concurring in part and dissenting in part:
■While I join in the 'balance of the court’s opinion, I am unable to agree that plaintiff is not entitled to recover the costs it incurred in building the four rejected preproduction models. The court bases its holding for defendant here on the ground that plaintiff should have, but did not, follow certain advisory specifications, and so “in rejecting the teaching of the advisories plaintiff assumed the risk that its own techniques would not yield an acceptable result.” The court, I think, misperceives the risk that plaintiff ran when it opted, in the first instance, for its own welding techniques over those found in the advisory specifications. Moreover, I think it does so precisely because it fails to appreciate the difference between the Government’s design specifications, part of which were advisory, and the Government’s performance specifications.
All are by now agreed that the performance specifications which plaintiff tried to meet when it built the first four pre-production models were impossible of attainment, even with the employment of the advisories’ techniques. The parties stipulated this to be true and the board’s opinion of February 21,1975, page 13, although thinking this to be irrelevant, said in pertinent part:
* * * it should now be clear that the specifications were defective in specifying ballistic requirements that could not be met consistently under either the mandatory or advisory specifications. * * *.
It is not true, as the court seems to be saying, that plaintiff assumed all conceivable risks that it would not be able to meet the performance specifications when it opted to disregard certain advisory design specifications. When it did the latter, plaintiff assumed the risk, and only the risk, that it would not meet performance specifications ‘possible of performance. Plaintiff decidedly did not run the risk that it *222would be impossible to comply with the performance specifications. Plaintiff’s choice of welding techniques had no effect whatever on the performance requirements. Plaintiff cannot, within the precedents, be held to have assumed the risk of impossibility with respect to specifications unless it designed them1 or else contractually agreed to assume the risk, neither of which was the case here. J. A. Maurer, Inc. v. United States, 202 Ct. Cl. 813, 485 F. 2d 588 (1973).
Based on the above, I think plaintiff is entitled to an equitable adjustment in the amount of its coste in constructing the original four preproduction models, and I dissent from the contrary holding of the court.
The court’s citations to Bethlehem Corp. v. United States, 199 Ct. Cl. 247, 462 F. 2d 1400 (1972), and Austin Co. v. United States, 161 Ct. Cl. 76, 314 F. 2d 518, cert. denied, 375 U.S. 830 (1963), are inapposite. In Bethlehem, the Government wrote the performance specifications in reliance on the contractor’s statements regarding what was attainable; in Austin, the contractor itself drew up the performance specifications. Here, however, the contractor took no part in the creation of the performance specifications. It therefore simply does not follow from the cited cases that the risk of impossibility as to the end requirements (as distinguished from the design specifications) ever became plaintiff’s responsibility. When plaintiff elected .to ignore the advisories, it assumed only the risk that its design would not meet the Government’s performance requirements.