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lineboy_nz
29th Mar 2004, 16:28
I was in wake turbulence on finals.
Some people said to go around, some said to pitch forward.
How do you decide?
My current thinking is go-around.
Any arguments for lowering your nose and descending out of it?

172 pilot here.

zerozero
29th Mar 2004, 17:46
...or nearly so.

The reason forward pressure is taught is because a natural reaction is to pull back on the yoke if you're descending.

But if you're upside down and descending and you pull back, you'll point the nose straight at the ground.

Another thing to consider, the vortex sinks at a fairly constant rate (about 900fpm). You may not want to descend back into it for another encounter.

But if you pull back, your airspeed will deteriorate, placing you closer to the stall and degrade your control effectiveness.

Lots of things to consider. Every situation is different.

One thing you should always know before you follow a larger airplane is the wind direction.

If it's calm, you can expect nice stable vortices. If you have strong gusts, the vortices will break up and drift with the wind.

If you have a steady 10kt crosswind, the downwind vortex will travel downwind but the upwind vortex will remain stationary.

Of course the best advice is to avoid the wake altogether but sometimes we just get caught. In that case you have to make some very fast calculations and judgements.

There are no hard and fast rules--only good and bad judgement.

Fly safe.

nosewheelfirst
29th Mar 2004, 17:47
if it exists at goes all the way down to the runway so unless you can land before the larger aircraft i would not suggest it

Go around you've got more height to play with and get out of trouble

lineboy_nz
29th Mar 2004, 17:57
thats what i thought. my aerodrome has heavy helicopters doing IFR approaches to the active runway. is this ideal for pre-PPL (A) students on night VFR training?

alf5071h
29th Mar 2004, 20:09
Assuming that from your good airmanship you should have been above the flight path of the preceding aircraft planning to land long if at all; then the appropriate action would be to pull up to remain above the vortex and to go around to reposition for a stable approach after the vortex has dissipated.

For a nice simple guide to Wake Turbulence see: Wake Turbulence, (http://www.caa.govt.nz/) go to Safety Information / Publications / Wake Turbulence.

Also see UK CAA GENERAL AVIATION SAFETY SENSE LEAFLET 15B Wake Vortex, cannot find a link, and FAA AC 90-23E (http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/WebSearchDefault?SearchView&Query=AC%2090-23E&SearchOrder=1&SearchMax=0&SearchWV=TRUE&SearchFuzzy=FALSE&Start=1&Count=100#).