Do you fancy paying 20% more for your maintenance?

What Chris says :)

Flight time goes in my aircraft logbook, block time goes in my logbook.

Exactly!

My engine has done 1600hrs airborne time but the “hobbs” meter (in my case a time counter which runs when the RPM is over 1200) is reading 1920hrs.

Do you idle the engine @ 1200RPM most of the time ?

I find it difficult that you ran the engine >1200RPM for 320 hours out of 1600 hours FT …

The classic mechanical engine tachs are set to log 100% @ a pre-determined RPM setting, ie. usually between 2100 and 2600 . At 1200 RPM they log virtually zero time.

I suspect that your eletronic tach probably logs whole minutes every time you exceed 1200 RPM even for a couple of seconds.

Nonetheless, I find that +20% to be high vs the flight time, but very similar to typical Hobbs time, ie. the time the main battery is connected.

Actually, there is another reason to idle @ 1200RPM when you have a Lycoming: it ensure the cam is getting enough splash oil .

Whatnext: Being based where I am and flying to larger airports mostly I usually see up to 30 minutes difference between Block and Flight, sometimes less, sometimes more. 20 minutes is the minimum, certainly for first flight of the day when engine warm up and full checks are done. If I count around 50 flights to a 100 hour check, this would mean 25 hours earlier. Or TBO some 500 hours earler which would be around 25% then. If I have to divide the fixed costs by 1500 instead of 2000 hours…. or by 75 instead of 100 for the yearly check… means a hefty increase in hourly price.

I have always been told that it is flight time which gets recorded (don’t have a hobbs meter) and that is how we do it.

I have always been told that it is flight time which gets recorded (don’t have a hobbs meter) and that is how we do it.

Same here, but the question remains, if “the way we always did it” still compiles with the current regulations. Can only be solved if someone works his way through EASA Part M (not me, not now however ).