Section 171.9

14 CFR Ch. I (1-1-19 Edition)

(c) The monitor is checked periodically, during the in-service test evaluation period, for calibration and stability The tests are made with a standard  - Reference and variable phase signal generator -  and associated test
equipment, including an oscilloscope
and portable field detector. In general,
the ground check is conducted in
accord- ance with section 8.4 of FAA
Handbook AF P 6790.9  - Maintenance
Instruction for VHF Omniranges - ,
adapted for the facility concerned.
(d) Flight tests to determine the facility-s adequacy for operational requirements and compliance with applicable  - Standards and Recommended
Practices -  are conducted in accordance
with the  - U.S. Standard Flight Inspection Manual - , particularly section 201.
(e) After January 1, 1975, the owner of
the VOR shall modify the facility to
perform in accordance with paragraph
3.3.5.7 of Annex 10 to the Convention on
International Civil Aviation within 180
days after receipt of notice from the
Administrator that 50 kHz channel
spacing is to be implemented in the
area and that a requirement exists for
suppression of 9960 Hz subcarrier
harmonics.
[Doc. No. 5034, 29 FR 11337, Aug. 6, 1964, as
amended by Amdt. 171-7, 35 FR 12711, Aug. 11,
1970; Amdt. 171-9, 38 FR 28557, Oct. 15, 1973]

Section 171.9 Installation requirements.
(a) The facility must be installed according to accepted good engineering
practices, applicable electric and safety codes, and the installation must
meet at least the Federal Communication Commission-s licensing requirements.
(b) The facility must have a reliable
source of suitable primary power, either from a power distribution system
or locally generated, with a supplemental standby system, if needed.
(c) Dual transmitting equipment
with automatic changeover is preferred
and may be required to support certain
IFR procedures.
(d) There must be a means for determining, from the ground, the performance of the equipment, including the
antenna, initially and periodically.
(e) A facility intended for use as an
instrument approach aid for an airport
must have or be supplemented by (de-

pending on circumstances) the following ground-air or landline communications services:
(1) At facilities outside of and not immediately adjacent to controlled airspace, there must be ground-air communications from the airport served by
the facility. Separate communications
channels are acceptable.
(2) At facilities within or immediately adjacent to controlled airspace,
there must be the ground-air communications required by paragraph (e)(1)
of this section and reliable communications (at least a landline telephone)
from the airport to the nearest FAA
air traffic control or communication
facility.
Paragraphs (e) (1) and (2) of this section are not mandatory 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 factor, the requirements of paragraphs (e)
(1) and (2) of this section may be reduced to reliable communications (at
least a landline telephone) from the
airport to the nearest FAA air traffic
control or communication facility, if
an adjacent FAA facility can communicate with aircraft during the proposed instrument approach procedure,
at least down to the minimum en route
altitude for the controlled airspace
area.
[Doc. No. 5034, 29 FR 11337, Aug. 6, 1964, as
amended by Amdt. 171-7, 35 FR 12711, Aug. 11,
1970; Amdt. 171-16, 56 FR 65664, Dec. 17, 1991]

Section 171.11 Maintenance and operations
requirements.
(a) The owner of the facility must establish an adequate maintenance system and provide qualified maintenance
personnel to maintain the facility at
the level attained at the time it was
commissioned. Each person who maintains a facility must meet at least the
Federal Communications Commission-s
licensing requirements and show that
he has the special knowledge and skills

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