Using the elevation feature on Google Earth (appears to be accurate) you can trace out the terrain on the approach path to runway 18.
Some observations.
The house pictured with debris in the yard and tree damage is located 1.0nm from the threshold at an elevation of 766 feet, 122 feet above the elevation at the threshold (644 feet).
The aircraft appears to have impacted the trees at a height of around 50-70 feet agl, or 172-192 feet above the threshold, or 816-836 feet asl.
At 1.0nm (6076 feet) from the threshold the altitude corresponding to a 3.24 degree glidepath (GPS approach) would be 1036 feet asl. (tan(3.24) X 6076 + 644 + 48)).
At 0.61nm (3706 feet) from the threshold and on the centerline (+/- 200 feet) the terrain rises to 835 feet, 191 feet above the elevation at the thresold.
If they hit the trees at the lower of the estimated altitude of 50 feet (816 feel asl) at 1.0nm final it seems possible that the threshold and PAPI's might have been obscured by the sloping hill (835 feet located 0.61nm from the threshold).
At 0.61nm (3706 feet) from the threshold the altitude corresponding to a 3.24 degree glidepath would be 902 feet asl. (tan(3.24) X 3706 + 644 + 48)). This is 67 feet above the 835 foot terrain (hill).
Some questions.
Is my math correct ?
Is the elevation feature on Google Earth that accurate ? Appears so when checked against known elevation points on the airport.
A 67 foot clearance over terrain just over half a mile from a runway threshold is interesting. What are the glidepath terrain clearance parameters used for certification of non-precision instrument approaches ?
Given the terrian clearance would you get a warning using a TAWS or EGPWS system flying this approach at the correct 3.24 degree glidepath ?
JC