Chisau1

On a Transport CofA plane there is a 150hr check which costs almost as much as the annual. But if the plane is at say 145hrs and you are only 2wks away from the annual (i.e. it has done 145 hours since the previous annual) it pays to ground it for the 2wks, because the annual is a superset of the 150hr check anyway (and also the 150hr check is a superset of the 50hr check so don't waste money on a 50hr check if the 150hr one is 5hrs away). You’ve got to watch the hours carefully and all pilots need to be briefed on this! You can get a 10% extension, i.e. 5hrs.

There is also a prop fund if it is a VP prop but it isn’t much, a few quid an hour.

It should be clear which costs are hourly based:

Fuel
50hr check
150hr check
engine fund
prop fund
other lifed parts e.g. vacuum pump

and which are fixed costs e.g.

insurance
hangarage
annual
start annual

Each pilot should pay the landing fee there and then. Or you could have an account for fuel+landings at your home airfield and get everyone to cough up say once a month. This is an area where you need to particularly trust people because it has been known for someone to fill up at some far away place in Europe and fly away; eventually the CAA locates the plane on the airfield's behalf and contacts the registered owner...

Yes, the engine overhaul cost needs to include removal/refitting – this is likely to be around £1000.

The hourly rate MUST at least cover the variable (hourly) costs otherwise you are literally losing money on every flight. How you cover the fixed costs depends on the set-up. If you own a plane yourself, you just pay them when they come up, or you can stuff £20 notes into a box with a slot in it, each time you fly :O

In a group, one would estimate annual hours and divide it up, and this is what gives rise to the normal monthly standing order payment - the alternative to that would be a higher hourly rate. There is always a hidden subsidy from higher-hour members to lower-hour members, or vice versa; this cannot be avoided.

If you own/control a plane yourself and rent it out, you need to charge a good excess above the hourly cost, and this will contribute towards the fixed costs (in this case, you will most likely find that if you charge a market-competitive rental, you will need a good 300+ hours of rental a year to cover the fixed costs). And yes, you will get lots of people saying they will do say 50hrs/year when in fact they do just 5, etc… so you need to be able to cover the costs yourself if you need to.

If the engine blows up within the warranty you are OK. Other than that, unexpected repairs need to be paid for somehow, and unsuprisingly this can result in disputes in group owned planes.

Forgot to add: hourly maintenance is based on AIRBORNE TIME. So taxiing time costs nothing (except for the fuel). One could get into a debate about hobbs time etc etc but basically if anyone charges for any ground time (as most schools do) this is just a way to make more money or, putting it another way, to keep the official hourly cost appear lower. It's very difficult to make this fair to all, unless you rent out dry and have a fuel flowmeter!

Wise words indeed above re careful management of flying hours around the 150 hr / annual mark. Interesting you mention extensions... my frustrating experience suggests that succes there depends on whether or not you're one of the 'chosen few' with your engineer (!)

I have been subjected to the phrase "we don't give extensions for operating reasons" ... particularly galling when the engineers concerned are pretty awful at managing their own timelines / spares ordering etc etc etc... Only extension they'd give was to the calendar aspect (not the hours) due to their inability to get the previous aeroplane out on time. Great. And entirely different to my own ethos when I used to work as a professional engineer... but that was on HMFC's pointy jets!