34. The commander of a flying machine on, or in the pattern of traffic at, an aerodrome shall 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 shall obey any instructions which may be given to him by means of such signals:
Provided that he shall not be required to obey the signals referred to in rule 48 (Marshalling Signals) if in his opinion it is inadvisable to do so in the interests of safety.