39.—(1) Subject to paragraph (2), the pilot-in-command of a flying machine on, or in the pattern of traffic flying at, an aerodrome shall—
(a)observe such visual signals as may be displayed at or directed to him from the aerodrome by the authority of the person in charge of the aerodrome; and
(b)obey any instructions which may be given to him by means of such signals.
(2) The pilot-in-command of a flying machine shall not be required to obey such signals if it is inadvisable to do so in the interests of safety.