Performing 360 on final for wake turbulence?

nddons

nddons

Touchdown! Greaser!
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Stan
I was sitting in a conference room all day today in Irvine, CA (and enjoying the 75 degree F swing in temps from Milwaukee), and watched a fair number of 737s and other large aircraft landing on 5700 ft 19R at John Wayne / Orange County (KSNA) - Class C.

Also interspersed were some GA aircraft - Cessnas, Cirrus, etc., working into the traffic pattern. While my vantage point wasn't great, and while SNA does have a parallel 19L 2887 x 75 runway, my impression was that some GA aircraft seemed to turn base to final earlier than I think I would have landing behind a large aircraft.

Winds were light (calm to 7 kts), and were crossing right to left.

Finally one aircraft appeared to turn base to final shortly after a 737, and performed a left 360 before landing at the airport. I'm only guessing, but I suspect he may have been concerned about wake turbulence.

Sooo, here's my question: If I were in that situation, and perhaps turned base too early, would I call the tower and request a 360? What if the tower called on downwind "Cessna 12345 number two cleared to land" and only well into the base to final turn do I realize I could be in trouble? I understand I am PIC of the aircraft and can't let my clearance force me to land if it is unsafe. I also understand that a go-around is probably the best move here (while staying above the glide path of the heavy aircraft). But is a 360 also appropriate in this situation?
 
in most light singles, especially with a 5700 foot long runway, it really isnt that hard to fly above the glide path of a 737, and touchdown beyond its touchdown point, and get stopped well before the end.

I suspect that any 360 on final was a request from ATC for spacing purposes.
 
I agree with Tony. I think the 360 was for separation. I would never use a 360 on final to let wake turbulence subside, I would simply go around. After I complete the 360, I don't think much wake would dissipate by the time I rejoin the final and would rather go back up and nail a stabilized approach rather than turn in a circle on 1/2 mile final.

Since HPN tower enjoys sequencing us between B717s, GV's, CL60's, and other large biz jets, I'm very used to and comfortable with wake turbulence procedures. With a 6,548 ft. runway, there is plenty of room too.

To answer your question, you could request a 360, but I'm not sure it would solve anything. ATC is supposed to append "caution wake turbulence" to your landing clearance if sequenced behind a B737 (assuming you're in a small aircraft). If you would like to buy more time because of the wake advisory, I would probably ask to extend my downwind and offer to square it off when I'm ready to turn base.
 
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If you turn final and then decide you need a 360 for wake turbulence spacing, yes, you must ask Tower before you do it. If they don't approve it, you have your 91.3(b) authority to take whatever action is necessary to avoid that wake turbulence, but you may have to answer for your action before the FSDO if it screws up the tower controller's day and he writes a PD on you. The big question the Inspector will ask is why you turned base so close behind the 737 that you had to make that 360 for spacing and why you didn't just take a go-around and set up again.
 
tonycondon said:
in most light singles, especially with a 5700 foot long runway, it really isnt that hard to fly above the glide path of a 737, and touchdown beyond its touchdown point, and get stopped well before the end.

I suspect that any 360 on final was a request from ATC for spacing purposes.
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You could be right, Tony, though I was looking for another aircraft on final and didn't see it - unfortunately I was head down in the conference room doing actual work.:(

I'm curious - isn't 5,700 ft a relatively tight strip for a 737? Are you saying that since it is short, the 737 would have to touch down pretty early (say right at 1,000 ft vs. a 1,500 floating landing), and thus lift (and wake turbulence) would cease relatively early, allowing a GA aircraft to land safely on, say, the 2nd 50% of the runway?
 
Stan- I'm wondering if turning base to final earlier helps to stay above the wake turbulance. They are high for the end of the runway, but not so high for landing "long"
 
Ron Levy said:
If you turn final and then decide you need a 360 for wake turbulence spacing, yes, you must ask Tower before you do it. If they don't approve it, you have your 91.3(b) authority to take whatever action is necessary to avoid that wake turbulence, but you may have to answer for your action before the FSDO if it screws up the tower controller's day and he writes a PD on you. The big question the Inspector will ask is why you turned base so close behind the 737 that you had to make that 360 for spacing and why you didn't just take a go-around and set up again.
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Well, the point I would make is that if one thinks the spacing is bad, the thing NOT to do is to do a 360. One should just execute a go around and do the whole pattern again. Controllers get real testy when you do things in the pattern they are not expecting. BTDT as a passenger.
 
nddons said:
I'm curious - isn't 5,700 ft a relatively tight strip for a 737? Are you saying that since it is short, the 737 would have to touch down pretty early (say right at 1,000 ft vs. a 1,500 floating landing), and thus lift (and wake turbulence) would cease relatively early, allowing a GA aircraft to land safely on, say, the 2nd 50% of the runway?
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Yeah, it is a little tight. The big jet pilots will not apologize for a firm landing at the 1,000 foot mark. And for light airplanes, they could land between the 2 and 3 thousand foot marker and have plenty to get stopped in.
 
Greg Bockelman said:
Yeah, it is a little tight. The big jet pilots will not apologize for a firm landing at the 1,000 foot mark. And for light airplanes, they could land between the 2 and 3 thousand foot marker and have plenty to get stopped in.
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Thanks for the insight, Greg. It was good to meet you at KJVL.
 
I would think a bugsmasher flying a 360 on final would be a really good way to **** off a controller. Honestly, if a pilot can't manage to land long on a 5700ft runway in a 172, well.......
 
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nddons said:
I'm curious - isn't 5,700 ft a relatively tight strip for a 737?
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Disney's 737 was at SBY (5500 feet) during the Eisner v. Disney lawsuit trial in Georgetown DE a couple of years ago. KGED (5000 feet) was a bit too short for them to load enough fuel to get back to Orlando and still take off legally.
 
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