So for mechwarriors, the ATB fan-made injury system works for me, though I modify the die rolls to be closer to btech.
For each point of MW damage:
Roll location (6 becomes chest, 7 becomes head, 8 becomes abdomen, otherwise standard btech rolls.) This is mostly for descriptive purposes.
Roll to see if each point is a critical (8+ like normal), on a crit it counts as 2 wounds to the location. 2 and 12 make additional crit roll as normal since I am trying to mimic btech.
1 damage to location=flesh wound
2 damage=sprain/concussion/broken rib/bruised kidney
3 damage=broken bone/internal bleed
4 damage=location disabled until replacement limb/long term physical therapy
5+ damage=location permanently disabled/crippled. Head wounds prevent piloting. Missing an arm or leg makes things very hard. Permanent chest/abdomen wounds greatly reduce your endurance (darth vader style mechanical ventilator perhaps?)
So if you take 4 damage, you would roll 4 locations.
I just rolled 9, 7, 9, 7. So 2 hits to the head, 2 to the left leg (unlucky location rolls for this poor guy)
For crit rolls, I rolled a 9, 7, 5, 5. So the left leg takes 3 total wounds, and the head takes two. So this mechwarrior suffers from a concussion and a broken right leg.
Recovery time with treatment is the total number of wounds squared--thus the example above took 4 wounds, so is out for 16 days getting a plate and screws in his leg to fix the break.
I allow an otherwise dead pilot (6 hits) to recover as long as my player has a medivac/mash surgical vehicle. So the 3.5 ton MASH bay with 1 theater can save a pilot if they are quick enough, though with 6 wounds (plus all the critical damage they might roll) they will be out for a long time, or may never pilot a mech again like Greyson from the GDL. If you dont have enough MASH units, you have to start triage deciding who you save. MASH is one of those alpha strike unit specials you dont see much, so its good to give it some use.
Since you are using alpha strike, if the crit says UNIT DESTROYED (crit roll 12) treat it as 6 btech hits (dead unless you brought MASH), if it is Ammo (Crit roll 2) add 2 hits. Then make an ejection skill roll, which is skill+6. If you fail this roll, take 1 damage for each 2 you failed by (+2 if you suffered an ammo crit). Thus your skill 4 pilot's mech in alpha strike is destroyed to damage (no ammo or head crit), and makes an ejection roll with a target of 10 for falling then ejecting. He rolls an 8, and takes 1 damage escaping his fallen machine.
