SCE group PS014 SCE group title Navigation Aids Navigation aids to enable the installation and its structures to be visible to marine and aviation traffic and to signal a safe line of approach or departure for helicopters, thereby preventing collision with the installation. To alert marine vessels (offshore only) and aircraft of the position of the installation so that they may take timely action to avoid the area Aircraft warning obstruction) lights on masts or flare stacks onshore/offshore) • Main, secondary and subsidiary navigation lights offshore Foghorns (offshore) At system level