Section 171.313

14 CFR Ch. I (1-1-19 Edition)
TABLE 8C - AUXILIARY DATA - Continued
Data content

Type
of data

Maximun
time between transmissions
(Seconds)

Bits
used

Back azimuth antenna alignment with runway centerline.
Spare ...........................................................
Parity ............................................................

...........

....................

...........
...........

....................
....................

Word
(See
note 6)

NOTE 1: Parity bits I70 to I76 are chosen to
satisfy the equations which follow:
For BIT I70:
Even = (I13 + ... + I18) + I20 + I22 + I24 + I25
+ I28 + I29 + I31 + I32 + I33 + I35 + I36 + I38 + I41
+ I44 + I45 + I46 + I50 + (I52 + ... + I55) + I58 +
I60 + I64 + I65 + I70
For BIT I71:
Even = (I14 + ... + I19) + I21 + I23 + I25 + I26
+ I29 + I30 + I32 + I33 + I34 + I36 + I37 + I39 + I42
+ I45 + I46 + I47 + I51 + (I53 + ... + I56) + I59 +
I61 + I65 + I66 + I71
For BIT I72:
Even = (I15 + ... + I20) + I22 + I24 + I26 + I27
+ I30 + I31 + I33 + I34 + I35 + I37 + I38 + I40 + I43
+ I46 + I47 + I48 + I52 + (I54 + ... + I57) + I60 +
I62 + I66 + I67 + I72
For BIT I73:
Even = (I16 + ... + I21) + I23 + I25 + I27 + I28
+ I31 + I32 + I34 + I35 + I36 + I38 + I39 + I41 + I44
+ I47 + I48 + I49 + I53 + (I55 + ... + I58) + I61 +
I63 + I67 + I68 + I73
For BIT I74:
Even = (I17 + ... + I22) + I24 + I26 + I28 + I29
+ I32 + I33 + I35 + I36 + I37 + I39 + I40 + I42 + I45
+ I48 + I49 + I50 + I54 + (I56 + ... + I59) + I62 +
I64 + I68 + I69 + I74
For BIT I75:
Even = (I13 + ... + I17) + I19 + I21 + I23 + I24
+ I27 + I28 + I30 + I31 + I32 + I34 + I35 + I37 + I40
+ I43 + I44 + I45 + I49 + (I51 + ... + I54) + I57 +
I59 + I63 + I64 + I69 + I75
For BIT I76:
Even = I13 + I14 + ... + I75 + I76
NOTE 2: Code for I56 is: 0 = conical; 1 =
planar.

Range of values

Least
significant
bit

12

Section20.47Section to 20.47Section (See note 3) ..

0.01Section

16
7

......................................................
(See note 1) .................................

.........
.........

NOTE 3: The convention for the coding of
negative numbers is as follows: Section MSB is the
sign bit; 0 = + ; 1 = Section.
 - Other bits represent the absolute value.
The convention for the antenna location is
as follows: As viewed from the MLS approach
reference datum looking toward the datum
point, a positive number shall represent a location to the right of the runway centerline
(lateral offset) or above the runway (vertical
offset), or towards the stop end of the runway (longitudinal distance).
The convention for the antenna alignment
is as follows: As viewed from above, a positive number shall represent clockwise rotation from the runway centerline to the respective zero-degree guidance plane.
NOTE 4: Data Word A3 is transmitted at intervals of 1.0 seconds or less throughout the
approach Azimuth coverage sector, except
when back Azimuth guidance is provided.
Where back Azimuth is provided transmit at
intervals of 1.33 seconds or less throughout
the approach Azimuth sector and 4.0 seconds
or less throughout the back Azimuth coverage sector.
NOTE 5: When back Azimuth guidance is
provided, transmit at intervals of 1.33 seconds or less throughout the back Azimuth
coverage sector and 4.0 seconds or less
throughout the approach Azimuth coverage
sector.
NOTE 6: The designation  - A1 -  represents
the function identification code for  - Auxiliary Data A -  and address code number 1.

866

VerDate Sep<11>2014

08:20 May 17, 2019

Jkt 247048

PO 00000

Frm 00876

Fmt 8010

Sfmt 8010

Y:\SGML\247048.XXX

247048