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.
No. I would not retract the flaps that low in that situation.
I agree with the above. I would not consider 500' AGL, even with a significant positive uptrend, to be out of the windshear. That's just too close to the ground for something to suddenly start trending the other way. You wouldn't change the configuration that low during a normal take-off or go around, so why do it so soon in windshear? You're more likely to throw off your FO who is not expecting it, setting your flight deck up for confusion in a dangerous moment. That's not to say that sometimes we have to think outside of the box, but I don't think this is one of those moments to throw surprises at your winger. I do understand your thinking - Flaps 30 to 15 is less drag, so that surely should improve performance. But, it's also less lift. Less lift at a time when maximizing lift production is the key to a successful outcome. That's why Mr. Boeing says not to change the configuration. It would not be a very nice day to lose that lift right at the moment that your trend goes the other way.
I vaguely remember being told by our engineering staff during a ground school a few years ago that for a flap overspeed excursion of up to 15 knots, it's just a visual inspection. I remember that this instructor was prone to exaggeration at times, so I do take the number with a grain of salt, but I don't think an overspeed of a few knots warrants much from an engineer. I stand ready to be corrected by much more knowledgeable people on the matter, but even if it's 10 knots, a flap can be fixed if it's in a million pieces. I can't.
I would also question if Flap Load Relief triggered. It should have if you exceeded 176 knots in either an NG or Max, so even if you did exceed the Flap 30 limit for a few seconds, FLR should have taken care of it for you.