separation may be anticipated.

Examples of CWT F category would be A320 series and 73s. CWT Cs include 763s (and smaller) and A300s. Even C17s are CWT category C. The only Cat A planes flying are A380s and the cat D line is for heavies where there is not enough data collected yet (like the 77X) Directly behind applies to departures and on approach is self explanatory.

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And i'd like to add, you may always request more time if you are uncomfortable with the spacing, but please make your request before you cross the hold short line, as the controller might be counting on using the minimum separation in order to get you going before the next arrival.
 
greg1016 said:
This is not the most up-to-date information. Radar separation--not time-- is used as long as radar is available. These rules are what is applied when the new consolidated wake turbulence have not yet been adapted at a particular airport.

Below I will post the CWT chart. A common scenario is an "F" departing behind a "C." An F need 3.5nm of radar spacing behind a C. The separation may be anticipated.

Examples of CWT F category would be A320 series and 73s. CWT Cs include 763s (and smaller) and A300s. Even C17s are CWT category C. The only Cat A planes flying are A380s and the cat D line is for heavies where there is not enough data collected yet (like the 77X) Directly behind applies to departures and on approach is self explanatory.

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Thanks for the correction and the updated tables, this is enlightening. :)

Taking a wild guess at climb out speed being ~180 KIAS (V2 + ???) that’s 3 Nm/minute. So under the old 2 minute rule you would potentially have 6 nm of spacing between the heavy 767 and the A320/737. Dropping that down to 3.5 nm anticipated seems like a pretty big change!
 
inigo88 said:
Thanks for the correction and the updated tables, this is enlightening. :)

Taking a wild guess at climb out speed being ~180 KIAS (V2 + ???) that’s 3 Nm/minute. So under the old 2 minute rule you would potentially have 6 nm of spacing between the heavy 767 and the A320/737. Dropping that down to 3.5 nm anticipated seems like a pretty big change!
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It is. Even under the old rules we could use 5nm radar separation and 5nm was always closer than 2 minutes. When I am trying for minimum separation at 3.5nm I usually end up with ~4nm anyway. I used CWT at my last 3 towers, but my current tower adopted it late, while I was in training. It was a major topic of discussion because I already knew how to apply the rules and they couldn't believe running a large behind a heavy that close was okay. It is rare we see anything larger than a C at the current shop, so it is easy to commit the various situations to memory.
 
Got rocked pretty good yesterday morning out of IAH climbing through 100’. We were in a 321. Preceding a/c was a Spirit 320Neo. Dead calm winds. Rolled about 30 deg. Lasted a couple of seconds. Got out of it, turned the AP on, and said “Welp, that was fun”…
 
roundout said:
That's not very 737 of you
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That is true. Tomorrow is my first time in almost 70 days, thanks to having to fly these other gray colored hoopties in the meantime. I'm excited to not don 50 lbs of gear, gsuit, ejection seat harness while sucking on an oxygen mask, but instead sip some coffee and gossip about all the HAL news for a nice transcon. That and they do pay us quite a bit better flying the cattle car
 
///AMG said:
That is true. Tomorrow is my first time in almost 70 days, thanks to having to fly these other gray colored hoopties in the meantime. I'm excited to not don 50 lbs of gear, gsuit, ejection seat harness while sucking on an oxygen mask, but instead sip some coffee and gossip about all the HAL news for a nice transcon. That and they do pay us quite a bit better flying the cattle car
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Do love me a transcon And virtually endless supply of coffee. Especially the Alaska Stumptown.
 
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