There is no such licence as a 'Frozen ATPL'. The term is used in (mostly) UK/Europe as shorthand for someone who has gained a Commercial Pilot Licence, Instrument Rating and passed all theory exams for the Airline Transport Pilot Licence. Increasingly, completing a Multi Crew Co-operation course is being included in the mix. By then the pilot will have logged a couple of hundred hours flight experience. A CPL allows the person to work as a pilot in public transport operations but does not allow the person to be the Pilot-in-command ie Captain, of an aircraft that requires two or more pilots. To be PIC of a multi-crew aircraft type in public transport operations you must hold an ATPL.
Over time the CPL pilot can accrue more hours until eventually reaching the minimum experience required for the issue of an ATPL ie 1500 hours with various sub-totals within the 1500 hrs. On satisfactory completion of a flight test or similar recurrency training, and with the requisite flight experience the pilot may then apply for the issue of an ATPL. This is referred to as 'unfreezing the ATPL'. Not that they had an ATPL to 'unfreeze' in the first place but that's colloquial English for you....
Last edited by Tinstaafl; 4th February 2011 at 23:29.