Necessary refers to a "necessary expense" as defined in IRS Publication 463.  Necessary is one of the tests that must be passed in order for an employee business expense or travel expense to be tax deductible.  IRS Publication 463 defines a necessary expense as one that is:

...helpful and appropriate for your business. An expense does not have to be required to be considered necessary.

For flight crew tax returns and airline tax preparation purposes that means an expense is considered necessary if it is considered helpful for airline flight crew employment tasks.  Furthermore, the aviation employer does NOT have to require the expense for it to be a legitimate airline-related employee business expense.  A great example of this is a calculator that an airline first officer keeps in his or her flight case for performing weight and balance tasks.  The airline employer may not require that pilots carry a calculator, but the calculator could easily be determined to be necessary based on the above definition of a necessary expense.

 

To learn more about how to determine whether or not an airline employee business expense is tax deductible, click here to visit an EZPERDIEM.COM Article that describes the methodology an airline pilot or flight attendant should go through deducting a given expense.  The EZPERDIEM.COM Expense Processor^TM makes it simple to calculate airline pilot and flight attendant tax deductions for a given tax year.

 

See also, ordinary expense and personal expense.