Originally Posted by lomapaseo
Not a very significant statement. The idea behind certification is to certify it safe today. New concepts need apply today's knowledge both in their design and certification. Old concepts which have seasoned experience under continued airworthiness review certainly have less questions to answer.
Boeing managed to get the 737NG certified as a variant of previous 737s, even with a completely new wing. If they had had to meet the latest requirements significant changes would have had to have been made to the fuselage to meet emergency exit requirements. Compare the exits on an A321 (certified under newer requirements) with those on the 737-800 and 737-900 which used old 737 "grandfather rights".