In two actions to recover under an aircraft accident insurance policy, the defendant in both actions, American Home Assurance Company, appeals from (1) an order of the Supreme Court, Westchester County (Beisheim, J.), dated February 17,1982, which, inter alia, granted plaintiffs’ motions for summary judgment; and (2) a judgment of the same court entered thereon on March 4, 1983. 11 Appeal from the order dismissed (see Matter of Aho, 39 NY2d 241, 248). H Judgment modified, on the law, by deleting the provisions awarding interest to plaintiffs from August 6, 1980, in the amount of $41,050.68; order dated February 17, 1982, modified accordingly. As so modified, judgment affirmed, and matter remitted to the Supreme Court, Westchester County, for reconsideration of the computation of interest in accordance herewith, and thereafter for entry of an appropriate amended judgment. H When relying on an exclusionary clause, the insurer must show not only that its interpretation of the clause is reasonable, but that the clause cannot be reasonably interpreted in any other way (see Sincoff v Liberty Mut. Fire Ins. Co., 11 NY2d 386; American Home Assur. Co. v Hartford Ins. Co., 74 AD2d 224; American Fid. Fire Ins. Co. v Pardo, 32 AD2d 536). Plaintiffs have advanced, without resort to extrinsic evidence, a fair interpretation of the exclusionary clause in question under which it is inapplicable to *804the facts of the case at bar. The defendant insurer, having relied for its defense solely upon this clause, cannot prevail at trial, and the granting of summary judgment to plaintiffs was therefore appropriate, f Interest on the judgment should not, however, have been computed from the date of death, but rather from the date on which the cause of action for breach of contract accrued (CPLR 5001, subd [b]), which in this case is the date on which the insured was first entitled to demand payment. Under the terms of this policy, payment was due upon the receipt of written proofs of loss. If the. insurer failed to provide such forms within 15 days of the giving of notice of the claim, however, the requirement would be deemed complied with upon the submission of “written proof covering the occurrence, the character and the extent of the loss for which claim is made”. It can be inferred that the insurer did not provide the required form, since it is not contained in the record and its absence was not a basis for defense of this action. Interest will run, therefore, from either 15 days after the giving of notice of the claim, or the submission of the alternative proof, whichever was later. Because these facts do not appear in the current record, however, the matter must be remitted to the Supreme Court, Westchester County, so that they can be determined and the interest can be recomputed accordingly. O’Connor, Brown and Eiber, JJ., concur.