Reliability of jet engines

[NacelleStrake]

I've been tracking the progress of a relatives European charter flight on t'internet and it never ceases to amaze me the fact that after a four to five hour flight the aircraft is 'turned-around' in an hour and then sent back screaming down the runway for the return four to five hours flight.

No one ever seems to check the water/oil levels while the aircraft is on stand.

Why are modern jet engines sooooooooo reliable?

[MarkerInbound]

Modern aircraft have indicating systems that report to the crew system status. And some planes will in effect text message the company the same info so the ground staff has advance information on what is required. My company requires maintenance to sign off a transit check every time the aircraft. They are usually waiting by the cockpit door for the flight crew to get out of the way.

Jet engines should not be burning much oil and hydraulic systems should not be leaking so normally the check is to see that the levels are up. Lavs and water tanks should be serviced every time the plane lands but a trained crew has this covered in 20 minutes.