Long-Range Cruise

Long-Range Cruise (LRC) is a speed setting calculated to achieve 99% of the maximum specific air range (distance per unit of fuel burned). It is slightly faster than Maximum Range Cruise (MRC) speed, sacrificing just 1% of fuel efficiency for a meaningful increase in cruise speed, typically 3-5% faster.

The rationale for LRC over MRC is economic: the tiny increase in fuel cost is more than offset by reduced flight time, which translates to lower crew costs, better aircraft utilization, and improved schedule reliability. LRC represents the practical optimum for airlines balancing fuel cost against time-related costs.

LRC speed varies with aircraft weight (decreasing as fuel is burned), altitude, and temperature. The FMS continuously recalculates and adjusts LRC speed throughout the flight. Other common cruise modes include:

• Cost Index cruise: Balances fuel cost against time cost based on an airline-specific ratio
• Mach cruise: Fixed Mach number regardless of weight changes
• Economy cruise: Minimum total operating cost speed