(2) Approved maximum stress levels are not exceeded with the buildup of ice on the rotorcraft or do not cause serious decreases in component life;
(3) Inlets, vents, and drains (such as a fuel vent, engine inlet, or transmission cooler air inlet) remain unobstructed; and
(4) Autorotation characteristics are acceptable with maximum ice accretion between de ice cycles.
b. Also, because rotorcraft characteristics, configurations, and critical surface areas can differ within the rotorcraft’s flight and operating envelopes, you should:
(1) Show by analysis that your rotorcraft can perform a destination-hold for 30 minutes in the continuous maximum icing conditions of 14 CFR part 29, Appendix C as a means of compliance with 14 CFR § 29.1419. (See AC 29-2C.) The rotorcraft performance may limit the altitude to a value less than that of 14 CFR part 29, Appendix C. For the analysis, you should configure your rotorcraft at the most critical weight, center-of-gravity, and altitude with the IPS operating. Your analyses must be verified by natural or simulated icing tests within the certificated icing environment. (See AC 29-2C.)
(2) Show that your rotorcraft can operate safely in continuous icing conditions for 15 minutes after recognition of any single IPS failure if a single ice protection system and power source is used, as required by 14 CFR §§ 27.1419 and 29.1419 for showing safe operation in icing conditions. (See ACs 27-1B and 29-2C.) You can show the rotorcraft’s ability to operate safely for 15 minutes by analysis or test (or a combination of analysis and tests). The icing conditions should be the same as those used for showing that the rotorcraft can hold in 30 minutes of icing. The rotorcraft must be free from excessive and rapid structural divergence within the certificated icing environment and rotorcraft flight and operating envelopes. (See AC 29-2C.)
(3) You must provide a means to advise the crew when the rotorcraft is in icing conditions if the ice protection system does not operate continuously. Flight crews need this information or detection system to activate the IPS according to Rotorcraft Flight Manual (RFM) procedures.
(4) You do not have to provide autorotational performance data for rotorcraft that have a Category A powerplant installation. (Categories A and B rotorcraft are defined in 14 CFR § 29.1.) For safe operations in icing conditions, as required by 14 CFR §§ 27.1419 and 29.1419, rotorcraft certificated for flight in icing conditions must be capable of autorotational landings with the ice protection system operating. You should evaluate the autorotational entry, steady state, and flare-entry flying qualities, and you should evaluate the rotorcraft performance with an ice load.
(5) Since the Category A rotorcraft enroute performance can vary as the ice protection system operates, a mean value of cyclic torque is acceptable provided the rate of climb is not less than zero at any time for complying with the requirement for safe operation during in-flight icing.
(6) Following an icing event, you should address the rotorcraft’s hover performance for terminating a mission, such as for hovering or vertical descent.
(7) You must evaluate the rotorcraft’s handling qualities if ice can collect on any surface, to show safer operations in icing conditions as required by 14 CFR §§ 27.1419 and
29.1419. When ice can accrete on unprotected surfaces, the rotorcraft must have satisfactory visual flight rules (VFR) and instrument flight rules (IFR) handling qualities.
(8) You must evaluate the maximum effects of icing on the ability of components, such as fuel tank vents, cooling vents, and antennas, to perform their intended functions. See table 1 of this AC for carburetor and fuel system protection requirements.
(9) Show compliance with 14 CFR §§ 27.1309 and 29.1309. You must protect your rotorcraft to minimize lightning strike risks. The general rules of 14 CFR §§ 27.1309(a), (b), and
(c) and 29.1309(a), (b), and (c) are designed to ensure acceptable lightning protection.
(10) You must consider ice protection of the air data system sensors, probes, windshields, inlets, and exposed control linkages.
(11) Delayed activation of the ice protection system should not result in hazardous conditions. You should address any rotorcraft characteristic changes as cautionary information in the RFM.
(12) You must address icing-related malfunction of the rotor blade droop stop and resulting potential hazards to the rotorcraft, its occupants, and ground personnel.
(13) You must consider ice shedding hazards to ground personnel or equipment following flight in icing conditions.
c. Assessing icing-related performance losses should include not only the drag and weight of the ice but also electrical or other load demands of the ice protection system and any performance changes resulting from ice accretion on the rotor blades.
d. As with fixed-wing aircraft, you must provide an analysis to show the rotorcraft’s IPS is acceptable as required by 14 CFR §§ 27.1419 and 29.1419. Perform this analysis based on the rotorcraft’s operational needs, as discussed in section 10.2.1 of this AC. Besides the analysis showing the rotorcraft can operate safely in icing conditions, you must verify the analysis and show the effectiveness of the ice protection system and its components by flight tests of the rotorcraft or its components in measured natural atmospheric icing conditions. You may also use the following, as necessary.
(1) Laboratory dry air or simulated icing tests, or a combination of both.
(2) Flight dry air tests.
(3) Flight tests of the rotorcraft or its components in measured simulated icing conditions.
e. You should provide or identify means for determining the hazardous ice on critical rotorcraft parts, either by a reliable and safe natural warning or by an ice detection system.
10.2.1 Rotorcraft: Compliance: Analyses. You should perform analyses to determine the conditions that are critical for safe operation of your rotorcraft in the certificated icing environment (the design points) for your rotorcraft’s ice protection, including those for rotor blades, windshield, engine inlet(s), air data sensors, and other components. Present your analyses to the FAA for acceptance before performing flight tests in icing conditions. The analyses should show the rotorcraft will operate safely at the design points. Also, you must address both the continuous maximum and intermittent maximum icing conditions of 14 CFR part 29, Appendix C as limited by the rotorcraft’s performance envelope. Verify the IPS design icing conditions used for compliance by test. Pay specific attention to the qualification and design of the ice protection system and its components. Address the effects of ice accretion on component installations, such as search-and-rescue hoists and equipment for emergency landings on water. Also, address the effects of ice on the rotorcraft’s structural properties and performance and handling qualities. Use analyses, bench tests, and dry air flight tests or simulated icing tests, as necessary, to achieve these assurances.
a. Your analysis should include an assessment of preactivation and intercycle ice accretion.
The analysis should also include performance limits of sensors used in an automated IPS. An automated system using outside air temperature (OAT) should have a total system accuracy of ±1 °C, or better. If an automated system uses measured LWC, or if a warning is provided based on measured LWC, consider conservative use of the measured LWC because of the inaccuracies and poor precision of measured LWC. Also, LWC measurements fluctuate significantly during natural icing conditions. After you review the analyses and find them acceptable, conduct tests to verify the analyses and to confirm the rotorcraft can operate safely in the required icing conditions.
b. You should evaluate rotor blade stability with ice accretions to ensure structural dynamic instability will not occur in icing conditions. You may use analyses to perform this assessment.
Your analyses should consider failure of the most critical segment of the rotor blade IPS. You may also use experimental means, such as attaching critical simulated ice shapes to the blades and using a whirl stand or wind tunnel, to perform this analysis.
c. You should also evaluate the effects of ice accretion on the rotorcraft components’ structural fatigue and life cycle resulting from vibrations. You must substantiate the static and fatigue strength of the rotor blade with heater mats and consider any effect of the heater mat on fatigue strength of the blades.
d. You should perform a detailed failure modes and effects analysis of the ice protection system.
e. You should give careful attention to the installation, ice protection, and performance of air data sensors and ice detectors. These systems may experience wide ranges of airspeeds and local flow angles. Position error corrections for airspeed, altitude, and angle of attack may be significant. See appendix K of this AC for guidance on installation and acceptance of ice detectors.
f. Icing analysis information is in section 8.1 of this AC.
10.2.2 Rotorcraft: Compliance: Tests. As required by 14 CFR §§ 27.1419 and 29.1419, approval of rotorcraft IPS must include flight tests in natural icing conditions. Laboratory, icing wind tunnel, or simulated icing tests cannot be used individually or collectively for showing compliance with rotorcraft ice protection requirements. Currently, laboratories, icing wind tunnels, and tankers cannot duplicate the combinations of LWC, drop size and distribution, flow fields, and random ice-shedding behaviors found in natural icing conditions testing.
10.2.2.1 Rotorcraft: Compliance: Natural Icing Flight Tests.
a. You should conduct natural icing tests in conditions as close to the critical design conditions as possible. Also, show enough correlation between the analyses to ensure the rotorcraft will operate safely throughout the required icing envelope. Finding natural icing at all the critical icing conditions may not be practical.
b. Prerequisites for natural icing flight test include:
(1) A rotorcraft conforming to its type design and capable of IFR and IMC flight.
(2) FAA acceptance of an analysis showing that the rotorcraft can operate safely at critical design points in both the continuous maximum and intermittent maximum conditions of 14 CFR part 29, Appendix C. This includes qualification of the ice protection systems, and the analyses of the rotorcraft’s structural integrity and the rotorcraft’s performance and handling.
(3) A detailed failure modes and effect analysis of the ice protection system.
(4) Assessment of the rotor blade’s structural stability with critical ice accretions. This ensures that structural dynamic instability will not occur in icing conditions.
c. Certification flight-testing should be extensive enough to provide assurances that either induced or random ice shedding does not present a hazard. For example, you should consider the effects of vibration from asymmetric ice shedding from rotor blades (imbalance rotor) or the impact of shed ice on the rotorcraft airframe. You may use the following to determine unacceptable ice shedding.
(1) Vibrations sufficient to make flight-deck instruments difficult to read;
(2) Vibrations exceeding the structural or fatigue limits of any rotorcraft part (e.g., rotor blade, mast, or transmission components); or
(3) Dangerous impact of shed-ice on essential parts, such as the tail rotor. (See section 8.2.1.4 of this AC.)
d. You should review certification flight test instrumentation for accuracy and sampling rates. This includes structural strain measurements and optical recordings of ice accretions on critical surfaces. You should use strain measurements to determine ice-imposed structural stress 36
and to verify structural stress and fatigue analyses used for such components as the main rotor blades, main rotor hub components, rotating and fixed controls, horizontal stabilizer, tail rotor, etc. (See section 8.2.1.1 of this AC for additional guidance on rotorcraft compliance tests.)
e. Additional guidance on showing compliance using natural icing flight tests is in section 8.2.1 of this AC.
10.2.2.2 Rotorcraft: Compliance: Dry Air Flight Tests.
a. Dry air flight tests are usually the first evaluation of the IPS. Thermal data from dry air tests may be useful in validating the IPS thermal analysis. See section 8.2.2 of this AC for guidance, recognizing that there are operational and configuration differences between fixedwing airplanes and rotorcraft.
b. You may use dry air testing with simulated critical ice shapes to show safe rotorcraft performance and handling qualities. You may also use ice shapes to show acceptable structural stability and fatigue characteristics of the rotor blades. Test both normal operation and failed IPS simulated ice shapes. Dry air testing with simulated ice shapes will aid you in showing compliance with the required regulations and significantly reduces flight-test costs.
c. Section 8.2.2.6 of this AC contains flight safety guidance for flights with simulated ice shapes.
10.2.2.3 Rotorcraft: Compliance: Simulated Icing Flight Tests. Icing tankers have not been able to produce icing plumes with drop sizes and distributions that reproduce all the icing envelope conditions required for certification. The large water droplet sizes produced by the icing tankers have typically been a problem in simulation icing conditions. Also, the breadth of the icing tanker plume typically has been inadequate to immerse the entire rotorcraft. However, the tanker should be able to produce a uniform icing cloud that will immerse the entire rotor system. The tanker should also have a means of consistently controlling and changing the cloud characteristics. (See section 8.2.3 of this AC.)
10.2.2.4 Rotorcraft: Compliance: Wind Tunnel Tests. Wind tunnel tests of rotorcraft are typically more complex and difficult than those of fixed-wing aircraft. Rotation of the rotor blades, the scale of wind tunnel model rotor blades, and the complex flow field produced by the rotor disk contribute to the wind tunnel testing difficulty. Although the typical high aspect ratio of rotor blades allows confident use of two-dimensional (2D) analyses, these analyses should address the rotating blade’s spanwise flow field and spanwise unfrozen water flow, unless the applicant proves that these considerations are insignificant. You should consider the effects of the rotor’s slipstream on ice accretion on other components of the rotorcraft, if appropriate. (See section 8.2.4 of this AC.)
10.3 Rotorcraft Flight Manual.
a. You should include all icing-related limits (including limits for flight into instrumented meteorological conditions), procedures (normal and emergency), and caution notes in the Rotorcraft Flight Manual (RFM). The RFM should state whether the rotorcraft is certificated to 37
operate in freezing rain or freezing drizzle. The cautionary notice should include procedures for identifying and avoiding freezing precipitation. Caution notes provided by the applicant should also address:
(1) The hazard caused by inducing asymmetric ice shedding by using rapid control inputs or rotor speed changes, unless that procedure is a last resort;
(2) Losses in range, climb rate, and hover capability following significant exposure to icing conditions;
(3) The need for clean rotor blade surfaces before flight. Surfaces should be cleaned with an approved cleaning solvent or ground deicing and anti-icing fluids before rotating the rotor blades;
(4) Changes in autorotation characteristics resulting from ice accretion; and
(5) The potential hazards of shed-ice to ground personnel, deplaning passengers, and equipment.
11. AIRCRAFT FROST AND CLEAR ICE CONSIDERATIONS.
Frost and clear ice developed during ground operations may adversely affect safe flight.
Appendix V of this AC contains guidance on removing frost and clear ice from airframe surfaces before takeoff.
12. AIRPLANE DE/ANTI-ICING BEFORE TAKEOFF.
a. No person may takeoff in an aircraft when frost, ice, or snow is adhering to the wings, control surfaces, propellers, engine inlets, or other critical surfaces of the aircraft. (See 14 CFR §§ 91.527, 121.629(b), and 135.227(a).) AC 20-117, AC 135-16, AC 135-17, AC 120-58, and AC 120-60 provide additional information on deicing and anti-icing of aircraft before takeoff.
Flight Standards Information Bulletins for Air Transportation (FSAT) are published yearly, containing the latest deicing and anti-icing fluid holdover time guidelines and the most recent information available on operating in ground icing conditions. Airplane operators use this information to develop aircraft ground deicing and anti-icing programs required by 14 CFR §§
121.629(c) and 135.227(b)(3).
b. Aircraft are deiced before takeoff and, as required, anti-iced using thickened pseudoplastic fluids. This procedure provides temporal protection from ice adhering to the aircraft’s surfaces before takeoff. It does not ensure that ice will not accrete on aircraft surfaces during takeoff and in flight. The presence of thickened fluid may affect the airplane’s performance and handling qualities because the fluids may not completely flow off the aircraft surfaces before liftoff. Fluid residue may cause increased pilot control forces during takeoff and climb for airplanes with reversible control surfaces. The fluid may also collect in the bays of airplanes with aerodynamically or weight balanced control surfaces, resulting in unbalanced control surfaces, unexpected changes in control forces, and control surface vibrations. Also, anti-icing fluid may collect and evaporate in quiet cove areas, like those along control surface hinge lines.
When the residue of the evaporated anti-icing fluid is rehydrated by rain or during washing of the airplane, it may freeze and lock the control surface when the airplane climbs to altitudes with subfreezing temperatures. The freezing point depressant, usually a glycol compound, evaporates when the anti-icing fluid dries.
c. The Society of Automotive Engineers (SAE) G-12 Committee and the International Standard Organization (ISO) have published aerospace material standards (AMS), and aerospace recommended practices (ARP) for deicing and anti-icing fluids and methods for deicing and antiicing airplanes. (See section 14, references 4 through 9 for SAE specifications for deicing and anti-icing fluids, recommended aircraft deicing and anti-icing practices, and the functional requirements of deicing and anti-icing vehicles.)
d. The FAA has not published airworthiness standards for showing acceptance of deicing and anti-icing fluids. However, you must comply with the airworthiness requirements of 14 CFR parts 23, 25, 27, and 29 and the operating requirements of 14 CFR parts 121 and 135 before conducting flights into icing conditions. The FAA annually provides deicing and anti-icing fluids holdover time guidelines, a list of available fluids, and other information useful to the aircraft operator for complying with 14 CFR §§ 121.629 and 135.227 in an FSAT.
13. EXTENDED RANGE OPERATION WITH TWO-ENGINE AIRPLANES (ETOPS) ICING CONSIDERATIONS.
a. When seeking approval for extended range operations for a twin-engine airplane, applicants should consider the effects of ice accretion and engine power extraction resulting from operation of IPS. You should follow the guidance provided in AC 120-42A. The Administrator may authorize operation of a two-engine airplane over a route that contains a point farther than 1-hour flying time from an acceptable airport (14 CFR § 121.161). An airplane operating under ETOPS guidelines with a failed engine or following a decompression of the passenger cabin may have to descend and cruise for extended periods at altitudes and airspeeds conducive to icing. It may also be exposed to icing conditions at the diversion terminal area. (See section 14, reference 1.) The exposure to icing conditions during the diversion potentially may be much longer than the time considered acceptable for approval of the IPS in 14 CFR parts 23 and 25.
b. AC 120-42A advises you to address the following:
(1) During type design evaluation, you should show that acceptable engine limit margins exist for conducting extended duration single-engine operation at all approved power levels and in all expected environmental conditions. This assessment should account for the effects of added engine loading demands (anti-ice, electrical, etc.). This may be necessary during the single-engine flight phase associated with the diversion.
(2) You should show the airframe and propulsion ice protection provides acceptable capability (airplane controllability, aircraft performance, etc.) for the intended diversion. This should account for the likely engine-out diversion flight plan, including decent, cruise, holding, approach, and landing.
(3) The critical fuel plan should add 5 percent to the calculated fuel burn from the critical way point. This would allow for errors in wind forecasts. The fuel plan should also allow a 5 percent penalty in fuel mileage if the fuel mileage deterioration is unknown. The critical fuel plan should include fuel burn associated with Configuration Deviation List items, airframe and engine anti-icing. It should also account for ice buildup on unprotected surfaces if icing conditions are likely to be encountered during the diversion.
(4) You should provide airplane performance information in the appropriate section of the AFM. This information should warn about extended range operation environmental hazards that can cause a significant decline in aircraft performance, such as ice buildup on the unprotected surfaces of the airplane.
(5) You should include systems redundancy levels acceptable for extended range operations in the master minimum equipment list (MMEL), including ice protection.
c. AC 120-42A suggests you evaluate the aerodynamic effects of ice accretion on the airplane resulting from icing conditions likely to be encountered during a diversion. Fuel loading should also consider the drag resulting from the ice accreted during a diversion. This accompanies the power extractions associated with operation of the ice protection system. You should ensure the engine limit margins exist to allow operation of the ice protection systems during a one-engine-inoperative diversion to an alternate airport. During the evaluation, consider other engine power extractions (such as cabin pressurization, electrical power, and hydraulics conditions) at the critical airplane weight, altitude, ambient temperature, and airspeed condition.
Provide airplane performance information reflecting these considerations in the AFM. You may reference this consideration to other documents in the AFM.
d. Redundancy of the IPS beyond those required by 14 CFR §§ 23.1309 and 25.1309 should conform with the risk analysis method presented in AC 120-42A. The MMEL should be compatible with the results of the safety reliability evaluation. Also, consider the IPS capability with an in-operative engine for acceptable equipment and systems operation during likely icing conditions. Preserve acceptable electrical power, hydraulics, system and equipment cooling, air data system information, and windshield visibility during the diversion.
e. You may select the most critical ice accretion shape, as allowed by AC 120-42A and 14 CFR §§ 23.1419 and 25.1419, to show your compliance with the AC 120-42A and other icing requirements. You may interpret acceptable compliance as safe flight. Section 6.3 of this AC discusses demonstration of safe flight. AC 120-42A addresses ice accretion on unprotected surfaces, focusing only on large turbine-powered transports with thermal anti-icing systems.
You should also address normal-operation ice buildups on protected surfaces for types of airplanes where you would expect such accretions. Normal-operation ice buildups include intercycle ice roughness and runback ice resulting from extended operation in icing conditions.
You may use simulated ice shapes to show compliance and conformity with the rules and the guidance provided in AC 120-42A. (See appendix R of this AC.) Following the guidance in AC 120-42A may require consideration of ice-related drag at higher airspeeds than those required to show compliance with 14 CFR §§ 23.1419 and 25.1419. You should consider ice buildups on airplane components and surfaces that are no longer ice protected because of an engine failure. You should also consider ice accretion on the inoperative-engine nacelle and 40
engine components and runback ice or intercycle ice accretion resulting from lower ice protection performance with an inoperative-engine.
f. Since AC 120-42A states you should consider icing conditions likely to be encountered during the diversion, you should have enough knowledge of the likely icing conditions for the selected diversion routes to define those icing conditions confidently. You should also provide acceptable information to back up the selected diversion icing condition. Selection of the diversion icing condition likelihoods should be conservative and compatible with the overall safety risk assessment of the airplane for ETOPS operations.
g. Having established the diversion icing conditions and duration, you may determine the critical ice shapes for the diversion as describe in appendix R of this AC.
h. You should show that primary ice detectors are able to perform their intended function reliably during the diversion. (See appendix K of this AC.)
i. You should show the reliability of other essential systems (such as the APU or ram air turbine) in the icing conditions associated with ETOPS.
14. REFERENCES.
1. “Aircraft Icing Handbook,” FAA Technical Report DOT/FAA/CT-88/8-1 (1991), 3 vols. FAA Technical Center, Atlantic City, N.J. 08405.
2. “Wing Inspection Lights – Design Criteria,” SAE ARP4087.
3. “Rotor Blade Electrothermal Ice Protection Design Considerations,” SAE AIR1667A, pp. 13-24.
4. Fluid, Aircraft Deicing/Anti-Icing, Non-Newtonian, (Pseudoplastic), SAE Types II, III, and IV, SAE AMS1428 (Last Revision).
5. Deicing/Anti-Icing Fluid, Aircraft, SAE Type I, SAE AMS1424 (current).
6. Deicing Fluid, Aircraft, Ethylene Glycol Base, SAE AMS1425 (current).
7. Deicing/Anti-Icing Fluid, Aircraft, Propylene Glycol Base, SAE AMS1427 (current).
8. Aircraft Deicing/Anti-Icing Methods (Supplement 1), SAE ARP4737SUP1.
9. Self-Propelled De-Icing/Anti-Icing Vehicles—Functional Requirements, ISO11077.
10. “In Situ Measurements of the Airplane Icing Environment in Winter Storms Over the Western North Atlantic Ocean,” Tank, W., Patnoe, Isaac, G., Cober, S., and Stapp, J., AIAA 94-0483, 39th Aerospace Sciences Meeting & Exhibit, 10-13 January 1994, Reno, Nevada.
41 (and 42)
APPENDIX A. RELATED REGULATIONS AND DOCUMENTS A.1 REGULATIONS. Table A.1 shows the regulations related to icing certification for 14 CFR parts 23, 25, 27, and 29 aircraft. Table A.2 shows the regulations for icing certification for engines. Table A.3 shows the airworthiness icing regulations for 14 CFR part 35 propellers, and table A.4 shows the operating rules. Regulations noted in the appendix without amendment level are at the latest amendment before the publication date of this AC.
A-1
APPENDIX A. RELATED REGULATIONS AND DOCUMENTS (CONTINUED) Table A-1. Related 14 CFR Parts 23, 25, 27, and 29 Regulations Subpart Part 23 Airworthiness Standards: Normal, Utility, Acrobatic, and Commuter Category Airplanes Part 25 - Airworthiness Standards: Transport Category Airplanes Part 27 – Airworthiness Standards: Normal Category Rotorcraft Part 29 – Airworthiness Standards: Transport Category Rotorcraft B-Flight § 23.4 9, Stalling period § 23.65, Climb: All engines operating § 23.67(e)(2), Climb:
One-engine inoperative § 23.67(e)(3), Climb:
One-engine inoperative § 23.71, Glide: Singleengine airplanes § 23.75, Landing Distance § 23.77, Balked landing § 23.143, General— Controllability and Maneuverability § 23.171, General – Stability § 23.201, Wing level stall § 23.203, Turning flight and accelerated turning stalls § 23.207, Stall warning § 23.251, Vibration and buffeting § 25.103, Stalling speed § 25.117, Climb:
general § 25.119, Landing Climb: All engines-operating § 25.121, Climb: One engine-inoperative § 25.123, En route flight paths § 25.125, Landing § 25.143, General— Controllability and Maneuverability § 25.171, General – Stability § 25.201, Stall demonstration § 25.203, Stall characteristics § 25.207, Stall warning § 25.237, Wind velocities § 25.251, Vibration and buffeting § 25.253, High-speed characteristics § 27.65, Climb: all engines operating § 27.67, Climb: one engine inoperative § 27.71, Glide performance § 27.7, Performance at minimum operating speed § 27.75, Landing § 27.79, Limiting height-speed envelope § 27.141, General— Flight Characteristics § 29.45, General— Performance § 29.49, Performance at minimum operating speed § 29.51, Takeoff data:
general § 29.64, Climb: General § 29.71, Helicopter angle of glide:
Category B § 29.75, Landing:
General § 29.87, Height-velocity envelope § 29.141, General— Flight Characteristics A-2
APPENDIX A. RELATED REGULATIONS AND DOCUMENTS (CONTINUED) Table A-1. Related 14 CFR Parts 23, 25, 27, an d 29 Regulations (Continued) Subpart Part 23 Airworthiness Standards: Normal, Utility, Acrobatic, and Commuter Category Airplanes Part 25 - Airworthiness Standards: Transport Category Airplanes Part 27 – Airworthiness Standards: Normal Category Rotorcraft Part 29 – Airworthiness Standards: Transport Category Rotorcraft D-Design and Construction § 23.601, General § 23.603, Materials and workmanship § 23.605, Fabrication methods § 23.607, Fasteners § 23.609, Protection of structure § 23.611, Accessibility provisions § 23.613, Material strength properties and design values § 23.629, Flutter § 23.685(a), Control system details § 23.773, Pilot compartment view §§ 23.775(f) and (g), Windshields and windows § 23.859(i), Combustion heater fire protection, drains § 23.863, Flammable fluid fire protection § 25.601, General § 25.603, Materials § 25.605, Fabrication methods § 25.607, Fasteners § 25.609, Protection of structure § 25.611, Accessibility provisions § 25.613, Material strength properties and design values § 25.629, Aeroelastic stability requirements § 25.685(a), Control system details § 25.773(b)(1)(ii), Pilot compartment view § 25.775(d), Windshields and windows § 25.859(i), Combustion heater fire protection, drains § 25.863, Flammable fluid fire protection § 25.875, Reinforcement near propellers § 27.601, General § 27.603, Materials § 27.605, Fabrication methods § 27.607, Fasteners § 27.609, Protection of structure § 27.611, Inspection provisions § 27.613, Material strength properties and design values § 27.629, Flutter § 27.685(a), Control system details § 27.859(k), Combustion heater fire protection, drains § 27.863, Flammable fluid fire protection § 29.601, General § 29.603, Materials § 29.605, Fabrication methods § 29.607, Fasteners § 29.609, Protection of structure § 29.611, Inspection provisions § 29.613, Material strength properties and design values § 29.629, Flutter and divergence § 29.685(a), Control system details § 29.773(b)(1)(ii), Pilot compartment view § 29.859(i), Combustion heater fire protection, drains § 29.863, Flammable fluid fire protection A-3