Defendants appeal from a judgment in favor of plaintiff in an action to recover 1953 taxes paid under protest to the Tax Collector of Los Angeles County upon the assessment of five airplanes.
Facts: Plaintiff is a Delaware corporation, with its principal place of business in the county of Los Angeles. It is engaged in business as a common carrier of freight by air, operating in interstate and foreign commerce under a certificate issued by the Civil Aeronautics Board.
On the assessment date in 1953, the first Monday in March, plaintiff owned and operated 37 aircraft of two different types. It had 27 C-46 planes, which were used only in its domestic commercial service. These planes did not have a sufficient range for overseas flying. They were assessed at a portion of their book value determined by computing the percentage of the total time, during a test period selected by the county assessor, that the planes were physically present in the county of Los Angeles. The tax on these planes is not disputed.
Plaintiff also operated 10 DC-4 planes in flying the Pacific airlift under control of the military authorities and in support of the war in Korea. The route of this lift was from the United States to Tokyo, Japan. Five of these planes were leased by plaintiff and five were owned by it. Plaintiff’s interest in the leased planes was assessed on the same formula applied to the C-46 planes. This tax is undisputed.
The other five DC-4- planes that were operated on the Pacific airlift were removed from the remainder of plaintiff’s fleet of 37 planes by the co-unty assessor and were assessed at 100 per cent of their value ivithout regard to the time they were physically present in the county. The difference between the amount of the tax paid on the full assessment of these five planes and the amount which would have been taxed if the assessor had assessed them on the same basis as all the other planes is the amount sought to be recovered.
Plaintiff filed a petition for redetermination of the assessment before the Los Angeles County Board of Supervisors, *317sitting as a board of equalization, for the year 1953-1954. After two hearings before the board, the application for relief was denied. The tax was subsequently paid under protest. Thereafter plaintiff filed this suit for recovery against the county of Los Angeles and the city of Burbank. The city was made a defendant as required by section 5138 of the Revenue and Taxation Code.*
Questions: First. Does defendant county have the power to assess an ad valorem property tax upon the full value of aircraft which are regularly flown in interstate and foreign commerce and physically present in the county only a part of the time during the period for which the tax is collected?
No. The five planes involved were used chiefly in the performance of the Pacific airlift instituted in 1950 as a result of the Korean war, and operations during the period in question were scheduled by the military authorities and not by the Civil Aeronautics Board.
A proper decision of this case rests upon the application of four United States Supreme Court decisions. In 1944 the Supreme Court of the United States decided, in Northwest Airlines, Inc. v. Minnesota, 322 U.S. 292 [64 S.Ct. 950, 88 L.Ed. 1283, 153 A.L.R. 245], that Minnesota, the home port state of the airline, could levy a property tax on the entire value of a fleet of planes in spite of the fact that the same planes were admittedly taxed on a portion of their value by six of the seven other states through which they operated.
In 1949 the Supreme Court, in Ott v. Mississippi Talley Barge Line, 336 U.S. 169 [69 S.Ct. 432, 93 L.Ed. 585], modified the rule previously laid down in Northwest Airlines, Inc. v. Minnesota, supra. The Ott ease involved barges and tugs operated up and down the Mississippi River and owned by a corporation domiciled in Ohio. These tugs and barges were taxed on an apportioned basis by the State of Louisiana, where *318they made certain irregular stops. The court held that Louisiana could tax the vessels on a portion of their value. With reference to the question of the due process aspect of a tax of this type, the court stated at page 174: “So far as due process is concerned the only question is whether the tax in practical operation has relation to opportunities, benefits, or protection conferred or afforded by the taxing State. (Citation. ) Those requirements are satisfied if the tax is fairly apportioned to the commerce carried on within the State.”
In 1952 the Supreme Court, in Standard Oil Co. v. Peck, 342 U.S. 382 [72 S.Ct. 309, 96 L.Ed. 427, 26 A.L.R2d 1371], involving vessels travelling on the Mississippi River, adopted the rule that a domiciliary state could not tax the full value of property located only part of the time within a state without constituting an unreasonable burden upon interstate commerce and thus violating the due process clause of the United States Constitution. The court said at page 384: “No one vessel may have been continuously in another state during the taxable year. But we do know that most, if not all, of them were operating in other waters and therefore under Ott v. Mississippi Barge Line Co., supra, could be taxed by the several states on an apportionment basis. The rule which permits taxation by two or more states on an apportionment basis precludes taxation of all of the property by the state of the domicile. (Citation.) Otherwise there would be multiple taxation of interstate operations and the tax would have no relation to the opportunities, benefits, or protection which the taxing state gives those operations. ’ ’
In 1954 the Supreme Court, in Braniff Airways, Inc. v. Nebraska State Board of Eq. & A., 347 U.S. 590 [74 S.Ct. 757, 98 L.Ed. 967], applied the rule previously laid down in Standard Oil Co. v. Peck, supra, to aircraft flying in interstate commerce. This case involved a fleet of planes which had its home port in the State of Minnesota, but which was used in and out of the taxing state, Nebraska. Nebraska imposed an apportioned ad valorem tax on the equipment, based upon the percentage of time in and out of the state. The court said at page 600: “We perceive no logical basis for distinguishing the constitutional power to impose a tax on such aircraft from the power to impose taxes on river boats.”
It thus appears that the United States Supreme Court has now held that the rule which permits taxation by two or more states on an apportioned basis precludes taxation on all the property by the state of domicile.
*319In Standard, Oil Co. v. Peck, supra, at page 384, the court said: ‘ ‘ Those cases, though exceptional on their facts, illustrate the reach of the taxing power of the state of the domicile as contrasted to that of the other states. But they have no application here since most, if not all, of the barges and boats which Ohio has taxed were almost continuously outside Ohio during the taxable year. . . . The rule which permits taxation by two or more states on an apportionment basis precludes taxation of all of the property by the state of the domicile. (Citation.) Otherwise there would be multiple taxation of interstate operations and the tax would have no relation to the opportunities, benefits, or protection which the taxing state gives those operations.”
A taxpayer resisting an ad valorem tax on personal property based on an unapportioned assessment does not have the burden of showing that other states have actually imposed a tax on such property. He is entitled to an assessment on an apportionment basis if the record shows that he was, during a tax year, receiving substantial benefits and protection in more than one state.
In the present case, there was no apportionment with respect to the assessment of the five planes. Therefore, as a matter of law, the tax was not levied upon a proper basis.
The holding in Slick Airways, Inc. v. County of Los Angeles, 140 Cal.App.2d 311 [295 P.2d 46], is in accord with the foregoing views. In that ease, a fairly apportioned assessment on planes of this type was determined by the Los Angeles County Assessor. The company had its principal place of business in California in 1952 and 1953. The court, at page 312, had this to say with reference to the normal assessment procedure in Los Angeles County: “Plaintiff is engaged in flying a fleet of airplanes in interstate and foreign commerce. Such airplanes, under the practice of the county assessor of Los Angeles County, are assessed on the basis of a fair allocation of time, to wit, the ratio of the time spent in Los Angeles County as compared to total time.”
Thereafter, the court properly recognized that under the circumstances present, which were similar to those in the instant case, the county of Los Angeles had authority to tax only a portion of the value of the planes. In referring to the decision of the United States Supreme Court in Braniff Airways, Inc. v. Nebraska State Board of Eq. & A., supra, the court, at page 314, said: “The Supreme Court, in upholding the validity of the tax, said, at page 600: ‘The limitation im*320posed by the Due Process Clause upon state power to impose taxes upon such instrumentalities was succinctly stated in the Ott Case: “So far as due process is concerned the only question is whether the tax in practical operation has relation to opportunities, benefits, or protection conferred or afforded by the taxing State.” ’ ”
Second. When relief from an improper assessment is sought from the hoard of supervisors sitting as a hoard of equalization, and denied in the belief that the only issue is one of law for the courts, is the applicant hound hy this decision on an appeal to the superior court?
No. Defendants argue that plaintiff is entitled to a trial “of factual matter which should have been but was not presented to said Board for determination.” This question is not presented to this court, because the trial court rendered its decision without consideration of any evidence offered before the trial court, basing it upon a question of law.
Security-First National Bank v. County of Los Angeles, 35 Cal.2d 319 [217 P.2d 946], relied on by defendants, is not applicable to the facts of the present case, for in that ease no application for relief was filed with the board of supervisors.
The duties of a board of supervisors sitting as a board of tax equalization are prescribed in article XIII, section 9, of the California Constitution, which reads, in part: “The boards of supervisors of the several counties of the State shall constitute boards of equalization for their respective counties, whose duty it shall be to equalize the valuation of the taxable property in the county for the purpose of taxation. ...”
The duties of the board are fully set forth by this court in Universal Consolidated Oil Co. v. Byram, 25 Cal.2d 353, 356-357 [153 P.2d 746] : “It must be conceded, of course, that it is well settled in this state that to the authorized county board of equalization has been confided the duty of determining ‘the value of the property under consideration for assessment purposes upon such basis as is used in regard to other property, so as to make all the assessments as equal and fair as is practicable’; that in discharging this duty, ‘the board is exercising judicial functions, and its decision as to the value of the property and the fairness of the assessment so far as amount is concerned constitutes an independent and conclusive judgment of the tribunal created by law for the determination of that question,’ adjudicating necessarily that ‘the property is assessed at the same value proportionately as all the other property in the county’,- that such adjudication *321‘cannot be avoided unless the board has proceeded arbitrarily and in willful disregard of the law intended for their guidance and control, with the evident purpose of imposing unequal burdens upon certain of the taxpayers ... or unless there be something equivalent to fraud in the action of the board’; and that ‘Mere errors in honest judgment as to the value of the property will not obviate the binding effect of the conclusion of the board.’ (Citations.) While not classifiable with any aspect of fraud or bad faith, the lack of due process distinguishing the procedural phase of these equalization matters as submitted to the board furnishes an equally appropriate basis for the court’s intervention in protection of the plaintiffs’ constitutional rights.” (Emphasis added.)
The court said, at page 360 [3] et seq.: “The fundamental premise of the plaintiffs recourse to the court for relief rests upon the proposition that, as with any ad valorem tax, their constitutional right to an equalization hearing comprehends a decision in the light of the evidence there introduced before any determination becomes final as to them. (Citations.)
As any tax proceeding is in invitum in nature, each step must be taken in compliance with law or the proceeding is void. The equalization stage is no exception to this rule.
Compliance with the constitutional requirement for an equalization hearing is not met unless the substance as well as the form of the hearing is granted to the complaining taxpayer. (Citation.) Typical illustrations of the denial of procedural due process which have been held to invalidate purported equalization determinations are: One man hearings (citation); the taking of evidence without the presence of the taxpayer or his representative (citations); the refusal to allow reasonable opportunity for cross-examination (citation); the refusal to permit reasonable argument (citation); reliance in the concluding steps upon the advice of the assessor or the assessor’s attorney, particularly if done secretly (citation) ; and the attempted determination of a ease by members of the board who did not hear the evidence, if their vote be necessary to the determination (citation).
“In line with these instances of the denial of procedural due process are the present cases. The concluding steps of the equalization proceeding are many times the most essential to the preservation of the taxpayer’s rights.”
Again the court said, at page 362 [6]: “As appears from the numerous authorities cited in the forepart of this opinion, the respective county board of equalization is the fact*322finding body designated by law to remedy excessive assessments (Cal. Const., art. XIII, §9), and Avhen that tribunal, after due hearing and Avithin the limits of reasonable discretion, makes its findings on the ¡acts, such decision is final and conclusive. ’ ’
It is evident from the foregoing authority that when a board of equalization purports to decide a question of law, or refuses to hear a case on the ground that it involves only a question of law to be decided by the courts, a taxpayer has the right to resort to the courts for determination of such question.
In the present case, there was no dispute as to the facts, a question of law alone being presented to the board of equalization, as appears from the following excerpt from the transcript :
“Mr. Jessup [Member of the Board] : Mr. West, there is no chance of you and this gentleman sitting down and working this thing out?
“Mr. Anson [Deputy County Counsel] : There is a very definite legal issue other than the facts; I don’t think there is too much of a quarrel as regards the facts.
“Mr. Hahn [Member of the Board] : There’s no quarrel with the facts, but a legal question ?
“Mr. Anson: Primarily a legal question; that is, as far as the five aircraft covered under this second item are concerned. ’ ’
(See also Mahoney v. City of San Diego, 198 Cal. 388, 403 [9] [245 P. 189], where an arbitrary method of property valuation adopted by the assessor and approved by the board of supervisors was held a proper subject for court review.)
Applying the foregoing rule to the present case, it appears that plaintiff sought relief before the board of equalization. This relief was denied solely because the board, on the advice of its counsel, applied an improper principle of constitutional law. Therefore, plaintiff properly applied to the superior court for relief.
In light of the foregoing, the trial court was correct in holding that defendant county had exceeded its power to tax the airplanes here involved and in entering judgment in favor of plaintiff.
The judgment is affirmed.
Shenk, J., and Sehauer, J., concurred.
Section 5138 of the Revenue and Taxation Code reads: ‘‘Within six months after the payment, an action may be brought against a county or a city in the superior court to recover the taxes paid under protest. “If all or any portion of the taxes paid under protest and sought to be recovered were collected by officers of the county for a city, an action must be brought against the city for the recovery of such taxes and judgment must be sought against the city. Where actions are brought against both a county and a city such actions may be joined in one complaint.
“Any city for which county officers collect taxes may provide for the defense by counsel for the county of actions brought against the city under this article, in which event it shall be the duty of such counsel to defend such actions, or the city may provide that such actions shall be defended by its own counsel.”