pilot signal

noun

Nautical.

1. a signal, as a flag or light, used to request a pilot.
2. a signal to indicate that a pilot is on board.

Example Sentences

In 2010, Sanford stood with Correction Capt. Robert Johnson to call on FCC officials to act on a petition to let the state start a pilot signal jamming program.

From Seattle Times

On one side is the city of Auckland, lying in a hollow, and extending up the steep hills on either side; while opposite to it, on the north shore of the Frith of Thames, is a large round hill, used as a pilot signal station.

From Project Gutenberg