- An ETOPS group 1 Significant System—
- Has fail-safe characteristics directly linked to the degree of redundancy provided by the number of engines on the airplane.
- Is a system, the failure or malfunction of which could result in an IFSD, loss of thrust control, or other power loss.
- Contributes significantly to the safety of an ETOPS diversion by providing additional redundancy for any system power source lost as a result of an inoperative engine.
- Is essential for prolonged operation of an airplane at engine inoperative altitudes.
- An ETOPS group 2 significant system is an ETOPS significant system that is not an ETOPS group 1 significant system.
Extended Operations (ETOPS) Significant System
Source: 14 CFR Federal Aviation Regulations §1