From the article...
"Flight-data recorder information indicates that the trijet was configured with 30° take-off flaps. The inquiry associates this setting with a modification known as the ‘Quiet Wing’ which was developed for the 727 in order to reduce noise.
The ‘Quiet Wing’ system is designed to increase take-off performance through modifications including a flap and aileron droop, to increase lift and thereby cut perceived noise on the ground."
First time I have ever heard of a flaps 30 takeoff. Did plenty of flaps 25 takeoffs in a similar sort of runway and elevation. That is a lot of drag when an engine is lost along with the other damage. I wonder if quickly reducing some flap, even if speed is slow would be advantageous.