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827 

Federal Aviation Administration, DOT 

§ 171.107 

§ 171.101 Scope. 

This subpart sets forth minimum re-

quirements for the approval and oper-
ation of non-Federal Simplified Direc-
tional Facilities (SDF) that are to be 
involved in the approval of instrument 
flight rules and air traffic control pro-
cedures related to those facilities. 

§ 171.103 Requests for IFR procedure. 

(a) Each person who requests an IFR 

procedure based on an SDF that he 
owns must submit the following infor-
mation with that request: 

(1) A description of the facility and 

evidence that the equipment meets the 
performance requirements of § 171.109 
and the standards and tolerances of 
§ 171.111, and is installed in accordance 
with § 171.113. 

(2) A proposed procedure for oper-

ating the facility. 

(3) A proposed maintenance organiza-

tion and a maintenance manual that 
meets the requirements of § 171.115. 

(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 as prescribed in § 171.111(k), and 
an acceptable standard of performance. 
Previous equivalent operational experi-
ence with a facility with identical de-
sign and operational characteristics 
will be considered in showing compli-
ance with this paragraph. 

(b) After the Federal Aviation Ad-

ministration inspects and evaluates 
the facility, it advises the owner of the 
results and of any required changes in 
the facility or the maintenance manual 
or maintenance organization. The 
owner must then correct the defi-
ciencies, if any, and operate the facil-
ity for an in-service evaluation by the 
Federal Aviation Administration. 

§ 171.105 Minimum requirements for 

approval. 

(a) The following are the minimum 

requirements that must be met before 
the Federal Aviation Administration 
will approve an IFR procedure for a 
non-Federal Simplified Directional Fa-
cility: 

(1) A suitable frequency channel 

must be available. 

(2) The facility’s performance, as de-

termined by air and ground inspection, 

must meet the requirements of 
§§ 171.109 and 171.111. 

(3) The installation of the equipment 

must meet the requirements of 
§ 171.113. 

(4) The owner must agree to operate 

and maintain the facility in accord-
ance with § 171.115. 

(5) The owner must agree to furnish 

periodic reports as set forth in § 171.117, 
and agree to allow the FAA to inspect 
the facility and its operation whenever 
necessary. 

(6) The owner must assure the FAA 

that he will not withdraw the facility 
from service without the permission of 
the FAA. 

(7) The owner must bear all costs of 

meeting the requirements of this sec-
tion and of any flight or ground inspec-
tions made before the facility is com-
missioned, except that the FAA may 
bear certain of these costs subject to 
budgetary limitations and policy estab-
lished by the Administrator. 

(b) If the applicant for approval 

meets the requirements of paragraph 
(a) of this section, the FAA commis-
sions the facility as a prerequisite to 
its approval for use in an IFR proce-
dure. The approval is withdrawn at any 
time the facility does not continue to 
meet those requirements. In addition, 
the facility is licensed by the Federal 
Communications Commission. The 
Federal Aviation Administration rec-
ommends cancellation or nonrenewal 
of the Federal Communications Com-
mission license whenever the frequency 
channel is needed for higher priority 
common system service. 

§ 171.107 Definition. 

As used in this subpart: 

SDF 

(simplified directional facility) 

means a directional aid facility pro-
viding only lateral guidance (front or 
back course) for approach from a final 
approach fix. 

DDM 

(difference in depth of modula-

tion) means the percentage modulation 
depth of the larger signal minus the 
percentage modulation depth of the 
smaller signal, divided by 100. 

Angular displacement sensitivity 

means 

the ratio of measured DDM to the cor-
responding angular displacement from 
the appropriate reference line.