Here's a list of new sounds currently being used in 2.18. This is subject to change at any time. Anything missing from the list is still using damage1. Sorry for the formatting.
Global
Tire roll trumble
Engine overspeed knock1
WWI planes damage sounds
Machinegun damlm3
Engine dameng0
Left wheel dammw1
Right wheel dammw0
Tail skid daml1
Pilot Wound pwound
Inner Lower Wing damhw1
Outer Lower Wing damhw0
Inner Upper Wing damhw2
Outer Upper Wing damhw1
Inner Middle Wing damhw2
Outer Middle Wing damhw3
Inner Lower Wing Skin damsf1
Outer Lower Wing Skin damsf0
Inner Upper Wing Skin damsf1
Outer Upper Wing Skin damsf0
Inner Middle Wing Skin damsf1
Outer Middle Wing Skin damsf0
Horizontal Stab damh0
Horizontal Stab Skin damsf0
Vertical Stab damm2
Vertical Stab Skin damsf1
Elevator damm0
Elevator Control damlm2
Elevator Skin damsf1
Rudder damm1
Rudder Control damlm2
Rudder Skin damsf0
Aileron Lower damm0
Aileron Upper damm0
Aileron Lower Control damlm2
Aileron Upper Control damlm2
Aileron Lower Skin damsf0
Aileron Upper Skin damsf0
Rear Fuse damh1
Rear Fuse Skin damsf0
Forward Fuse Skin dammm0
