840
14 CFR Ch. I (1–1–19 Edition)
§ 171.301
keep the original of each form at the
facility and send a copy to the appro-
priate FAA Regional Office at the end
of each month in which it is prepared.
However, where an FAA approved re-
mote monitoring system is installed
which precludes the need for periodic
maintenance visits to the facility,
monthly reports from the remote mon-
itoring system control point must be
forwarded to the appropriate FAA Re-
gional Office, and a hard copy retained
at the control point.
(c)
Technical Performance Record
(
FAA
Form 418
). FAA Form 418 contains a
record of system parameters, recorded
on each scheduled visit to the facility.
The owner or his maintenance rep-
resentative shall keep the original of
each month’s record at the facility and
send a copy of the form to the appro-
priate FAA Regional Office.
Subpart J—Microwave Landing
System (MLS)
S
OURCE
: Docket No. 20669, 51 FR 33177,
Sept. 18, 1986, unless otherwise noted.
§ 171.301
Scope.
This subpart sets forth minimum re-
quirements for the approval, installa-
tion, operation and maintenance of
non-Federal Microwave Landing Sys-
tem (MLS) facilities that provide the
basis for instrument flight rules (IFR)
and air traffic control procedures.
§ 171.303
Definitions.
As used in this subpart:
Auxiliary data
means data trans-
mitted in addition to basic data that
provide ground equipment siting infor-
mation for use in refining airborne po-
sition calculations and other supple-
mentary information.
Basic data
means data transmitted by
the ground equipment that are associ-
ated directly with the operation of the
landing guidance system.
Beam center
means the midpoint be-
tween the
¥
3 dB points on the leading
and trailing edges of the scanning
beam main lobe.
Beamwidth
means the width of the
scanning beam main lobe measured at
the
¥
3 dB points and defined in angu-
lar units on the boresight, in the hori-
zontal plane for the azimuth function
and in the vertical plane for the ele-
vation function.
Clearance guidance sector
means the
volume of airspace, inside the coverage
sector, within which the azimuth guid-
ance information provided is not pro-
portional to the angular displacement
of the aircraft, but is a constant fly-
left or fly-right indication of the direc-
tion relative to the approach course
the aircraft should proceed in order to
enter the proportional guidance sector.
Control Motion Noise (CMN)
means
those fluctuations in the guidance
which affect aircraft attitude, control
surface motion, column motion, and
wheel motion. Control motion noise is
evaluated by filtering the flight error
record with a band-pass filter which
has corner frequencies at 0.3 radian/sec
and 10 radians/sec for azimuth data and
0.5 radian/sec and 10 radians/sec for ele-
vation data.
Data rate
means the average number
of times per second that transmissions
occur for a given function.
Differential Phase Shift Keying (DPSK)
means differential phase modulation of
the radio frequency carrier with rel-
ative phase states of 0 degree or 180 de-
grees.
Failure
means the inability of an
item to perform within previously
specified limits.
Guard time
means an unused period of
time provided in the transmitted signal
format to allow for equipment toler-
ances.
Integrity
means that quality which
relates to the trust which can be placed
in the correctness of the information
supplied by the facility.
Mean corrective time
means the aver-
age time required to correct an equip-
ment failure over a given period, after
a service technician reaches the facil-
ity.
Mean course error
means the mean
value of the azimuth error along a
specified radial of the azimuth func-
tion.
Mean glide path error
means the mean
value of the elevation error along a
specified glidepath of the elevation
function.
Mean-time-between-failures (MTBF)
means the average time between equip-
ment failures over a given period.
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