Drift down vs single engine service ceiling
Here is my question; is drift down ceiling different then single engine service ceiling? Why I am asking is the King Air manual has a Single engine service ceiling chart and people are using as drift down. They are entering the chart at OAT that is derived from flight level temps and using those figures as opposed the OAT temps on the ground at takeoff, resulted numbers are much different to say the least. I say there are no published drift down charts published for this aircraft and the chart is used incorrectly if using FL OATs. Which is correct please?