Article 5
1. Belgium shall take all the necessary measures to recover from the beneficiary the aid mentioned in Articles 1 and 2 and unlawfully made available to it. The aid mentioned in Article 1 may however remain partly unrecovered, for the portion that does not exceed the ceiling, in compliance with the conditions laid down in Article 4. The recovery shall be effected immediately in accordance with the procedures of national law, insofar as they allow immediate and effective enforcement of the present Decision. The aid to be recovered shall include interest running from the date at which it was made available to the beneficiary to the date of recovery. The interest shall be calculated on the basis of the reference rate used for calculating the subsidy equivalent for regional aid. It shall be calculated on a compound basis. 2. If the conditions laid down in Article 4 are not complied with for a portion of the aid, whether that portion corresponds to a category of aid or an aided route, or if the terms for balancing the agreements concluded between Ryanair and BSCA are substantially altered, Belgium shall be required to recover all the corresponding aid referred to in the said article.