Caution! Jet Wake Turbulence. (Busy LA Air Traffic)

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Don
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Caution! Jet Wake Turbulence. (Busy LA Air Traffic)

Post by Don »

I am thinking, "Hanger Talk" is a good place discuss and share flying experiences with other pilots. Yesterday, I was flying from El Monte, KEMT back to my base Torrance Airport, KTOA here in Southern California. I do this flight several times a week and am very familiar with the Class Bravo airspace floor at 2500 feet just south of El Monte airport. This Bravo airspace is for arriving aircraft at LAX. That said, SoCal Approach normally has the ILS descending LAX traffic at about 4000 feet MSL above my position. I have just engaged the AP and we are level at 2300 feet MSL. El Monte tower informs me that a Southwest 737 is on a downwind leg to LAX and it passes two miles behind me west to east. The 737 then turns a right base at 2600 feet and parallels my left wing. Next, the 737 turns right for LAX final and passes over me with only 300 feet vertical separation. I was quite surprised that he was only at 2600 feet MSL and took a few photos of the 737 while it was on right base and then the last photo as it started turning right final. Now, at this point, I am truly concerned about invisible jet wake turbulence. So I disconnected the AP to start a quick decent but there was Cessna traffic 600 feet below me. At this point I just held the stick tightly and hoped for the best. I believe the controller at the El Monte tower was also surprised that SoCal Approach allowed this to happen with so little separation.
I tried to attach the MP3 ATC audio file to this post but it would not load. So I transferred the ATC audio file to a private youtube format along with a few cell phone photos of the encounter. See link below.
https://youtu.be/e4CMVjwewnw
SW 737 300 FEET ABOVE US ON BASE TO FINAL.jpg
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Re: Caution! Jet Wake Turbulence. (Busy LA Air Traffic)

Post by Lou »

Interesting. Two thoughts. 1. If he's cleared for the visual, then isn't he responsible for separation, and ATC is only advising? and 2. Wake turbulance from a clean medium category airplane is probably not too bad, not that I'd want to test it.
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Re: Caution! Jet Wake Turbulence. (Busy LA Air Traffic)

Post by Don »

That is something I do not want to test either. There has been several fatal accidents here near John Wayne airport from Jet Wake Turbulence. One accident killed all five aboard including the CEO of In & Out Burger. That was going through my head as the 737 passed above.
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Re: Caution! Jet Wake Turbulence. (Busy LA Air Traffic)

Post by jb642DA »

Don - you certainly had a valid reason to be concerned!!

Flying through the wake turbulence from a 737, especially with it slow and configured for approach/landing can ruin your day quickly. You do not want to tangle with it at all. As a rule of thumb, the wake turbulence will settle at about 3-500 fpm and will move with the prevailing wind.

Check out this 2006 AOPA Safety article about a Piper Saratoga's encounter with a 737's wake in the traffic pattern. The article also has some AIM references in it.
https://www.aopa.org/training-and-safet ... raft-apart
and here's the full NTSB Final report -
https://www.ntsb.gov/about/employment/_ ... 154&akey=1

Here are a couple of other links re: "wake turbulence" and avoiding it -

https://www.boldmethod.com/learn-to-fly ... urbulence/

http://code7700.com/aero_wing_tip_vortices.htm
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Re: Caution! Jet Wake Turbulence. (Busy LA Air Traffic)

Post by Don »

Thank you John for the links which I read.
I was told way back when by my CFI that the wing vortex would sink about 1000 feet per minute in calm wind and that is what I have been using for the past 15 years of flying.
I took the liberty to cut and paste the following from the link you supplied as it may be useful to others here. One of the good things of the G1000 is that it gives you wind direction and speed. This is a useful tool in dead reckoning where the jet wake turbulence may fall relative to your aircraft's position.

"If you're flying in busy airspace or around large aircraft, keep track of the windspeed and direction. If winds are calm, remember that wingtip vortices will have a tendency to remain along an aircraft's flight path and will not dissipate quickly. According to the FAA, vortices descend at an initial rate of about 300 to 500 feet per minute for about 30 seconds. The descent rate decreases and eventually approaches zero between 500 and 900 feet below the flightpath. Flying at or above the flightpath always provides the best method for avoidance".
votex.jpg
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Re: Caution! Jet Wake Turbulence. (Busy LA Air Traffic)

Post by jb642DA »

You're welcome Don! There's a lot of good "stuff" in those links!!
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