Originally Posted by
RandomPerson8008
I’m asking because of the new HKG SID’s.
To make crossing restrictions some crews are maintaining takeoff flaps and climbing at ~ V2 + 10 to 4000 on NADP 2 runways. Thrust reduction on NADP 2 is based on flaps reaching 5 (selected at V2 + 40) while takeoff flaps are 10 or 20 for the 747. So, thrust reduction is not happening until 4000 when the first crossing restriction is met, which can take more than 3 minutes in a 980,000 lb airplane on a 35C day.
A genx2b67 failed and this technique was blamed due to it staying in takeoff thrust for 3 minutes (even though it’s rated to stay in takeoff thrust for 5 minutes or 10 if an engine failure has occurred on another engine).
Some airlines pay for proper performance analysis, others let crew make it up on the go and blow engines up. You pay for what you get.
There is nothing special about the HKG SIDs, if you cannot make an SID altitude just let delivery know what you can do.