Another finding...the systems file portion of the aircraft xdp also references effects files. So as a test I put some new voice effects into it thus:
<Systems>
<System ID="nose_structure" Name="nose structure">
<Threshold Level="100" Effect="Library" Parameter="
fx_b_bandits10" Location="emitter_damage_nose"/>
<Threshold Level="100" Effect="Library" Parameter="fx_engfire_m" Location="emitter_damage_nose"/>
<Threshold Level="100" Effect="Library" Parameter="fx_engfire_s" Location="emitter_damage_nose_piece"/>
<Threshold Level="100" Effect="Library" Parameter="fx_flmdebris_s" Location="emitter_damage_nose_piece"/>
<Threshold Level="100" Effect="Break" Parameter="" Location=""/>
</System>
<System ID="coolant_reservoir" Name="coolant reservoir">
<Threshold Level="20" Effect="Library" Parameter="fx_fuelleak_s" Location="emitter_coolant"/>
<Threshold Level="100" Effect="Library" Parameter="fx_fuelleak_m" Location="emitter_coolant"/>
<Threshold Level="100" Effect="Break" Parameter="" Location=""/>
</System>
<System ID="oil_reservoir" Name="oil reservoir">
<Threshold Level="20" Effect="Library" Parameter="fx_oilleak" Location="emitter_oil"/>
<Threshold Level="100" Effect="Library" Parameter="fx_oilleak" Location="emitter_oil"/>
<Threshold Level="100" Effect="Break" Parameter="" Location=""/>
</System>
<System ID="engine_one" Name="engine">
<Threshold Level="25" Effect="Library" Parameter="
fx_b_bandits10" Location="emitter_damage_engine_right"/>
<Threshold Level="50" Effect="Library" Parameter="fx_fuelleak_s" Location="emitter_damage_engine_right"/>
<Threshold Level="60" Effect="Library" Parameter="fx_oilleak" Location="emitter_damage_engine_right"/>
<Threshold Level="80" Effect="Library" Parameter="fx_engfire_s" Location="emitter_damage_engine_right"/>
<Threshold Level="85" Effect="Library" Parameter="fx_engfire_m" Location="emitter_damage_engine_right"/>
<Threshold Level="90" Effect="Library" Parameter="fx_engfire_l" Location="emitter_damage_engine_right"/>
<Threshold Level="100" Effect="Library" Parameter="fx_airexpl_m" Location="emitter_damage_engine_right"/>
<Threshold Level="100" Effect="Library" Parameter="fx_engfire_l" Location="emitter_damage_engine_right"/>
What this means is when that part gets hit you hear a voice. What's the point in that I hear you ask??
Well thinking of James' bombers you could have a crew member telling you what part of your aircraft is hit, eg "Skipper, port engine's on fire"
More possibilities!