Hi,
Mutt and other members, thanks for the feedback.
FAR 25.1001 — Requires a fuel jettison system unless it can be shown that the airplane meets the climb requirements of FAR 25.119 and 25.121(d) at maximum takeoff weight, less the actual or computed weight of fuel necessary for a 15-minute flight comprising a takeoff, go-around, and landing at the airport of departure.
According to my understanding (narrow minded) of this regulation is that the installation of fuel jettison system is not related to overweight landing matter or land ASAP. The goal of installing fuel jettison system is to comply with the FAR 25.119 and 25.121(d).
To comply with FAR 25.1001, the 747 and MD-11, for example, require a fuel jettison system. Some models, such as the 777 and some 767 airplanes have a fuel jettison system installed, but it is not required by FAR. Other models such as the DC-9, 717, 737, 757, and MD-80/90 do not require, or do not have, a fuel jettison system based on compliance with FAR Part 25.119 and 25.121(d).
The Boeing guy who wrote the article and the quote above stated that: to comply with FAR 25.1001,
the 747 and MD-11, for example, require a fuel jettison system.
To my understanding (again narrow minded), B 747 requires the fuel jettison system in order to comply with FAR 25.1001. I believe the fuel jettison system is a requirement for B747 certification and operation and not an option for operation.
It seems to me that Mutt has different opinion based on his posts:
” Correct........... I have never seen a B747 limited by this restriction, but the MD11 can be at hot/high airports.“
So although the regulation pertaining to fuel dumping may not be an issue, the ability to land ASAP might lead a manufacturer to install a fuel dump system, or an airline to purchase the option”.
5LY (post#10) said that the B777300ER is only approach climb limited at sea level from above about 37 deg c. According to Boeing guy quote's the jettison system is not required for the B777 but it is installed. I think the fuel jettison for B777 is an option because it improves aircraft performance as shown in this example.
So my question is: how come a B777-300ER is only approach limited at sea level and at 37 deg c and the Boeing 747 is not limited by FAR25.119 and 25.121(d)? (even at hot/high runway)
I am not arguing here, I am just trying to understand.
Your opinions are welcome.
Regards