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CFR Final Rule
 Federal Register Information
[Federal Register: January 31, 1983 (Volume 48, Number 21)]
[Page 4374]
Header Information
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Parts 27 and 29
[Docket No. 21180; Amendment Nos. 27-19 and 29-21]
Rotorcraft Regulatory Review Program; Amendment No. 1
 Preamble Information
Regulatory Information
Adoption of the Amendment
Accordingly, Parts 1, 27, and 29 of the Federal Aviation Regulations (14 CFR Parts 1, 27, and 29) are amended as follows, effective March 2, 1983.
PART 1--DEFINITIONS AND ABBREVIATIONS
1. By amending Sec. 1.1 by adding the following definitions after the definitions of "Category:"
Sec. 1.1 General definitions.
* * * * *
"Category A," with respect to transport category rotorcraft, means multiengine rotorcraft, means multiengine rotorcraft designed with engine and system isolation features specified in Part 29 and utilizing scheduled takeoff and landing operations under a critical engine failure concept which assures adequate designated surface area and adequate performance capability for continued safe flight in the event of engine failure.
"Category B," with respect to transport category rotorcraft, means single-engine or multiengine rotorcraft which do not fully meet all Category A standards. Category B rotorcraft have no guaranteed stay-up ability in the event of engine failure and unscheduled landing is assumed.
* * * * *
PART 27--AIRWORTHINESS STANDARDS; NORMAL CATEGORY ROTORCRAFT
2. By removing the word "and" at the end of Sec. 27.421(b)(1); by adding a new Sec. 27.141(b)(3); and by adding a sentence to the end of Sec. 27.141(c) to read as follows:
Sec. 27.141 General.
* * * * *
(b) * * *
(3) Sudden, complete control system failures specified in Sec. 27.695 of this part; and
* * * * *
(c) * * *Requirements for helicopter instrument flight are contained in Appendix B of this part.
3. By adding a new Sec. 27.1419 to read as follows:
Sec. 27.1419 Ice protection.
(a) To obtain certification for flight into icing conditions, compliance with this section must be shown.
(b) It must be demonstrated that the rotorcraft can be safely operated in the continuous maximum and intermittent, maximum icing conditions determined under Appendix C or Part 29 of this chapter within the rotorcraft altitude envelope. An analysis must be performed to establish, on the basis of the rotorcraft's operational needs, the adequacy of the ice protection system for the various components of the rotorcraft.
(c) In addition to the analysis and physical evaluation prescribed in paragraph (b) of this section, the effectiveness of the ice protection system and its components must be shown by flight tests of the rotorcraft or its components in measured natural atmospheric icing conditions and by one or more of the following tests as found necessary to determine the adequacy of the ice protection system:
(1) Laboratory dry air or simulated icing tests, or a combination of both, of the components or models of the components.
(2) Flight dry air tests of the ice protection system as a whole, or its individual components.
(3) Flight tests of the rotorcraft or its components in measured simulated icing conditions.
(d) The ice protection provisions of this section are considered to be applicable primarily to the airframe. Powerplant installation requirements are contained in Subpart E of this part.
(e) A means must be identified or provided for determining the formation of ice on critical parts of the rotorcraft. Unless otherwise restricted, the means must be available for nighttime as well as daytime operation. The rotorcraft flight manual must describe the means of determining ice formation and must contain information necessary for safe operation of the rotorcraft in icing conditions.
4. By adding an Appendix B to Part 27 to read as follows:
Appendix B--Airworthiness Criteria for Helicopter Instrument Flight
I. General. A normal category helicopter may not be type certificated for operation under the instrument flight rules (IFR) of this chapter unless it meets the design and installation requirements contained in this appendix.
II. Definitions. (a) VYI means instrument climb speed, utilized instead of VY for compliance with the climb requirements for instrument flight.
(b) VNEI means instrument flight never exceed speed, utilized instead of VNE for compliance with maximum limit speed requirements for instrument flight.
(c) VMINI means instrument flight minimum speed, utilized in complying with minimum limit speed requirements for instrument flight.
III. Trim. It must be possible to trim the cyclic, collective, and directional control forces to zero at all approved IFR airspeeds, power settings, and configurations appropriate to the type.
IV. Static longitudinal stability. (a) General. The helicopter must possess positive static longitudinal control force stability at critical combinations of weight and center of gravity at the conditions specified in paragraph IV (b) or (c) of this appendix, as appropriate. The stick force must vary with speed so that any substantial speed change results in a stick force clearly perceptible to the pilot. For single-pilot approval, the airspeed must return to within 10 percent of the trim speed when the control force is slowly released for each trim condition specified in paragraph IV(b) of this appendix.
(b) For single-pilot approval;
(1) Climb. Stability must be shown in climb throughout the speed range 20 knots either side of trim with--
(i) The helicopter trimmed at VYI;
(ii) Landing gear retracted (if retractable); and
(iii) Power required for limit climb rate (at least 1,000 fpm) at VYI or maximum continuous power, whichever is less.
(2) Cruise. Stability must be shown throughout the speed range from 0.7 to 1.1 VN or VNEI, whichever is lower, not to exceed  20 knots from trim with--
(i) The helicopter trimmed and power adjusted for level flight at 0.9 VN or 0.9 VNEI, whichever is lower; and
(ii) Landing gear retracted (if retractable).
(3) Slow cruise. Stability must be shown throughout the speed range from 0.9 VMINI to 1.3 VMINI or 20 knots above trim speed, whichever is greater, with--
(i) the helicopter trimmed and power adjusted for level flight at 1.1 VMINI; and
(ii) Landing gear retracted (if retractable).
(4) Descent. Stability must be shown throughout the speed range 20 knots either side of trim with--
(i) The helicopter trimmed at 0.8 VN or 0.8 VNEI (or 0.8 VLE for the landing gear extended case), whichever is lower;
(ii) Power required for 1,000 fpm descent at trim speed; and
(iii) Landing gear extended and retracted, if applicable.
(5) Approach. Stability must be shown throughout the speed range from 0.7 times the minimum recommended approach speed to 20 knots above the maximum recommended approach speed with --
(i) The helicopter trimmed at the recommended approach speed or speeds;
(ii) Landing gear extended and retracted, if applicable; and
(iii) Power required to maintain a 3° glide path and power required to maintain the steepest approach gradient for which approval is requested.
(c) Helicopters approved for a minimum crew of two pilots must comply with the provisions of paragraphs IV(b)(2) and IV(b)(5) of this appendix.
V. Static lateral directional stability. (a) Static lateral-directional stability must be positive throughout the approved ranges of airspeed, power, and vertical speed. In straight, steady sideslips up to  10° from trim, directional control position must increase in approximately constant proportion to angle of sideslip. At greater angles up to the maximum sideslip angle appropriate to the type, increased directional control position must produce increased angle of sideslip.
(b) During sideslips up to  10° from trim throughout the approved ranges of airspeed, power, and vertical speed, there must be no negative dihedral stability perceptible to the pilot through lateral control motion or force. Longitudinal cyclic movement with sideslip must not be excessive.
VI. Dynamic stability. (a) For single-pilot approval--
(1) Any oscillation having a period of less than 5 seconds must damp to 1/2 amplitude in not more than one cycle.
(2) Any oscillation having a period of 5 seconds or more but less than 10 seconds must damp to 1/2 amplitude in not more than two cycles.
(3) Any oscillation having a period of 10 seconds or more but less than 20 seconds must be damped.
(4) Any oscillation having a period of 20 seconds or more may not achieve double amplitude in less than 20 seconds.
(5) Any aperiodic response may not achieve double amplitude in less than 6 seconds.
(b) For helicopters approved with a minimum crew of two pilots--
(1) Any oscillation having a period of less than 5 seconds must damp to 1/2 amplitude in not more than two cycles.
(2) Any oscillation having a period of 5 seconds or more but less than 10 seconds must be damped.
(3) Any oscillation having a period of 10 seconds or more but less than 20 seconds must be damped.
(4) Any oscillation having a period of 20 seconds or more may not achieve double amplitude in less than 20 seconds.
(5) Any aperiodic response may not achieve double amplitude in less than 6 seconds.
(b) For helicopters approved with a minimum crew of two pilots--
(1) Any oscillation having a period of less than 5 seconds must damp to 1/2 amplitude in not more than two cycles.
(2) Any oscillation having a period of 5 seconds or more but less than 10 seconds must be damped.
(3) Any oscillation having a period of 10 seconds or more may not achieve double amplitude in less than 10 seconds.
VII. Stability augmentation system (SAS). (a) If a SAS is used, the reliability of the SAS must be related to the effects of its failure. The occurrence of any failure condition which would prevent continued safe flight and landing must be extremely improbable. For any failure condition of the SAS which is not shown to be extremely improbable--
(1) The helicopter must be safely controllable and capable of prolonged instrument flight without undue pilot effort. Additional unrelated probable failures affecting the control system must be considered; and
(2) The flight characteristics requirements in Subpart B of Part 27 must be met throughout a practical flight envelope.
(b) The SAS must be designed so that it cannot create a hazardous deviation in flight path or produce hazardous loads on the helicopter during normal operation or in the event of malfunction or failure, assuming corrective action begins within an appropriate period of time. Where multiple systems are installed subsequent malfunction conditions must be considered in sequence unless their occurrence is shown to be improbable.
VIII. Equipment, systems, and installation. The basic equipment and installation must comply with Secs. 29.1303, 29.1431, and 29.1433 through Amendment 29-14, with the following exceptions and additions:
(a) Flight and Navigation Instruments. (1) A magnetic gyro-stablized direction indicator instead of a gyroscopic direction indicator required by Sec. 29.1303(h); and
(2) A standby attitude indicator which meets the requirements of Secs. 29.1303(g) (1) through (7) instead of a rate-of-turn indicator required by Sec. 29.1303(g). For two-pilot configurations, one pilot's primary indicator may be designated for this purpose. If standby batteries are provided, they may be charged from the aircraft electrical system if adequate isolation is incorporated.
(b) Miscellaneous requirements. (1) Instrument systems and other systems essential for IFR flight that could be adversely affected by icing must be adequately protected when exposed to the continuous and intermittent maximum icing conditions defined in Appendix C of Part 29 of this chapter, whether or not the rotorcraft is certificated for operation in icing conditions.
(2) There must be means in the generating system to automatically de-energize and disconnect from the main bus any power source developing hazardous overvoltage.
(3) Each required flight instrument using a power supply (electric, vacuum, etc.) must have a visual means integral with the instrument to indicate the adequacy of the power being supplied.
(4) When multiple systems performing like functions are required, each system must be grouped, routed, and spaced so that physical separation between systems is provided to ensure that a single malfunction will not adversely affect more than one system.
(5) For systems that operate the required flight instruments at each pilot's station--
(i) Only the required flight instruments for the first pilot may be connected to that operating system;
(ii) Additional instruments, systems, or equipment may not be connected to an operating system for a second pilot unless provisions are made to ensure the continued normal functioning of the required instruments in the event of any malfunction of the additional instruments, systems, or equipment which is not shown to be extremely improbable;
(iii) The equipment, systems, and installations must be designed so that one display of the information essential to the safety of flight which is provided by the instruments will remain available to a pilot, without additional crewmember action, after any single failure or combination of failures that is not shown to be extremely improbable; and
(iv) For single-pilot configurations , instruments which require a static source must be provided with a means of selecting an alternate source and that source must be calibrated.
IX. Rotorcraft Flight Manual. A Rotorcraft Flight Manual or Rotorcraft Flight Manual IFR Supplement must be provided and must contain--
(a) Limitations. The approved IFR flight envelope, the IFR flightcrew composition, the revised kinds of operation, and the steepest IFR precision approach gradient for which the helicopter is approved;
(b) Procedures. Required information for proper operation of IFR systems and the recommended procedures in the event of stability augmentation or electrical system failures; and
(c) Performance. If VYI differs from  climb performance at and with maximum continuous power throughout the ranges of weight, altitude, and temperature for which approval is requested.
PART 29--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT
5. By revising Sec. 29.1 to read as follows:
Sec. 29.1 Applicability.
(a) This Part prescribes airworthiness standards for the issue of type certificates, and changes to those certificates, for transport category rotorcraft.
(b) Transport category rotorcraft must be certificated in accordance with either the Category A or Category B requirements of this Part. A multiengine rotorcraft may be type certificated as both Category A or Category B with appropriate and different operating limitations for each category.
(c) Rotorcraft with a maximum weight greater than 20,000 pounds and 10 or more passenger seats must be type certificated as Category A rotorcraft.
(d) Rotorcraft with a maximum weight greater than 20,000 pounds and nine or less passenger seats may be type certificated as Category B rotorcraft provided the Category A requirements of Subparts C, D, E, and F of this Part are met.
(e) Rotorcraft with a maximum weight of 20,000 pounds or less but with 10 or more passenger seats may be type certificated as Category B rotorcraft provided the Category A requirements of Secs. 29.67(a)(2), 29.79, 29.1517, and of Subparts C, D, E, and F of this Part are met.
(f) Rotorcraft with a maximum weight of 20,000 pounds or less and nine or less passenger seats may be type certificated as Category B rotorcraft.
(g) Each person who applies under Part 21 for a certificate or change described in paragraphs (a) through (f) of this section must show compliance with the applicable requirements of this Part.
6. By revising Sec. 29.79(a) to read as follows:
Sec. 29.79 Limiting height-speed envelope.
(a) If there is any combination of height and forward speed (including hover) under which a safe landing cannot be made under the applicable power failure condition in paragraph (b) of this section, a limiting height-speed envelope must be established for--
(1) Category A. Combinations of weight, pressure altitude, and ambient temperature for which takeoff and landing are approved; and
(2) Category B.
(i) Altitude, from standard sea level conditions to the maximum altitude for which takeoff and landing are approved; and
(ii) Weight, from the maximum weight (at sea level) to the highest weight approved for takeoff and landing at each altitude. For helicopters, this weight need not exceed the highest weight allowing hovering out-of-ground-effect at each altitude.
* * * * *
7. By amending Sec. 29.141 by removing the word "and' at the end of Sec. 29.141(b)(1), adding a new Sec. 29.141(b)(3), and adding a sentence to the end of Sec. 29.141(c) to read as follows:
Sec. 29.141 General.
* * * * *
(b) * * *
(3) Sudden, complete control system failures specified in Sec. 29.695 of this part; and
(c) * * * Requirements for helicopter instrument flight are contained in Appendix B of this Part.
Sec. 29.877 [Reserved]
8. by removing Sec. 29.877 and marking it "Reserved."
9. By revising Sec. 29.1321(b) to read as follows:
Sec. 29.1321 Arrangement and visibility.
* * * * *
(b) Each instrument necessary for safe operation, including the airspeed indicator, gyroscopic direction indicator, gyroscopic bank-and-pitch indicator, slip-skid indicator, altimeter, rate-of-climb indicator, rotor tachometers, and the indicator most representative of engine power, must be grouped and centered as nearly as practicable about the vertical plane of the pilot's forward vision. In addition, for rotorcraft approved for IFR flight--
(1) The instrument that most effectively indicates attitude must be on the panel in the top center position;
(2) The instrument that most effectively indicates direction of flight must be adjacent to and directly below the attitude instrument;
(3) The instrument that most effectively indicates airspeed must be adjacent to and to the left of the attitude instrument; and
(4) The instrument that most effectively indicates altitude or is most frequently utilized in control of altitude must be adjacent to and to the right of the attitude instrument.
* * * * *
10. By adding a new Sec. 29.1419 to read as follows:
Sec. 29.1419 Ice protection.
(a) To obtain certification for flight into icing conditions, compliance with this section must be shown.
(b) It must be demonstrated that the rotorcraft can be safely operated in the continuous maximum and intermittent maximum icing conditions determined under Appendix C of this part within the rotorcraft altitude envelope. An analysis must be performed to establish, on the basis of the rotorcraft's operational needs, the adequacy of the ice protection system for the various components of the rotorcraft.
(c) In addition to the analysis and physical evaluation prescribed in paragraph (b) of this section, the effectiveness of the ice protection system and its components must be shown by flight tests of the rotorcraft or its components in measured natural atmospheric icing conditions and by one or more of the following tests as found necessary to determine the adequacy of the ice protection system;
(1) Laboratory dry air or simulated icing tests, or a combination of both, of the components or models of the components.
(2) Flight dry air tests of the ice protection system as a whole, or its individual components.
(3) Flight tests of the rotorcraft or its components in measured simulated icing conditions
(d) The ice protection provisions of this section are considered to be applicable primarily to the airframe. Powerplant installation requirements are contained in Subpart E of this part.
(e) A means must be identified or provided for determining the formation of ice on critical parts of the rotorcraft. Unless otherwise restricted, the means must be available for nighttime as well as daytime operation. The rotorcraft flight manual must describe the means of determining ice formation and must contain information necessary for safe operation of the rotorcraft in icing conditions.
11. By revising Sec. 29.1517 to read as follows:
Sec. 29.1517 Limiting Insight-speed envelope.
For Category A rotorcraft, if a range of heights exists at any speed, including zero, within which it is not possible to make a safe landing following power failure, the range of heights and its variation with forward speed must be established, together with any other pertinent information, such as the kind of landing surface.
12. By amending Sec. 29.1587 by removing the word "and" at the end of paragraph (b)(5); by redesignating (b)(6) as (b)(7), and by adding a new (b)(6) to read as follows:
Sec. 29.1587 Performance information.
* * * * *
(b) * * *
(6) The height-speed envelope except for rotorcraft incorporating this as an operating limitation; and
* * * * *
13. By adding an Appendix B to Part 29 to read as follows:
Appendix B--Airworthiness Criteria for Helicopter Instrument Flight
I. General. A transport category helicopter may not be type certificated for operation under the instrument flight rules (IFR) of this chapter unless it meets the design and installation requirements contained in this appendix.
II. Definitions. (a) VYI means instrument climb speed, utilized instead of VY for compliance with the climb requirements for instrument flight.
(b) VNEI means instrument flight never exceed speed, utilized instead of VNE for compliance with maximum limit speed requirements for instrument flight.
(c) VMINI means instrument flight minimum speed, utilized in complying with minimum limit speed requirements for instrument flight.
III. Trim. It must be possible to trim the cyclic, collective, and directional control forces to zero at all approved IFR airspeeds, power settings, and configurations appropriate to the type.
IV. Static longitudinal stability. (a) General. The helicopter must possess positive static longitudinal control force stability at critical combinations of weight and center of gravity at the conditions specified in paragraphs IV (b) through (f) of this appendix. The stick force must vary with speed so that any substantial speed change results in a stick force clearly perceptible to the pilot. The airspeed must return to within 10 percent of the trim speed when the control force is slowly released for each trim condition specified in paragraphs IV (b) through (f) of this appendix.
(b) Climb. Stability must be shown in climb throughout the speed range 20 knots either side of trim with--
(1) The helicopter trimmed at VYI;
(2) Landing gear retracted (if retractable); and
(3) Power required for limit climb rate (at least 1,000 fpm) at VYI or maximum continuous power, whichever is less.
(c) Cruise. Stability must be shown throughout the speed range from 0.7 to 1.1 VN or VNEI, whichever is lower, not to exceed  20 knots from trim with--
(1) The helicopter trimmed and power adjusted for level flight at 0.9 VN or 0.9 VNEI, whichever is lower; and
(2) Landing gear retracted (if retractable).
(d) Slow cruise. Stability must be shown throughout the speed range from 0.9 VMINI to 1.3 VMINI or 20 knots above trim speed, whichever is greater, with--
(1) The helicopter trimmed and power adjusted for level flight at 1.1 VMINI; and
(2) Landing gear retracted (if retractable).
(e) Descent. Stability must be shown throughout the speed range 20 knots either side of trim with--
(1) The helicopter trimmed at 0.8 VN or 0.8 VNEI (or 0.8 VLE for the landing gear extended case), whichever is lower;
(2) Power required for 1,000 fpm descent at trim speed; and
(3) Landing gear extended and retracted, if applicable.
(f) Approach. Stability must be shown throughout the speed range from 0.7 times the minimum recommended approach speed to 20 knots above the maximum recommended approach speed with--
(1) The helicopter trimmed at the recommended approach speed or speeds;
(2) Landing gear extended and retracted, if applicable; and
(3) Power required to maintain a 3° glide path and power required to maintain the steepest approach gradient for which approval is requested.
V. Static lateral-directional stability. (a) Static directional stability must be positive throughout the approved ranges of airspeed, power, and vertical speed. In straight, steady sideslips up to  10° from trim, directional control position must increase in approximately constant proportion to angle of sideslip. At greater angles up to the maximum sideslip angle appropriate to the type, increase directional control position must produce increased angle of sideslip.
(b) During sideslips up to  10° from trim throughout the approved ranges of airspeed, power, and vertical speed there must be no negative dihedral stability perceptible to the pilot through lateral control motion or force. Longitudinal cycle movement with sideslip must not be excessive.
VI. Dynamic stability. (a) Any oscillation having a period of less than 5 seconds must damp to 1/2 amplitude in not more than one cycle.
(b) Any oscillation having a period of 5 seconds or more but less than 10 seconds must damp to 1/2 amplitude in not more than two cycles.
(c) Any oscillation having a period of 10 seconds or more but less than 20 seconds must be damped.
(d) Any oscillation having a period of 20 seconds or more may not achieve double amplitude in less than 20 seconds.
(e) Any aperiodic response may not achieve double amplitude in less than 9 seconds.
VII. Stability augmentation system (SAS). (a) If a SAS is used, the reliability of the SAS must be related to the effects of its failure. The occurrence of any failure condition which would prevent continued safe flight and landing must be extremely improbable. For any failure condition of the SAS which is not shown to be extremely improbable--
(1) The helicopter must be safely controllable and capable of prolonged instrument flight without undue pilot effort. Additional unrelated probable failures affecting the control system must be considered; and
(2) The flight characteristics requirements in Subpart B of Part 29 must be met throughout a practical flight envelope.
(b) The SAS must be designed so that it cannot create a hazardous deviation in flight path or produce hazardous loads on the helicopter during normal operation or in the event of malfunction or failure, assuming corrective action begins within an appropriate period of time. Where multiple systems are installed, subsequent malfunction conditions must be considered in sequence unless their occurrence is shown to be improbable.
VIII. Equipment, systems, and installation. The basic equipment and installation must comply with Subpart F of Part 29 through Amendment 29-14, with the following exceptions and additions:
(a) Flight and navigation instruments. (1) A magnetic gyro-stabilized direction indicator instead of the gyroscopic direction indicator required by Sec. 29.1303(h); and
(2) A standby attitude indicator which meets the requirements of Secs. 29.1303(g) (1) through (7), instead of a rate-of-turn indicator required by Sec. 29.1303(g). If standby batteries are provided, they may be charged from the aircraft electrical system if adequate isolation is incorporated. The system must be designed so that the standby batteries may not be used for engine starting.
(b) Miscellaneous requirements. (1) Instrument systems and other systems essential for IFR flight that could be adversely affected by icing must be provided with adequate ice protection whether or not the rotorcraft is certificated for operation in icing conditions.
(2) There must be means in the generating system to automatically de-energize and disconnect from the main bus any power source developing hazardous overvoltage.
(3) Each required flight instrument using a power supply (electric, vacuum, etc.) must have a visual means integral with the instrument to indicate the adequacy of the power being supplied.
(4) When multiple systems performing like functions are required, each system must be grouped, routed, and spaced so that physical separation between systems is provided to ensure that a single malfunction will not adversely affect more than one system.
(5) For systems that operate the required flight instruments at each pilot's station--
(i) Only the required flight instruments for the first pilot may be connected to that operating system;
(ii) Additional instruments, systems, or equipment may not be connected to an operating system for a second pilot unless provisions are made to ensure the continued normal functioning of the required instruments in the event of any malfunction of the additional instruments, systems, or equipment which is not shown to be extremely improbable;
(iii) The equipment, systems, and installations must be designed so that one display of the information essential to the safety of flight which is provided by the instruments will remain available to a pilot, without additional crew-member action, after any single failure or combination of failures that is not shown to be extremely improbable; and
(iv) For single-pilot configurations, instruments which require a static source must be provided with a means of selecting an alternate source and that source must be calibrated.
IX. Rotorcraft Flight Manual. A Rotorcraft Flight Manual or Rotorcraft Flight Manual IFR Supplement must be provided and must contain--
(a) Limitations. The approved IFR flight envelope, the IFR flightcrew composition, the revised kinds of operation, and the steepest IFR precision approach gradient for which the helicopter is approved;
(b) Procedures. Required information for proper operation of IFR systems and the recommended procedures in the event of stability augmentation or electrical system failures; and
(c) Performance. If VYI differs from VY, climb performance at VYI and with maximum continuous power throughout the ranges of weight, altitude, and temperature for which approval is requested.
14. By adding an Appendix C to Part 29 to read as follows:
Appendix C
(a) Continuous maximum icing. The maximum continuous intensity of atmospheric icing conditions (continuous maximum icing) is defined by the variables of the cloud liquid water content, the mean effective diameter of the cloud droplets, the ambient air temperature, and the interrelationship of these three variables as shown in Figure 1 of this appendix. The limiting icing envelope in terms of altitude and temperature is given in Figure 2 of this appendix. The interrelationship of cloud liquid water content with drop diameter and altitude is determined from Figures 1 and 2. The cloud liquid water content for continuous maximum icing conditions of a horizontal extent, other than 17.4 nautical miles, is determined by the value of liquid water content of Figure 1, multiplied by the appropriate factor from Figure 3 of this appendix.
(b) Intermittent maximum icing. The intermittent maximum intensity of atmospheric icing conditions (intermittent maximum icing) is defined by the variables of the cloud liquid water content, the mean effective diameter of the cloud droplets, the ambient air temperature, and the interrelationship of these three variables as shown in Figure 4 of this appendix. The limiting icing envelope in terms of altitude and temperature is give in Figure 5 of this appendix. The interrelationship of cloud liquid water content with drop diameter and altitude is determined from Figures 4 and 5. The cloud liquid water content for intermittent maximum icing conditions of a horizontal extent, other than 2.6 nautical miles, is determined by the value of cloud liquid water content of Figure 4 multiple by the appropriate factor in Figure 6 of this appendix.
(Sec. 313(a), 601, 603, and 604 Federal Aviation Act of 1968 (49 U.S.C. 1354(a), 1421, 1423, and 1424); sec. 6(c) Department of Transportation Act (49 U.S.C. 1655(c))
Note.-- The FAA has determined that the benefits of this amendment, in providing an increased level of safety to passengers traveling in rotorcraft while at the same time recognizing and providing for the unique qualities and capabilities of rotorcraft, far outweigh the burdens and that this amendment; (1) Involves a regulation which is not a major rule under Executive Order 12291; and (2) is not a significant rule under the Department of Transportation Regulatory Policies and Procedures (44 FR 11034; February 26, 1979). A final regulatory evaluation prepared for this action is contained in the regulatory docket. A copy of it may be obtained by contacting the person identified under the caption "FOR FURTHER INFORMATION CONTACT."
Footer Information
Issued in Washington, DC, on January 6, 1983.
J. Lynn Helms,
Administrator.
[FR Doc. 83-2510 Filed 1-30-83; 8:45 am]
BILLING CODE 4910-13-M
Comments
Document History
Notice of Proposed Rulemaking Actions:
Notice of Proposed Rulemaking. Notice No. 80-25; Issued on 12/15/80.
Other Final Rule Actions:
Not Applicable.
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