850
14 CFR Ch. I (1–1–24 Edition)
§ 171.275
(iii) The station power emission and
frequencies of the ISMLS localizer,
glide path, beacon markers, and associ-
ated compass locators, if any.
(iv) The hours of operation.
(v) Station identification call letters
and method of station identification
and the time spacing of the identifica-
tion.
(vi) A description of the critical parts
that may not be changed, adjusted, or
repaired without an FAA flight check
to confirm published operations.
(d) The owner or his maintenance
representative must make a ground
check of the ISMLS facility periodi-
cally in accordance with procedures ap-
proved by the FAA at the time of com-
missioning, and must report the results
of the checks as provided in § 171.275.
(e) Modifications to an ISMLS facil-
ity may be made only after approval by
the FAA of the proposed modification
submitted by the owner.
(f) The owner or the owner’s mainte-
nance representative must participate
in inspections made by the FAA.
(g) Whenever it is required by the
FAA, the owner must incorporate im-
provements in ISMLS maintenance.
(h) The owner or his maintenance
representative must provide a suffi-
cient stock of spare parts, including
solid state components, or modules to
make possible the prompt replacement
of components or modules that fail or
deteriorate in service.
(i) FAA approved test instruments
must be used for maintenance of the
ISMLS facility.
(j) The mean corrective maintenance
time of the ISMLS equipment may not
exceed 0.5 hours, with a maximum cor-
rective maintenance time of not great-
er than 1.5 hours. This measure applies
to failures of the monitor, transmitter
and associated antenna assemblies,
limited to unscheduled outage and out-
of-tolerance conditions.
(k) The mean time between failures
of the ISMLS equipment may not be
less than 1,500 hours. This measure ap-
plies to unscheduled outages, out-of-
tolerance conditions, and failures of
the monitor, transmitter, and associ-
ated antenna assemblies.
(l) Inspection consists of an examina-
tion of the ISMLS equipment to ensure
that unsafe operating conditions do not
exist.
(m) Monitoring of the ISMLS radi-
ated signal must ensure a high degree
of integrity and minimize the require-
ments for ground and flight inspection.
The monitor must be checked periodi-
cally during the in-service test evalua-
tion period for calibration and sta-
bility. These tests and ground checks
of glide slope, localizer, and marker
beacon radiation characteristics must
be conducted in accordance with the
maintenance requirements of this sec-
tion.
§ 171.275 Reports.
The owner of the ISMLS facility or
his maintenance representative must
make the following reports at the indi-
cated time to the appropriate FAA Re-
gional Office where the facility is lo-
cated.
(a)
Facility Equipment Performance and
Adjustment Data
(
FAA Form 198
). The
FAA Form 198 shall be filled out by the
owner or his maintenance representa-
tive with the equipment adjustments
and meter readings as of the time of fa-
cility commissioning. One copy must
be kept in the permanent records of the
facility and two copies must be sent to
the appropriate FAA Regional Office.
The owner or his maintenance rep-
resentative must revise the FAA Form
198 data after any major repair, mod-
ernization, or retuning to reflect an ac-
curate record of facility operation and
adjustment. In the event the data are
revised, the owner or his maintenance
representative shall notify the appro-
priate FAA Regional Office of such re-
visions, and forward copies of the revi-
sions to the appropriate FAA Regional
Office.
(b)
Facility Maintenance Log
(
FAA
Form 6030
–
1
). FAA Form 6030–1 is a per-
manent record of all the activities re-
quired to maintain the ISMLS facility.
The entries must include all malfunc-
tions met in maintaining the facility
including information on the kind of
work and adjustments made, equip-
ment failures, causes (if determined)
and corrective action taken. In addi-
tion, the entries must include comple-
tion of periodic maintenance required
to maintain the facility. The owner or
his maintenance representative must
851
Federal Aviation Administration, DOT
§ 171.303
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.