Inverted
mmmmmm wine
I swear you can learn everything on YouTube and it’s freakin awesome. Here’s a guy walking us through a 5-part series on the 737 flap system and opening inspection panels and getting his hands on everything as he goes. But I thought this video was the most relevant:
View: https://youtu.be/Wx3JldRu3VM?si=8ZfpAUTwOpBa2QLV
My take is that between speed brakes, landing gear and flaps, there is probably some truth to the assertion that the flap system is the least robust of the three - reason being that downstream of the PDU in the gear bay you have this Rube Goldberg contraption of torque tubes, gear boxes, worm gears and tracks that can bind up or jam if subject to excessive aerodynamic loading.
BUT - I would also venture to say that since Boeing has had 60 years to gather data on the 737, their flap extension speeds are probably pretty well tested at this point and they haven’t reduced the operating limitations. So in absence of an actual feedback loop from your airline’s maintenance department saying “here’s how many hours we are supposed to get out of these systems according to the manufacturer and here’s what YOU knuckleheads are making us change them at instead” then I would continue extending them any time below the published operating limitation and not give it a second thought.
The argument “You can extend them at X but I extend them at Y instead to reduce wear and tear” doesn’t really make sense, because airplanes are complex systems of thousands of interdependent components that are all wearing at different rate, and they all must be tracked by mx. Every time you raise and lower the gear you’re creating wear and tear, and every time you take off and land you’re wearing and tearing the airframe (another cycle towards its eventual fate in the desert).
So be mindful of the operating limitations, be especially careful with the operating limitations on the systems that are probably the weak links, but then still use those systems as they were intended to be used.
That is a fantastic breakdown. His channel is actually really really good.