Fri Jul 16, 2004 5:12 am
Another aspect is the certification of an updated existing design. With the FAA's Changed Product Rule (
CPR), "Significant" changes to an aircraft require it to meet the latest regulations. The
CPR motto is "Enhancing safety by applying the latest airworthiness standards".
This is only part of the reason, and not the entire reason for not redesigning older aircraft. But it does enter into the cost equation (money) as described by AmericanAirFan in reply #3.
Basically, for a significant change to a product you must START with the LATEST amendment of the regulations, and then justify why you do not meet that for every regulation. This is called the "top down approach" to developing the certification basis.
Basically, old design would have difficulty in meeting items such as dynamic seats, system safety, interior structures, flammability, HIRF & Lightning, environmental systems, etc.
Boeing Flown: 701,702,703;717;720;721,722;731,732,733,734,735,73G,738,739;741,742,743,744,747SP;752,753;762,763;772,773,788.