АС 29-2B 7/3097
(xiv) Limited Artificial and Natural Icing Tests, Production UH-60A Helicopter (Reevaluation), Final Report, August 1981, USAAEFA Project No. 80-14.
(6) Further Icing Experiments on an Unheated Nonrotating Cylinder, National Research Council, Canada Report LTR-LT-105, dated November 1979, by J.R.
Stallabrass and P.F. Hearty.
(7) Ludlam, F.H., Heat Economy of a Rimed Cylinder, Quarterly Journal, Royal Meteorological Society, Vol. 77, 1951.
(8) U.S. Army AMRDL Reports:
USAAMDL TR 73-38, Ice Protection Investigation For Advanced Rotary Wing Aircraft, J.B. Werner, August 1973, AD 7711182.
(ii) Werner, J.B., The Development of an Advanced Anti-Icing/Deicing Capability for U.S. Army Helicopters, Volume 1, Design Criteria and Technology Considerations, USAAMRDL - TR-75-34A, Eustis Directorate, U.S. Army Air Mobility R&D Laboratory, November 1975, AD A019044.
(ill) Werner, J.B., The Development of an Advanced Anti-Icing/Deicing Capability for U.S. Army Helicopters, Volume 2, Ice Protection System Application to the UH-1H Helicopter, USAAMRDL - TR-75-34B, Eustis Directorate, U.S. Army Air Mobility Research and Development Laboratory, November 1975, AD A019049.
(iv) USAAMRDL-TR-76-32, Ottawa Spray Rig Tests of an Ice Protection System Applied to the UH-1H Helicopter, November 1976, AD A0034458.
(v) USARTL-TR-78-48, Icing Tests of a UH-1H Helicopter with an Electrothermal Ice Protection System Under Simulated and Natural Icing Conditions, April 1979.
(vi) USAAMRDL-TR77-36, Final Report, Natural Icing Flights and Additional Simulated Icing Tests of a UH-IH Helicopter Incorporating an Electrothermal Ice Protection System, July 1978, AD A059704.
(9) Technical Feasibility Test of Ice Phobic Coatings for Rain Erosion in Simulated Flight Conditions, U.S. Army Test and Evaluation Command, Final Report, 4-AI-192-IPS-001, August 1980.
(10) Technical Feasibility Test of Ice Phobic Coatings in Simulated Icing Flight Conditions, U.S. Army TECOM, Final Report, 4-CO-160-000-048, September 1980.
(11) Aircraft Icing, NASA Conference Publication 2086, FAA-RD-78-109, July 1978.
1062 Par 693
(12) Helicopter Icing Review, FAA Technical Center, Final Report, FAA-CT-80-210, September 1980.
(13) National Icing Facilities Requirements Investigation, Final Report, FAA Technical Center, FAA-CT-81-35, March 1981.
(14) Aircraft Icing, AGARD Advisory Report No. 127, November 1978.
(15) Rotorcraft Icing - Review and Prospects, AGARD Advisory Report, AR-166, September 1981.
(16) Advisory Circular 20-117, Hazards Following Ground Deicing and Ground Operations in Conditions Conducive to Aircraft Icing, December 17, 1982.
(17) Olson, W., Experimental Comparison of Icing Cloud Instruments, January 1983, NASA TM 83340.
(18) JUH-1H Redesigned Pneumatic Boot Deicing System Flight Test Evaluation. Hayworth, L., Graham, M., August 1987. USAAEFA Edwards AFB, California. Project No. 83-13.
(19) An Appraisal of the Single Rotating Cylinder Method of Liquid Water Content Measurement, National Research Council Canada Report LTR-LT-92, dated November 1978, by J.R. Stallabrass.
Par 693 1063
AC 29-2B 7/3097 40 - 30 - AMBIENT TEMPERATURE - DEG F 20 10 - -10 2000 4000 6000 8000 10,000
PRESSURE ALTITUDE - FT FIGURE 693-1. CONTINUOUS ICING - TEMPERATURE VS ALTITUDE LIMITS Figures 693-1 through 4 represent the approach to a 10,000-foot altitude limit.
See Paragraph b(5)(iii) for a discussion of this approach.
1064 Par 693
40 30 AMBIENT TEMPERATURE - DEG F 20 • 10 - -10 2000 4000 6000 8000 10,000
PRESSURE ALTITUDE - FT FIGURE 693-2. INTERMITTENT ICING - TEMPERATURE VS ALTITUDE LIMITS Figures 693-1 through 4 represent the approach to a 10,000-foot altitude limit.
See Paragraph b(5)(iii) for a discussion on this approach.
par 693 1065
AC 29-2B 7/3097
1.0 - LIQUID WATER CONTENT - GRAMS/CUBIC METER 0.8 - SEA LEVEL TO 10,000 FT PRESSURE ALTITUDE O. 6 AMBIENT TEMP °F 32
0.4 O.. 2 10 20 30 40 50
MEAN EFFECTIVE DROP DIAMETER - MICRONS FIGURE 693-3. CONTINUOUS ICING - LIQUID WATER CONTENT VS. DROP DIAMETER Figures 693-1 through 4 represent one approach to a 10,000-foot altitude limit.
See Paragraph b(5) (iii) for a discussion on this approach.
1066 Par 693
2.0 SEA LEVEL TO 10,000 FT PRESSURE ALTITUDE LIQUID WATER CONTENT - GRAMS/CUBIC METER 1.6
AMBIENT TEMP
- 32 °F
1.2 -14 °F 8
- 0 °F .4 10 20 30 40 50
MEAN EFFECTIVE DROP DIAMETER - MICRONS FIGURE 693-4. INTERMITTENT ICING - LIQUID WATER CONTENT VS DROP DIAMETER Figures 693-1 through 4 represent one approach to a 10,000-foot altitude limit.
See Paragraph b(5) (IiI) for a discussion of this approach.
Par 693 1067
АС 29-2B 7/3097
694.-700. RESERVED.
Intentionally Left Blank 1068 (thru 1074) Par 694
701. RESERVED.
Intentionally Left Blank 1075 Par 701
SECTION 39. MISCELLANEOUS EQUIPMENT
702. § 29,1431 ELECTRONIC EQUIPMENT.
a. Background. This section contains some specific requirements for electronic equipment in the rotorcraft. The principal requirements of this section are that radio and navigation equipment must be free from hazards, both in themselves and in their effect on any other items installed in the rotorcraft, and that operation of the radio and navigation equipment does not interfere with operation of any other required avionics.
b. Procedures. In showing compliance with this section, tests and analysis should be performed as necessary to determine that:
(1) All radio and navigation equipment is installed and operated in such a manner that it does not result in hazards to the rotorcraft. It also should not have an effect on any other components of the rotorcraft such that a hazardous condition is created. Note that consideration should be given to the effects of critical environmental conditions.
(2) All radio and navigation systems and equipment should be installed and operated in a manner that will not have a detrimental effect on the proper functioning of any electronic equipment or system required by the FAR. It should be noted that §§ 29.1301 (reference Paragraph 617) and 29.1309(b) through (d) (reference Paragraph 621) apply to all installed equipment and systems and § 29.1309(a) applies to all systems and equipment required by Parts 21 through 49. As an example of showing compliance with this section, consider a high frequency radio (HF) system installation. The first thing to determine is that the installation and operation of the HF system cannot create a hazard. Consideration may be necessary in hazardous situations such as precipitation on the antenna. Next, it should be determined that the operation of the HF does not cause interference to a system whose functioning is required by the FAR. An example of unacceptable interference would be if operating the HF transmitter caused one of the navigation radios to malfunction.
(3) Finally, it should be determined that other systems do not interfere with the HF system. Additional guidance on the testing of avionics equipment and installation is contained in Paragraph 776.
703. § 29.1433 VACUUM SYSTEMS.
a. Explanation. Vacuum systems have been utilized on some rotorcraft to provide an energy source for the flight instruments. This specific rule addresses the potential hazards which are peculiar to vacuum system installations. The possible fire hazards presented by these systems are of particular concern.
1076 Par 702
b. Procedure. The following items should be specifically addressed when evaluating a vacuum system installation:
(1) Pressure and Temperature Protection. The high pressure outlet of the vacuum pump should have a means to automatically relieve the pressure if it becomes excessively high or the air temperature becomes excessively hot.
(2) Fire Hazard Protection. The components of the vacuum system which are mounted in a designated fire zone should be fire resistant. This includes engine or transmission driven pumps if they are in a fire zone. The discharge side of the pump may emit flammable fluids. This discharge side of the pump, along with its associated lines and fittings, should meet the criteria in Paragraph 585 of this AC.
704. § 29.1435 HYDRAULIC SYSTEMS.
a. Reference Regulations. The following sections of Part 29 are either incorporated in the provisions of § 29.1435 or are otherwise applicable to hydraulic system design:
(1) Section 29.695. Paragraph 287 of this advisory circular covers power boost and power operated control systems.
(2) Section 29.861. Paragraph 361 of this advisory circular covers fire protection of structure, controls, and other parts.
(3) Section 29.863. Paragraph 362 of this advisory circular covers flammable fluid fire protection.
(4) Section 29.1183. Paragraph 585 of this advisory circular covers lines, fittings, and components.
(5) Section 29.1185. Paragraph 586 of this advisory circular covers flammable fluids.
(6) Section 29.1189. Paragraph 588 of this advisory circular covers shutoff means.
(7) Section 29.1309. Paragraph 621 of this advisory circular covers the requirements for functioning and reliability, and prevention of hazards if malfunctions or failures occur.
(8) Section 29.1322. Paragraph 633 of this advisory circular covers warning, caution, and advisory lights.
Par 703 1077
b. System Design. It is assumed that the hydraulic system is to be utilized to operate the primary control system of the rotorcraft and the rotorcraft cannot be safely operated without the hydraulic system.
(1) Section 29.1309, Paragraphs (a) and (b), provides for functioning reliably under any foreseeable operating condition and prevention of hazards after any malfunction or failure.
(2) The substantiating data should include a failure analysis that considers every possible system component failure, such as (but not limited to) ruptured lines, pump failure, regulator failure, ruptured seals, clogged filters, broken pilot valve connections, etc.
(3) The requirements of § 29.1309(a) and (b) are met by dual independent hydraulic systems from the reservoir, hydraulic pump, regulator, connecting tubing, and hoses through the actuators. There must be no commonality in the fluid-containing components. A break in one system should not result in fluid loss in the remaining system.
(4) The pumps should be separated as far as practicable; i.e., on opposite sides of the rotor drive transmission, on separate engines, or one pump on an engine and the other on the rotor drive transmission. The tubing and hoses should also be routed with as much physical separation as practicable. The purpose of this separation is to prevent total loss of the hydraulic systems in the event of a malfunction such as fire, or rotor burst wherein one projectile could disable both systems.
(5) Dual actuators must be designed to assure that any single failure, such as a cracked housing, broken interconnecting input, or output link, does not result in loss of total hydraulic system function.
(6) If the assumption under (b) above does not apply and the pilot can control the rotorcraft without undue fatigue after loss of the hydraulic system, then a single hydraulic system is acceptable.
(7) The pressure-indicating system required by § 29.1435, Paragraph (a)(3), can be satisfied with a dial, vertical scale, or digital indicator. The indicator should enable the crew to detect pressure trends. Paragraph 633 of this advisory circular concerns § 29.1322 regarding proper colors for annunciators if they are used to supplement the indicating system.
(8) An analysis or a combination of analysis and tests must be included in the substantiating data file to show compliance with Paragraphs (a)(1), (a)(2), and (a)(4) of § 29.1435.
1078 Par 704
(9) Extra caution should be exercised to assure that control input forces at the mechanical connection to the actuator pilot valves do not exceed their intended value.
Consideration should be given to the most adverse tolerance buildup in parts fabrication and control system rigging.
(10) The substantiating data should show that the hydraulic components will perform their intended function reliably under the most adverse continuous and short-time environmental conditions to which they are exposed. These variables include but are not limited to temperature, humidity, vibration, altitude, and shock.
Paragraph 621, b(2)(i), of this advisory circular is a method of temperature correction to cover the entire operating temperature envelope being certified.
(11) The system component strength must be sufficient for its material fatigue life to exceed the number of cycles imposed by pump ripple pressure.
c. Installation Precautions and Fire Protection.
(1) All components and tubing routed through fire zones may be designed to comply with the fire protection requirements of §§ 29.1183, 29.1185, and 29.1189. As an alternative, a fireproof shield may be used around the component to be protected.
The component should be sufficiently protected to assure fluid leakage will not occur and fuel the fire.
(2) All hydraulic lines should be sufficiently isolated from the engine bleed air lines, environmental control unit, oil cooler, or other heat source to assure expected line life.
(3) If flammable hydraulic fluid is used, the hydraulic components should be isolated from ignition sources to assure that failure of any of the hydraulic components will not result in a fire or explosion. In the case of electrical ignition sources in the proximity of hydraulic components, the electrical equipment should be hermetically sealed or otherwise substantiated as not being an ignition source. (Reference Paragraph 621b(1)(i) of this advisory circular.)
(4) The installation detail should be thoroughly reviewed for adequacy of line clamping and clearance from sharp edges. As much physical separation as possible should be provided between hydraulic lines and electrical cables.
(5) While the control system is being moved from stop to stop, observation should be made to determine that hose flexing and tube bending is minimized.
d. Testing.
(1) Individual components should be substantiated by either vendor's or primary manufacturer's laboratory test reports. These tests should establish Par 704 1079