Federal Aviation Administration, DOT Section 171.311 Wind Velocity: The ground equipment shall remain within monitor limits with wind velocities of up to 70 knots from such directions that the velocity component perpendicular to runway centerline does not exceed 35 knots. The ground equipment shall withstand winds up to 100 knots from any direction without damage. Hail Stones: 1.25 centimeters (1-2 inch) diameter. Rain: Provide required coverage with rain falling at a rate of 50 millimeters (2 inches) per hour, through a distance of 9 kilometers (5 nautical miles) and with rain falling at the rate of 25 millimeters (1 inch) per hour for the additional 28 kilometers (15 nautical miles). Ice Loading: Encased in 1.25 centimeters (1-2 inch) radial thickness of clear ice. Antenna Radome De-Icing: Down to Section6 SectionC (20 SectionF) and wind up to 35 knots. The signal format must meet the following minimum requirements: (a) Frequency assignment. The ground components (except DME/Marker Beacon) must operate on a single frequency assignment or channel, using time division multiplexing. These components must be capable of operating on any one of the 200 channels spaced 300 KHz apart with center frequencies from 5031.0 MHz to 5090.7 MHz and with channel numbering as shown in Table 1a. The operating radio frequencies of all ground components must not vary by more than Section10 KHz from the assigned frequency. Any one transmitter frequency must not vary more than Section50 Hz in any one second period. The MLS angle/data and DME equipment must operate on one of the paired channels as shown in Table 1b. (d) The transmitter frequencies of an MLS must be in accordance with the frequency plan approved by the FAA. (e) The DME component listed in paragraph (a)(4) of this section must comply with the minimum standard performance requirements specified in subpart G of this part. (f) The marker beacon components listed in paragraph (b)(4) of this section must comply with the minimum standard performance requirements specified in subpart H of this part. TABLE 1a - FREQUENCY CHANNEL PLAN Frequency (MHz) Channel No. 500 501 502 503 504 505 506 507 508 509 510 511 Section 171.311 Signal format requirements. The signals radiated by the MLS must conform to the signal format in which angle guidance functions and data functions are transmitted sequentially on the same C-band frequency. Each function is identified by a unique digital code which initializes the airborne receiver for proper processing. 598 599 600 601 698 699 ........................................................................... ........................................................................... ........................................................................... ........................................................................... ........................................................................... ........................................................................... ........................................................................... ........................................................................... ........................................................................... ........................................................................... ........................................................................... ........................................................................... * * * * * ........................................................................... ........................................................................... ........................................................................... ........................................................................... * * * * * ........................................................................... ........................................................................... 5031.0 5031.3 5031.6 5031.9 5032.2 5032.5 5032.8 5033.1 5033.4 5033.7 5034.0 5034.3 5060.4 5060.7 5061.0 5061.3 5090.4 5090.7 TABLE 1b - CHANNELS Channel pairing DME parameters Interrogation DME No. * 1X .................... ** 1Y .................. * 2X .................... ** 2Y .................. * 3X .................... ** 3Y .................. * 4X .................... ** 4Y .................. * 5X .................... VHF freq. MHz .................... .................... .................... .................... .................... .................... .................... .................... .................... MLS angle freq. MHz .................... .................... .................... .................... .................... .................... .................... .................... .................... MLS Ch. No. Reply Pulse codes Freq. MHz .............. .............. .............. .............. .............. .............. .............. .............. .............. DME/P Mode DME/N Sections 1025 1025 1026 1026 1027 1027 1028 1028 1029 12 36 12 36 12 36 12 36 12 IA Sections FA Sections .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. Freq. MHz 962 1088 963 1089 964 1090 965 1091 966 843 VerDate Sep<11>2014 08:20 May 17, 2019 Jkt 247048 PO 00000 Frm 00853 Fmt 8010 Sfmt 8010 Y:\SGML\247048.XXX 247048 Pulse codes Sections 12 30 12 30 12 30 12 30 12