Yesterday we learned that the A330, alias Princess, will lie when you interfere with her flight idle descent. Now guys... what can you expect? You interfered with her plan. Perhaps she is just getting even by making your life a little harder. Or perhaps... she's playing with you.
Besides, she's not really lying ... just delaying the truth. Not to mention, she will give you other indications that you're not going to make your profile... you just have to look for them.
Isn't that always the way... the signs are there, you just have to open your eyes?
The best indication that you will make your level off is the blue level-off arrow. But the level-off arrow doesn't instantaneously tell you when you'll level off, instead it continues to recalculate your level off based on your descent speed.
As you go above profile because ATC slowed you up, the blue arrow will continue to creep away. This should be your first indication that you'll be high. The second indication will be the Chinese glide slope. But then, these little green dots will only provide data that you're off your descent by more than 200 feet when they're pegged. Personally, I like the progress page the best.
Bottom line: We need drag to get her down. Interesting enough, the blue level-off arrow doesn't look at speed brakes. However, when you use the speed brakes to get her back on profile, the blue arrow will creep towards you because you're increasing your descent and putting yourself closer to the level off. Basically, you're actually taking her below her flight idle profile because you have to.
Once the blue arrow has moved to where you want the plane to level off, you can stow the speed brakes and she will continue to make that blue arrow level off point. Why? She wasn't counting on speed brakes to make it, therefore when you take them away... she doesn't care. She's on her profile based on your altitude and speed.
Morale of this story... learn how to read your Princess. You might have to babysit her. I'm still learning her ways, and using 3 to 1 for descent planning as a backup. Back to the back to the basics... 30 miles at 10,000 feet is a safe gouge.
Enjoy the Journey!