ATPL Performance: Legislation and Regulatory Framework

032-01-01Pablo Asensio Martínez2026-04-012 min

Regulatory Framework

Performance regulations ensure that aircraft can safely complete a flight even in the event of an engine failure at the most critical moment.

ICAO Annex 6

The International Civil Aviation Organization (ICAO) sets the standards in Annex 6 "Operation of Aircraft". It defines performance classes based on the number of engines and the aircraft's ability to continue flight after an engine failure.

EASA Regulations (CS - Certification Specifications)

In Europe, EASA defines the airworthiness codes:

  • CS-25: Large Aeroplanes (Turbine powered, MTOM > 5,700 kg, or > 19 seats).
  • CS-23: Normal, Utility, Aerobatic, and Commuter Aeroplanes (MTOM $\le$ 5,670 kg, $\le$ 19 seats).

Performance Classes

Operational regulations (like EU-OPS) divide aeroplanes into classes for performance purposes:

Performance Class A

  • Aircraft: Multi-engine turbojets (any mass/seats) and multi-engine turboprops (if > 5,700 kg or > 9 seats).
  • Requirement: Must be able to continue flight to a suitable aerodrome after an engine failure at any point (except during a very short period during take-off before $V_1$).
  • Safety Level: Highest standard of safety.

Performance Class B

  • Aircraft: Propeller-driven aeroplanes with $\le$ 9 seats and MTOM $\le$ 5,700 kg.
  • Requirement: Generally single-engine or multi-engine aircraft that may not be able to maintain altitude after an engine failure. In case of engine failure, a forced landing might be necessary.
  • Safety Level: Lower than Class A; relies on the ability to reach a landing site.

Performance Class C

  • Aircraft: Large reciprocating (piston) engine aeroplanes (mostly legacy aircraft like DC-6, Constellation).
  • Requirement: Similar to Class A but with slightly less stringent climb gradients.

Airworthiness vs. Operations

  • Airworthiness: Ensures the aircraft is built to perform (e.g., can climb at 2.4% gradient with one engine inoperative).
  • Operations: Ensures the aircraft is operated safely in specific conditions (e.g., checking if that 2.4% gradient clears the mountains on a specific departure).