To determine whether they may conduct a particular low-visibility operation, an airline pilot primarily must consult:

In low-visibility operations, airline pilots must adhere to specific protocols and requirements that govern their operations. The correct approach is to consult the employer's Operating Specifications (OpSpecs). OpSpecs outline the operational limits and procedures that an airline is authorized to conduct under its certification.

These documents are tailored to individual airlines and can include pertinent information about the specific types of low-visibility operations the airline is equipped to manage, the equipment that must be onboard, required pilot qualifications, and the training necessary to safely conduct such operations. Utilities like visibility minima, equipment requirements, and other operational parameters for low-visibility situations are explicitly documented in OpSpecs, making it crucial for pilots to review them before conducting these operations.

While the Federal Aviation Regulations (Parts 91 and 121) lay the foundational legal framework for aviation safety, and advisory circulars provide guidance and best practices, it is the OpSpecs that directly relate to the specific operational capabilities of the airline. Additionally, the airline's safety manual may contain useful guidelines and safety protocols, but it is the OpSpecs that dictate what is permissible for that airline in the context of regulatory compliance and operational readiness.