My club has 2 O-200's affected by this issue. Teledyne Continental SIL98-9A gives 12 years OR 1800 hours. However, there is no 'whichever occurs first'. Does this imply a choice between the two? The lack of a 'whichever occurs first' does not appear to be simply semantics, 'cos the very next paragraph pertains to aerial spraying, where the recommendation is 12 years OR 1200 hours WHICHEVER OCCURS FIRST (my capitalisation). Definitely no choice there then.
Doesn't the wording of CAP 747 GR24 still allow the CAA to grant 'extensions' (don't have it in front of me but my recollection is of a 'decision tree' diagram to this effect)? It's specifically a CAA extension, not one granted by a maintenance organisation.
Having spoken to a CAA chap, it's been suggested that a written case for extension (on a case-by-case basis) submitted to CAA might help. What's folk's views on that? (steps back to fit kevlar before retreating to bunker)