Always should be some chance for escape once hunter/killer on the trail
When "escape" is used, it does not necessarily mean speed XCOMcraft vs speed of enemy but added into that whatever "tricks" can be employed, chaff, electronic counter measures (ECM), decoy missiles, particular pilot skill, evasive tactics even ie using terrain features such as clouds or "Hollywood improbabilities" such as unexpected intervention of another air force or an occasional feature anomalies (oh Iron Mountain, fly by that and the UFO compasses go wacko).
How this might work is in the dogfight phase instead of the usual range UI engagement buttons the player clicks one of the following buttons:
1 use pilot skill (you evade the UFO and no damage, but encounter continues/ you evade the UFO and it cannot find you, encounter ends, you fail to evade, and UFO encounter continues, you screw up double damage from UFO next strike )
2 use ecm (you evade the UFO and no damage, / you evade the UFO and it cannot find you, encounter ends, you fail to evade encounter continues. whoops, double damage from UFO next strike )
3 use defensive gunnery (you fire back, and UFO is driven off encounter ends, UFO takes a hit, encounter continues, you miss encounter continues, UFO takes hit but double damage from UFO's next strike(note the UFO can never be destroyed, just driven off)),
4 use acceleration (if simply faster you escape encounter ends, if not encounter continues, you mess up and double damage from UFO's next strike)
5 Use anomaly (becomes randomly available if at all after a certain amount of time, when clicked on a message displays the type of anomaly you took advantage of (ie "your MAYDAY has alerted a local airforce interceptor wing which chases away the UFO," encounter ends). If you mess up TRIPLE damage from UFO next strike against you.
"Encounter continues" means UFO hunter Killer is following attacking you and depending upon its firepower and your craft type is how long it will take before you are downed. Options that result in "no damage" mean your actions interrupted the normal attack rhythm of the hunter killer for a few seconds. Options that result in the hunter killer doing double or triple damage could be game scaled to mean 25% or more damage than usual against your craft.
You continue to select any available option until
you escape,
the hunter killer is driven off
or you are downed
(NOTE there is a recharge period for an option after selection and developing technology will give higher chances of certain options suceeding).
FYI
Since the dogfight UI is arranged for range the encounter alternately, depending on success of options would increase/ decrease range as follows
--encounter continues at current range
--distance between Hunter killer and XCOM craft decreases (increasing chance of UFO to strike, using all its weapons)
--distance between Hunter killer and XCOM craft increases (decreasing chances of UFO to strike, its short range weapons cannot be used)
--distance increases off the scale and XCOM craft escapes hunter killer, encounter ends
Also consider XCOM craft is equipped with "chaff" and /or "ECM console" etc is at the expense of carrying something else, but gives those respective options to use for escape in the event of an occasional hunter killer attack.
I assume over ocean, everyone dies.
Higher percentage of death, as per Countdown, rafts etc can save people /equipment
Does this actually spawn a mission or is it just a touch-and-go crash site?
A. If it spawns a mission, who will be the enemy?
No aliens, as they consider their job done in removing the immediate threat; just opportunistic human "scavengers," local milita, gangs etc; and missions not always 100% spawned so you are not "grinding" against scavengers and abortable so you can just pay a ransom to get your soldiers back. Sprites that can be used for hostile human scavengers are already well represented in some mods.
And should the survivors spawn as xcom and fight as well?
Yes as per above.
Or should they spawn as civilians you need to save?
No
Or should they not spawn at all and just be recovered at the end?
variable mission generation is perhaps 25%, the rest of the time persons and a percentage of materials recovered showing up at the base in a few days / weeks later.
Or killed if you lose/abort.
Mission Abort gives chance to ransom survivors from hostile locals
B. If it doesn't spawn a mission, can we just simplify it that survivors come back home by public transport after certain amount of days?
yes