I wondered the same, so last week I contacted Honeywell on exactly that point. Honeywell confirmed it was AFN2.
Very interesting!
I can see the AAIB possibly just referring the unit as its base model name RESCU406AFN but it also refers to it containing a 'set' of batteries rather than a 'pair' and makes reference to '6000 units' which clearly must be the original model.
The first safety recommendation (2013-16) refers specifically to the RESCU406AFN model but the second recommendation (2013-17) refers to "installations of
Lithium-powered Emergency Locator Transmitter systems" which I assume means both mark 1 and mark 2.
For some reason the mark 2 model has the wording RESCU406AFN on the case, which may be the cause of the confusion.
Very strange!
