and the frequency tolerance shall not exceed 50Hz.
(ｪ｡ｪ)The percentage of modulation of the identification signal shall be between the limits of 5 and 15 percent.
(ｪｪ)The identification signal shall be transmitted by the International Morse Code consisting of three letters, at a rate of approximately seven words per minute, and shall be repeated at approximately equal intervals, not less than six times per minute.
(ｪｪ｡)Where two carriers are transmitted from the localizer, the relative phases of the modulations of the two identification signals shall be such as to avoid the occurrence of nulls within the coverage of the localizer.
(ｪｪ｢)In the event that two localizers are installed for a single runway, an interlocking device shall be produced to avoid the simultaneous transmission of the two radio frequency carriers (except the case when said localizer is a localizer of (he Facility Performance Category 1-ILS which transmits the radio waves with different frequencies and do not affect operations when simultaneously transmitted).
(ｪｪ｣)The localizer antenna system shall be located on the extension of the centerline of the runway at the stopping end.
(ｪｪ､)Two sets of transmitters shall be provided so that either one can be used by switching over when necessary.
(ｪｪ･)A dummy antenna shall be provided.
(ｪｪｦ)A standby isolated power unit shall be provided.
(ｪｪｧ)Monitoring equipment shall be provided.
(ｪｪｨ)The monitoring equipment shall consist of an automatic monitoring system which is designed to provide a warning to the designated control points as soon as possible, within a limit of 10 seconds for a localizer of the Facility Performance Category I-ILS, 5 seconds for a localizer of the Facility Performance Category II-ILS or 2 seconds for a localizer of the Facility Performance Category III-ILS, when any of the following deviations from the established values or malfunctions arise, and with the additional function of automatic and simultaneous switchover to the standby transmitter, and the further function of terminating the transmission of the localizer when said deviations or malfunctions persist even after switching over to the standby equipment.
I. The position of the course line fails to comply with the requirements specified in (ｪ･). However, for a localizer of the Facility Performance Category III-ILS, the case when the deviation between the projection of the course line and the distance from the centre at the approach end of the runway threshold shall exceed 6.0 meters.
II. The case when the deviation of the displacement sensitivity at the intersection of the half sector and the vertical plane of the approach end of the runway threshold shall exceed 17 percent.
III. A reduction of antenna output power to less than 50 percent of the normal value, where one carrier is emitted from the localizer in compliance with
