|Quoting A342 (Reply 3):|
Maybe they had planned to use the same facility as class E aircraft, but why should an exemption be made for them ?
We are talking about two totally different things here. Airports rate airplanes by two different catagories, wingspan (aircraft design group, or ADG, for FAA it is ADG I-VI
, ICAO it is class A-F, currently) or fuselage lenght (FAA and ICAO ARFF Index A-F, currently). The ADG is all about what size runway and taxiway safety areas need to be protected, thus this directly effects airport design. Simply put, the larger the wingspan, the larger the safety areas. ARFF Index is all about the fire fighting capability of the airport. ARFF means Aircraft Rescue and Fire Fighting. The assumption has always been the longer the fuselarge, the more passenger and fuel carrying capability of the aircraft. Cargo only is in this equasion if it is classified as hazardous cargo.
The new B-747-800F/I will be an ADG VI
(class F) aircraft, but is currently suppose to be able to make a 90 degree turn on the same taxiway configueration as the current B-747-400/F/ER/ERF
, even though it has a longer wheel base. Here the limiting factor is when and where the main landing gear wheels leave the full strenght pavement, onto the shoulders using either the judgemential oversteer method, or the cockpit over centerline method to manuver while taxiing. The B-747-800 is suppose to be able to stay on the current 75' wide taxiway system, according to what Boeing has already told airports around the world. The A-380-800, by comparison, does have a longer wheelbase and needs intersecting taxiway fillets installed on all 75' wide taxiways, in order to make a 90 degree turn. But, in this respect, simply because the wingspan of both exceeds 220', both aircraft will be classified as ADG VI
, or class F aircraft.
Now when it comes to ARFF Index, the current design of the B-747-800 is still an ARFF Index E aircraft (201'-240' long), while the A-380-800 is an ARFF Index F (a new catagory) aircraft (241' +). The ARFF Index referrs to a combination of the number and types of fire trucks, amount of water, and amount of fire fighting foam initially carried to the scene of a on airport crash of this lenght of aircraft. ARFF Index also has timing requirements for the airport's fire fighters, from their normal fire stations. The FAA requires the first rescue/fire fighting capable truck to arrive within 3 minutes, and all trucks (to meet the minimum index) within 4 minutes. Additional fire fighters that arrive that exceed the ARFF Index, are not timed.
So, when comparing the B-747-800 to the A-380-800, from an airport position, they are two different classes of aircraft.