A brief look at the book by Graham McBain on Aircraft Liens and Detention Rights
which has chapters on the law on aircraft liens and
detention rights in over 80 countries, reveals that the concept of some type of
possessory lien or right of retention exists in most jurisdictions; and it is not surprising that the Official Commentary in Appendix XIIC shows that most Contracting States that declared specifically rather than generally as
to NCRIs included a form of repairer’s lien. Being possessory in most cases means that they are largely secret liens or rights of retention
unless one knows that the aircraft is undergoing repair or maintenance at the time. Systems have developed to fit the liens into filings that are public in some jurisdictions, but even in the case of the United States described below, this
has not eliminated possessory liens for repair.