Question: What is Duration, when Test Flight is Taxi test #2?
SQL: SELECT "Duration" FROM "2-16237630-3" WHERE "Test flight" = 'Taxi test #2';

Question: What it Duration, when Test Flight is Free flight #3?
SQL: SELECT "Duration" FROM "2-16237630-3" WHERE "Test flight" = 'Free flight #3';

Question: What is Date, when Comment is Tailcone on, lakebed landing, and when Duration is 5min 34 s?
SQL: SELECT "Date" FROM "2-16237630-3" WHERE "Comment" = 'Tailcone on, lakebed landing' AND "Duration" = '5min 34 s';

Question: What is Crew, when Date is July 26, 1977?
SQL: SELECT "Crew" FROM "2-16237630-3" WHERE "Date" = 'July 26, 1977';