AFP - Investigators scrambled on Sunday to determine if pilot error was to blame for the fiery crash of a Soviet-era airliner that killed Polish President Lech Kaczynski and 96 others. The presidential party was en route to a memorial service for Poles massacred by Soviet troops in World War II when its Tupolev Tu-154 airliner crashed in thick fog while approaching Smolensk airport, in the west of Russia. The disaster sent Poland into shock.