The Validity, Perfection and Enforceability of Security Interests in Aircraft and Spares in The Netherlands - Air and Space Law View The Validity, Perfection and Enforceability of Security Interests in Aircraft and Spares in The Netherlands by Berend J.H. Crans - Air and Space Law The Validity, Perfection and Enforceability of Security Interests in Aircraft and Spares in The Netherlands Berend J.H. Crans 21 3 Air and Space Law