Abbreviations and Definitions AC advisory circular ACO aircraft certification office ADF automatic direction finding ADI attitude direction indicator AEO all engines operating AFCS automatic flight control systems AGL above ground level AHRS attitude heading reference system Amdt. Amendment APU auxiliary power unit ATC air traffic control BIM blade inspection method CAM cockpit area microphone CAR Civil Air Regulations CAS calibrated air speed CBIM cockpit blade inspection method CDP critical decision point CG center of gravity CPS cycles per second CRFS crash resistant fuel system CRT cathode ray tube CVR cockpit voice recorder DER designated engineering representative DME distance measuring equipment ECAS engine caution advisory systems ECU environmental control unit EFIS electronic flight instrument system EFP engine failure point EHE exhaust heat exchanger ELT emergency locator transmitter EMI electromagnetic interference EMS emergency medical service EOL end of life FAA Federal Aviation Administration FADEC full authority digital engine control FAR Federal Aviation Regulations FMEA failure mode and effects analysis FPM feet per minute FPS feet per second GPS global positioning system HF high frequency HIRF high intensity radiated fields HRD high rate of discharge HUMS health and usage monitoring systems HV height-velocity IAS indicated airspeed ICAO International Civil Aviation Organization ICS inter-communication system IFR instrument flight rules GE in ground effect IIDS integrated instrument display system ILS instrument landing system IMC instrument meteorological conditions INS inertial navigation system ISA international standard atmosphere ISIS integral spar inspection system ITT inter-turbine temperature KCAS knots calibrated airspeed KIAS knots indicated air speed KTAS knots true airspeed LDP landing decision point LWC liquid water content MCP maximum continuous power MGT measured gas temperature MSL mean sea level MVD median volume diameter NDI non-destructive inspection NM nautical mile NPRM notice of proposed rulemaking NTSB National Transportation Safety Board NVG night vision goggles XX
7/30/97 OAT outside air temperature OEl one engine inoperative OGE out of ground effect PBA pitch bias actuator PCF post crash fire PIO pilot induced oscillation PSIG pounds per square inch gauge QPL qualified parts list RFM rotorcraft flight manual RFMS rotorcraft flight manual supplement RPM revolutions per minute RTCA Radio Technical Commission of Aeronautics RVR runway visual range SAE Society of Automotive Engineers SAS stability augmentation system SCAS stability and control augmentation systems SRM structural repair manual STC supplemental type certificate STOL short takeoff and landing TBO time between overhaul TC type certificate TCDS type certificate data sheet TDP takeoff decision point TIA type inspection authorization TIR type inspection report TOT turbine outlet temperature TSO: technical standard order TVP true vapor pressure VBIM visual blade inspection method VFR visual flight rules VMC visual meteorological conditions VOR very high frequency omnidirectional range radio VSI vertical speed indicator V/STOL vertical/short takeoff and landing VTOL vertical takeoff and landing AC 27-1A WAT weight, altitude, temperature Altitudes HD density altitude HP pressure altitude V speeds VD diving speed VH speed in level flight with maximum continuous power VMO maximum operating limit speed VNE never-exceed speed VTOSS takeoff safety speed for Category A rotorcraft VX speed for best angle of climb VY speed for best rate of climb MMO maximum operating mach number N speeds NF free turbine speed NG gas generator speed NP power turbine speed NR rotor speed Coefficients CD coefficient of drag CL coefficient of lift CP coefficient of power CT coefficient of thrust XXI
CHAPTER 1. PART 21
CERTIFICATION PROCEDURES FOR PRODUCTS AND PARTS (Amendment 21-50)
1.-3. RESERVED.
4. § 21.16 SPECIAL CONDITIONS.
a. Ihe 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 Rotorcraft Standards Staff, ASW-110. That office will ensure coordination with the affected agency and industry elements including the Assistant Chief Counsel.
All comments will be considered and the disposition documented by the Rotorcraft Directorate. ASW-100 will issue the special conditions.
b. Basis for Development.
(1) Special conditions are justified on the basis of the existing Part 27 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 term. 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/AUTHORITY 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/AUTHORITY 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.
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(3) Before proposing special conditions, the certification staff should very thoroughly analyze the existing regulations and ensure they are inadequate or inappropriate in light of a new and novel design feature.
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5.-7. RESERVED.
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8. § 21.31 TYPE DESIGN.
The regulatory basis for requiring data to define the design is contained in § 21.31.
This section is self-explanatory and broad enough in scope to give the certification staff access to sufficient data to determine compliance with Part 27.
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9.-11. RESERVED Intentionally Left Blank Par 9 7 (thru 9)
АС 27-1A 7130/97
12. § 21.33 INSPECTION AND TESTS.
a. Applicant Responsibility. Section 21.33 requires the applicant to:
(1) Ensure the test rotorcraft conforms to the type design. This must be accomplished prior to presentation to the FAA/AUTHORITY for testing.
(2) Conduct all inspections and tests necessary to determine compliance with the airworthiness and noise requirements.
b. FAA/AUTHORITY Responsibility.
(1) The design evaluation engineers should ensure 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 27.
(2) As changes to the rotorcraft are made during the test program, the flight test crew should ensure that the appropriate design evaluation engineer concurs with the change and the conformity inspection of the change has been conducted.
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AC 27-1A 7/30/97
13.-15. RESERVED.
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AC 27-1A 7130/97
16. § 21.35 (Amendment 21-59) FLIGHT TESTS.
a. Explanation.
(1) 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 21.35 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/AUTHORITY in report form for evaluation to determine what verification flight tests the FAA/AUTHORITY 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/AUTHORITY 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/AUTHORITY'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/AUTHORITY 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/AUTHORITY engineering flight tests are necessary.
These tests are normally specified in the Type Inspection Authorization (TIA). At the same time the FAA/AUTHORITY must know and agree to the applicant's proposed means of data acquisition, 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. Tests which are particularly important in the early stages of the program are:
(i) Airspeed calibration. All tests involving airspeed depend upon the calibration.
(ii) Engine power available determination.
(ill) Engine cooling.
(4) Test Groupings.
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Weight and CG. In addition to the regulatory relationship of one test to another, efficient testing requires that consideration be given to the accomplishment of as many tests on a single flight as can be accommodated successfully.
(ii) 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.
(i) Prior to initiating official FAA/AUTHORITY flight tests, a conformity inspection of the test aircraft must be accomplished. This is needed to ensure that the test aircraft is in the proper configuration or "conforms" to the engineering drawings and documents that have been submitted to FAA/AUTHORITY, 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.
(ії) Certification Handbook 8110.4, Paragraph 67, contains a requirement that the applicant must keep the FAA/AUTHORITY advised of any configuration changes to the aircraft. The manufacturing inspector should keep the FAA/AUTHORITY flight test pilot apprised of any change which may affect safety of the test aircraft or may influence test results.
(ili) 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 rule was determined.
(iv) The flight test pilot must ensure that the FAA/AUTHORITY manufacturing inspector and the certification engineer are aware of all configuration changes found necessary as a result of FAA/AUTHORITY tests. The manufacturing inspector is responsible for ensuring that all changes are incorporated into production drawings after the design data reflecting the change have been approved by the certification engineer.
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(v) 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 ensure that they perform their intended function and are reliable.
(її) 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 16b(1) above to ensure that significant changes resulting from type certification tests can be incorporated on the aircraft prior to F&R tests.
(ili) All components of the rotorcraft should be periodically operated in sequences and combinations likely to occur 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 aircraft 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.
(vi) See Handbook 8110.4, Paragraph 166(c), for additional information and procedures.
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