My question was purposely provocative, and seems to have reached its goal........
Bone's question is not so silly, and your explanations are not so straitforward.
He's not trying to make things more difficult, he's got a doubt and we should try to answer clearly (and since we are supposed to know, it's interesting to see
what we know before asking Boeing).
The first question was:
For the T/O phase,when does the time limit start...upon reaching 650C or setting of T/O thrust?
and the second was:
And if 650C is not reached during T/O, can the engines be operated at that power setting indefinitely,provided the max continuous limit is adhered to?
I think the mistake lies in focusing on the limit itself, rather than on the temperature
range .
A range, like a segment, is defined by two points.
At takeoff, the EGT is supposed to exceed the Max Con limit, but not the 650 limit.
You are allowed to operate for 5' in this
range , the Takeoff
range , in which you are even if you don't necessairily reach 650.
Reverend, saying that
you are allowed to operate that engine for 5 minutes at 650C when it reaches that temperature.
only confuses ideas.
Even if you don't reach that temperature you are in the Takeoff range because you've exceeded 625.
That's why I asked about 649!
It doesn't matter if you
personally would regard 649C the same as 650C
.
The fact is that you are in the Takeoff RANGE.
Going back to the first question: when to start timing?
academically, when the EGT enters the Takeoff range (625-650).
Second question: in my opinion YES, if the EGT is kept within 625 there's no time limit, even if the setting is for takeoff.