Appendix G to Part 121 - Doppler Radar and Inertial Navigation System (INS): Request for Evaluation; Equipment and Equipment Installation; Training Program; Equipment Accuracy and Reliability; Evaluation Program
14:3.0.1.1.7.32.3.1.13 : Appendix G
Appendix G to Part 121 - Doppler Radar and Inertial Navigation
System (INS): Request for Evaluation; Equipment and Equipment
Installation; Training Program; Equipment Accuracy and Reliability;
Evaluation Program
1. Application authority. (a) An applicant for authority
to use a Doppler Radar or Inertial Navigation System must submit a
request for evaluation of the system to the responsible Flight
Standards office charged with the overall inspection of its
operations 30 days prior to the start of evaluation flights.
(b) The application must contain:
(1) A summary of experience with the system showing to the
satisfaction of the Administrator a history of the accuracy and
reliability of the system proposed to be used.
(2) A training program curriculum for initial approval under §
121.405.
(3) A maintenance program for compliance with subpart L of this
part.
(4) A description of equipment installation.
(5) Proposed revisions to the Operations Manual outlining all
normal and emergency procedures relative to use of the proposed
system, including detailed methods for continuing the navigational
function with partial or complete equipment failure, and methods
for determining the most accurate system when an unusually large
divergence between systems occurs. For the purpose of this
appendix, a large divergence is a divergence that results in a
track that falls beyond clearance limits.
(6) Any proposed revisions to the minimum equipment list with
adequate justification therefor.
(7) A list of operations to be conducted using the system,
containing an analysis of each with respect to length, magnetic
compass reliability, availability of en route aids, and adequacy of
gateway and terminal radio facilities to support the system. For
the purpose of this appendix, a gateway is a specific navigational
fix where use of long range navigation commences or terminates.
2. Equipment and equipment installation - Inertial Navigation
Systems (INS) or Doppler Radar System. (a)
Inertial Navigation and Doppler Radar Systems must be installed in
accordance with applicable airworthiness requirements.
(b) Cockpit arrangement must be visible and useable by either
pilot seated at his duty station.
(c) The equipment must provide, by visual, mechanical, or
electrical output signals, indications of the invalidity of output
data upon the occurrence of probable failures or malfunctions
within the system.
(d) A probable failure or malfunction within the system must not
result in loss of the aircraft's required navigation
capability.
(e) The alignment, updating, and navigation computer functions
of the system must not be invalidated by normal aircraft power
interruptions and transients.
(f) The system must not be the source of cause of objectionable
radio frequency interference, and must not be adversely affected by
radio frequency interference from other aircraft systems.
(g) The FAA-approved airplane flight manual, or supplement
thereto, must include pertinent material as required to define the
normal and emergency operating procedures and applicable operating
limitations associated with INS and Doppler performance (such as
maximum latitude at which ground alignment capability is provided,
or deviations between systems).
3. Equipment and equipment installation - Inertial Navigation
Systems (INS). (a) If an applicant elects to use an
Inertial Navigation System it must be at least a dual system
(including navigational computers and reference units). At least
two systems must be operational at takeoff. The dual system may
consist of either two INS units, or one INS unit and one Doppler
Radar unit.
(b) Each Inertial Navigation System must incorporate the
following:
(1) Valid ground alignment capability at all latitudes
appropriate for intended use of the installation.
(2) A display of alignment status or a ready to navigate light
showing completed alignment to the flight crew.
(3) The present position of the airplane in suitable
coordinates.
(4) Information relative to destinations or waypoint
positions:
(i) The information needed to gain and maintain a desired track
and to determine deviations from the desired track.
(ii) The information needed to determine distance and time to go
to the next waypoint or destination.
(c) For INS installations that do not have memory or other
inflight alignment means, a separate electrical power source
(independent of the main propulsion system) must be provided which
can supply, for at least 5 minutes, enough power (as shown by
analysis or as demonstrated in the airplane) to maintain the INS in
such condition that its full capability is restored upon the
reactivation of the normal electrical supply.
(d) The equipment must provide such visual, mechanical, or
electrical output signals as may be required to permit the flight
crew to detect probable failures or malfunctions in the system.
4. Equipment and equipment installation - Doppler Radar
Systems. (a) If an applicant elects to use a Doppler Radar
System it must be at least a dual system (including dual antennas
or a combined antenna designed for multiple operation), except
that:
(1) A single operating transmitter with a standby capable of
operation may be used in lieu of two operating transmitters.
(2) Single heading source information to all installations may
be utilized, provided a compass comparator system is installed and
operational procedures call for frequent cross-checks of all
compass heading indicators by crewmembers.
The dual system may consist of either two Doppler Radar units or
one Doppler Radar unit and one INS unit.
(b) At least two systems must be operational at takeoff.
(c) As determined by the Administrator and specified in the
certificate holder's operations specifications, other navigational
aids may be required to update the Doppler Radar for a particular
operation. These may include DME, VOR, ADF, ground-based radar, and
airborne weather radar. When these aids are required, the cockpit
arrangement must be such that all controls are accessible to each
pilot seated at his duty station.
5. Training programs. The initial training program for
Doppler Radar and Inertial Navigation Systems must include the
following:
(a) Duties and responsibilities of flight crewmembers,
dispatchers, and maintenance personnel.
(b) For pilots, instruction in the following:
(1) Theory and procedures, limitations, detection of
malfunctions, preflight and inflight testing, and cross-checking
methods.
(2) The use of computers, an explanation of all systems, compass
limitations at high latitudes, a review of navigation, flight
planning, and applicable meteorology.
(3) The methods for updating by means of reliable fixes.
(4) The actual plotting of fixes.
(c) Abnormal and emergency procedures.
6. Equipment accuracy and reliability. (a) Each Inertial
Navigation System must meet the following accuracy requirements, as
appropriate:
(1) For flights up to 10 hours' duration, no greater than 2
nautical miles per hour of circular error on 95 percent of system
flights completed is permitted.
(2) For flights over 10 hours' duration, a tolerance of ±20
miles cross-track and ±25 miles along-track on 95 percent of system
flights completed is permitted.
(b) Compass heading information to the Doppler Radar must be
maintained to an accuracy of ±1° and total system deviations must
not exceed 2°. When free gyro techniques are used, procedures shall
be utilized to ensure that an equivalent level of heading accuracy
and total system deviation is attained.
(c) Each Doppler Radar System must meet accuracy requirements of
±20 miles cross-track and ±25 miles along-track for 95 percent of
the system flights completed. Updating is permitted.
A system that does not meet the requirements of this section will
be considered a failed system.
7. Evaluation program. (a) Approval by evaluation must be
requested as a part of the application for operational approval of
a Doppler Radar or Inertial Navigation System.
(b) The applicant must provide sufficient flights which show to
the satisfaction of the Administrator the applicant's ability to
use cockpit navigation in his operation.
(c) The Administrator bases his evaluation on the following:
(1) Adequacy of operational procedures.
(2) Operational accuracy and reliability of equipment and
feasibility of the system with regard to proposed operations.
(3) Availability of terminal, gateway, area, and en route
ground-based aids, if required, to support the self-contained
system.
(4) Acceptability of cockpit workload.
(5) Adequacy of flight crew qualifications.
(6) Adequacy of maintenance training and availability of spare
parts.
After successful completion of evaluation demonstrations, FAA
approval is indicated by issuance of amended operations
specifications and en route flight procedures defining the new
operation. Approval is limited to those operations for which the
adequacy of the equipment and the feasibility of cockpit navigation
has been satisfactorily demonstrated. [Doc. No. 10204, 37 FR 6464,
Mar. 30, 1972, as amended by Amdt. 121-207, 54 FR 39293, Sept. 25,
1989; Docket FAA-2017-0733, Amdt. 121-379, 82 FR 34398, July 25,
2017; Docket FAA-2018-0119, Amdt. 121-380, 83 FR 9173, Mar. 5,
2018]