There are missions in FSX during which you declare an emergency - or rather - your copilot declares the emergency while you fly the plane.
Though i have to say to implement emergency handling into FSX or FS9 would be easy. All they would have to do is clear you direct to the airport and ask you if you want equipment rolling? if you say yes fire trucks pull alongside your plane after landing.
If it is an engine failure the controller can simply provide you a heading to the nearest airprot.
thats it.
really only like 3 ATC Responses would have to be added to the game
1. " Roger, squak emergency, fly heading XXX, the destination airport is at your 11 o'clock 8 miles, you are cleared for landing on the runway of your choice - do you need us to roll the equipment?"
2. "Roger equipment standing by, good luck." or "Roger, equipment on alert, but not rolling."
3. "Roger, copy that you need to land at the nearest airport... the nearest airport is XXX at your 3 o'clock, 4 miles, fly heading 050 you're cleared for immediate landing on any runwayt. good luck"
Yup, the superficial communictions setup would be pretty simple. As would be the animated fire/crash emergency vehicles (although they's have to "know" how to avoid any taxiing AI aircraft already on the ground).
The one "technical detail" in that scenario is what to do with all of the existing AI traffic when you get cleared for the emergency landing. So coding would have to be written to set up a holding pattern diversion for the AI...... similar to a instantly implementable AISmooth. That way you can get priority landing and the AI will get out of your way.
And what those emergency vehicles should actually DO if you DO crash upon landing!
Do they just sit there and wait? 
best,
......................john

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