Did Air France's accident rate change with introduction of the AirBus (up or down)?
AF took their first Airbus in 1974 (an A300B2).
AF's hull losses in accidents were:
1940s - 22
1950s - 24
1960s - 9
1970s - 2 (one B747; one Caravelle)
1980s - 3 (one B747; one A300 caused by engine failure (GE CF6); A320 Habsheim)
1990s - 2 (one B747; one B737)
2000s - 3 (one Concorde; one A340 Toronto; one A330 Atlantic)
...data from Aviation Safety Network.
Assuming the number of flights was increasing over time, this shows a big drop in the rate of hull losses from the '70s on. So the period with Airbuses in the fleet has been the safest. Of course the accident rate since the '70s might have been equally good with Boeings instead of Airbuses.