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 Flight Standards District Office or
International Field 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
(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) orDoppler 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
(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
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.