The variables for dropping out of TC are stored in the Data\Cfg\Main file, under the [TIME COMPRESSION] heading. This is what it looks like in stock 1.5:
Code:
[TIME COMPRESSION]
TimeStop=0
RealTime=1
LandProximity=4
CriticalDamage=1
CrewEfficiency=128;1
AirEnemyDetected=1
SoundEffects=2
CharacterAnim=4
EnemyDetected=8
RadioReport=8
Particles=8
PrayState=8
HunterState=32
3DRender=32
Maximum=8192
This means that TC will drop to 8 when you detect an enemy or receive a radio transmission, 4 when you're in shallow waters, and 1 when you detect an enemy aircraft or have been critically damaged.