Heavy Medivac losses led engineering crews to perform unsanctioned upgradesadding injectors that pump oxygen-rich fuel into the exhaust streamto increase engine output. The first attempts, while successful at getting Medivacs out of fire zones, resulted in heavy stress-induced damage to the turbines and, in rare cases, to the ships airframe. When questioned, neither engineering crews nor soldiers revealed who was responsible for the changes. Dominion officers determined that it was cheaper to upgrade the whole Medivac fleet than to discipline an entire troop company.