The operator of a helicopter with a maximum approved passenger seating configuration of more than nine seats operated in terms of regulation 127.01.1, on a scheduled or non-scheduled public air transport service operation, shall not operate the helicopter unless such helicopter is equipped with airborne weather radar or other equivalent equipment whenever such helicopter is being operated by night or in IMC in areas where thunderstorms or other potentially hazardous weather conditions, regarded as detectable with airborne weather radars, may be expected to exist along the route.