Jim:

The aft gear doors removal mod was done strictly for safety. The intent was to remove the drag associated with the aft clamshell doors when cycling the gear. The concern here was the cycling of the doors during single engine operation. The POH states that aircraft cannot maintain altitude on one engine with doors open. The gear door mod solves this at no penalty in speed or noise.

A secondary benefit to this mod is that you get rid of two actuators and four hydraulic lines, therefore there are less places to spring a leak.

Gear up landings was not a factor in this mod since the strut doors (forward main gear doors) are the ones that take most of the damage unless your doors are hanging open. The strut doors are the ones that are getting hard to find if you do have a gear up landing.

The best solution for a gear up landing (aside from proper maintenance) is a big ADF antenna in the belly or a cargo pod.

Ray Torres