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14 CFR Ch. I (1–1–24 Edition)
§ 171.305
Microwave Landing System (MLS)
means the MLS selected by ICAO for
international standardization.
Minimum glidepath
means the lowest
angle of descent along the zero degree
azimuth that is consistent with pub-
lished approach procedures and obsta-
cle clearance criteria.
MLS Approach Reference Datum
is a
point at a specified height located
vertically above the intersection of the
runway centerline and the threshold.
MLS back azimuth reference datum
means a point 15 meters (50 feet) above
the runway centerline at the runway
midpoint.
MLS datum point
means a point de-
fined by the intersection of the runway
centerline with a vertical plane perpen-
dicular to the centerline and passing
through the elevation antenna phase
center.
Out of coverage indication (OCI)
means
a signal radiated into areas outside the
intended coverage sector, where re-
quired, to specifically prevent invalid
removal of an airborne warning indica-
tion in the presence of misleading guid-
ance information.
Path Following Error (PFE)
means the
guidance perturbations which could
cause aircraft displacement from the
desired course or glidepath. It is com-
posed of the path following noise and of
the mean course error in the case of
azimuth functions, or the mean glide-
path error in the case of elevation
functions. Path following errors are
evaluated by filtering the flight error
record with a second order low pass fil-
ter which has a corner frequency at 0.5
radian/sec for azimuth data or 1.5 radi-
ans/sec for elevation data.
Path following noise (PFN)
means that
portion of the guidance signal error
which could cause displacement from
the actual mean course line or mean
glidepath as appropriate.
Split-site ground station
means the
type of ground station in which the azi-
muth portion of the ground station is
located near the stop end of the run-
way, and the elevation portion is lo-
cated near the approach end.
Time division multiplex (TDM)
means
that each function is transmitted on
the same frequency in time sequence,
with a distinct preamble preceding
each function transmission.
§ 171.305 Requests for IFR procedure.
(a) Each person who requests an IFR
procedure based on an MLS facility
which that person owns must submit
the following information with that re-
quest:
(1) A description of the facility and
evidence that the equipment meets the
performance requirements of §§ 171.309,
171.311, 171.313, 171.315, 171.317, 171.319,
and 171.321 and is fabricated and in-
stalled in accordance with § 171.323.
(2) A proposed procedure for oper-
ating the facility.
(3) A proposed maintenance organiza-
tion and a maintenance manual that
meets the requirements of § 171.325.
(4) A statement of intent to meet the
requirements of this subpart.
(5) A showing that the facility has an
acceptable level of operational reli-
ability and an acceptable standard of
performance. Previous equivalent oper-
ational experience with a facility with
identical design and operational char-
acteristics will be considered in show-
ing compliance with this subparagraph.
(b) FAA inspects and evaluates the
MLS facility; it advises the owner of
the results, and of any required
changes in the MLS facility or in the
maintenance manual or maintenance
organization. The owner must then
correct the deficiencies, if any, and op-
erate the MLS facility for an in-service
evaluation by the FAA.
§ 171.307 Minimum requirements for
approval.
(a) The following are the minimum
requirements that must be met before
the FAA approves an IFR procedure for
a non-Federal MLS facility:
(1) The performance of the MLS facil-
ity, as determined by flight and ground
inspection conducted by the FAA, must
meet the requirements of §§ 171.309,
171.311, 171.313, 171.315, 171.317, 171.319,
and 171.321.
(2) The fabrication and installation of
the equipment must meet the require-
ments of § 171.323.
(3) The owner must agree to operate
and maintain the MLS facility in ac-
cordance with § 171.325.
(4) The owner must agree to furnish
operational records as set forth in
§ 171.327 and agree to allow the FAA to