Recordkeeping refers to IRS rules established in IRS Publication 463. If flight crew members have deductible travel, entertainment, gift, or transportation expenses, they must be able to prove (substantiate) certain elements of the aviation-related tax write off. This is accomplished with adequate recordkeeping techniques. If flight crews keep timely and accurate records, then the pilot or flight attendant will have support to show the IRS if their tax return is ever examined via an IRS audit.