December 29, 20232 yr With a relatively light takeoff gross weight of 284,000 lbs, I'm seeing a super-anemic climb rate of ~700-800 fpm climbing through the high 20s. Climb performance is largely a function of thrust-to-weight ratio. A full-loaded 747-400 at 875,000 lbs with four of the same CF6 engines has a thrust-to-weight ratio of 0.26, and can climb at 2000-3000 fpm in the 20s. Compare that to a 280,000 lb A300-600F with a whopping thrust to weight ratio of 0.43--the A300 should be able to hold well over 3000 fpm in this altitude range. Something is way off in the FD thrust curves. Also, the A/T stayed stuck in TOGA power no matter what was set in the TRP--it showed climb mode, and a target of 101.4% N1, and the throttles remained firewalled at 104.2%.
December 30, 20232 yr Author I have not been able to duplicate the A/T stuck issue. Is there a way to change the profile speeds in the FMS? The default profile climb is setting a target of 325KIAS, where the manuals show 300/0.78 as the standard climb. A climb with a manual 300/0.78 speed schedule produces better climb performance.
December 31, 20232 yr 15 hours ago, w6kd said: I have not been able to duplicate the A/T stuck issue. Is there a way to change the profile speeds in the FMS? The default profile climb is setting a target of 325KIAS, where the manuals show 300/0.78 as the standard climb. A climb with a manual 300/0.78 speed schedule produces better climb performance. I got 310KIAS offered but this is with using cost index 0 but at a risk of putting your econ cruise below the green dot speed. Though i am not liking the idea of having to change the cost index for climb, cruise and descent. Best outcome for climb once constrains are off is to use lvl chg.
Create an account or sign in to comment