My brown pants moment (wingtip vortices)

Wingtip vortices descend at about 500 fpm to the surface, and spread out at about 5 kt, so a 5 kt crosswind will keep the upwind vortex over the runway. They don’t bounce but carry on spinning on the ground.

Take off before the take-off point of the heavy ahead, then turn away. Land beyond the touchdown point of the heavy. Or wait 3 minutes if these options are unavailable.

I used to instruct at Kai Tak, Hong Kong, fitting in between 747s and Tristars. We never had an incident.

I don’t get it. What Chris says is that vortices don’t bounce up, just continue down (which is what i was taught). Peter did the sensible thing and aimed at staying above the Citation’s glide path. Plus there was 3 mins separation. Peter got hit at 300 ft. So did these vortices bounce up, or did Peter finally not manage to stay above the glide path?

Should have read the above referenced FAA circular, where it says on page 15 para a.1 that vortices can rebound. Probably quite rare though.

aart wrote:

So did these vortices bounce up, or did Peter finally not manage to stay above the glide path?

We will never know but probably just dropped into the vortex from above.

Here! you can see a vortex rising. Not really a rebound, I admit. The existence of rebounding vortices is mentionned in a detailed report which you can find on the net. Apparently, it happens rather with the combination of crosswind on final.

Report

@RobertL18C Thanks for posting the FAA circular. Very useful for hazzard awareness.
However, as usual they are referring to situations of heavy and super aircraft, which resutls in use of very long runways.
Here options increase for the smaller GA aircraft type.
Peter’s situation encountering wake turbulence from a light jet using a short type runway (for the jet), limits any available options for the light GA aircraft.
In my opinion, the circular does not sufficiently address this type of hazzard enough.
For example there might not be a glide slope to use for the GA airfcraft for landing and staying high.
Further, the jet may stay high and decend more steeply towards the threshold.
Finally it may be much harder to judge the jet’s touch down area, since the GA aircraft may not follow on long final, but may be downwind when the landing jet is spotted.
Then there is the short runway, where it may not be possible to land with long enough distance away from the jets touch down area.
The hazzard is further increased with smaller light aircraft using the airfield featuring very short wings, for example the RV and LA type aircraft.
That would increase the problem much more, even with non jet-landing traffic being present, as the incident discussed here regarding the Robin hitting wake turbulence from a single engine Antonov in Germany demonstrated.
@Peter_Mundy
Your report is extremely useful for all of us to learn from. Can you confirm what type of aircraft during this wake turbulence episode you were in?

complex-pilot wrote:

Of course, it’s the pilot that needs to space correctly behing landing traffic. ATC will only be able to pass on advisories, they won’t do more in this situation.

Really? I thought that ATC was under the obligation to apply turbulence category separation. At least that’s what both the textbook and ICAO documents say and what I wrote in my IR written exam. Not that it will necessarily be enough, of course.

airways wrote:

Here! you can see a vortex rising.

Here is the link. The one previously posted did not work for me.

Airborne_Again wrote:

I thought that ATC was under the obligation to apply turbulence category separation. At least that’s what both the textbook and ICAO documents say

Not for arriving VFR flights