As I understand it, if you have a CPL and are deriving an income from flying, then things like training, upgrades, renewals, headsets, charts etc are tax deductible (Headset would be depreciated)
If you have a CPL but derive your income from elsewhere then it is not tax deductible.
People can run into complications from Workers Comp when flying for work.
But why not make an appointment with a tax accountant and get an expert opinion?