AC 29-2, CHG 1 78/6T/IT SECTION 41. MARKINGS AND PLACARDS
29.1541 General (See par. 781.) O9IT FAR 29.1543 Instrument Markings: General (See par. 781) 09IT
29.1545 Airspeed Indicator (See par. 781) O9TT
29.1547 Magnetic Direction Indicator • 09TT
29.1549 Powerplant Instruments (See par. 781)
29.1551 011 Quantity Indicator (RESERVED)
29.1553 Fuel Quantity Indicator (RESERVED)
29.1555 Control Markings (RESERVED) FAR 29.1557 Miscellaneous Markings and Placards (RESERVED) FAR 29.1559 Limitations Placard (RESERVED) FAR 29.1561 Safety Equipment (RESERVED) FAR 29.1565 Tail Rotor (RESERVED)
752.-761. RESERVED SECTION 42. ROTORCRAFT FLIGHT MANUAL * 762. FAR 29.1581 General 1203 763- FAR 29.1583 Operating Limitations 1211
764. FAR 29.1585 Operating Procedures 1213
765. FAR 29.1587 Performance Information 1215
766. FAR 29.1589 Loading Inrormation 1217 •
767.-774. RESERVED CHAPTER 3 - MISCELLANEOUS AIRWORTHINESS
775. IFR Certification 1237
776. Certification Procedure for Helicopter Avionics Equipment 1253
777. Standardized Test Procedure for Helicopter DC Electrical 1267 Standardized Test Procedure for Helicopter Generator Cooling 1273 Annunciator Panels 1275
780. RESERVED
781. Instrument Markings: General, Airspeed, and Powerplant 1281 XII
CHAPTER 1. PART 21
CERTIFICATION PROCEDURES FOR PRODUCTS AND PARTS (Amendment 21-50) * 1.-3. RESERVED.
4. $ 21.16 SPECIAL CONDITIONS.
The Process. Chapter 2, Section 1, paragraph 8 of the Type Certificate Handbook, Order 8110.4, provides detailed guidance on the special conditions process. However, much of that material has been outdated with the implementation of the Aircraft Certification Directorate Program. Rotorcraft special conditions are processed through the Helicopter Policy and Procedures Staff, ASW-110. That office will assure coordination with the affected agency and industry elements including the Regional Counsel. All comments will be considered and the disposition documented by the Rotorcraft Directorate. ASW-l will issue the special conditions.
b. Basis for Development.
(l) Special conditions are justified on the basis of the existing Part 29 being inadequate or inappropriate due to novel or unusual design features of the rotorcraft to be certificated.
(2) The phrase "novel or unusual" as used in § 21.16 is a very relative As used hereafter in applying § 21.16 to justify the issuance of special conditions, "novel or unusual" will be taken with respect to the state of technology envisaged by the applicable airworthiness standards of this subchapter. It must be recognized that in some areas which will vary from time to time, the state of the regulations may somewhat lag the state of the art in new design because of the rapidity in which the state of the art is advancing in civil aeronautical design and because of the time required to develop the experience base needed by the FAA to proceed with general rulemaking. Applicants for type certification of a new design have the opportunity to mitigate the impact of not knowing the precise airworthiness standards to be applied for "novel or unusual design features by consulting with the FAA early in their certification planning when such features are suspected or known by the applicant to exist. It should also be recognized that, because of the intentional objective nature of the airworthiness standards of this subchapter, many new design features which might be thought of as "novel or unusual" may already be adequately covered by existing regulations, thus obviating the need to issue special conditions.
(3) Before proposing special conditions, the certification staff should very thoroughly analyze the existing regulations and assure they are inadequate or inappropriate in light of a new and novel design feature.
Chap 1 Par 1 1 (thru 7)
AC 29-2, CHG 1 11/19/84
5.-7. RESERVED.
8. £ 21.31 TYPE DESIGN.
The regulatory basis for requiring data to define the design is contained in § 21.31. This section 1s self-explanatory and broad enough in scope to give the certification staff access to sufficient data to determine compliance with Part 29.
9.-11. RESERVED.
12. 21.33 INSPECTION AND TESTS.
a. Applicant Responsibility. Section 21.33 requires the applicant to:
(1) Assure the test rotorcraft conforms to the type design. This must be accomplished prior to presentation to the FAA for testing.
(2) Conduct all inspections and tests necessary to determine compliance with the airworthiness and noise requirements.
b. FAA Responsibility.
(1) The design evaluation engineers should assure that the type design is adequate in their technical area and that the inspections and tests to be conducted are appropriate and sufficient to show compliance with Part 29.
(2) As changes to the rotorcraft are made during the test program, the flight test crew should assure that the appropriate design evaluation engineer concurs with the change and the conformity inspection of the change has been conducted.
13.-15. RESERVED.
Chap 1 8 (thru 20) Par 5
* 16. § 21.35 FLIGHT TESTS.
a • Explanation•
(l) This section outlines the requirements of the applicant for aircraft type certification and should be used in conjunction with Order 8110.4, Section
5. section zi.35 requires, in part, that the applicant conduct sufficient flight tests to show compliance with the flight requirements throughout the proposed flight envelope. The results of the applicant's flight test should be submitted to the FAA in report form for evaluation to determine what verification flight tests the FAA may elect to conduct. The report should conclude that in the applicant's opinion the test aircraft complies with the applicable certification requirements. The FAA verification flight test should include, but not be limited to, the critical or marginal results contained in the applicant's flight test report. The FAA's role in the certification effort is not envisioned to be one of conducting day-to-day routine flight tests with the applicant, but only to verify his results through limited sampling. In certain tests, such as high altitude testing at a remote mountain site, there is an advantage in conducting flight tests concurrently with the applicant. Additionally, the FAA can provide technical flight test assistance to the applicant in certain cases. This can be done after a cursory review and a letter of authorization is issued to the flight test crew.
(2) Preflight Test Planning. After the applicant's flight test report is reviewed, it should be determined what FAA engineering flight tests are necessary. These tests are normally specified in the Type Inspection Authorization (TIA). At the same time the FAA must know and agree to the applicant's proposed means of data aquisition, reduction, and expansion of the flight test data, The adequacy of the test instrumentation should be evaluated prior to official type certification tests (reference paragraph 24).
(3) Order of Testing. The Federal Aviation Regulations are so worded that the results of some flight tests have a definite bearing on the conduct of other tests. For this reason, and to minimize retesting, careful attention should be given to the order of testing. The exact order of testing will be determined only by considering the particular rotorcraft and test program involved. lests which are particularly important in the early stages of the program are:
(1) Airspeed calibration: All tests involving airspeed depend upon the calibration.
(11) Engine power available determination.
(111) Engine cooling.
(4) Test Groupings.
Weight and c.g.: In addition to the regulatory relationship of one test to another, efficient testing requires that consideration be given to the acoomplishment of as many tests on a single flight as can be accommodated successfully.
Chap 1 Par 16 21
AC 29-2, CHG 1 11/19/84 * (11) Special instrumentation. Similarly, consideration should be given to grouping of tests that involve special instrumentation. Examples of these are takeoff and landing tests which usually require group equipment to record horizontal distance, height, and time. Ground calibration of the airspeed indicating system can be accomplished at the same time. It is the applicant's responsibility to provide the necessary instrumentation.
b. Procedures.
(1) Type Certification Flight Tests.
(1) Prior to initiating official FAA flight tests, a conformity inspection of the test aircraft must be accomplished. This is needed to assure that the test aircraft is in the proper configuration or "conforms" to the engineering drawings and documents that have been submitted to FAA, evaluated, and approved. It is absolutely essential to know the configuration being tested in any engineering flight evaluation. Conformity inspection prior to TIA flight tests assures that testing will not be wasted because of configuration uncertainties.
Certification Handbook 8110.4, paragraph 67, contains a requirement that the applicant must keep the FAA advised of any configuration changes to the aircraft. The manufacturing inspector should keep the FAA flight test pilot apprised of any change which may affect safety of the test aircraft or may influence test results.
(111) Results of the conformity inspection and the engineering flight test program must be documented. This is normally done in the Type Inspection Report (TIR). Results may be documented in any acceptable engineering format.
The report should be in sufficient detail to clearly show how compliance with each appropriate section of the rules was determined.
(iv) The flight test pilot must assure that the FAA manufacturing inspector and certification engineer are aware of all configuration changes found necessary as a result of FAA tests. The manufacturing inspector is responsible for assuring that all changes are incorporated into production drawings after the design data reflecting the change have been approved by the certification engineer.
Additional flight test responsibilities, procedures, and requirements during the certification flight test process are contained in Certification Handbook 8110.4, Section 5, Flight.
(2) Function and Reliability Tests.
(1) A comprehensive and systematic check of all aircraft components must be made to assure that they perform their intended function and are reliable.
(11) Function and reliability (F&R) testing must be accomplished on an aircraft which is in conformity with the approved production configuration.
F&R testing should follow the type certification testing described in paragraph
(1) above to assure that significant changes resulting from type certification tests can be incorporated on the aircraft prior to F&R tests.
Chap 1 22 Par 16
11/19/84 ILLUSTRATIONS AC 29-2, CHG 1 The first block of digits in the figure number denotes the associated paragraph number. The second block of digits denotes the figure number within the paragraph. The figure is located at the end of the paragraph.
Figure No. Title Page 58-1 Shaft Horsepower vs. Turbine Outlet Temperature - Sea Level Standard Day 99 58-2 Uninstalled Takeoff Power Available 100 58-3 Installed Takeoff Power Available 101 Power Assurance Check Chart 102 Takeoff Performance Category A 105 Category A Vertical Takeoff Profile, Ground Level Heliport 112 Category A Vertical Takeoff Profile, Pinnacle 113 Conventional Takeoff Profile, Category B 116 Autorotational Characteristics - Typical 121 67-1 Category A Conventional Landing - Clear Heliport 132 67-2 Category A Vertioal Landing 132 69-1 Height-Velocity (HV) Diagram 139 69-2 Altitude/Weight Accountability 140 85-1 Static Longitudinal Stability 162 '110~7 Vibration Demonstration Points 195 137-1 Load Factor - Gross Weight Curve 232 249-1 Example of Casting Load Sheet, Retract Actuator Support - 407 Landing Gear 386-1 Continuous Icing - Temperature vs. Altitude Limits 649 386-2 Intermittent Icing - Temperature vs. Altitude Limits 650 386-3 Continuous Icing - Liquid Water Content vs. Drop Diameter 651 386-4 Intermittent Icing - Liquid Water Content vs. Drop Diameter 652 425-1 Cantilevered Shaft, First Critical Speed 687 425-2 Shaft Between Support Bearings, First Critical Speed 687 * 516-1 Additional Cooling Test Point 815 518-1 All-Engine-Critical Altitude 821 * 775-1 Helicopter Dynamic Stability Requirements for IFR 1252 XIII
* (111) All components of the rotorcraft should be periodically operated in sequences and combinations likely to ocour in service. Ground inspections should be made at appropriate intervals to identify potential failure conditions;
however, no special maintenance beyond that described in the aircraft maintenance manual should be allowed.
(iv) A complete record of defects and failures should be maintained along with required servicing of aircraft fluid levels. Results of this record should be consistent with inspection and servicing information provided in the airoraft maintenance manual.
(v) A certain portion of the F&R test program may emphasize systems, operating conditions, or environments found particularly marginal during type certification tests.
(v1) See Handbook 8110.4, paragraph 166(c), for additional information and procedures.
17.-23. RESERVED.
24. § 21.39 FLIGHT TEST INSTRUMENT CALIBRATION AND CORRECTION REPORT •
a. Explanation. It is the applicant's responsibility to provide instrumentation for all parameters needed to show compliance with the airworthiness regulations.
(1) For those data which are necessary to show compliance with the regulations, a permanent record should be established. A permanent record is acceptable in either graphical or photographic form, and in some instance a manual recording may be satisfactory.
(2) Regardless of the record form, the accuracy of the record must be established by reference to a laboratory standard traceable to the National Bureau of Standards.
(3) If multiplexing is used, the time base must be synchronized to a reference point from which the magnitude of each parameter can unquestionably be determined. Also, the sampling rate should be sufficiently frequent to assure that the maxima, minima, and trends of magnitude of the parameter are recorded with respect to time.
b. Procedure. Prior to conducting flight tests, the FAA flight test team should review the applicant's flight test instrumentation calibration and correction report.
Chap 1 Par 16 23
AC 29-2, CHG 1 11/19/84 * (1) Normally the frequency of instrument calibration should not exceed 90 days. However, the frequency of recalibration varies with the consistency of the instrumentation under consideration. For example, cyclic and collective position is sometimes calibrated immediately before and after a flight where these parameters are used to provide oritical flight data. Six months is a typical interval for recording/signal conditioning and nonstrain gage sensors, while one year 18 typical for strain gaged components. Also, environmental effects such as vibration, humidity, temperature, etc., should be considered when determining whether recalibration is necessary.
(2) The highest and lowest magnitude of the parameter being recorded should be considered when establishing the scale for instrumentation. Ideally, the highest magnitude throughout the flight would fall on the maxinum indicating point of the recording. •
25.-30. RESERVED.
Chap 1 24 (thru 60) Par 24
SECTION 4. FLIGHT CHARACTERISTICS
80. § 29.141 (through Amendment 29-19) FLIGHT CHARACTERISTICS - GENERAL.
a. Explanation,
(1) This regulation prescribes the general flight characteristics required for certification of a transport category helicopter. Specifically, it states that the helicopter shall comply with the flight oharacteristics the reference to "altitude" in § 29.141(a) (1) is correctly interpreted as "density altitude ‚' Density altitude is, of course, a function of pressure altitude and ambient temperature, hence the need to account for ambient temperature effects.
Additional fiight characteristics required for instrument flight are contained in paragraph 775 of this advisory circular.
(2) Generally the aircraft structural (load level) survey accounts for inoreases with airspeed and power. If the takeoff power rating exceeds the maximum continuous power rating, and the structural survey has been conducted under the assumption that takeoff power is not used at speeds above Vy, the otorcraft Flight Manual must limit takeoff power to speeds of Vy and below. I akeoff power is structurally substantiated throughout the flight envelope, and appropriate portions of the controllability, maneuverability, and trim requirements of §$ 29.141 through 29.161 are met at takeoff power levels, no flight manual entry is needed. Obviously if transmission limits for MC and
(3) During the flight characteristics testing, the controls must be rigged in accordance with the approved rigging instructions and tolerances. The control system rigging must be known prior to testing. In addition to the normal rigging procedures, any programmed control surfaces which may be operated by dynamic pressure, electronics, etc., must also be calibrated. During the flight test program, it is frequently necessary to rig a control, such as the swashplate or tail rotor blade angle, to the allowable critical extreme of the tolerance band. For example, it would be necessary to rig the tail rotor to the minimum allowable blade angle if meeting the requirements of § 29.143(c) would be in question. The same consideration must be given to all helicopter controls and moveable aerodynamic surfaces where questionable compliance with the regulations may exist. If the rotor-induced vibration characteristics of the helicopter are significantly affected and require time-consuming rigging for such things as acceptable ride comfort, then the rotor(s) should be rigged to the allowable extreme tolerance limits to determine compliance, for example, with § 29.251.
AC 29-2, CHG 1 11/19/84
(4) During the FAA flight test program, the crew should be especially alert for conditions requiring great attentiveness, high skill levels, or exceptional strength. If any of these features appear marginal, it is advisable to obtain another pilot's opinion and to carefully dooument the results of these evaluations. Section 29.141(b) provides the regulatory basis for these strength and skill requirements. The general requirements for a smooth transition capability between appropriate flight conditions are also included in § 29.141(b). These requirements must also be met during appropriate engine failure conditions for each category of rotorcraft.
(5) For night or IFR approval, § 29.141(c) contains the general regulatory reference which requires additional characteristics for night and IFR flight. The appropriate flight test procedures are included in other portions of this order.
81. § 29.143 (through Amendment 29-19) CONTROLLABILITY AND MANEUVERABILITY.
a. Explanation.
(1) This regulation contains the basic controllability requirements for transport rotorcraft. It also specifies a minimum maneuvering capability for required conditions of flight. The general requirements for control and for maneuverability are summarized in § 29.143(a) which is largely self-explanatory.
The hover condition is not specifically addressed in § 29.143(a) (2) so that the general requirement may remain applicable to all rotorcraft types, including those without hover capability. For helicopters, the hover condition clearly applies under "any maneuver appropriate to the type."
*
(2) Paragrapha (b) through (e), § 29.143, include more specific flight conditions and highlight the typical areas of concern during a flight test program.
Section 29.143(b) specifies flight at VNE with oritical weight, center of gravity (c.g.), rotor rpm, and power. Adequate cyclic authority must remain at VNE for nose down pitohing of the rotorcraft and for adequate roll control. Nose down pitohing capability is needed for control of gust response and to allow necessary flight path changes in a nose down direction.
Roll control is needed for gust response and for normal maneuvering of the aircraft. In the past, 10 percent control margin has been applied as an appropriate minimum control standard. The required amount of control power, however, has very little to do with any fixed percentage of remaining control There are foreseeable designs for which 5 percent remaining is adequate and others for which 20 percent may not be enough. The key is, can the remaining longitudinal control travel at VNE generate a clearly positive nose down pitching moment, and will the remaining lateral travel allow at least 30-degree banked turns at reasonable roll rates? Moderate lateral control reversals should be included in this evaluation and since available roll control can diminish with sideslip, reasonable out of trim conditions (directionally) should be investigated. This "control remaining" philosophy must also be applied for other flight conditions specified in this section.
Chap 2 152 Par 80
(11) Section 29.143(c) requires a minimum 17-knot control capability for hover and takeoff in winds from any azimuth. Control capability in wind from 0 to at least 17 knots must also be shown for any other appropriate maneuver near the ground such as rolling takeoffs for wheeled rotorcraft. These requirements must be met at all altitudes approved for takeoff and landing. On helicopters incorporating a tail rotor, efficiency of the tail rotor decreases with altitude so that a given sideward flight condition requires more pedal deflection, a higher tail rotor blade angle, and more horsepower. Hence, directional capability in sideward flight (or at critical wind azimuth) is most critical during testing at a high altitude site. Hover controllability, height-velocity, and hover performance are the three regulatory requirements that ordinarily determine the shape of the limiting weight-altitude-temperature (WAT) curve for takeoff and landing at high density altitudes. For Category A rotorcraft, of course, one engine inoperative climb performance requirements may also influence the WAT limit curve.
(111) Section 29.143(d) requires adequate controllability when an engine fails. This requirement specifies conditions under which engine failure testing must be conducted and includes minimum required delay times. * (A) For rotorcraft which meet the engine isolation requirements of Category A, demonstration of sudden complete single-engine failure is required at critical conditions throughout the flight envelope including hover, takeoff, engine lure trant to ling xium continue fer for takeoff power where appropriate) including reasonable engine torque splits. For multiengined Category A installations (3 or more engines) subsequent engine failures should be conducted utilizing the same criteria as that used for first engine failure. The applicant may limit his flight envelope for subsequent failures. Initial or sequential engine failure tests are ordinarily much less severe than the "last" engine failure test required by § 29.75(b) (5). The conditions for last engine failure are maximum continuous power, or 30-minute power if that rating is approved, level flight, and sudden engine failure with the same pilot delay of l second or normal pilot reaction time, whichever is greater.
(B) For Category B, demonstration of sudden complete power failure is required at critical conditions throughout the flight envelope. This includes speeds from zero to VNE (power-on) and conditions of hover, takeoff, climb at Vy, and high speed flight up to VNE. Maximum continuous power is specified prior to the failure, and for cruise conditions, no pilot reaction may begin prior to 1 second or normal pilot reaction time (whichever is greater).
Normal pilot control motions which are part of the pilot task of flight path control are not subject to the 1-second restriction on pilot reaction. The term "oruise" also includes cruise climb and cruise descent conditions. Normal pilot reaction times are used elsewhere. Although this requirement specifies maximum continuous (MC) power, it does not limit engine failure testing to MC power.
takeoff power rating is authorized for hover or takeoff, engine failure testing must also be accomplished for those conditions in order to comply with § 29.63(c). Following power failure, rotor speed, flapping, and aircraft dynamic characteristios must stay within structurally approved limits.
Chap 2 Par 81 153
AC 29-2, CHG 1 11/19/84 * Section 29.143(e) addresses the special case in which a VNE (power-off) 1s established at an airspeed value less than VNE (power-on). For this case, engine failure tests are still required at speeds up to and including VNE (power-on) and the rotorcraft must be capable of being slowed to VNE (power-off) in a controlled manner with normal pilot reactions and skill. There 18, however, no controllability requirement for stabilized power-off flight at speeds above 1.1 VNE (power-off) when VNE (power-off) 1s established per § 29.1505(c).
Application of the controllability requirement for pitch, roll, and yaw at speeds of 1.1 VNE (power-off) and below is similar to that described above for power-on testing at VNE. Sufficient directional control must exist to allow straight flight in autorotation during all approved maneuvers including 30 degrees banked turns up to VNE (power-off) with some small additional allowance for gust control, Adequate controllability margins must exist in all axes throughout the approved autorotative flight envelope. Testing to VNE at MC power per § 29.143(b), 1.1 VNE at power for .9 VH per $ 29.175(b) or 9 29.1505, and to
1.1 VNE (power-off) in autorotation per § 29.143(e) should be sufficient to assure adequate control margin during a descent condition at high speed and low power. The high speed, power-on descent condition should be checked for adequate control margin as a "maneuver appropriate to the type." There has been one instance where insufficient directional pedal was available to maintain a reasonable trimmed sideslip angle with low power at very high speeds, and a case where there was insufficient forward and lateral cyclic available to reach the power on VNE. The insufficient directional pedal margin was due to the offset vertical stabilizers. The lack of cyclic stick margin was because the cyclic stick migrated to the right as power was reduced, and the control limits were ciroular. This provided less total available forward cyclic stick travel when the cyclic was moved right and forward about 45° from the center position. Each of the above helicopters was certificated with a rate of descent limitation to preclude operation in the control limited area.
An evaluation of the emergency descent capability of the helicopter should be made, either analytically or through flight test. Areas of consideration are the rate of descent available, the maximum approved altitude, and the time before a catastrophic failure following the loss of transmission oil pressure, a fuselage fire, or other similar failure. Each helicopter should have the capability to descend to sea level and land from the maximum certificated altitude within the time period established as safe following a critical failure.
b. Procedures.
Flight test instrumentation should include ambient parameters, all flight control positions, rotor rpm, main and tail rotor flapping (if appropriate), engine power instruments, and throttle position. Flight controls that are projected to be near their limits of authority should be rigged to the most adverse production tolerance. A very accurate weight and balance computation is needed along with a precise knowledge of the aircraft's weight/c.g. variation as fuel is burned.
Chap 2 154 Par 81