So, as you may know, the MD-90 has movable control surfaces on the engine pylons called pylon flaps:
When the MD-90 was developed, it was discovered that the larger engines were heavy enough that they made it difficult to recover from stalls in certain situations.
So when the yoke is pushed near full forward position, and (presumably) when certain airspeed/AOA conditions exist, the pylon flaps deploy hydraulically to provide additional nose-down authority.
Here's the thing: They appear to literally NEVER get cycled.
I work at an airport where MD-90s appear constantly, and I've never seen the pylon flaps deployed during control checks. No MD-90 pilot I've spoken with has ever seen them deployed. And three MD-90 maintenance technicians with whom I've had contact each said the same.
Additionally, I can't seem to find a single photo or video anywhere on the web showing the pylon flaps in the deployed position.
So is it true that these potentially quite critical control surfaces are literally never cycled? If so, how in the world can it be ensured they will function properly when needed?
EDIT: Removed an unnecessary word.