To maintain the airplane's total energy state, (EKIN plus EPOT), we need greater altitude (EPOT), higher airspeed (EKIN), or some combination of the two.
Landing--Insufficient EKIN and EPOT (stall/spin): In this fatal traffic pattern accident, the pilot was observed banking too steeply (estimated to be 50 deg.) while turning from base to final at constant altitude and too low an airspeed.
At the airplane's airspeed, there was insufficient EKIN for the bank angle used and insufficient EPOT for the pilot to pitch down to convert EPOT to EKIN.
Landing--Too much EPOT and EKIN: In an attempt to land a Mooney M20J with too much EPOT (altitude) above the runway, the pilot pitched the nose down and dived for it.
With too much EPOT over the runway, a go-around/rejected landing should have been performed.