AC 120-28C 3/9/84 Appendix 3 APPENDIX 3. CATEGORY III FAIL-OPERATIONAL ROLLOUT CONTROL SYSTEMS PURPOSE. This appendix contains criteria for the approval of fail-operational rollout control airborne equipment and installation.
2. GENERAL CRITERIA. installation, and test methods should be based on a consideration of factors such as the intended function of the installed system, its accuracy, reliability, and The type certification approval for the equipment, system failure features, as well as the operational concepts in paragraph 7 of this AC. In addition, approval should be based on demonstrated compatibility with ground facilities designated as U.S. Type II or U.S. Type III. The guidelines and procedures contained herein are considered acceptable methods of determining transport category airplane airworthiness for use of fail-operational rollout control systems in Category IIIb operations.
After touchdown and until the point where safe manual control of the aircraft by the crew using visual references is assured, aircraft system failures (when considered separately or in conjunction with other system failures that are not shown to be extremely improbable) cannot preclude the joint pilot/rollout control system from controlling the aircraft and maintaining the aircraft on the runway and stopping the aircraft within the runway length available. Additionally, these failure conditions cannot present cockpit cues or indications to the pilot which could cause him/her to attempt a manual rollout using visual reference. These capabilities should be demonstrated under the most critical conditions expected in
3. EQUIPMENT APPROVAL CRITERIA. As in Appendix 1.
4. SYSTEM PERFORMANCE CRITERIA AFTER TOUCHDOWN FOR LATERAL STEERING CONTROL. The performance of the rollout control system should be consistent with the performance of the flight guidance and control system required for Category III approach and landing. In addition, it should be shown by a combination of performance of the rollout control system is satisfactory. Demonstrations in demonstration and analysis, for wet and dry runway surface conditions, that the simulated or actual reduced visibility, representative of expected conditions in which the system is to be used, should also be conducted if system operation is dependent on crew actions or manual control.
a. The following environmental conditions are to be considered in meeting the criteria of this appendix:
configurations used in meeting the airworthiness requirements for a Category III (1) The full range of environmental conditions and airplane system should be considered, including headwinds of at least 25 knots, tailwinds of at least 10 knots, and crosswinds of at least 15 knots. These environmental and configurations demonstrated during airworthiness approval of the Category III conditions and airplane configurations should be compatible with the conditions airborne systems as specified in Appendix 1 of this AC.
(2) The range of certificated runway conditions (dry and wet) should be considered.
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Appendix 4 APPENDIX 4. DECELERATION SYSTEMS FOR CATEGORY IIIB PURPOSE. This appendix contains criteria for approval of airborne equipment and installation of deceleration systems used in Category IIIb operations.
2. CRITERIA FOR AUTOMATIC BRAKING, DECELERATION DISPLAYS, OR RUNWAY REMAINING SYSTEMS. If automatic braking, deceleration displays, groundspeed displays, or runway remaining indicators are used for credit under paragraph 9c of this AC, a means will be demonstrated for the flightcrew to determine that deceleration of the airplane is proceeding satisfactorily or that the airplane will reach a complete stop prior to reaching the end of the runway.
a. If used, an automatic braking system should allow antiskid protection and have manual reversion capability. An automatic braking system should provide smooth and continuous deceleration from touchdown until the airplane comes to a complete stop on the runway and provide the following:
(1) Disconnect must not create unacceptable additional crew workload or crew distraction from normal rollout braking.
120753 (2) Normal operation of the automatic braking system should not interfere with the rollout control system. Manual override of the automatic braking system must be possible without excessive brake pedal forces or interference with the rollout control system. The system should not be susceptible to inadvertent
(3) A positive indication of system disengagement and a conspicuous indication of system failure should be provided.
(4) No malfunction of the automatic braking system should interfere with either pilots' use of the manual braking system.
b. If an automatic braking system is installed for rollout deceleration credit, demonstrated wet and dry runway landing distances, based upon the use of the automatic landing system with automatic throttle, for each mode of the automatic braking system, should be determined in a manner consistent with Section 25.125 of the FAR and presented in the airplane flight manual as performance information. Procedures should be established to permit pilots, prior to landing, to determine the automatic brake setting needed to obtain a safe stop on the runway being used for landing.
3. APPROVED AIRPLANE FLIGHT MANUAL. Upon satisfactory completion of an engineering inspection and test program, the FAA-approved airplane flight manual or supplement, and markings or placards, if appropriate, should reflect the following:
a. Appropriate limitations, if necessary.
b. Revision to the performance section, if appropriate.
c. The airborne equipment, installation, and flightcrew procedures related to the Category IIIb deceleration system.
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Appendix 5 APPENDIX 5. SAMPLE OPERATIONS SPECIFICATIONS FOR AUTHORIZATION
TO CONDUCT CATEGORY III OPERATIONS Category III Operations (Example)
1. CATEGORY III OPERATIONS.
a . Landing Minima for Category Illa
(1) Category IIIa Fail-Passive Operations.
(i) B-727, DC-9-80, B-757, B-767 (A-300/B-747/DC-10/I-1011, if "proof of concept" acceptably demonstrated).
(A) Touchdown zone and mid 700 RVR (200 meters).
(B) DH 50 feet (15 meters) .
(2) Category IIIa Fail-Operational Operations.
(1) A-300, B-757, B-767, DC-10, L-1011 (A) Touchdown zone and mid 700 RVR (200 meters).
(B) AH 100 feet (30 meters).
(3) Category IIIb Fail-Operational Operations.
(1) A-300, B-757, B-767, DC-10, L-1011 (A) Touchdown zone and mid 600 RVR (175 meters) .
(B) AH 100 feet (30 meters).
(11) A-300, B-757, B-767, DC-10, I-1011 (A) Touchdown zone, mid, and rollout 300 RVR (100 meters).
(B) AH 100 feet (30 meters).
NOTE: Requires the use of an automatic rollout control system approved for Category 11lb.
b. Pilot Qualifications. The minima prescribed in subparagraph a are authorized for only those pilots in command and seconds in command who have completed the approved Category III training program and who have been certified by a company check airman or an FAA inspector (for Foreign Flag Air Carriers - certified by the State of the Operator) as being qualified for Category Illa or Category IIIa and Category IIIb operations. No pilot in command shall be authorized to conduct Category III operations in turbojet aircraft unless he/she 1 Par 1
Appendix 5 has had at least 300 hours as pilot in command in turbojet aircraft, including 100 hours in the Category III type aircraft.
Required Airborne Equipment. In addition to the flight instruments and radio navigation equipment required by applicable FAR, the following equipment 1s required and must be used for Category III operations (specify by type aircraft authorized - see example in paragraph la(1)(i) of this appendix).
(1) For the B-727 aircraft for fail-passive Category Illa - in addition to the flight instruments and radio navigation equipment required for Category II operation:
Itemized list including: automatic approach coupler with fail-passive automatic landing system and dual radio altimeters.
(ii) An immediate aural disconnect warning shall be provided in addition to the flashing red light.
(2) For the DC-9-80, B-757, B-767 for fail-passive Category IIla - itemized list which includes the equipment specified in the Airplane Flight Manual.
(3) For the A-300, B-757, B-767, DC-10, I-1011 aircraft for fail-operational Category IIla - itemized list which includes the equipment specified in the Airplane Flight Manual.
(4) For the A-300, B-757, B-767, DC-10, L-1011 aircraft for fail-operational Category IIIb - itemized list.
(i) The equipment specified in subparagraph c(3), plus
(ii) Rollout control system approved for Category IIIb, and
(iii) Automatic braking or other means specified in this AC, paragraph 9c.
d. Required RVR Equipment.
(1) For Category IIIa operations and for Category IIIb operations with minima of 600 RVR (175 meters), the following transmissometers are required:
Three transmissometers are required unless it can be shown that two transmissometers can meet the operational needs for a particular airport.
when three transmissometers are installed, touchdown and mid are controlling and rollout provides advisory information to pilots.
(ii) If only two transmissometers are required, they must be touchdown and rollout, both are controlling.
(2) For Category IIIb operations using fail-passive rollout control systems with minima below 600 RVR (175 meters), three transmissometers are required and touchdown, mid, and rollout are controlling.
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(3) For Category IIIb operations using fail-operational rollout control systems with minima below 600 RVR (175 meters), three transmissometers are normally required and touchdown, mid, and rollout are controlling. However, in the event that one transmissometer is temporarily inoperative, these operations may continue using the two remaining transmissometers and both RVR reports are controlling.
e. Operating Limitations. A Category IIIa ILS approach shall not be started when the controlling RVR of the landing runway is reported to be less than Category Il minima or a Category IIIb approach started when weather is reported below Category IIIa minima unless:
(1) The airborne equipment required by paragraph c of this section is operating satisfactorily.
(2) All required elements of the ground system, except sequence flashing lights, are in normal operation.
(3) The crosswind component on the landing runway is 10 knots or less.
(4) For Category IIIa - Runway field length as specified in paragraph 7g of this AC.
(5) For Category IIIb.
Minima 600 RVR (175 meters). (Runway field length as specified in paragraph 7g of this AC.)
(il) Minima 300 RVR (100 meters). (Runway field length as specified in paragraph 7g of this AC.)
£ . Missed Approach.
For Category IIIa approaches with a fail-passive Flight Control System, a missed approach will be initiated:
If the controlling RVR is reported to decrease below the applicable minima prior to reaching the DH. However, if the aircraft is established on the final approach segment when this report is received, the approach may be continued to the DH:
reference with the touchdown zone or touchdown zone lights. th the touche one or touted on one stabiehed adequate visual
(iii) If, after passing the DH, visual reference is lost or a reduction in visual reference occurs which prevents the pilot from continuing to verify that the aircraft will touchdown in the touchdown zone.
When a failure in the automatic landing system occurs prior to touchdown. However, if the failure occurs in conditions such that the pilot has adequate visual reference to land manually, and the pilot determines that continuing a landing would be a safe course of action, the pilot may land manually following a failure of the airborne system, ground system, or visual aid.
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(v) If the pilot determines that an automatic touchdown cannot be safely accomplished within the touchdown zone.
If prior to DH, any of the required elements of the ground system become inoperative. However, Category III approaches and landings may be continued if sequence flashers are inoperative.
(2) For fail-operational Category Illa approaches with a rollout control system and for Category IIIb approaches, a missed approach will be initiated:
If the controlling RVR is reported to decrease below the applicable minima prior to reaching the AH. However, if the aircraft is established on the final approach segment when this report is received, the approach may be continued to the AH. Unless a fail-passive rollout control system is used for Category IIIa/Category IIIb (600 RVR) operations, or a failoperational rollout control system is used for Category IIlb operations with
(11) If the pilot determines that an automatic touchdown cannot be safely accomplished within the touchdown zone.
(iii) If, prior to the AH, the pilot cannot determine that the rollout control system is available.
(iv) When a failure occurs prior to the AH in one of the required systems in the aircraft.
If prior to AH or DH, as applicable, any of the required elements of the ground system become inoperative. However, Category III approaches and landings may be continued if sequence flashers are inoperative.
Subparagraph f does not preclude continuation of a higher minimum Category approach if the system failure does not affect the systems required for the higher approach minima.
NOTE: Notwithstanding subparagraph i, it a failure occurs in conditions such that the pilot has sufficient visual cues to land the aircraft manually, and if the pilot determines that continuing a landing would be a safe course of action, the pilot may: (1) following partial failure of a fail-operational system, land automatically using the remaining fail-passive automatic system or land manually; (2) following failure of a ground ILS guidance component, land manually, or (3) following failure of a visual aid, land the aircraft either automatically or manually.
h. Authorized Airports. The certificate holder is authorized Category III operations at the following airports and runways.
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i. Example of an acceptable format to specify required airborne equipment for a specific airplane in the operations specifications as required in paragraph 1c. The required equipment for a specific aircraft would be as specified in the approved Airplane Flight Manual.
OPERATIONS SPECIFICATIONS PART C, Page_ Required Airborne Equipment - In addition to the flight instruments and radio navigation equipment required by FAR, Part 121, the following equipment is required for Category III operation:
REQUIRED ASA LAND 2* ASA LAND 3* ASA LAND 3* EQUIPMENT 700 RVR/50' DH 700 RVR/100' AH 600 RVR/100' AH Autopilot Flight Director Display 2 3 2 Electronic ADI 2** 2** 2** ILS Deviation 2** 2** 2** Radio Alt Readout 2** 2** 2** AFDS Mode 2** 2** 2** Annunciation Missed Approach Electronic ADI or FD Pitch Command Attitude Guidance Autoland Status Annunciator 1# 2 2 Inertial Reference Unit (in NAV Mode) 2*** 3 3 Autothrottle System As Required With With AC Electrical Power Source 2 2 2 Rollout Guidance NR NR With Hydraulic System 3 3 3 Windsheild Wipers With With With Autoland Status Annunciator.
** Must be supplied by seperate symbol generators.
*** Associated with engaged autopilot.
Must be operative for the pilot monitoring the approach below 100 feet.
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