Vy/Vx during windshear recovery and EGPWS recovery

[Major Nevitt]

Windshear

Hi

I guess the cofusion is from "windshear" being EGPWS mode 7.

The correct action to be taken will depend on what aircraft you are operating and the warning given or conditions experienced.

I can only speak for my company and our SOP'S. We operate 737 efis.

If predictive windshear is active and "windshear ahead" warning is given, for example on the approach then a normal go around may be the preferred option if actual windshear is not experienced.

If windshear is experienced then the windshear recovery procedure is flown.

This procedure is very different from a normal go around.

1 Disconnect Autopilot
2 Press Toga and aggressively apply max thrust*
3 when max thrust is set disconnect auto throttle
4 roll wings level and pitch up to approx 15 degrees nose attitude
5 retract the speedbrake if extended
6 follow the flight director TOGA guidance


Note that apart from the speedbrake there is no change of config until clear of windshear.

Also note that airspeed is not to be chased. If you follow the fd's they may take you in and out of the stick shaker.

This is a very involved two crew operation with the non handling pilot playing a vital monitoring role, particularly with respect to vertical speed.


* If a terrain warning occurrs the firewall the thrust levers and head for sector safe!

Again other GPWS warnings associated with the different modes will, where neccessary make use of firewalling the thrust levers and keeping the existing config.

Hope this is of some help.

MN


The answer then is that in a windshear or egpws go around you will be right at the back of the drag curve trying to gain max height over min distance.

When considering even a normal go around I would of thought that Vy had little significance.