Wheels up/Wheels down
 

Here's something to discuss:


Take a high time airframe such as a 727, 737, 747 or whatever you like, but keep it in the realm of high usage (a'la international cargo, transcon flights etc.).


The question is this: Does the bird spend more time with it's gear up or down?

In operational service, probably gear up. But when you take it out for heavy Mx I'm sure the gear down (or gear removed completely) time catches up.

What about at the end of it's service life, which time is higher if you stopped timing after the last shutdown?

At the end of service life, from roll off the line to final shut down, I would put my money on more time on the ground than in the air. Definitely so for aircraft flying shorter stage lengths. Probably closer for the long-haul aircraft that fly 10 hrs at a time then swap crews and go out on another long haul in 2 hours. But I'd still guess that they spend more time shutdown, in mx, and on the gate then they do in the air.

Yeah, there's a whole bunch of time spent in heavy Mx.

Also newer planes fly a lot. Older planes (with low mortgage payments but higher operating costs) tend to fly less, like one trip per day (or week). A brand-new widebody might fly more than it sits, but only until it's first heavy Mx.