Originally Posted by
joshuahsong
I am a captain flying the B737NG and MAX.
Recently, I encountered severe windshear during an ILS approach, which led me to initiate a go-around. I did not change the aircraft configuration from the Flaps 30 landing configuration (gear down, flaps 30). However, because of the severe windshear, the airspeed fluctuated by more than ±15 knots.
I tried to keep the airspeed within limits using pitch control, but the airspeed briefly exceeded the Flaps 30 placard speed of 175 knots for a few seconds.
After this experience, I started wondering whether the Boeing Windshear Escape Maneuver must be followed strictly in every situation. In a scenario like mine—where the aircraft was already above 500 ft AGL, with a strong positive climb rate (more than +2000 fpm and stable)—would it make sense to select Flaps 15 to prevent exceeding the flap placard speed?
I’m questioning whether my thought process is flawed, and I’d like to hear how other 737 pilots think about this.
Going back to the OP, if you are doing the WEM because you had a reactive WS warning or you decided enough was enough given the conditions, then if the initial actions were performed correctly you should be at max thrust following the FDs in TOGA and keeping the config; if the speed gets a bit frisky then so be it. The PM should be monitoring the aircraft performance as they know you are executing a WS GA because you said so.
At some point following this, you need to assess whether or not the conditions that caused you to discontinue the approach in this manner are still present and affecting you negatively. If not, then it is SOP in most outfits to call a GA which should trigger config changes in the normal way and start the process of rebuilding the flight path into something less frantic. The trap as I see it is to mix up the two stages which leads to confusion - either continue the WEM or change to a standard GA, don’t do half and half as the poor PM will have some big question marks over their head at that point.
There’s also the consideration about the environment. Is it just gusty and turbulent or is there microburst activity? (Which the WEM is ultimately there to counter). If it’s strong winds and/or mechanically induced turbulence then I would be quicker to revert to normal flight as opposed to the powerful vertical and horizontal shears associated with convective activity/downdraughts.