Everyone thought so all along, but since the Chief Counsel said otherwise, everyone was wrong all along. Don't it make you want to strangle Mangiamele for asking the question? But for that, Flight Standards wouldn't ever have bothered anyone about it, since they didn't seem to think there was anything wrong with it.
Actually, I think it was the FAA Chief Counsel who said tax deductions are not compensation, in an interpretation some time ago.
Actually the FAA Chief Counsel said in the first Angel Flight opinion that the tax deduction
was compensation and Angel Flight needed a Part 135 certificate. Fortunately, the opinion was requested by Senator Phil Gramm who didn't much like it. The Chief Counsel reversed itself, but only for policy, not legal reasons.
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"As a matter of policy, taking into consideration the fact that Congress
has specifically provided for the tax deductibility of some costs of
charitable acts, we will not treat charitable deduction of such costs,
standing alone, as constituting "compensation or hire" for the
purpose of enforcing [Paragraph] 61.118 or Part 135. If taking a charitable
tax deduction for transporting persons or property is coupled
with any reimbursement of expenses, or other compensation of any kind, then
this policy does not apply."
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AFAIK, as recently as 2009's Silverberg letter, the charitable deduction not being treated as compensation has been applied only to charitable flights. I would hesitate expanding it beyond the charitable situation without guidance.