890
14 CFR Ch. I (1–1–24 Edition)
§ 171.321
(4) There is an error in the time divi-
sion multiplex synchronization of a
particular elevation function such that
the requirement specified in § 171.311(e)
is not satisfied and this condition per-
sists for more than one second.
(5) A failure of the monitor is de-
tected.
(b) The period during which erro-
neous guidance information is radiated
must not exceed the periods specified
in § 171.319(a). If the fault is not cleared
within the time allowed, radiation
shall cease. After shutdown, no at-
tempt must be made to restore service
until a period of 20 seconds has elapsed.
§ 171.321 DME and marker beacon per-
formance requirements.
(a) The DME equipment must meet
the performance requirements pre-
scribed in subpart G of the part. This
subpart imposes requirements that per-
formance features must comply with
International Standards and Rec-
ommended Practices, Aeronautical
Telecommunications, Vol. I of Annex
10 to ICAO. It is available from ICAO,
Aviation Building, 1080 University
Street, Montreal 101, Quebec, Canada,
Attention: Distribution Officer and
also available for inspection at the Na-
tional Archives and Records Adminis-
tration (NARA). For information on
the availability of this material at
NARA, call 202–741–6030, or go to:
http://
www.archives.gov/federal
_
register/
code
_
of
_
federal
_
regulations/ibr
_
loca-
tions.html.
(b) MLS marker beacon equipment
must meet the performance require-
ments prescribed in subpart H of this
part. This subpart imposes require-
ments that performance features must
comply with International Standards
and Recommended Practices, Aero-
nautical Telecommuncations, Vol. I of
Annex 10 to ICAO.
[Doc. No. 5034, 29 FR 11337, Aug. 6, 1964, as
amended at 69 FR 18803, Apr. 9, 2004]
§ 171.323 Fabrication and installation
requirements.
(a) The MLS facility must be perma-
nent and must be located, constructed,
and installed in accordance with best
commercial engineering practices,
using applicable electric and safety
codes and Federal Communications
Commission (FCC) licensing require-
ments and siting requirements of
§§ 171.313(b) and 171.317(b).
(b) The MLS facility components
must utilize solid state technology ex-
cept that traveling wave tube ampli-
fiers (TWTA) may be used. A maximum
level of common modularity must be
provided along with diagnostics to fa-
cilitate maintenance and trouble-
shooting.
(c) An approved monitoring capa-
bility must be provided which indicates
the status of the equipment at the site
and at a remotely located maintenance
area, with monitor capability that pro-
vides pre-alarm of impending system
failures. This monitoring feature must
be capable of transmitting the status
and pre-alarm over standard phone
lines to a remote section. In the event
the sponsor requests the FAA to as-
sume ownership of the facility, the
monitoring feature must also be capa-
ble of interfacing with FAA remote
monitoring requirements. This require-
ment may be complied with by the ad-
dition of optional software and/or hard-
ware in space provided in the original
equipment.
(d) The mean corrective maintenance
time of the MLS equipment must be
equal to or less than 0.5 hours with a
maximum corrective maintenance time
not to exceed 1.5 hours. This measure
applies to correction of unscheduled
failures of the monitor, transmitter
and associated antenna assemblies,
limited to unscheduled outage and out
of tolerance conditions.
(e) The mean-time-between-failures
of the MLS angle system must not be
less than 1,500 hours. This measure ap-
plies to unscheduled outage, out-of-tol-
erance conditions, and failures of the
monitor, transmitter, and associated
antenna assemblies.
(f) The MLS facility must have a reli-
able source of suitable primary power,
either from a power distribution sys-
tem or locally generated. Adequate
power capacity must be provided for
the operation of the MLS as well as the
test and working equipment of the
MLS.
(g) The MLS facility must have a
continuously engaged or floating bat-
tery power source for the continued
normal operation of the ground station
891
Federal Aviation Administration, DOT
§ 171.325
operation if the primary power fails. A
trickle charge must be supplied to re-
charge the batteries during the period
of available primary power. Upon loss
and subsequent restoration of power,
the battery must be restored to full
charge within 24 hours. When primary
power is applied, the state of the bat-
tery charge must not affect the oper-
ation of the MLS ground station. The
battery must allow continuation of
normal operation of the MLS facility
for at least 2 hours without the use of
additional sources of power. When the
system is operating from the battery
supply without prime power, the ra-
dome deicers and the environmental
system need not operate. The equip-
ment must meet all specification re-
quirements with or without batteries
installed.
(h) There must be a means for deter-
mining, from the ground, the perform-
ance of the system including antenna,
both initially and periodically.
(i) The facility must have, or be sup-
plemented by, ground, air, or landline
communications services. At facilities
within or immediately adjacent to con-
trolled airspace, that are intended for
use as instrument approach aids for an
airport, there must be ground air com-
munications or reliable communica-
tions (at least a landline telephone)
from the airport to the nearest FAA
air traffic control or communication
facility. Compliance with this para-
graph need not be shown at airports
where an adjacent FAA facility can
communicate with aircraft on the
ground at the airport and during the
entire proposed instrument approach
procedure. In addition, at low traffic
density airports within or immediately
adjacent to controlled airspace, and
where extensive delays are not a fac-
tor, the requirements of this paragraph
may be reduced to reliable communica-
tions from the airport to the nearest
FAA air traffic control or communica-
tions facility. If the adjacent FAA fa-
cility can communicate with aircraft
during the proposed instrument ap-
proach procedure down to the airport
surface or at least down to the min-
imum en route altitude, this would re-
quire at least a landline telephone.
(j) The location of the phase center
for all antennas must be clearly
marked on the antenna enclosures.
(k) The latitude, longitude and mean
sea level elevation of all MLS anten-
nas, runway threshold and runway stop
end must be determined by survey with
an accuracy of
±
3 meters (
±
10 feet) lat-
erally and
±
0.3 meter (
±
1.0 foot)
vertically. The relative lateral and
vertical offsets of all antenna phase
centers, and both runway ends must be
determined with an accuracy of
±
0.3
meter (
±
1.0 foot) laterally and
±
0.03
meter (
±
0.1 foot) vertically. The owner
must bear all costs of the survey. The
results of this survey must be included
in the ‘‘operations and maintenance’’
manual required by section 171.325 of
this subpart and will be noted on FAA
Form 198 required by § 171.327.
[Doc. No. 20669, 51 FR 33177, Sept. 18, 1986, as
amended by Amdt. 171–16, 56 FR 65665, Dec.
17, 1991]
§ 171.325 Maintenance and operations
requirements.
(a) The owner of the facility must es-
tablish an adequate maintenance sys-
tem and provide MLS qualified mainte-
nance personnel to maintain the facil-
ity at the level attained at the time it
was commissioned. Each person who
maintains a facility must meet the
FCC licensing requirements and dem-
onstrate that he has the special knowl-
edge and skills needed to maintain an
MLS facility, including proficiency in
maintenance procedures and the use of
specialized test equipment.
(b) In the event of out-of-tolerance
conditions or malfunctions, as evi-
denced by receiving two successive
pilot reports, the owner must close the
facility by encasing radiation, and
issue a ‘‘Notice to Airmen’’ (NOTAM)
that the facility is out of service.
(c) The owner must prepare, and ob-
tain approval of, an operations and
maintenance manual that sets forth
mandatory procedures for operations,
periodic maintenance, and emergency
maintenance, including instructions on
each of the following:
(1) Physical security of the facility.
(2) Maintenance and operations by
authorized persons.
(3) FCC licensing requirements for
operations and maintenance personnel.