In the HVAC industry, it's not uncommon to use a portable gantry for replacing large electric motors, compressors, etc.
Available in aluminum, makes it easy to carry (I've roped them up to roofs, dismantled of course). The smaller ones are 1 ton capacity.
You should check local equipment rental yards, like this one:
Gantries | Rent Gantries | ABC Equipment Rental
Typically, you can rent the gantry and trolley without the hoist, if you like, and use your own chainfall, come-along, etc. Use the beam and one trestle, secure free end of beam on properly supported structure. Or adjust height of trestles independently (one in cockpit, the other on the cabin sole. They're quite versatile.