However, the present action for nuisance and inverse condemnation is predicated on facts peculiar to each prospective plaintiff. An approaching or departing aircraft may or may not give rise to actionable nuisance or inverse condemnation depending on a myriad of individualized evidentiary factors. While landing or departure may be a fact common to all, liability can be established only after extensive examination of the circumstances surrounding each party. Development, use, topography, zoning, physical condition, and relative location are among the many important criteria to be considered. No one factor, not even noise level, [FN 8] will be determinative as to all parcels.

[FN 8] For instance, it is conceivable the noise created by airport traffic may cause no actionable interference with land immediately adjoining the end of the runway -- because that land is used for a noisy industrial use, while the same air traffic may be causing substantial interference giving rise to liability to a single family residence miles away. Similarly, compare vacant lots zoned agricultural as opposed to those zoned residential. Contrast a home built in the heart of a residential area with one built next to the railroad tracks.

Plaintiffs attempt to avoid the application of Weaver to this case, and thereby to sustain the class, by avoiding the need for individual evaluation. They attempt to divide the parcels of land represented by the class into subclassifications and then to determine, as a group, the diminution in value for all members in each subclassification. This scheme fails in two respects.

First, the scheme necessarily requires plaintiffs to disregard all liability for other forms of damage (i.e., actual physical injury to the property). As we shall conclude below, the representative of a class may not be allowed to commit such a breach of a fiduciary duty. Hence, the proposed classification system is unacceptable.

Second, the scheme is incompatible with the fundamental maxim that each parcel of land is unique. (Civ. Code, § 3387; see also Porporato v. Devincenzi (1968) 261 Cal.App.2d 670, 677 [68 Cal.Rptr. 210].) Although this rule was created at common law, the very factors giving it vitality in the simple days of its genesis take on added significance in this modern era of development. Simply stated, there are now more characteristics and criteria by which each piece of land differs from every other.

We decline to alter this rule of substantive law to make class actions more available. Class actions are provided only as a means to enforce substantive law. Altering the substantive law to accommodate procedure would be to confuse the means with the ends -- to sacrifice the goal for the going. [FN 9]

[FN 9] The federal law on class actions is in accord. Rule 23 was not intended to make a change in the substantive law (see rule 82, Fed. Rules Civ. Proc.; Zahn v. International Paper Co. (1973) 414 U.S. 291 [38 L.Ed.2d 511, 94 S.Ct. 505]; Snyder v. Harris (1969) 394 U.S. 332 [22 L.Ed.2d 319, 89 S.Ct. 1053]); and the federal courts have been criticized where they have made such changes. (See Simon, Class Actions -- Useful Tool or Engine of Destruction (1971) 7 Lincoln L.Rev. 20, 22, 25, 27-31.)

Conversely, these uniqueness factors weigh heavily in favor of requiring independent litigation of the liability to each parcel and its owner. Because liability here is predicated on the impact of certain activities on a particular piece of land, the factors determinative of the close issue of liability are the specific characteristics of that parcel. The grouping and treating of a number of different parcels together, however, necessarily diminishes the ability to evaluate the merits of each parcel. The superficial adjudications which class treatment here would entail could deprive either the defendant or the members of the class -- or both -- of a fair trial. Reason and the constitutional mandates of due process compel us to deny sanction to such a proceeding.

The proposed classification system failing, [FN 10] the proposed class fails. It is true some questions common to the members of the class remain. But the class judgment rendered on these facts would not determine issues of sufficient number or substantiality to warrant class treatment. [FN 11] Most notably, the class judgment would fail to establish the basic issue of defendant's liability to the purported class. While we have held in several cases the failure of the class judgment to establish individual damage would not be fatal, in each the class judgment to be rendered would have established the basic issue of liability to the class. (See Collins v. Rocha, supra, 7 Cal.3d 232; Vasquez v. Superior Court, supra, 4 Cal.3d 800; Daar v. Yellow Cab Co., supra, 67 Cal.2d 695.) (16) Only in an extraordinary situation would a class action be justified where, subsequent to the class judgment, the members would be required to individually prove not only damages but also liability. There is nothing to indicate the instant action presents such an extraordinary situation.

[FN 10] Our decision here is consistent with Vasquez v. Superior Court, supra, where we pointed out the possibility of dividing a class into subclassifications. (4 Cal.3d 800, 821.) This decision serves to make explicit what was there implicit -- that there are limits outside of which the subclassification system ceases to perform a sufficiently useful function to justify the maintenance of the class action. The instant situation represents merely an example of facts falling outside these limits.

[FN 11] The federal cases are in accord in similarly disallowing class actions for airport nuisance and "inverse condemnation." (See Virginians for Dulles v. Volpe (E.D.Va 1972) 344 F.Supp. 573, 575; Town of East Haven v. Eastern Airlines, Inc. (D.Conn. 1971) 331 F.Supp. 16, 18.)

Inadequacy of Representation

We also conclude the trial court abused its discretion in certifying this class action for the reason the plaintiffs fail to adequately represent the members of the class.

To maintain a class action, the representative plaintiff must adequately represent and protect the interests of other members of the class. (La Sala v. American Sav. & Loan Assn. (1971) 5 Cal.3d 864, 871-872 [97 Cal.Rptr. 849, 489 P.2d 1113].) This requirement is a natural consequence of the equitable origins of the action and is the product in part of the relation between the res judicata effect of the class judgment on absent members and the requirements of due process. [FN 12] (Hansberry v. Lee (1940) 311 U.S. 32 [85 L.Ed. 22, 61 S.Ct. 115, 132 A.L.R. 741]; Carroll v. American Federation of Musicians of U.S. & Can. (2d Cir. 1967) 372 F.2d 155, 162.)

[FN 12] Similarly, federal law will not allow a class to be maintained except by a "representative" party. This party must fairly and adequately protect the interests of the class. (Rule 23 (a), Fed. Rules Civ. Proc.)

Damages recoverable in a successful nuisance action for injuries to real property include not only diminution in market value but also damages for annoyance, inconvenience, and discomfort (Kornoff v. Kingsburg Cotton Oil Co. (1955) 45 Cal.2d 265 [288 P.2d 507]); actual injuries to the land (Spaulding v. Cameron (1952) 38 Cal.2d 265 [239 P.2d 625]); and costs of minimizing future damages. (Barnes v. Berendes (1903) 139 Cal. 32 [69 P. 491, 72 P. 406].) The plaintiffs, however, seek only recovery for diminution in market value.

It is clear under California law a party cannot, as a general rule, split a single cause of action [FN 13] because the first judgment bars recovery in a second suit on the same cause. (3 Witkin, Cal. Procedure (2d ed. 1971) Pleadings, § 32, pp. 1715-1716.) (17c) As a result, by seeking damages only for diminution in market value, plaintiffs would effectually be waiving, on behalf of the hundreds of class members, any possible recovery of potentially substantial damages -- present or future. This they may not do.

[FN 13] While there are exceptions to this general rule, none would serve to protect a member of the class here whose interests are not adequately represented. (See 3 Witkin, Cal. Procedure (2d ed. 1971) Pleadings, § 32, p. 1717.)

[FN 14] While it is clear the class action cannot proceed under its present status, ordinarily the representative plaintiff would be afforded the opportunity to cure inadequate representation by amending the complaint. (La Sala v. American Sav. & Loan Assn., supra, 5 Cal.3d 864, 872.) Here, however, because amendment could not cure the failure of sufficient community of interest, affording such opportunity would serve no useful function.

Conclusion

Because we conclude there is insufficient community of interest here to sustain a class suit, and because plaintiffs, in violation of a fiduciary duty, would fail to adequately represent the members of the alleged class, we conclude the trial court's certification of this purported class constitutes a substantial abuse of discretion, for which mandamus lies as a remedy. (Vasquez v. Superior Court, supra, 4 Cal.3d 800, 805-806, 825; Chance v. Superior Court, supra, 58 Cal.2d 275, 278; State Farm etc. Ins. Co. v. Superior Court (1956) 47 Cal.2d 428, 432 [304 P.2d 13].)

The writ of mandamus is granted. The trial court is ordered to vacate its order certifying the class and to enter an order dismissing the class action portion of the above-entitled matter. The alternative writ of prohibition is discharged.

Wright, C. J., McComb, J., and Burke, J., concurred.

TOBRINER, J.

I dissent.

The issue before us is whether the trial court abused its discretion in certifying this case as a class action. The majority, however, give no deference to that court's exercise of its discretion. In a one-sided presentation, the majority opinion notes the individual issues which divide the proposed class, but pays little heed to the more significant common issues of law and fact which unite the class; observes the burden of class litigation but overlooks the far greater burden of individual suits; claims to protect the rights of class members to claim damages, but takes from them the most effective means of enforcing that right. The trial judge carefully weighed the benefits and burdens of a class proceeding, and concluded that maintenance of this suit as a class action would yield a substantial saving of time and expense; the majority lean on the scales.

"[T]he determination of the question whether a class action is appropriate will depend upon whether the common questions are sufficiently pervasive to permit adjudication in a class action rather than in a multiplicity of suits." (Vasquez v. Superior Court (1971) 4 Cal.3d 800, 810 [94 Cal.Rptr. 796, 484 P.2d 964, 53 A.L.R.3d 513]; see Collins v. Rocha (1972) 7 Cal.3d 232, 238 [102 Cal.Rptr. 1, 497 P.2d 225].) In the instant case, the underlying legal controversies respecting the liability of an airport for diminution of the market value of adjoining property, the defense of governmental immunity, and the matter of compliance with the claims statute present issues of law common to each member of the class. Common issues of fact include the expansion of airport operations, the schedule of arriving and departing aircraft, and the pattern and intensity of noise and vibrations emanating from the planes.

The diverse issues stressed in the majority opinion relate to the proof of damages, [FN 1] and arise only because of the variety of land use within the flight pattern of the San Jose Municipal Airport. Since the impact of noise and vibration upon property values may depend upon the use and location of the property, the determination of damage to a single family residence may have little in common with proof of damage to a parking lot two miles away. Yet within a subclass of single family homes, common issues may predominate over diverse issues; an appraiser, for example, might find it possible to use the same tools of analysis and record of comparable sales to appraise the market value of all residences in a neighborhood. Thus the presence of the diverse issues cited in the majority opinion need not operate to deprive the parties and the courts of the benefits of class litigation.

[FN 1] The majority stress the argument that the diverse and individual issues in the present case bear upon the question of liability as well as damages. In fact, all diverse issues here pertain only to the proof of the existence and amount of damages. Plaintiffs, however, assert counts for nuisance and inverse condemnation; in both counts the existence of some damage is an essential element of the cause of action. Thus in a technical sense the diverse issues in the present case go to the question of liability -- in that damage itself is an essential element of liability -- but this factor does not prove that diverse issues here predominate over common issues. It demonstrates, instead, that the distinction between issues of liability and issues of damages is not a useful tool for determining the desirability of a class action in cases in which damage is not an independent controversy but an element of the cause of action.

Rejecting the subclassification proposed by plaintiffs, the majority bar maintenance of this suit as a class action on three grounds: (1) that plaintiffs do not properly represent the members of the class; (2) that subclassification offends against the principle that each parcel of land is unique; and (3) that an unmanageable number of subclasses would be required. Each of these grounds lacks merit.

In order to eliminate issues which affect only a portion of the class, plaintiffs limited their prayer for damages to the diminution in market value caused by the flights, and declined to seek additional damages for annoyance, inconvenience, or actual physical injury. The majority maintain that plaintiffs' failure to claim damages for such harm constitutes a breach of the fiduciary duty owing by plaintiffs to the class they represent.

This court gave short shrift to a similar contention in Chance v. Superior Court (1962) 58 Cal.2d 275 [23 Cal.Rptr. 761, 373 P.2d 849]. In the present case, as in Chance, "all of the members of the instant class are ascertainable ..., and it is assumed that they will be given notice of the pending class ... action by registered mail or other like reliable method ..., thereby being afforded an opportunity to decide whether to appear and argue for any and all appropriate or available forms of redress desirable from their individual points of view ...." (58 Cal.2d at p. 290.) Thus the continued maintenance of this suit as a class action will permit the class members to choose between asserting their individual damage claims upon whatever theory they select and taking advantage of the economy and convenience of class representation.

Under these circumstances, the assertion that the plaintiffs are not properly representing the class, especially when presented by the defendant, strikes a hypocritical note. The majority opinion speaks of protecting the right of class members to damages, but destroys what may be the only efficient means of redress. The cost and inconvenience of individual litigation may very well dissuade many members of the class from instituting individual suits, and the result of the present decision will then be that such members will recover no damages for loss of market value nor for any other harm.

The majority's assertion that subclassification in the present case is incompatible with the maxim that each parcel of land is unique is both historically and logically unsound. This venerable maxim, which for centuries has served the useful but limited purpose of permitting equitable suits for specific performance of land sale contracts, has nothing to do with class actions. Uniqueness means only that each parcel of land differs in some particular from every other parcel, just as each person differs in some way from every other person. A valid classification, or subclassification, however, does not require that all members of the class possess identical characteristics; it requires only the existence of "issues common to the class as a whole sufficient in importance so that their adjudication on a class basis will benefit both the litigants and the court." (Vasquez v. Superior Court, supra, 4 Cal.3d at p. 811.) The unique character of each parcel of land would not, in itself, prevent a court from concluding that the common issues of fact and law concerning all parcels justified the proposed subclassification.

Indeed, this court and others have often entertained actions brought on behalf of a class composed of the owners of interests in real property. (See, e.g., Chance v. Superior Court, supra, 58 Cal.2d 275 (action to foreclose trust deeds); Bauman v. Islay Investments (1973) 30 Cal.App.3d 752 [106 Cal.Rptr. 889] (tenants' action to construe lease); Foster v. City of Detroit, Michigan (6th Cir. 1968) 405 F.2d 138 (inverse condemnation); Biechele v. Norfolk & Western Railway Co. (N.D.Ohio 1969) 309 F.Supp. 354 [7 A.L.R.Fed. 894] (nuisance).) The unique character of land did not destroy the classification in those cases; I perceive no reason why the maxim should carry greater weight in the present case.

Finally, the majority assert that since the liability to each landowner will depend upon the use of each parcel, and such variables as noise, vapor, and vibration, compounded by factors of distance and direction, the number of subclassifications required approaches a statistical permutation of these elements. The reasoning is statistically erroneous, since it assumes that each element listed is independent of every other element. If, as seems more likely, the degree of noise, vapor, and vibration each vary directly with distance from the flight path, then these elements are not independent factors and do not require separate classification. (Cf. People v. Collins (1968) 68 Cal.2d 319, 328-329 [66 Cal.Rptr. 497, 438 P.2d 33, 36 A.L.R.3d 1176].) The majority's reasoning is also legally meritless, for it assumes that each diverse issue compels the creation of a separate subclass, an assumption which conflicts with the principle that class litigation requires only that common issues predominate over diverse issues. [FN 2]

[FN 2] The majority's assertion that a great many subclasses would be required is pure supposition. The record before us does not indicate how many subclasses will be necessary, and the trial court has rendered no finding on that subject. If later in this litigation the trial court discovers that the number of subclasses is so large that management of the class action is unfeasible, it can then decertify this suit as a class action. (Vasquez v. Superior Court, supra, 4 Cal.3d at p. 821.)

I conclude that neither the grounds stated in the majority opinion, nor the diverse issues here present, preclude the maintenance of this suit as a class action. The substantial saving in judicial time and litigation expense which would result from use of the class action format fully justify the trial court's exercise of its discretion.

Mosk, J. and Taylor, J. [FN*] concurred.

[FN*] Assigned by the Chairman of the Judicial Council.