AC NO: 120-29 DATE: 9/25/70
FEDERAL AVIATION ADVISORY *
TAINISTRAIO CIRCULAR
CRITERIA FOR APPROVING CATEGORY I AND CATEGORY II LANDING MINIMA FOR FAR 121 OPERATORS REPRINTED OCTOBER 1979 THIS REPRINT INCLUDES CHANGES 1 THROUGH 3
DEPARTMENT OF TRANSPORTATION
FEDERAL AVIATION ADMINISTRATION FAA FORM 1320-8 (288) SUPERSEDES FAA FORM 28808 Initiated by: PS-410
AC NO: 120-29 DATE: 9/25/70
FEDERAL AVIATION ADVSORY
TAMINISTRAIO CIRCULAR
DEPARTMENT OF TRANSPORTATION
FEDERAL AVIATION ADMINISTRATION SUBJECT: CRITERIA FOR APPROVING CATEGORY I AND CATEGORY I1 LANDING MINIMA FOR FAR 121 OPERATORS
1. PURPOSE. This advisory circular combines into one circular material contained in Advisory Circulars 120-4B and 120-20. It sets forth criteria used by FAA in approving turbojet landing minima of less than 300-3/4 or RVR 4000 (Category I) and Category II minima for all aircraft.
2. CANCELLATION. Advisory Circulars 120-4B and 120-20 are hereby canceled.
3. APPLICABILITY. These criteria are applicable to operators holding operating certificates issued pursuant to Parts 121, 123 and 135 (large aircraft only). FAA grants approvals of these minima by amending the applicant's operations specifications.
Il. Jerrarese Gating Digit Standards Servio Initiated by: FS-410
AC 120-29 Page 1 9/25/70
TABLE OF CONTENTS Page No.
CHAPTER 1. COMBINED CRITERIA CATEGORIES I AND II
1. Definitions.
2. Airport Facilities.
3. U. S. Military and Foreign Airports.
4. Airborne Equipment.
5. Pilot Training and Proficiency Program.
6. Operational Requirements - Categories I and II.
7. Foreign Air Carriers.
CHAPTER 2. ADDITIONAL CATEGORY II CRITERIA
8. General.
9. Operational Procedures.
10. Airborne System Evaluation.
11. Operational Demonstration of the Low Approach System.
12. System Fault Detection.
13. Maintenance Program.
14. Approval of Category II Weather Minima.
APPENDIX 1. AIRWORTHINESS APPROVAL FOR CATEGORY II INSTALLATION
OF AIRBORNE NAVIGATION, INSTRUMENT, AND FLIGHT
CONTROL SYSTEMS IN TRANSPORT CATEGORY AIRCRAFT
1. Purpose.
2. General Criteria.
3. Equipment Approval Criteria.
4. Inspection and Test Program.
5. Reserved.
6. Approved Airplane Flight Manual or Markings or Placards.
7. Systems Performance Requirements.
8. Combined Systems Criteria.
9. Individual System Criteria.
APPENDIX 2. GROUND SYSTEM AND OBSTRUCTION CLEARANCE CRITERIA
FOR CATEGORY II OPERATIONS
1. Purpose.
2. General.
3. Section I - Category II Ground System.
4. Obstacle Clearance Criteria.
5. Special Obstruction Clearance Areas
6. Approach Light Area
7. Touchdown Area
8. Touchdown Area Transitional Surfaces
9. Missed Approach Area.
Page il AC 120-29 9/25/70
10. Glide Slope Angle. 12
11. Glide Slope Threshold Crossing Height. 12
12. Adjustment to Category II ILS Minimums. 12
13. Obstructions in the Missed Approach Area. 14
AC 120-29 Page 1 9/25/70 CHAPTER 1. COMBINED CRITERIA CATEGORIES I AND II
1. DEFINITIONS.
a . Category I. An instrument approach procedure which provides for approaches to a decision height (DH) of not less than 200 feet and visibility of not less than 1/2 mile or RVR 2400 (RVR 1800 with operative touchdown zone and runway centerline lights).
b. Category II. An instrument approach procedure which provides approaches to minima of less than DH 200 feet/RVR 2400 to as low as DH 100 feet/RVR 1200.
c. MALS/R. Medium Intensity Approach Lighting System with Runway Alignment Indicator Lights. (See Figure 27, AC 150/5300-2A)
d. SSALS/R. Simplified Short Approach Lighting System with Runway Alignment Indicator Lights. (See Figure 25, AC 150/5300-2A)
2. AIRPORT FACILITIES. The Category I and Category II weather minima shown in Figure 1-l below may be authorized at U. S. civil airports based on the ground aids specified therein. Additional details concerning Category II requirements are contained in Appendix 2.
3. U.S. MILITARY AND FOREIGN AIRPORTS.
a. Category l• The Category l landing minima specitied in Figure i-l below may also be authorized at U. S. military and foreign airports when the applicant shows that the ground facilities are equivalent to the facilities specified in Figure 1-l. ICAO Annex 14 recommends rather than requiring sequenced flashing lights as an adjunct to the ICAO standard precision approach light system. Therefore, the minima specified in Figure 1-l requiring ALSF-l may be authorized at U. S. military and foreign airports without sequenced flashing lights, if the approach light system provides adequate guidance.
The following systems are considered to be equivalent to the U. S.
standard configuration "A" ALS (ALSF-1):
(1) U. S. configuration "B."
(2) NATO standard (C).
(3) Navy composite (U. S.).
(4) Calvert (British).
(5) Centerline (high intensity).
(6) Centre Row DOT standard.
Chap 1 Par 1
Page 2 AC 120-29 9/25/70
WEATHER MINIMA AND REQUIRED GROUND FACILITIES ALSF-1 SSALS/R A11 WX Number of Aircraft and MALS 7 TDZ CL Runway Transmissometers Weather Minima Category HIRL • MIRI Marking Category X Or CL One - When RVR 200-1/2/RVR 2400 D Jets operative Category X or CL Not applicable 200-1/2 A, B, and C Jets Category One - Required RVR 2000 D Jets Category One - Required RVR 1800 A, B and C Jets A11 One - Required RVR 1600 and Aircraft for RVR 1200 less than 1800 and DH less than 200 feet.
Iwo - Required for RVR less than 1600.
Figure 1-1
AC 120-29 Page 3 9/25/70 Category II. Category Il minima may be authorized at foreign airports when the electronic and visual ground aids are equivalent to those specified in Appendix 2. FAA will evaluate each such airport and will give major consideration to the approach light system, high intensity runway lights, in-runway lights, runway marking, and visibility reporting procedures. Although the systems at foreign airports may not exactly conform to U. S. standards, it is important that pilots receive adequate visual cues and accurate weather reports.
Satisfactory procedures for controlling ground vehicles and aircraft while taxiing to prevent interference with transmitted electronic guidance signals should be included as a major consideration for approving Category II at U. S. military and foreign airports.
4. AIRBORNE EQUIPMENT. Approval of Category I or Category II minima is based on installation of the equipment specified in Figure 1-2. Use of improved barometric altimeters has not been shown in Figure 1-2 as a means of identifying the Category Il decision height, since at this writing only one air carrier has such approval and no other carriers have expressed an interest. However, this should not be construed as rescinding the existing authorization nor does it preclude consideration of individual requests and subsequent approvals if such applicants' demonstrate the accuracy of their barometric altimeters by means of a test program acceptable to FAA.
5. PILOT TRAINING AND PROFICIENCY PROGRAM.
Category Il Ground Training (All Aircraft). The applicant's approved training program must be amended to provide training for pilots in command and seconds in command in the following subjects:
(1) The operational characteristics, capabilities and limitations of the Category II ILS and visual aids (e.g., approach lights, in-runway lights, transmissometers, etc.).
(2) The operational characteristics, capabilities and limitations of the Category II airborne system to be used by the applicant, including the following, as appropriate:
(a) The flight director system.
(b) The automatic approach coupler (including split axis).
(c) The system used to identify the decision height.
(d) The instrumentation and display systems.
(e) Automatic throttle systems.
Other systems and devices peculiar to the applicant's installation; i.e., computed go-around guidance, failure warning systems, etc.
Chap 1 Par 3
Page 4 AC 120-29 9/25/70
AIRBORNE EQUIPMENT REQUIREMENTS
CATEGORIES I AND II CAT IÙ Minimum Requirements (Turbojet Only) CAT I (All Aircraft) Single Flight Director 1/ or Required Minimum requirement - Two- Single Automatic Approach engine propeller aircraft only.
Coupler 2/ Instrument Failure Warning System Dual ILS and Glide Slope Receivers Optional 3/ Required plus flight crew assignments and procedures specified in Note 3/ below.
Not required (N.R.) Required Single Flight Director with N.R. Required Dual Displays 1/ and Single Automatic Approach Coupler 2/ or Two Independent Flight Director Systems Equipment for Identification N.R. Required. Can be:
of Decision Height (1) Radar altimeter, or
(2) Inner Markers.
Missed Approach Attitude N.R. Required. Can be:
Guidance (1) Attitude gyros with calibrated pitch markings, Or
(2) Flight director pitch command, or
(3) Computed pitch command.
Auto Throttle System N.R. Required all turbojets if operations based on dual flight directors. Also required any aircraft using split axis couplers if applicant can't show it does not significantly reduce pilot workload.
Rain Removal Equipment N.R. Required Single axis flight directors if basic glide slope information displayed on same instrument.
2 Split axis acceptable.
3/ If improved failure warning system not provided for CAT I operations applicant must establish flight crew procedures and duty assignments to provide immediate detection of essential instrument and equipment Such procedures and assignments are required for Category II operations.
Figure 1-2
AC 120-29 Page 5 9/25/70
(3) The following additional subjects will be covered during initial and recurrent proficiency checks of pilots in command and seconds in command:
(a) Resolution of the decision height.
(b) Missed approach technique using fixed or computed attitude guidance display, as appropriate.
(c) Runway Visual Range; its use and limitations.
(d) The use of visual cues associated with the runway environment during Category II weather conditions with different glide slope angles, cockpit cutoff angles, and the altitude at which these visual cues are normally discernible.
(e) Transition from nonvisual to visual flight during RVR 1600, 1200 and subsequent lower values such as 1000 and 800 using an approved aircraft simulator with a visual system or other training aids, such as films.
(f) The effect of vertical and horizontal wind shear.
(g) Review of the Category II operations specifications.
b. Flight Training - Categories I and II. The initial and recurrent training requirements for pilots in command and seconds in command are shown in Figure 1-3. The maneuvers are categorized according to the low approach system installed in the applicant's aircraft.
6. OPERATIONAL REQUIREMENTS - CATEGORIES I AND II. The applicant's minimum equipment list and operations manual must be amended to include the following, as appropriate:
Operations Based on Dual Flight Directors or Single Flight Director and Approach Coupler.
(1) Category I Operations.
(a) Both systems must be operative at the time of flight release if a combination of weather reports and forecasts indicates the weather at the destination airport will be below 3/4-mile visibility or RVR 4000 at the estimated time of arrival, and the pilot in command has not demonstrated a raw data ILS approach.
Chap 1 Par 5
PILOT FLIGHT TRAINING REQUIREMENTS CAT I 2/ CAT II Turbojets Only All Aircraft
LOW PIC Approach System Maneuvers 1/ Initial/Recurrent 3/ Initial/Recurrent 3/ Dual Flight (a) Two ILS approaches Satisfactorily Satisfactorily Director to 100 feet; from demonstrate (a) to demonstrate (a) to one a landing will a company check a company check be accomplished pilot or an FAA pilot or an FAA and from the other inspector. inspector.
a missed approach.
Flight Two ILS approaches Satisfactorily Satisfactorily Director and to 100 feet; one demonstrate (b) to demonstrate (b) to Approach using flight a company check a company check Coupler (Dual director and one pilot or an FAA pilot or an FAA Flight using auto coupler; inspector. 4/ inspector. 4/ Director from one a landing CAT II) will be accomplished and from the other a missed approach.
Single Flight (c) One raw data ILS Satisfactorily Satisfactorily Director or approach to 200 demonstrate (c), demonstrate (c), (d) Approach feet. (d) and (e) to a and (e) to a company Coupler (d) One ILS approach company check pilot check pilot or an to 100 feet using or an FAA FAA inspector.
flight director or inspector. Applicable to twoapproach coupler. engine propeller From one of the aircraft only.
specified in (c) and (d), a landing accomplished; from the other, a missed s1/ Either an aircraft or an approved visual simulator may be used. When accomplished in an aircraft, a hood will be used to simulate the weather. When accomplished in an approved visual simulator, the system must simulate the appropriate category of weather, ceiling and visibility, and be equipped with an appropriate lighting system which depicts the approach and runway lights.
2/ Seconds in command not expressly prohibited by the operator from conducting Category II approaches will meet the same initial and recurrent flight training requirements specified for pilots in command. In any case, each second in command will demonstrate to a company check pilot or FAA inspector his ability to perform his assigned function during initial and recurrent training.
*3/ If pilot qualified in more than one type aircraft, check may be accomplished in one such type if approach guidance systems installed in each type are comparable. Otherwise, check will be accomplished at least annually in each type.
4 Coupler demonstration need not be accomplished during recurrent training if pilot qualified to use flight director and approach coupler. However, two ILS approaches must be conducted to accomplish the landing and missed approach requirements.
Figure 1-3 Page 6