Airships by day
55. (1) An airship flying during the day in any of the circumstances referred to in paragraph (2) shall display two black balls suspended below the control car so that one is at least 4 metres above the other and at least 8 metres below the control car.
(2) The circumstances are as follows—
(a)if the airship is not under command;
(b)if it has voluntarily stopped its engines; or
(c)if it is being towed.
(3) For the purposes of this rule and rule 54—
(a)an airship shall be deemed not to be under command when it is unable to execute a manoeuvre which it may be required to execute by these Rules; and
(b)an airship shall be deemed to be making way when it is not moored and is in motion.