EDIT::
Originally Posted by BOAC
Over 27 seconds it went from a 3 degree Vref approach to a stall. There is no way you can get anything from an 'average' RoD.
In those 27 seconds the RoD was approximately constant at 11.11 fps. At the average airspeed of 115 kts the flight path gradient was 5.72 % (3.28 degrees).
The airspeed dropped at an approximately constant rate of 1.85 kt per second (0.0972 g).
The average drag-to-weight ratio is then 0.0572 + 0.0972 = 0.154 and the lift-to-drag ratio is 1/0.154 = 6.5
The argument is about the rate of energy dissipation.
Total energy is the sum of potential energy per unit mass (height) and kinetic energy (speed). Within certain limits, potential and kinetic energy are interchangeable.
The rate of dissipation of total energy is a function of thrust minus drag per unit weight. With the engines at idle, thrust is negligible, so the rate of energy dissipation is determined by drag-per-unit-weight, the reciprocal of L/D.
An L/D of 6.5 at zero thrust produces either a flight path angle of 8.8 degrees (15.4%) at constant speed or a deceleration of 3 kt/second (0.154*g) at constant height, or anything in between.
What is the basis of your 3000 fpm?