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ATPL » Performance – Helicopter » Definitions Terminology and Abbreviations

51.2 Definitions Terminology and Abbreviations

51.2.2 Explain the meaning of the following:

(a) alternate (ALTN)

ALTN Alternate or alternating (light alternates in colour)

ALTN Alternate (aerodrome)

Alternate aerodrome means

an aerodrome to which an aircraft may proceed when it becomes either impossible or inadvisable to proceed to or land at the aerodrome of intended landing:

(b) best rate of climb (Vy or BROC)


(c) best rate of climb - single engine (Vyse or BROC)


(d) Category A operations

Cat A means

  • a multi-engine helicopter
  • designed with engine and system isolation features
  • capable of operations using take-off and landing data
  • scheduled under a critical engine failure concept
  • which assures adequate designated surface area and adequate performance capability
  • for continued safe flight or safe rejected take-off

Category A

provides for critical engine failure performance capability to achieve either a safe reject or continue.

(e) Category B operations

Cat B means

a single-engine or a multi-engine helicopter that does not meet Cat A standards.

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