Calculating costs - tach or hobbs?

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Calculating costs - tach or hobbs?

Postby gshep on Fri Mar 21, 2014 7:58 pm

I am fairly new at this, I have done 2 flights to date and hope to do many more. I have been researching cost calculation for tax purposes and am a bit confused.

I have a good handle on the variable cost (as this is what the IRS allows) per hour to operate my plane - fuel, oil plus ramp fees, etc. And I had planned to base my deductions on this hourly cost plus incidentals. In all my calculations on variable costs per hour I have used clock hours, as if using hobbs time, the same way I log my flight time. I had planned to use this clock hour calculation for tax purposes. What confuses me are the fields on the PnP flight form:
STARTING TACH TIME_____________ENDING TACH TIME_______________HOURS________
as if tach hours are supposed to be used in the cost/hr calculation.

Should I be using tach hours for variable cost calculations instead?
Should I change the form to "hobbs start/end" to suit my calculations?
Should I find the conversion for hobbs to tach on my plane?
Should I just use straight expenses for the flight, for example cost to fill up during/after the trip?
Does it matter as long my tax accountant (my wife) understands the method used and we document it?
Am I over-thinking it? :)

How do others handle this?
VFR Pilot - KFFC (Peachtree City, GA)
Posts: 84
Joined: Sun Aug 04, 2013 5:26 pm
Last Visit: Sat Jun 07, 2014 12:29 pm

Re: Calculating costs - tach or hobbs?

Postby mikegreen on Tue Mar 25, 2014 11:29 am


It is just for record keeping - if you know/have a calc for your operating costs, you should use that. You can also deduct driving to/from the airport, any towels, treats, crates, etc as well.

I'm not aware of any PNP pilot going thru an audit; so just stick to best practices by logging everything and keeping copies or scans of receipts/etc.

My post-flight list includes:
update log book, indicating it was a PNP trip
update google docs PNP flight log
update the thread with "we're done!" and any pictures
save PNP thread to a PDF in my PNP folder
save pictures I took at pickup/dropoff airports (which are geo-tagged on the iphone) to my PNP folder

Cessna 182RG, IFR
Based KMGY, Dayton, OH
Posts: 429
Joined: Fri Nov 19, 2010 9:33 am
Location: Dayton, OH (MGY)
Last Visit: Thu Jul 24, 2014 5:58 pm

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