Turbosina

Gonna nominate myself for the absolutely terrible ILS I flew today.

We were close behind a Super in our little RJ, in IMC, so I clicked off the AP so I could stay a dot high on GS, then clicked off the FD because its 'fly down' commands were getting distracting. Ended up off centerline and high. I made it work, and we were never outside our SOP tolerances, and we landed in the TDZ, but it was one of those days where you just feel like you've forgotten how to fly. Oh well. Hopefully tomorrow will be better...

Riverside

When you say you weren't outside sop. That means you probably were.

Packrat

You need to check out the FAA video on how wingtip vortices work. Unless you had a tailwind, there's no need for you to ever fly an ILS "a dot high". Doing that only puts your vortices in the next guy's glide path.

Dolphinflyer

He was in a RJ following a Super. Good catch in case a C-172 was next on approach.

I'll go for the 1/2-1 dot high in that case too depending on ceiling height. I see your point if the Super's are never a dot high and tailwinds are never present on approach.

Packrat

Tailwinds, sure. But a Super is probably flying a coupled approach.

contrails

I've encountered significant wake turbulence on glideslope with no tailwind and I'm sure hundreds others on this forum have, too.

Sometimes the vortices behave like the textbook ones, sometimes they don't. Sometimes local effects like a thermal could hold them up in place right in the glideslope with no tailwind at all.

If you feel wake starting, be a pilot and come up 1/4 or a half dot on the G/S.

Tool-of-the-day would be the one who drones along through the wake waiting for the really good jolt of it down low around 100-200', the kind that can push an RJ or even E170 size jet laterally right off the runway course.

I even had to go around last year in a 717 following an A330. At 200' we hit wake that quickly pushed us to the side and got us in an uncorrectable spot. Nothing could be done but go-around.

WesternSkies

Understanding the different sciences:
Chemistry = smells bad
Biology = tastes bad
Physics= experiment didn't work right

rickair7777

They should provide wake separation in IMC. In my experience visuals are where you need to fly high.

Packrat

Right, at 200' where the vortices didn't have the vertical distance to descend. That's where you're going to have your problem, not on 10 mile final.

And it doesn't take a heavy to roll your airliner up. I got rolled in a DC-9 by the wake of an H-53. Your 737 could easily roll an RJ.

Turbosina

You're right, theoretically if all aircraft are on the electronic G/S, and there's proper spacing, the vortices will sink out of the following aircraft's way. Theoretically only a significant tailwind should create cause for concern.

That's theory. Then there's the reality of one's own experience, which I suppose affects how we all fly. A few years back I had a rather unforgettable first-hand experience in which I was rolled fully inverted at 1000' AGL on final behind an A300. Fortunately I'd had upset training, so I'm here to talk about it. Unloaded the wing with a very firm push and kept 'er rolling all the way around -- the roll was too abrupt to follow the natural instinct, which is of course to stop the roll and reverse it.

The spacing on final was fine, but it happened anyways. And I've hit enough vortices at 100' AGL while following a heavy that I'm acutely aware of the danger they present. Haven't we all?

So, yeah, maybe I'm a bit paranoid. But this morning, I could actually see the darn vortices coming off the preceding traffic, as they created rather beautiful patterns in the cloud tops. I'm guessing the preceding aircraft was right on G/S, but all I knew was, I wasn't going to fly through those swirling mists. Once in IMC, I couldn't very well avoid the vortices visually anymore.

Anyhow, what I shouldhave done was kept the A/P engaged and used V/S mode to control the descent rate (instead of coupling to the G/S for descent.). That would have kept us slightly above the G/S while taking care of the lateral track automatically.

You are, of course, absolutely correct that if we all flew the G/S a dot high, we'd create wake issues for other aircraft behind us. That's a very good point.