Chapter 2 – Aircraft Requirements

2.1  Certification

Aircraft Certification

In general, aircraft certification for CAT II and CAT III operations must be in accordance with the applicable editions of the Federal Aviation Administration (FAA) Advisory Circulars (AC) 120-29A Appendix 3 (Airborne Systems for Category II) and 120-28D Appendix 3 (Criteria for Approval of Category III Weather Minima for Takeoff, Landing and Rollout) respectively.

Certification Requirements for CAT II

The aircraft must first meet the aircraft certification requirements of Part V of the CARs. Table 2-1 indicates the airborne equipment requirements for older aircraft previously certified for CAT II operations which were specified in the previous version of this manual (TP 1490 Third Edition, October 1990). Newer aircraft are typically being certified to the requirements of Table 2-2.

Table 2-1: Typical Airborne Equipment Requirements for CAT II Certification of older aircraft

Single Flight Director with dual displays and single automatic approach coupler; or two independent Flight Director Systems Required, except for 2 engine propeller aircraft and rotorcraft, which require a single Flight Director or a single automatic Approach Coupler
Dual Instrument Landing System (ILS) localizer and Glide Slope Receivers Required
Equipment to identify Decision Height Radio Altimeter Required
Avionics Failure Warning System Required
Missed Approach Attitude Guidance

Required. May be:

  1. Attitude gyros with calibrated pitch markings; or

  2. Flight Director pitch command; or

  3. Computed pitch command.

Auto-Throttle System Required for all turbojets if operations based on dual flight directors or if split axis coupler used. Not required for propeller aircraft unless split axis couplers used.
Ice and Rain Protection

Required. To include:

  1. a protection system for windshield; and

  2. a heat source for each airspeed system pitot tube installed.

Communication Equipment Two independent very high frequency (VHF) air-ground communication systems are required.

Duplicated Instruments:

  1. two gyroscopic pitch and bank indicating systems;

  2. two gyroscopic direction indicating systems;

  3. two airspeed indicators;

  4. two sensitive altimeters adjustable for barometric pressure;

  5. two vertical speed indicators.


NOTE: The equipment in this table is representative of some installations previously certified by Transport Canada. See Table 2-2 for typical certified installations in newer aircraft.

Table 2-2: Typical Equipment Installations for CAT II Certification Approval of newer aircraft

Two independent Flight Directors Required.
Two ILS receivers Required.
Two Air Data Computers Required.
Two Gyro Platforms Required. To include two inertial reference systems (IRS) or two attitude and heading reference systems (AHRS) or two gyro systems.
Two Radar Altimeters Required. To include independent displays.
Two Flight Director mode enunciations Required. To include independent enunciation systems.
Duplicated Flight Instruments Required. To include two primary flight displays (PFDs) or two sets of electronic attitude director indicators (EADI) / electronic horizontal situation indicators (EHSI) or two full sets of primary flight instruments.
Avionics Failure Warning system Required. To include ILS comparator and avionics equipment warning system.
Missed Approach guidance Required. To include two independent Flight Director Go-around modes.
Communication Equipment One VHF communication radio required.
Duplicated equipment to enunciate DH Required. To include two displays of DH enunciation.
Ice and Rain Protection Required. To include a protection system for each windshield.
Excessive deviation monitor Required. To include two independent monitors.

NOTE: The equipment in this table is representative of installations recently certified by Transport Canada

Certification Requirements for CAT III

Airborne equipment certification requirements will vary depending on whether the operation is CAT III (A), (B) or (C). Such certifications will be dealt with on an individual aircraft type basis.

2.2  Maintenance

2.2.1  General

  1. The air operator’s maintenance control system must address all applicable equipment listed in the component concordance tables (table 2-1 and 2-2 of this chapter for CAT II, see reference 2.1.3 for CAT III) which includes the quantity required, the minimum required and all applicable aircraft maintenance tests as applicable in the AFM and/or Maintenance Manual.

  2. While there may be differences in the operational capability, avionics equipment capability level and required maintenance, between aircraft certified for CAT II operation and those certified for CAT III, this section does not distinguish between those differences; i.e., the details provided in the operator’s maintenance control system will be predicated on the level of operation for which the program is developed.

2.2.2  Equipment Approval

The configuration or specifications of the equipment installed for CAT II or III operation must be certified.  For Cat I certified aircraft, additional avionics equipment and/or modification to or substitution of installed equipment may be necessary in an upgrading program leading to CAT II or III certification. This may be accomplished by an OEM modification or by STC as part of a modification. The instructions for continued airworthiness (ICA) for the aircraft must include supplemental ICAs which address these modifications.

A newer aircraft may be type certificated for CAT II/III when delivered to an operator and consequently will already have applicable ICA that address CAT II/III maintenance requirements.

2.2.3  Maintenance Control System

The following general requirements relate to the development of an operator’s maintenance control system in support of CAT II/III operations.

  1. to ensure the high level of performance and reliability required for aircraft automatic flight control and related systems for CAT II/III certification and operation, the operator’s technical dispatch procedures and maintenance schedule(s) must take into account the requirements of CAT II/III operations. A copy of the Maintenance Control Manual and affected maintenance schedules must be submitted to the local Transport Canada Center (TCC) for approval.

  2. An operator may apply for approval of their proposed maintenance schedule in advance of a formal application being submitted for CAT II/III approval. When submitting the proposed maintenance schedule for approval, the operator should indicate that Cat II/III operation is intended. The responsible TCCA inspector will review the maintenance schedule development to become familiar with it and to provide guidance to the operator.

  3. It is not the intent of this section to establish a fixed approved maintenance schedule format for all operators conducting CAT II/III operations; however, sufficient data relating to at least the items detailed in paragraph 2.2.4 of this document must be provided, so that a comprehensive evaluation can be made.

2.2.4  Maintenance Control Manual

The Maintenance Control Manual must address at least the following:

  1. maintenance, calibration and verification of the accuracy of the aircraft systems related to CAT II or III operation, in accordance with the type certificate holder’s ICAs, any applicable supplemental ICAs and requirements included in the approved maintenance schedule;

  2. technical dispatch procedures for CAT II or III operations that includes;

    1. de-rating of the aircraft from CAT II or III status because the integrity of one or more of the systems required for such operation is in doubt, or when required by paragraph 2.2.5;

    2. de-rating of the aircraft because of a defect, inspection or calendar criteria, if applicable; and

    3. returning the aircraft to CAT II or III status following required maintenance;

  3. initial and update training for all personnel that have tasks related to CAT II/III maintenance schedule including log book entries, placarding and returning to service criteria; and

  4. reliability monitoring program that includes procedures for reporting findings.

2.2.5  De-rating of Operational Status      

The aircraft CAT II or III operational status must be de-rated, (i.e., CAT III to CAT II or CAT I, or CAT II to CAT I), in accordance with the requirements of the AFM, the AFM supplement, AOM, ICAs and/or the MEL as appropriate, under any of the following conditions:

  1. the discovery of any defect to an aircraft system essential to CAT II or III operation;

  2. when the integrity of an aircraft system essential to CAT II or III operation is in doubt;

  3. when maintenance is undertaken that disturbs a system required for CAT II or III operation;

  4. when required by either the AFM, the AFM supplement, the MEL or a maintenance requirement, and the aircraft has not performed a successful approach in actual CAT II or III conditions or in VMC, or in IMC not lower than CAT I minima, conducted to CAT II minima, CAT III minima, or to an autoland as the case may be, done with a fully capable and equipped airplane on a fully functioning facility with no aircraft or vehicle within the ILS sensitive area while following a procedure that is focussed on annunciation, functionality and overall performance of the equipment during the previous thirty days by a CAT II/III qualified flight crew, which must be supported by a journey log entry;

    NOTE 1: Although CAT II/III system certification on most modern aeroplanes is maintained by performing a system ground check, some older generations of aeroplane still require operational flight checks for CAT II/III. This option is intended for these older aeroplanes and systems for which the performance of a successful CAT II or III approach during the previous 30 days is the preferred method to confirm systems operational suitability and for aeroplanes and systems for which this option is allowed as an alternative to the system ground check in the AFM, AFM supplement, MEL or Instructions for Continuing Airworthiness (ICAs). Since these approaches may be done in conditions other than CAT II/III weather conditions, it is expected that the air operator will develop a procedure that will ensure that the appropriate level of safety (including monitoring for traffic in VMC) is maintained throughout the approach.

    NOTE 2: The intent of the reference to aircraft or vehicle within the ILS sensitive area is intended for the flight crew members to understand that if they become aware, either from ATS or by their own observation, that an aircraft or vehicle is/was within the ILS sensitive area during the approach, the aeroplane need not be downgraded, even if the approach and/or autoland were unsuccessful. However, a successful approach is still required within the 30 day period. Alternatively, if the operator has a maintenance procedure (AFM, MEL or other approved process) in place that provides an alternative for the need for operational confirmation of system performance, then no approaches are required.

  5. when the flight crew reports an unsuccessful landing due to poor aircraft systems performance; or

  6. when the aircraft has failed a CAT II/III required systems ground check.      

The procedures specified in the AFM, the AFM supplement, AOM and/or the MEL as appropriate, must apply in respect of de-rating the operational status of an aircraft, and information relating to the de-rated status, including the reason for de-rating, must be entered in the appropriate aircraft record(s).

2.26  Upgrading of Operational Status

Following de-rating and defect rectification, the aircraft CAT II or III system may be returned to a higher operational status, or to full operational status in accordance with the requirements of the AFM, the AFM supplement, AOM and/or the MEL as appropriate. In the absence of the preceding requirements, the aircraft CAT II/III system may be returned a higher operational status, or to full operational status by:

  1. an appropriate system ground check conducted in accordance with the applicable AMM, and certified by the issuance of a maintenance release; and/or

  2. a successful approach, as applicable, flown by a CAT II/III qualified flight crew in VMC, or in IMC not lower than CAT I minima, conducted to CAT II minima, CAT III minima, or to an autoland as the case may be, done with a fully capable and equipped airplane on a fully functioning facility with no aircraft or vehicle within the ILS sensitive area while following a procedure that is focussed on annunciation, functionality and overall performance of the equipment and certified by a statement to that effect entered in the aircraft journey log. Following CAT II/III systems upgrading and provided all appropriate certifications and related aircraft record entries have been made, the placard installed in respect of the de-rating must be removed or the status annunciator set to indicate the current operational status; and/or

  3. successful completion of calendar criteria as applicable.

    NOTE 1: Aircraft equipped with older CAT II/III system may require both a ground check and a successful CAT II or III approach performance confirmation, while other generation of equipment may require one or the other.

    NOTE 2: A CAT II or III approach referred to in Sections and 2.2.6 consists of a coupled ILS approach with an autoland (if the aircraft is equipped with an autoland system) and this approach may be flown on any category ILS facility. In the case of upgrading of operational status (Section 2.2.6), the approach must be flown in meteorological conditions at or above those required for CAT I operations.