Maximum Landing Mass: Restrictions

What Is Maximum Landing Mass?

Maximum landing mass (MLM), sometimes called maximum landing weight, is the greatest mass at which an aircraft is allowed to land. This value is set by the manufacturer based on structural strength and is further limited by operational and performance factors at the destination.

Types of Landing Mass Limits

• Structural Limit: The maximum the airframe can safely withstand on landing. Exceeding this risks damage to landing gear, wings, and fuselage.
• Performance Limit: Determined by runway length, surface condition, obstacles, airport elevation, and temperature. If conditions reduce braking or require longer stopping distances, the performance-limited landing mass may be lower than the structural limit.
• Runway Strength: Some airports have pavement strength restrictions (PCN/ACN). If the runway cannot support the aircraft at its structural MLM, the actual permitted landing mass may be further reduced.

Regulated Landing Mass

The regulated landing mass is the lower of the structural and performance-limited landing masses. This is the binding operational limit for any flight.

Calculating Landing Mass

To ensure compliance:

1. Calculate landing mass by subtracting trip fuel from take-off mass.
2. Verify this value does not exceed the regulated landing mass at the destination.
3. If necessary, reduce take-off mass or adjust fuel/cargo before departure.

Landing Overweight Consequences

Landing above MLM can cause:

• Structural damage (gear, airframe)
• Compromised braking and stopping performance
• Breach of legal and insurance requirements

Key Points for ATPL Exams

• MLM is always the most restrictive of structural or performance limits.
• Always check both limits for each destination and runway.
• Allowed take-off mass must ensure the aircraft can arrive below the regulated landing mass after burning trip fuel.