Originally Posted by
Jan Olieslagers
If this be universally sooth, I've been doing it wrong all the while. Up till now,
-) I was taught above all, there should be PERFECT alignment between the entries in pilot's log, plane's log, and a/d log
-) at all the places where I've flown, the plane's log had to mention Hobb's time
As a result, my pilot's log mentions nothing but Hobb's time. I suppose it's a minor issue but can't help wondering about the legal background, and about the possible consequences.
I don't know about Belgium, but in UK terms, you've certainly been doing it wrong.
Hobbs time is engine start to engine stop.
So, arguably, you could start the engine, sit there chatting for 50 minutes, then take the brakes off, taxi for 5 minutes, do a 5 minute circuit and land and shut down.
It's certainly true that the engine has logged an hour, but certainly in the UK, you'd have logged 10 minutes as a pilot.
If you were in the military however, logging take-off to landing, you'd log 5 minutes for that hour strapped in. And similarly, the wing has seen no significant loads except for those five minutes - so it is not unusual, or unreasonable, that the aeroplane maintenance is based upon take-off to landing.
In effect you have three different times:
(1) Engine running time
(2) Length of sortie (brakes off to brakes on)
(3) Length of flight (take-off to landing)
Each meaning different things, depending upon what is important.
Also many aeroplanes don't use a Hobbs, they use a tacho, which increments proportional to RPM - and again is an acceptable means of scheduling aircraft maintenance.
For that matter, it's not unusual to do an engine high power ground run to test something or other, but without any intention of leaving the ground. This would increment the Hobbs - and needs entering in the engine logbook, but most certainly is not flying time and shouldn't be recorded as such in any personal logbook, or in the aircraft logbook.
To allow for this, my personal PLOG sheets (like, I'm sure, many people, I simply created my own using Word and occasionally tweak it to suit my personal flying habits), record tacho/Hobbs before flight, engine start, brakes off, take-off, land, brakes on, shutdown, end tacho/Hobbs. Sooner or later, I seem to need all of those numbers.
G