Valuing General Aircraft

The California Constitution provides that all property is subject to taxation (property taxes).  In addition to real property such as land, structures and vineyards, the county assessor is responsible for the valuation of four main categories of personal property; boats, aircraft, equipment used in a trade or business and manufactured homes not on a permanent foundation. For the 2020-2021 tax year, Napa County assessed 270 aircraft with a total assessed value of $128,192,027.  The annual valuation of aircraft as of the January 1 lien date is governed by specific laws and regulations that require close cooperation between the aircraft owner and assessor division staff.

Pursuant to California Revenue and Taxation Code Section 5364 the State Board of Equalization in Sacramento has approved the Aircraft Bluebook Price Digest, a commercial valuation guide, which the Assessor must use to assess individual aircraft.  The guide is published each fall and gives a base average value (BAV) for most aircraft in general aviation use by model and year built.  The State Board has also mandated that each County Assessor use only 90% of the BAV to insure that a conservative valuation is used as a starting point.

Adjustment Factors

The reduced BAV is adjusted for a number of factors.  The first factor is the amount of time on the airframe (usually the total hours the aircraft has flown since built).  The Digest publishers have researched the average airframe hours for the fleet of each model by year built.  If the subject aircraft being assessed in Napa County has more airframe hours than the fleet average, a downward value adjustment is given; if fewer hours, an upward adjustment.  The second factor is the number of hours on the engine(s) since major overhaul (SMOH).   Each aircraft engine must be overhauled after a certain number of hours based on manufacturer’s recommendations and Federal Aviation Administration (FAA) regulations.  The Digest gives the estimated cost of the overhaul, say $25,000 and the number of hours between overhauls, say 1500 hours.   Dividing $25,000 by 1500 gives a cost of $16 per hour.    If an engine is less than halfway to overhaul, say 600 out of 1500 hours, there is an upward adjustment calculated by 750 hours – 600 hours = 150 hours x $16/hr = $2,400 increase.   If the engine has 1200 hours on it, the downward adjustment would be 1200-750=450 hours times $16/hr= $7,200 reduction.

Standard Options

The BAV includes a number of items that are considered standard for that aircraft for that year.   These items include avionics, such as radios, glide slope, autopilots, electric trim; accessories such as larger fuel tanks and condition issues such as damage history, original logbooks, compliance with airworthiness directives, and paint/upholstery condition.  Aircraft owners need to update the Aircraft Owner Report that they file with this office annually to make sure that we have the most current information on the items covered by the BAV so that we can arrive at a correct value.

Sales Tax

Finally, California assessment practices require that sales tax be included with the value because sales tax and other charges such as delivery are part of the cost of putting an aircraft (or any item of business equipment) into service in California. Because the values for each model and year in the guide are used by jurisdictions across the country, the values do not include sales tax.   Aircraft start out with a fresh BAV each year because of market fluctuations unlike a desk or a computer which has an original acquisition cost that includes sales tax and is then factored each year to arrive at the January 1 value.  Thus the sales tax must be added to the adjusted BAV each year to arrive at a full cash value under California law.

Contact Information

Should you have any questions please contact Napa County Assessor-Recorder-County Clerk John Tuteur at 707.253.4459 or by e-mail [email protected]   More articles can be found at