Appendix A to Part 91 - Category II Operations: Manual, Instruments, Equipment, and Maintenance
14:2.0.1.3.12.16.9.1.25 : Appendix A
Appendix A to Part 91 - Category II Operations: Manual,
Instruments, Equipment, and Maintenance 1. Category II Manual
(a) Application for approval. An applicant for approval
of a Category II manual or an amendment to an approved Category II
manual must submit the proposed manual or amendment to the
responsible Flight Standards office. If the application requests an
evaluation program, it must include the following:
(1) The location of the aircraft and the place where the
demonstrations are to be conducted; and
(2) The date the demonstrations are to commence (at least 10
days after filing the application).
(b) Contents. Each Category II manual must contain:
(1) The registration number, make, and model of the aircraft to
which it applies;
(2) A maintenance program as specified in section 4 of this
appendix; and
(3) The procedures and instructions related to recognition of
decision height, use of runway visual range information, approach
monitoring, the decision region (the region between the middle
marker and the decision height), the maximum permissible deviations
of the basic ILS indicator within the decision region, a missed
approach, use of airborne low approach equipment, minimum altitude
for the use of the autopilot, instrument and equipment failure
warning systems, instrument failure, and other procedures,
instructions, and limitations that may be found necessary by the
Administrator.
2. Required Instruments and Equipment
The instruments and equipment listed in this section must be
installed in each aircraft operated in a Category II operation.
This section does not require duplication of instruments and
equipment required by § 91.205 or any other provisions of this
chapter.
(a) Group I. (1) Two localizer and glide slope receiving
systems. Each system must provide a basic ILS display and each side
of the instrument panel must have a basic ILS display. However, a
single localizer antenna and a single glide slope antenna may be
used.
(2) A communications system that does not affect the operation
of at least one of the ILS systems.
(3) A marker beacon receiver that provides distinctive aural and
visual indications of the outer and the middle markers.
(4) Two gyroscopic pitch and bank indicating systems.
(5) Two gyroscopic direction indicating systems.
(6) Two airspeed indicators.
(7) Two sensitive altimeters adjustable for barometric pressure,
each having a placarded correction for altimeter scale error and
for the wheel height of the aircraft. After June 26, 1979, two
sensitive altimeters adjustable for barometric pressure, having
markings at 20-foot intervals and each having a placarded
correction for altimeter scale error and for the wheel height of
the aircraft.
(8) Two vertical speed indicators.
(9) A flight control guidance system that consists of either an
automatic approach coupler or a flight director system. A flight
director system must display computed information as steering
command in relation to an ILS localizer and, on the same
instrument, either computed information as pitch command in
relation to an ILS glide slope or basic ILS glide slope
information. An automatic approach coupler must provide at least
automatic steering in relation to an ILS localizer. The flight
control guidance system may be operated from one of the receiving
systems required by subparagraph (1) of this paragraph.
(10) For Category II operations with decision heights below 150
feet either a marker beacon receiver providing aural and visual
indications of the inner marker or a radio altimeter.
(b) Group II. (1) Warning systems for immediate detection
by the pilot of system faults in items (1), (4), (5), and (9) of
Group I and, if installed for use in Category III operations, the
radio altimeter and autothrottle system.
(2) Dual controls.
(3) An externally vented static pressure system with an
alternate static pressure source.
(4) A windshield wiper or equivalent means of providing adequate
cockpit visibility for a safe visual transition by either pilot to
touchdown and rollout.
(5) A heat source for each airspeed system pitot tube installed
or an equivalent means of preventing malfunctioning due to icing of
the pitot system.
3. Instruments and Equipment Approval
(a) General. The instruments and equipment required by
section 2 of this appendix must be approved as provided in this
section before being used in Category II operations. Before
presenting an aircraft for approval of the instruments and
equipment, it must be shown that since the beginning of the 12th
calendar month before the date of submission -
(1) The ILS localizer and glide slope equipment were bench
checked according to the manufacturer's instructions and found to
meet those standards specified in RTCA Paper 23-63/DO-117 dated
March 14, 1963, “Standard Adjustment Criteria for Airborne
Localizer and Glide Slope Receivers,” which may be obtained from
the RTCA Secretariat, 1425 K St., NW., Washington, DC 20005.
(2) The altimeters and the static pressure systems were tested
and inspected in accordance with appendix E to part 43 of this
chapter; and
(3) All other instruments and items of equipment specified in
section 2(a) of this appendix that are listed in the proposed
maintenance program were bench checked and found to meet the
manufacturer's specifications.
(b) Flight control guidance system. All components of the
flight control guidance system must be approved as installed by the
evaluation program specified in paragraph (e) of this section if
they have not been approved for Category III operations under
applicable type or supplemental type certification procedures. In
addition, subsequent changes to make, model, or design of the
components must be approved under this paragraph. Related systems
or devices, such as the autothrottle and computed missed approach
guidance system, must be approved in the same manner if they are to
be used for Category II operations.
(c) Radio altimeter. A radio altimeter must meet the
performance criteria of this paragraph for original approval and
after each subsequent alteration.
(1) It must display to the flight crew clearly and positively
the wheel height of the main landing gear above the terrain.
(2) It must display wheel height above the terrain to an
accuracy of plus or minus 5 feet or 5 percent, whichever is
greater, under the following conditions:
(i) Pitch angles of zero to plus or minus 5 degrees about the
mean approach attitude.
(ii) Roll angles of zero to 20 degrees in either direction.
(iii) Forward velocities from minimum approach speed up to 200
knots.
(iv) Sink rates from zero to 15 feet per second at altitudes
from 100 to 200 feet.
(3) Over level ground, it must track the actual altitude of the
aircraft without significant lag or oscillation.
(4) With the aircraft at an altitude of 200 feet or less, any
abrupt change in terrain representing no more than 10 percent of
the aircraft's altitude must not cause the altimeter to unlock, and
indicator response to such changes must not exceed 0.1 seconds and,
in addition, if the system unlocks for greater changes, it must
reacquire the signal in less than 1 second.
(5) Systems that contain a push-to-test feature must test the
entire system (with or without an antenna) at a simulated altitude
of less than 500 feet.
(6) The system must provide to the flight crew a positive
failure warning display any time there is a loss of power or an
absence of ground return signals within the designed range of
operating altitudes.
(d) Other instruments and equipment. All other
instruments and items of equipment required by § 2 of this appendix
must be capable of performing as necessary for Category II
operations. Approval is also required after each subsequent
alteration to these instruments and items of equipment.
(e) Evaluation program - (1) Application. Approval
by evaluation is requested as a part of the application for
approval of the Category II manual.
(2) Demonstrations. Unless otherwise authorized by the
Administrator, the evaluation program for each aircraft requires
the demonstrations specified in this paragraph. At least 50 ILS
approaches must be flown with at least five approaches on each of
three different ILS facilities and no more than one half of the
total approaches on any one ILS facility. All approaches shall be
flown under simulated instrument conditions to a 100-foot decision
height and 90 percent of the total approaches made must be
successful. A successful approach is one in which -
(i) At the 100-foot decision height, the indicated airspeed and
heading are satisfactory for a normal flare and landing (speed must
be plus or minus 5 knots of programmed airspeed, but may not be
less than computed threshold speed if autothrottles are used);
(ii) The aircraft at the 100-foot decision height, is positioned
so that the cockpit is within, and tracking so as to remain within,
the lateral confines of the runway extended;
(iii) Deviation from glide slope after leaving the outer marker
does not exceed 50 percent of full-scale deflection as displayed on
the ILS indicator;
(iv) No unusual roughness or excessive attitude changes occur
after leaving the middle marker; and
(v) In the case of an aircraft equipped with an approach
coupler, the aircraft is sufficiently in trim when the approach
coupler is disconnected at the decision height to allow for the
continuation of a normal approach and landing.
(3) Records. During the evaluation program the following
information must be maintained by the applicant for the aircraft
with respect to each approach and made available to the
Adninistrator upon request:
(i) Each deficiency in airborne instruments and equipment that
prevented the initiation of an approach.
(ii) The reasons for discontinuing an approach, including the
altitude above the runway at which it was discontinued.
(iii) Speed control at the 100-foot decision height if auto
throttles are used.
(iv) Trim condition of the aircraft upon disconnecting the auto
coupler with respect to continuation to flare and landing.
(v) Position of the aircraft at the middle marker and at the
decision height indicated both on a diagram of the basic ILS
display and a diagram of the runway extended to the middle marker.
Estimated touchdown point must be indicated on the runway
diagram.
(vi) Compatibility of flight director with the auto coupler, if
applicable.
(vii) Quality of overall system performance.
(4) Evaluation. A final evaluation of the flight control
guidance system is made upon successful completion of the
demonstrations. If no hazardous tendencies have been displayed or
are otherwise known to exist, the system is approved as
installed.
4. Maintenance program
(a) Each maintenance program must contain the following:
(1) A list of each instrument and item of equipment specified in
§ 2 of this appendix that is installed in the aircraft and approved
for Category II operations, including the make and model of those
specified in § 2(a).
(2) A schedule that provides for the performance of inspections
under subparagraph (5) of this paragraph within 3 calendar months
after the date of the previous inspection. The inspection must be
performed by a person authorized by part 43 of this chapter, except
that each alternate inspection may be replaced by a functional
flight check. This functional flight check must be performed by a
pilot holding a Category II pilot authorization for the type
aircraft checked.
(3) A schedule that provides for the performance of bench checks
for each listed instrument and item of equipment that is specified
in section 2(a) within 12 calendar months after the date of the
previous bench check.
(4) A schedule that provides for the performance of a test and
inspection of each static pressure system in accordance with
appendix E to part 43 of this chapter within 12 calendar months
after the date of the previous test and inspection.
(5) The procedures for the performance of the periodic
inspections and functional flight checks to determine the ability
of each listed instrument and item of equipment specified in
section 2(a) of this appendix to perform as approved for Category
II operations including a procedure for recording functional flight
checks.
(6) A procedure for assuring that the pilot is informed of all
defects in listed instruments and items of equipment.
(7) A procedure for assuring that the condition of each listed
instrument and item of equipment upon which maintenance is
performed is at least equal to its Category II approval condition
before it is returned to service for Category II operations.
(8) A procedure for an entry in the maintenance records required
by § 43.9 of this chapter that shows the date, airport, and reasons
for each discontinued Category II operation because of a
malfunction of a listed instrument or item of equipment.
(b) Bench check. A bench check required by this section
must comply with this paragraph.
(1) It must be performed by a certificated repair station
holding one of the following ratings as appropriate to the
equipment checked:
(i) An instrument rating.
(ii) A radio rating.
(2) It must consist of removal of an instrument or item of
equipment and performance of the following:
(i) A visual inspection for cleanliness, impending failure, and
the need for lubrication, repair, or replacement of parts;
(ii) Correction of items found by that visual inspection;
and
(iii) Calibration to at least the manufacturer's specifications
unless otherwise specified in the approved Category II manual for
the aircraft in which the instrument or item of equipment is
installed.
(c) Extensions. After the completion of one maintenance
cycle of 12 calendar months, a request to extend the period for
checks, tests, and inspections is approved if it is shown that the
performance of particular equipment justifies the requested
extension.
[Doc. No. 18334, 54 FR 34325, Aug. 18, 1989, as amended by Amdt.
91-269, 66 FR 41116, Aug. 6, 2001; Docket FAA-2018-0119, Amdt.
91-350, 83 FR 9172, Mar. 5, 2018]