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• It is recommended that the following capability be available:
- Radar Altimeter
- Standby power for at least one pilot’s ILS/GLS navigation receiver and displays
- Rain removal capability
b. For approaches other than ILS, GLS, or MLS (e.g., RNAV, VOR, VOR/DME, NDB).
• 2 navigation receivers and associated displays of the type of the approach system to be used (unless otherwise authorized by FAA for the facilities and route to be used), or
• 2 FMS systems (unless use of 1 is authorized by FAA for the facilities and route to be used) which are capable of using the necessary NAVAIDs or equivalent (e.g., space vehicles (SVs)), or which can be monitored by using raw data NAVAID data (e.g., on an associated ND display or RDMI).
• Suitable navigation displays, attitude, vertical speed, and airspeed displays for each pilot (see paragraph 5.9 for details)
• Suitable failure annunciation visible to each pilot
• For ASR or PAR, at least 2 communication radios capable of receiving communications of ASR or PAR information.
/elevenoclock It is recommended that the following capability be available:
- Radar Altimeter
- Standby power for at least one pilot’s VOR or RNAV navigation receiver and displays
- Rain removal capability
c. For aircraft types and systems approved previously to issuance of this AC using earlier AC120-29A or equivalent criteria, the aircraft must have a system which meets that earlier criteria. While such systems may continue to be produced and installed for retrofit in aircraft, or may continue to be installed in new production aircraft or variants, or future derivatives of those types or variants, any additional credit permitted by this AC for Category I capability may be limited to those aircraft and systems meeting revised provisions of this AC, including those provisions shown in Appendix 2.
d. For requirements related to equipment inoperative dispatch pertaining to Category I approach capability see paragraph 5.22 below. For situations involving in-flight failure of equipment pertaining to Category I approach capability see paragraph 5.23 below.
5.3. Airborne Equipment for Category II. The following equipment (along with any applicable equipment otherwise specified above for Category I) is the minimum aircraft equipment considered necessary for an authorization for Category II.
a. Two independent navigation receivers, or equivalent, of each type intended for use, NOTE 1: The navigation receivers specified above may be provided as two or more integrated multi-sensor units (e.g., MMR), NOTE 2: For GLS, at least one data link receiver capable of receiving GBAS uplinked corrections for GNSS position fix correction data may be considered to be acceptable, when used with dual navigation receiver capability (e.g., dual GPSSU sensors) receiving GPS SV ranging information. Dual data link receivers capable of receiving GBAS uplinked corrections for GNSS are recommended.
b. A suitable Automatic Flight Control System, or manual flight guidance system, or both (e.g., flight director) as follows:
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• A system or systems designed to meet criteria of Appendix 3, or
• For aircraft types and systems approved previously to issuance of this AC using earlier AC 120-29A or equivalent criteria, the aircraft must have a system which meets that earlier criteria. While such systems may continue to be produced and installed for retrofit in aircraft, or may continue to be installed in new production aircraft or variants, or future derivatives of those types or variants, any additional credit permitted by this AC for Category II capability may be limited to those aircraft and systems meeting revised provisions of this AC, including those provisions shown in Appendix 3.
• At least 1 autopilot (AFGS) and at least dual flight director systems with an independent display for each pilot is recommended. Dual systems which provide the same information to both pilots, with the second system in “hot standby status” may be acceptable only if suitable comparison monitoring between the systems is available, and timely transfer to standby can be completed, and suitable annunciation to the flightcrew is provided.
c. A radar altimeter display for each pilot. (Note: At least 2 independent radar altimeters with a display for each pilot are recommended.)
d. Rain removal equipment is required for each pilot (e.g., windshield wiper, bleed air). (Note: hydrophobic coating is recommended for each applicable forward windshield, in lieu of rain repellent, due to environmental considerations.)
e. Flight instruments and annunciations which can reliably depict relevant aspects of the aircraft position relative to the approach path, attitude, altitude and speed, and aid in detecting and alerting the pilots in a timely manner to failures, abnormal lateral or vertical displacements during an approach, or excessive lateral deviation (see paragraph 5.9 for details).
f. Unless otherwise approved by FAA based on demonstration of acceptable pilot workload, an autothrottle system should be provided.
g. For requirements related to equipment inoperative dispatch pertaining to Category II approach capability see paragraph 5.22 below. For situations involving in-flight failure of equipment pertaining to Category II approach capability see paragraph 5.23 below.
5.3.1. Standard Category II Minima. Standard Category II minima are a DA(H) of 100 ft. HAT and RVR not less than 1200 ft. (350m).
5.3.2. Special Category II Authorizations. Special Category II minima may be authorized for certain qualifying ILS/GLS facilities (e.g., Type I ILS). Minima at these facilities may be restricted as follows depending on NAVAID, airport facility, and obstacle assessments by FAA. Order 8400.13 addresses certain standard provisions applicable to these authorizations. Other provisions may apply when proposed by the applicant, and approved by FAA. Any authorizations issued should be consistent with one or more of the following DA(H) and RVR paired provisions:
• DA(H) 150 ft. HAT RVR 1800
• DA(H) 150 ft. HAT RVR 1600
• DA(H) 100 ft. HAT RVR 1800
• DA(H) 100 ft. HAT RVR 1600
• DA(H) 100 ft. HAT RVR 1200
5.4. Automatic Flight Control Systems and Automatic Landing Systems. Automatic Flight Control Systems, Autoland Systems, or Manual Flight Guidance systems (e.g., HUD) are considered acceptable for use and are
Par 5 Page 61 recommended for Category I or II ILS, MLS, or GLS procedures which do not have NOTAM restrictions on localizer or glide slope or equivalent signals (e.g., Glide Slope unusable below 500 ft. HAT, or Localizer unusable inside threshold).
5.5. Flight Director Systems. Characteristics of Flight Director Systems (head down or head up) used for aircraft authorized for Category I or II should be compatible with the characteristics of any autopilot or autoland system used. Flight control systems that provide both autopilot control and flight director information may display, or may not display, flight director commands as appropriate for the system design and operator requirements. Regardless of whether Flight Director commands are provided, situational information displays of navigation displacement must also be provided to both flight crewmembers. To ensure that unacceptable deviations and failures can be detected, the displays must be appropriately scaled and readily understandable in the modes or configurations applicable.
5.6. Head up Display Systems. Head up Display systems used as the basis for a suitable Category I or II authorizations must provide guidance for one or both pilots as appropriate for the system design. If information is provided to only the flying pilot, then appropriate monitoring capability must be established for the non-flying pilot.
Monitoring tasks must be identified, and the non-flying pilot must be able to assume control of the aircraft in the event of system failure or incapacitation of the pilot using the HUD (e.g., for a safe go-around or completion of rollout). Head up Display Systems acceptable for Category I or II must meet provisions of Appendix 2 or 3 respectively, or acceptable earlier criteria specified by the FAA and referenced in an AFM.
5.7. Enhanced/Synthetic Vision Systems. Enhanced/Synthetic Vision Systems based on millimeter wave radar or other such sensors may be used to ensure the integrity of other flight guidance or control systems in use during Category I or II operations. They must be demonstrated to be acceptable to FAA in a proof of concept evaluation and they must otherwise meet the requirements of Appendix 2 or 3 of this AC as applicable. Use of Enhanced/Synthetic Vision Systems for purposes other than establishing the accuracy or integrity of flight guidance system performance must be demonstrated to be acceptable through proof of concept testing prior to identification of specific airworthiness and operation criteria.
5.8. Hybrid Systems. Hybrid systems (e.g., a fail passive autoland system used in combination with a monitored HUD flight guidance system) may be acceptable for Category I or II if the system provides the equivalent performance and safety to a non-hybrid system as specified for the minima sought (e.g., Category I or II).
a. Hybrid systems with automatic landing capability should be based on the concept of use of the automatic landing system as the primary means of control, with the manual flight guidance system serving as a backup mode or reversionary mode.
b. Any transition between hybrid system elements (e.g., control transition from autoland use to manual control HUD use, or for response to failures) must be acceptable for use by properly qualified flightcrews (e.g., qualified IAW part 121, an approved Advanced Qualification Program (AQP), or equivalent JAA criteria, as applicable, and standard industry practices). Transitions should not require extraordinary skill, training, or proficiency.
c. For any system which requires a pilot to initiate manual control at or shortly after touchdown, the transition from automatic control prior to touchdown to manual control using the remaining element of the hybrid system (e.g., HUD) after touchdown must be shown to be safe and reliable.
5.9. Instruments, Systems, and Displays. The following identifies Flight Instrument, Systems, and Display presentations requirements for Category I and Category II operations:
5.9.1. Instruments, Systems, and Displays for Category I.
a. Attitude indicators, EADIs or primary flight displays must be provided for each required pilot (pilot flying (PF) and pilot not flying (PNF)), or equivalent electro-mechanical instruments depicting attitude, barometric altitude, airspeed, and vertical speed.
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b. HSIs, EHSIs, NDs, or other equivalent navigation displays, with pertinent, reliable and readily understandable lateral situation information for both normal and non-normal conditions related to Category I landing and missed approach procedures, must be provided for each required pilot.
c. Instrument and panel layouts must follow accepted principles of flight deck design (e.g., basic-T format, conventions for airspeed altitude scales).
d. The location and placement of situation information/navigation displays must be appropriate for each required flight crewmember, and must be appropriately scaled and readily understandable in presentations or mode of display used.
e. Suitable redundant lateral, and where applicable, vertical path displacement information from the final approach course and specified glide path must be provided.
(1) For any operation intended for use with a DA(H) below 250 ft. HAT, lateral and vertical displacement information must be provided on the PFD, EADI, ADI, or equivalent to each pilot independently.
(2) For RNP operations with minima below 250 ft. HAT, the lateral and vertical displacement full-scale indication on the PFD, EADI, or attitude indicator should be as shown in Figure 5.9.2-1 and 5.9.2-2, unless otherwise approved by the FAA. It is recommended that these displacement indications be provided for any RNP approach operations.
(3) Different display sensitivities may be necessary for steep or shallow angle approaches.
(4) The 0.7 degree taper prior to the 100 ft. HAT for vertical display sensitivity is acceptable for most glide path angles. A taper of ¼ the glide path angle is an acceptable alternative, and would be preferred for steep or shallow glide path angles.
(5) The display sensitivities that are selected should be validated by simulator or flight evaluation.
f. Decision Altitude (Height) or Minimum Descent Altitude (Height) advisory indications that are readily understandable and appropriately distinctive plus marker beacon indications (middle marker, and outer marker), or equivalent, should be provided at each required pilot station.
NOTE: Unless otherwise approved by FAA, advisory indications should be expressed as either “RH” or “RA” for radar/radio height or altitude, and as “BARO” for barometric altitude. Flightdeck depiction of radio and barometric height or altitude advisories should not typically use the operational designations of “DH” or “MDA.”
g. Appropriate system status and failure annunciations suited to the guidance systems used, navigation sensors used, and any related aircraft systems (e.g., autopilot, flight director, electrical system) should be provided.
h. Automatic audio call-outs as described in paragraph 5.11 are recommended.
i. A suitable rain removal method is recommended for each pilot for Category I operations. Suitable methods typically include windshield wipers, bleed air windshield rain removal, or hydrophobic coatings.
5.9.2. Instruments, Systems, and Displays for Category II.
a. Attitude indicators, EADIs or primary flight displays must be provided for each required pilot (PF and PNF), or equivalent electro-mechanical instruments depicting attitude, barometric altitude, airspeed, and vertical speed plus suitable standby attitude information available to each required pilot.
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b. HSIs, EHSIs, NDs or other equivalent navigation displays with pertinent, reliable, and readily understandable lateral situation information for both normal and non-normal conditions related to Category II landing and missed approach procedures, must be provided for each required pilot.
c. Instrument and panel layouts must follow accepted principles of flight deck design (e.g., basic-T format, conventions for airspeed altitude scales).
d. The location and placement of situation information/navigation displays must be appropriate for each required flight crewmember, and must be appropriately scaled and readily understandable in presentations or mode of display used.
e. Suitable redundant lateral and vertical path displacement information from the final approach course and specified glide path must be provided.
(1) Lateral and vertical displacement information must be provided on the PFD, EADI, ADI or equivalent to each pilot independently.
(2) Lateral displacement expanded scale information must be provided to confirm that the aircraft position with respect to intended flight path and the landing runway on each PFD, EADI, ADI or equivalent (e.g., for ILS, a full scale sensitivity of 1 Dot (0.0775 ddm)), or the following criteria applicable to RNP.
(3) For RNP operations, the lateral and vertical displacement full-scale indication on the PFD, EADI, or attitude indicator should be as shown in Figure 5.9.2-1 and 5.9.2-2, unless otherwise approved by FAA. It is recommended that these displacement indications be provided for any RNP approach operations. Figure 5.9.2-1 and
5.9.2-2 shows that for the point on the approach path where the RNP portion of the path meets the angular portion of display limits, the display limit distance from nominal path (zero deviation) to full scale high or to full scale low display deviation is + 250 ft. (vertical displacement), and + 1 x RNP (lateral displacement). At the point on the approach path where the vertical angular display limit converges to a constant value (i.e., nominal path is at 100 ft.
HAT), the full-scale displacement is +24' (vertical displacement). At that point on the approach path where the lateral angular display limit converges to a constant value (i.e., runway threshold), the full scale displacement is +175 ft. (lateral displacement).
f. An autopilot or flight director system suitable for the minima to be authorized.
g. Unless otherwise approved by the FAA for Category II operations based on autopilot use alone, flight director(s), or command guidance information, should be provided for each pilot, suitable for the minima to be authorized - at least dual independent system capability must be installed for Category II operations for aircraft which are certificated with more than one required pilot.
NOTE: For Head Up Display (HUD) operations, availability of the information in items a, b, and e above on a HUD does not necessarily substitute for availability of this information on pertinent head-down displays (HDDs). Configurations found acceptable to FAA include use of a compatible HUD and HDDs at the Crewmember 1 (CM1/Captain) flight deck station, and suitable and comparable HDDs at the Crewmember 2 (CM2 /FO) flight deck station, each with adequate flight path display and failure annunciation. Use of other HUD/HDD configurations for CM1 and CM2 must be evaluated by FAA, and be determined to provide acceptable and equivalent or better capability.
h. Unless otherwise approved by FAA based on demonstration of acceptable pilot workload, an autothrottle system should be provided.
i. Decision Altitude (Height) advisory indications that are readily understandable and appropriately distinctive plus a display of radio altitude and marker beacon indications (inner marker, middle marker, and outer marker), or equivalent, should be provided at each required pilot station.
Page 64 Par 5 NOTE: Unless otherwise approved by FAA, advisory indications should be expressed as either “RH” or “RA” for radar/radio height or altitude, and as “BARO” for barometric altitude. Flight deck depiction of radio and barometric height or altitude advisories should not typically use the operational designations of “DH” or “MDA.”
j. Appropriate system status and failure annunciations suited to the guidance systems used, navigation sensors used, and any related aircraft systems (e.g., autopilot, flight director, electrical system) should be provided.
k. Automatic audio call-outs as described in paragraph 5.11 are recommended.
l. A suitable rain removal method is required for each pilot for Category II operations.
m. A demonstration of the suitability of any indications for non-normal configurations for which credit is sought (e.g., electrical configurations, hydraulic power).
Par 5 Page 65 Figure 5.9.2-1 Figure 5.9.2-2 ±1 7 5f t Mini m u m Display Deviation at threshold Maximum Display Deviation = RNP nm2 degree taper Deviation valid 1 mile beyond runway length Lateral Deviation ********** FAC defined by Runway Reference Waypoints ±24 feet Maximum Display Deviation ±250 feet Maximum Display Deviation
0.7 Degree taper Vertical Deviation 100 feet HAT
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5.10. Annunciations. Annunciations must be clear, unambiguous, and appropriately related to the flight control mode in use. The mode annunciation labels should not be identified by landing minima classification. For example, APPROACH, LAND 2, LAND 3, Single Land, Dual Land, are acceptable mode annunciation labels, whereas, “Category II,” “Category III,” etc., should not be used. Aircraft previously demonstrated for Category I or II which do not meet this criteria may require additional operational constraints to ensure the correct use of minima suited to the aircraft configuration.
5.11. Auto Aural Alerts.
a. Automatic Aural Alerts (automatic call-outs, voice callouts, etc.) of radar altitude, or call-outs approaching landing minimums, or call-outs denoting landing minimums are recommended and should be consistent with the design philosophy of the aircraft in question. However, any automatic call-outs used should not be of a volume or frequency that interferes with necessary flightcrew communications or normal crew coordination procedures.
Recommended automatic call-outs include a suitable alert or tone as follows:
(1) At 500 ft. (radar altitude), approaching minimums and at minimums, and
(2) Altitude call-outs during flare, such as at “50” ft., “30” ft. and “10” ft., or altitudes appropriate to aircraft flare characteristics.
b. Low altitude radio altitude call-outs, if used, should appropriately address the situation of higher than normal sink rate during flare, or an extended flare which may be progressing beyond the touchdown zone. Other alerts may be used when approved by the Administrator, if those alerts are consistent with that Operators approved procedures and minima, and do not impair crew communication.
5.12. Navigation Sensors.
a. Navigation sensors as noted in paragraph 4.3.7.1 through 4.3.7.4 and in 5.12.1 or 5.12.2 below may be used to support Category I or Category II Instrument Approach Procedures.
b. Navigation systems, procedures, sensors, or NAVAID signals cited in paragraphs 4.3.7.1 through 4.3.7.4 or in 5.12.1 or 5.12.2 may also use and take suitable credit for various forms of inertial or air data system capability when combined with capability of the sensors cited in the above provisions to improve accuracy, integrity, or availability performance (e.g., position or velocity complementary filtering, or Kalman filtering may be used, and appropriate credit taken for performance improvement).
5.12.1. Navigation Sensors for (xLS) - ILS, GLS, or MLS. For ILS, GLS, or MLS, various navigation sensors individually may be acceptable to support Category I or II operations. ILS localizer and glideslope signals are the primary means currently used for the determination of deviation from the desired path for lowest Category I or II operations. Criteria for acceptable ILS and MLS localizer and glide-slope receivers are included in Appendix 2 or 3 or in earlier acceptable criteria used by FAA for previous demonstrations of systems for Category I or II.
a. Other navigation information based upon GNSS, or SBAS/GBAS, may be used individually or in combination to satisfy the necessary accuracy, integrity, and availability for Category I or II. Navigation sensors other than ILS must meet equivalent ILS performance or appropriate RTCA or EUROCAE criteria for lowest Category I minima credit, unless otherwise authorized.
b. Appropriate marker beacon information, or equivalent, must be displayed to each pilot for the outer, middle and inner markers. The FAA may authorize appropriate substitutes for marker beacons for Category I or II based upon the use of suitable GNSS or SBAS/GBAS capabilities, or DME.
c. ADF capability, or equivalent capability, should be available as suitable for the planned route of flight or planned alternates (e.g., 14 CFR sections 91.205 (d)(2) and 121.349). For example, at least 1 ADF should be available for ILS procedures, unless the operator does not use ILS procedures with an NDB facility identified as an
Par 5 Page 67 approach transition or missed approach NAVAID, or if the operator has available and uses an approved RNAV capability providing equivalent or better performance to that provided by ADF/NDB. RNP-qualified aircraft may be considered to be eligible for ADF/NDB waypoint substitution any time the area navigation system (e.g., FMS) is able to provide RNP.3 or better capability, for each applicable equivalent procedure segment, or for use of an equivalent NDB waypoint. Any other RNAV capability substitution for use of ADF/NDB for instrument procedures should be as determined to be acceptable for that operator by the CMO (e.g., GNSS system substitution IAWAIM provisions).
Note: PAR may also be considered to be acceptable for Category I (also see 4.3.4.1.c and 4.3.8.8).
5.12.2. Navigation Sensors for Approaches other than ILS, GLS, or MLS. For approaches other than ILS, GLS, or MLS, the following sensors are considered to be acceptable for providing course guidance for Category I Operations (Note: Category II operations are not authorized exclusively using these sensors.):
• LOC
• LDA
• SDF
• BCRS
• RNAV (e.g., FMS)
• GPS
• VOR
• VOR/DME
• TACAN
• NDB
• NDB/DME
• Dual NDB
• ASR
• KRM (RMS)
5.12.3. Aircraft Navigation Reference Points, Wheel to Eye Height, and Wheel to Navigation Reference Point Height. To ensure suitable wheel height and clearance over the threshold of runways when following an electronic path (e.g., glideslope or VNAV) and when using visual references (e.g., VGSI/PAPI) aircraft manuals should specify and Operators should be aware of the height of the pilots eye reference point and the height of the navigation reference point (e.g., glideslope antenna) above the wheel path during landing. This is usually specific to each aircraft type. This information should be available to the operator and pilot, along with any guidance on the minimum acceptable runway threshold crossing height criteria for procedures, if applicable, and any constraints or recommendations for proper VGSI/PAPI use.
5.12.4. Threshold Crossing Height (TCH).
a. Typically, procedures are designated with vertical path runway threshold crossing height in the range of 50 to 55 ft. The maximum TCH for instrument approaches is usually limited to 60 ft. Unless otherwise accepted by FAA, aircraft should be able to use these standard facilities and any other facilities with a vertical path (glideslope or VNAV path) having a threshold crossing height specified as not less than 48 ft.
b. For operations on facilities where a threshold crossing height (glideslope or VNAV) is less than 48 ft., the operator and CHDO should consider the advisability of those operations on a case by case basis. Considerations should include any obstructions in the pre-threshold area, the amount the glideslope or VNAV path is below standard values, aircraft type and aircraft characteristics as proposed for the operation, whether the runway under-run area is a full load-bearing surface, placement of lighting aids (threshold lights/approach lights), availability, and suitability of VGSI/PAPI, weather minima to be used, and any other relevant factors.
5.13. Supporting Systems and Capabilities.
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5.13.1. Flight Deck Visibility. Forward and side flight deck visibility for each pilot should be provided as follows:
a. The aircraft should have a suitable visual reference cockpit cutoff angle over the nose for the intended operations, at the intended approach speeds, and for the intended aircraft configurations, as applicable (e.g., flap settings);
b. The aircraft’s flight deck forward and side windows should provide suitable visibility for taxi and ground operations in low visibility; and
c. Placement of any devices or structure in the pilot’s visual field which could significantly affect the pilot’s view for low visibility operations must be acceptable (e.g., HUD drive electronics, sun visor function or mountings).
5.13.2. Rain and Ice Removal.
a. Suitable windshield rain removal, ice protection, or defog capability should be provided as specified below:
(1) Installation of rain removal capability is recommended for Category I and required for Category II (e.g., windshield wipers, windshield bleed air).
(2) Installation of use of windshield hydrophobic coatings, or use of equivalent rain repellent systems which meet pertinent environmental standards are recommended.
(3) Installation of suitable windshield anti-ice or de-ice capability is recommended for Category I and required for Category II for aircraft intended to operate in known icing conditions during approach and landing.
(4) Installation of at least suitable forward windshield defog capability is recommended for aircraft subject to obscuration of the pilot’s view during humid conditions.
b. Aircraft subject to obscuration of the windshield due to rain, ice, or fogging of the pilot’s view which do not have protection, or which do not have adequate protection may require operational limitations on the conditions in which low visibility operations are conducted.
5.13.3. Miscellaneous Systems. Other supporting systems including instruments, radar altimeters, air data computers, inertial reference units, instrument switching, or capabilities such as flight deck night lighting, landing lights and taxi lights, position, turnoff, and recognition lights, flight data recorders, cockpit voice recorders, or other low visibility related aircraft systems must meet any appropriate criteria as specified in Appendix 2 or 3, in basic airworthiness requirements applicable to U.S. certificated aircraft or equivalent, or acceptable earlier criteria authorized by FAA for aircraft previously demonstrated to be acceptable for Category I or Category II operation (See paragraphs 5.20 and 5.21 for GPWS, TAWS and FDR provisions).
5.14. Go-Around Capability.
a. For aircraft authorized for instrument approaches, and particularly for aircraft intended for operation to Category II minima, evaluation of go-around capability should be based on both normal and any specified nonnormal operations, down to the lowest minima expected. Assessment should account for factors related to aircraft geometric limitations (e.g., fuselage attitude and potential for tail strike) during the transition to go around, limited visual cues, autoflight system mode switching if applicable, and any other pertinent factors identified by FAA. For aircraft in which a go-around from a very low altitude may result in an inadvertent touchdown, the safety of such a procedure should be established considering its effect on related systems, such as operation of autospoilers, automatic braking systems, autopilot/flight director mode switching, autothrottle operation and mode switching, reverse thrust initiation and other systems associated with, or affected by, a low altitude go-around.
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b. If an automatic or flight director go-around capability is provided, it should be demonstrated that a go-around can be safely initiated and completed from any altitude to touchdown. If an automatic go-around mode can be engaged at or after touchdown, it should be shown to be safe. The ability to initiate an automatic or flight director go-around at or after touchdown is not required or appropriate. Inadvertent selection of go-around after touchdown (either an automatic or flight director go-around capability) should have no adverse effect on the ability of the aircraft to safely rollout and stop.
c. Regardless of the flight guidance system used, availability of appropriate information to safely go-around should be available to the flightcrew, and the aircraft should have the capability to go-around. The go-around must be able to be initiated at any time during the approach to touchdown. Although flight guidance system go-around capability is not required, if such go-around capability is supported by a flight guidance system, that capability should be able to be selected at any time during the approach to touchdown. If a go-around mode of a flight guidance system is activated at a low altitude where the aircraft inadvertently touches the ground, the flightcrew should have access to adequate information to accomplish a safe go around, and the aircraft or flight guidance system should not exhibit any unsafe characteristic as a result of an inadvertent touchdown.
d. The following factors should typically be considered when evaluating the safety of a go-around from any point in the approach before touchdown:
(1) Go-around capability should address normal operating conditions, and may include specified nonnormal conditions (e.g., engine out) down to the lowest expected operating minimum.
(2) Factors related to any geometric limitations (such as tail strike) or configuration changes (such as flap retraction, or allowing for any necessary acceleration segment) of the aircraft during the transition to a go-around should be considered.
(3) Factors such as the autopilot, flight director, or autothrottle mode switching or automatic disconnect, minimizing altitude loss during transition to a go-around, and addressing any adverse consequences that might result from autopilot, flight director, or autothrottle malfunction should be considered.
(4) If a go-around could result in an inadvertent touchdown, the safety of such an event should be considered. The aircraft design and/or procedures used should accommodate relevant factors. Examples of relevant factors to consider include operation and acceleration characteristics of engines, failure of an engine, the operation of autothrottle, autobrakes, auto-spoilers, autopilot/flight director mode switching, and other systems (e.g., ground sensing logic) which could be adversely affected by an inadvertent touchdown.
(5) If the occurrence of any failure condition in the aircraft or its associated equipment could preclude a safe go-around from low altitude, then such failure conditions should be identified. In such a case, a minimum height may be specified from which a safe go-around was demonstrated if the failure occurs. If the failure occurs below the specified height, pilots should be made aware of appropriate procedures to be used, and the effects or consequences of any attempt to go-around.
e. If necessary, information should be provided to the flightcrew concerning appropriate procedures for low altitude go-around. If the ability to conduct approach and landing operations with an engine inoperative using low minima are intended (e.g., minima below an MDA(H) or DA(H) of approximately 250 ft. HAT), or if procedures for an engine failure during a low altitude go-around require special consideration or are significantly different than for any other go-around, then flightcrew procedures to safely conduct such an engine-out go-around should be addressed. If necessary, suitable information to safely conduct such a low altitude go-around should be provided to the flightcrew (e.g., flap configurations and flap retraction procedures, appropriate acceleration to a suitable goaround speed, appropriate use of auto-feather capability).
5.15. Excessive Deviation Alerting. Some method is recommended for being able to detect excessive deviation of the aircraft laterally and vertically during approach, and laterally during rollout, as applicable. The method used should not require excessive workload or undue attention. This provision does not require a specified deviation
Page 70 Par 5 warning method or annunciation, but may be addressed by parameters displayed on the ADI, EADI, or PFD. When a dedicated deviation warning is provided, its use must not cause excessive nuisance alerts.
5.16. Rollout Deceleration Systems or Procedures for Category I or II.
5.16.1. Stopping Means. A means to determine that an aircraft can be reliably stopped within the available length of the runway, considering ambient conditions, is recommended for any operation.
5.16.2. Antiskid Systems. Unless otherwise specified by FAA, aircraft authorized for Category I or Category II do not have specific antiskid system installation or use requirements beyond those specified in the applicable AFM, applicable FAA MMEL and MEL, and applicable field length operating rules.
5.17. Engine Inoperative Category II Capability. The following criteria are applicable to aircraft systems intended to qualify for “engine inoperative Category II” authorizations. Aircraft demonstrated to meet the provisions of Appendix 2 with an “engine inoperative” and have an appropriate reference to engine inoperative Category II capability in the FAA approved AFM are typically considered to meet the provisions listed below. Other aircraft which have an AFM showing only all-engine Category II capability may be operationally demonstrated for engine inoperative Category II capability IAW paragraph 5.19.1 through 5.19.3 and paragraph 10.5.
a. The AFM or equivalent reference (e.g., Operators manual) must suitably describe demonstrated approach and missed approach performance for the engine inoperative configuration, and the aircraft must meet pertinent criteria otherwise required for all-engine Category II or equivalent criteria. Suitable performance information should also be available to the pilot and, if applicable, the aircraft dispatcher, to ensure safe landing capability in the anticipated configuration and with anticipated speeds, and to establish safe go-around capability from DA(H) and, if applicable, for a balked landing from the TDZ (e.g., equivalent to an obstacle clearance takeoff procedure). When assessing engine out Category II capability, the following exceptions to all-engine Category II criteria may be used:
(1) The effects of a second engine failure when conducting Category II operations with an engine inoperative need not be considered,
(2) Crew intervention to re-trim the aircraft to address thrust asymmetry following engine loss may be permitted,
(3) Alternate electrical and hydraulic system redundancy provisions may be acceptable, as suited to the type design (e.g., bus isolation and electrical generator remaining capability must be suitable for the engine out configuration),
(4) Requirements to show acceptable approach performance may be limited to demonstration of acceptable performance during engine-out flight demonstrations (e.g., a safe approach to minima), and
(5) Approach or Landing system “status” should accurately reflect the aircraft configuration and capability.
b. Suitable information about flight guidance system capability must be available to the flightcrew in flight, particularly at the time of a “continuation to destination” or “diversion to alternate” decision. This is to determine that the aircraft can have an appropriate Category II approach capability when the approach is initiated (e.g., Nonnormal checklist specification of expected configuration during approach, autopilot or flight director status annunciation of expected mode capability).
c. The operator should consider system performance in appropriate weather conditions (e.g., winds, turbulence or wind gradients) to make a determination as to whether any weather related restrictions or limitations are appropriate.
5.18. Special Airports with Irregular Pre-Threshold Terrain. Not withstanding the fact that most aircraft systems that have completed airworthiness demonstrations consider irregular terrain in the pre-threshold area, special