An AA5? Total overkill? I experienced a few accidents during my 38 years in the industry and never closed an airport for this length of time for a small aircraft? Unless fuel contamination or some other influence the airport could have had on the accident aircraft? In fact fuel contamination can be checked very quickly! In my experiences with AAIB they are very aware of the need to re-open the airport and very happy to move light aircraft, but I left the UK in 2008 so things could have changed?