IATA Operational Safety Audit (IOSA) Standards Manual DSP 4.2: Minimum Flight Altitudes and En Route Performance

What does DSP 4.2 require?

Planned minimum flight altitudes are at least as high as the ones the authorities set; the OFP ensures a twin-engine aircraft losing its critical engine anywhere on the route can continue to an airport clearing terrain with the required margin; and aircraft with three or more engines have diversion planning for a second engine failure (DSP 4.2.1 to 4.2.3).