Its a mathematical equation.
7000' @ RIC
1500' @ 12nm BK
0' @ 3nm BK
The first 5500' to 6000' took the aircraft around 12 - 13 nm and the last 1500' approx 9 nm.
The radio call to the twr at 12 nm seems calm and at ease. Remember only a PAN was made so to this point there was seemingly no serious concern. Only when trying to maintain altitude to continue to BK did the pilot become aware of an increasing danger in his situation.
If the remaining engine did start to lose performance it was still able to carry the aircraft 9nm from 1500'. The first 5500' - 6000' would appear to have been lost voluntarily.
Even using the performance capabillity of that last 1500' the first 5500' should have taken the aircraft nearly 30nm.
This would have had the aircraft arriving overhead bk and having to loose altitude in the cct to land.
Dont give up altitude you may need later. It is the only safety margin you can bank on.
I had met this pilot on a number of occassions on a professional basis a few years back and this truely is a great tradgedy.