Question: on 19 April 1985 how many of number last flew
SQL: SELECT COUNT("Number") FROM "1-1997759-1" WHERE "Last flew" = '19 April 1985';

Question: what is the registration located on 31 January 1975 where first flew?
SQL: SELECT "Registration" FROM "1-1997759-1" WHERE "First flew" = '31 January 1975';

Question: at what location is the last flew on 11 June 2000
SQL: SELECT "Location" FROM "1-1997759-1" WHERE "Last flew" = '11 June 2000';

Question: how many number is located at registration F-BVFF?
SQL: SELECT COUNT("Number") FROM "1-1997759-1" WHERE "Registration" = 'F-BVFF';