1、835 Federal Aviation Administration, DOT 31.12 (4) From 100 MHz to 8 GHz, use radiated susceptibility tests at a minimum of 5 V/m. Doc. No. FAA200623657, 72 FR 44028, Aug. 6, 2007 PART 31AIRWORTHINESS STAND-ARDS: MANNED FREE BAL-LOONS Subpart AGeneral Sec. 31.1 Applicability. Subpart BFlight Require
2、ments 31.12 Proof of compliance. 31.14 Weight limits. 31.16 Empty weight. 31.17 Performance: Climb. 31.19 Performance: Uncontrolled descent. 31.20 Controllability. Subpart CStrength Requirements 31.21 Loads. 31.23 Flight load factor. 31.25 Factor of safety. 31.27 Strength. Subpart DDesign Constructi
3、on 31.31 General. 31.33 Materials. 31.35 Fabrication methods. 31.37 Fastenings. 31.39 Protection. 31.41 Inspection provisions. 31.43 Fitting factor. 31.45 Fuel cells. 31.46 Pressurized fuel systems. 31.47 Burners. 31.49 Control systems. 31.51 Ballast. 31.53 Drag rope. 31.55 Deflation means. 31.57 Ri
4、p cords. 31.59 Trapeze, basket, or other means pro-vided for occupants. 31.61 Static discharge. 31.63 Safety belts. 31.65 Position lights. Subpart EEquipment 31.71 Function and installation. Subpart FOperating Limitations and Information 31.81 General. 31.82 Instructions for Continued Airworthi-ness
5、. 31.83 Conspicuity. 31.85 Required basic equipment. APPENDIX A TO PART 31INSTRUCTIONS FOR CONTINUED AIRWORTHINESS AUTHORITY: 49 U.S.C. 106(g), 40113, 44701 44702, 44704. SOURCE: Docket No. 1437, 29 FR 8258, July 1, 1964, as amended by Amdt. 311, 29 FR 14563, Oct. 24, 1964, unless otherwise noted. S
6、ubpart AGeneral 31.1 Applicability. (a) This part prescribes airworthiness standards for the issue of type certifi-cates and changes to those certificates, for manned free balloons. (b) Each person who applies under Part 21 for such a certificate or change must show compliance with the appli-cable r
7、equirements of this part. (c) For purposes of this part (1) A captive gas balloon is a balloon that derives its lift from a captive lighter-than-air gas; (2) A hot air balloon is a balloon that derives its lift from heated air; (3) The envelope is the enclosure in which the lifting means is containe
8、d; (4) The basket is the container, sus-pended beneath the envelope, for the balloon occupants; (5) The trapeze is a harness or is a seat consisting of a horizontal bar or platform suspended beneath the enve-lope for the balloon occupants; and (6) The design maximum weight is the maximum total weigh
9、t of the bal-loon, less the lifting gas or air. Doc. No. 1437, 29 FR 8258, July 1, 1964, as amended by Amdt. 313, 41 FR 55474, Dec. 20, 1976 Subpart BFlight Requirements 31.12 Proof of compliance. (a) Each requirement of this subpart must be met at each weight within the range of loading conditions
10、for which certification is requested. This must be shown by (1) Tests upon a balloon of the type for which certification is requested or by calculations based on, and equal in accuracy to, the results of testing; and (2) Systematic investigation of each weight if compliance cannot be reason-ably inf
11、erred from the weights inves-tigated. VerDate Mar2010 14:10 Mar 01, 2011 Jkt 223043 PO 00000 Frm 00845 Fmt 8010 Sfmt 8010 Y:SGML223043.XXX 223043wwoods2 on DSK1DXX6B1PROD with CFRProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-836 14 CFR Ch. I (1111
12、Edition) 31.14 (b) Except as provided in 31.17(b), al-lowable weight tolerances during flight testing are +5 percent and 10 percent. Amdt. 314, 45 FR 60179, Sept. 11, 1980 31.14 Weight limits. (a) The range of weights over which the balloon may be safely operated must be established. (b) Maximum wei
13、ght. The maximum weight is the highest weight at which compliance with each applicable re-quirement of this part is shown. The maximum weight must be established so that it is not more than (1) The highest weight selected by the applicant; (2) The design maximum weight which is the highest weight at
14、 which compliance with each applicable struc-tural loading condition of this part is shown; or (3) The highest weight at which com-pliance with each applicable flight re-quirement of this part is shown. (c) The information established under paragraphs (a) and (b) of this section must be made availab
15、le to the pilot in accordance with 31.81. Amdt. 313, 41 FR 55474, Dec. 20, 1976 31.16 Empty weight. The empty weight must be deter-mined by weighing the balloon with in-stalled equipment but without lifting gas or heater fuel. Amdt. 314, 45 FR 60179, Sept. 11, 1980 31.17 Performance: Climb. (a) Each
16、 balloon must be capable of climbing at least 300 feet in the first minute after takeoff with a steady rate of climb. Compliance with the require-ments of this section must be shown at each altitude and ambient temperature for which approval is sought. (b) Compliance with the require-ments of paragr
17、aph (a) of this section must be shown at the maximum weight with a weight tolerance of +5 percent. Amdt. 314, 45 FR 60179, Sept. 11, 1980 31.19 Performance: Uncontrolled de-scent. (a) The following must be determined for the most critical uncontrolled de-scent that can result from any single failure
18、 of the heater assembly, fuel cell system, gas value system, or maneu-vering vent system, or from any single tear in the balloon envelope between tear stoppers: (1) The maximum vertical velocity attained. (2) The altitude loss from the point of failure to the point at which maximum vertical velocity
19、 is attained. (3) The altitude required to achieve level flight after corrective action is inititated, with the balloon descending at the maximum vertical velocity de-termined in paragraph (a)(1) of this sec-tion. (b) Procedures must be established for landing at the maximum vertical velocity determ
20、ined in paragraph (a)(1) of this section and for arresting that descent rate in accordance with para-graph (a)(3) of this section. Amdt. 314, 45 FR 60179, Sept. 11, 1980 31.20 Controllability. The applicant must show that the balloon is safely controllable and ma-neuverable during takeoff, ascent, d
21、e-scent, and landing without requiring exceptional piloting skill. Amdt. 313, 41 FR 55474, Dec. 20, 1976 Subpart CStrength Requirements 31.21 Loads. Strength requirements are specified in terms of limit loads, that are the maximum load to be expected in serv-ice, and ultimate loads, that are limit l
22、oads multiplied by prescribed factors of safety. Unless otherwise specified, all prescribed loads are limit loads. 31.23 Flight load factor. In determining limit load, the limit flight load factor must be at least 1.4. 31.25 Factor of safety. (a) Except as specified in paragraphs (b) and (c) of this
23、 section, the factor of safety is 1.5. (b) A factor of safety of at least five must be used in envelope design. A re-duced factor of safety of at least two may be used if it is shown that the se-lected factor will preclude failure due to creep or instantaneous rupture from VerDate Mar2010 14:10 Mar
24、01, 2011 Jkt 223043 PO 00000 Frm 00846 Fmt 8010 Sfmt 8010 Y:SGML223043.XXX 223043wwoods2 on DSK1DXX6B1PROD with CFRProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-837 Federal Aviation Administration, DOT 31.41 lack of rip stoppers. The selected fac-t
25、or must be applied to the more crit-ical of the maximum operating pres-sure or envelope stress. (c) A factor of safety of at least five must be used in the design of all fi-brous or non-metallic parts of the rig-ging and related attachments of the en-velope to basket, trapeze, or other means provide
26、d for carrying occupants. The primary attachments of the enve-lope to the basket, trapeze, or other means provided for carrying occupants must be designed so that failure is ex-tremely remote or so that any single failure will not jeopardize safety of flight. (d) In applying factors of safety, the e
27、ffect of temperature, and other oper-ating characteristics, or both, that may affect strength of the balloon must be accounted for. (e) For design purposes, an occupant weight of at least 170 pounds must be assumed. Doc. No. 1437, 29 FR 8258, July 1, 1964, as amended by Amdt. 312, 30 FR 3377, Mar. 1
28、3, 1965 31.27 Strength. (a) The structure must be able to support limit loads without detri-mental effect. (b) The structure must be substan-tiated by test to be able to withstand the ultimate loads for at least three seconds without failure. For the enve-lope, a test of a representative part is acc
29、eptable, if the part tested is large enough to include critical seams, joints, and load attachment points and members. (c) An ultimate free-fall drop test must be made of the basket, trapeze, or other place provided for occupants. The test must be made at design maximum weight on a horizontal surfac
30、e, with the basket, trapeze, or other means provided for carrying occupants, strik-ing the surface at angles of 0, 15, and 30 degrees. The weight may be distributed to simulate actual conditions. There must be no distortion or failure that is likely to cause serious injury to the oc-cupants. A drop
31、test height of 36 inches, or a drop test height that pro-duces, upon impact, a velocity equal to the maximum vertical velocity deter-mined in accordance with 31.19, whichever is higher, must be used. Doc. No. 1437, 29 FR 8258, July 1, 1964, as amended by Amdt. 314, 45 FR 60179, Sept. 11, 1980 Subpar
32、t DDesign Construction 31.31 General. The suitability of each design detail or part that bears on safety must be es-tablished by tests or analysis. 31.33 Materials. (a) The suitability and durability of all materials must be established on the basis of experience or tests. Mate-rials must conform to
33、 approved speci-fications that will ensure that they have the strength and other properties assumed in the design data. (b) Material strength properties must be based on enough tests of material conforming to specifications so as to establish design values on a statistical basis. 31.35 Fabrication m
34、ethods. The methods of fabrication used must produce a consistently sound structure. If a fabrication process re-quires close control to reach this objec-tive, the process must be performed in accordance with an approved process specification. 31.37 Fastenings. Only approved bolts, pins, screws, and
35、 rivets may be used in the struc-ture. Approved locking devices or methods must be used for all these bolts, pins, and screws, unless the in-stallation is shown to be free from vi-bration. Self-locking nuts may not be used on bolts that are subject to rota-tion in service. 31.39 Protection. Each par
36、t of the balloon must be suitably protected against deteriora-tion or loss of strength in service due to weathering, corrosion, or other causes. 31.41 Inspection provisions. There must be a means to allow close examination of each part that require repeated inspection and adjustment. VerDate Mar2010
37、 14:10 Mar 01, 2011 Jkt 223043 PO 00000 Frm 00847 Fmt 8010 Sfmt 8010 Y:SGML223043.XXX 223043wwoods2 on DSK1DXX6B1PROD with CFRProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-838 14 CFR Ch. I (1111 Edition) 31.43 31.43 Fitting factor. (a) A fitting fa
38、ctor of at least 1.15 must be used in the analysis of each fitting the strength of which is not proven by limit and ultimate load tests in which the actual stress conditions are simulated in the fitting and sur-rounding structure. This factor applies to all parts of the fitting, the means of attachm
39、ent, and the bearing on the members joined. (b) Each part with an integral fitting must be treated as a fitting up to the point where the section properties be-come typical of the member. (c) The fitting factor need not be used if the joint design is made in ac-cordance with approved practices and i
40、s based on comprehensive test data. 31.45 Fuel cells. If fuel cells are used, the fuel cells, their attachments, and related sup-porting structure must be shown by tests to be capable of withstanding, without detrimental distortion or fail-ure, any inertia loads to which the in-stallation may be sub
41、jected, including the drop tests prescribed in 31.27(c). In the tests, the fuel cells must be loaded to the weight and pressure equivalent to the full fuel quantity condition. Amdt. 313, 41 FR 55474, Dec. 20, 1976 31.46 Pressurized fuel systems. For pressurized fuel systems, each element and its con
42、necting fittings and lines must be tested to an ultimate pressure of at least twice the maximum pressure to which the system will be subjected in normal operation. No part of the system may fail or malfunction during the test. The test configuration must be representative of the normal fuel system i
43、nstallation and balloon configuration. Amdt. 313, 41 FR 55474, Dec. 20, 1976 31.47 Burners. (a) If a burner is used to provide the lifting means, the system must be de-signed and installed so as not to create a fire hazard. (b) There must be shielding to pro-tect parts adjacent to the burner flame,
44、and the occupants, from heat ef-fects. (c) There must be controls, instru-ments, or other equipment essential to the safe control and operation of the heater. They must be shown to be able to perform their intended functions during normal and emergency oper-ation. (d) The burner system (including th
45、e burner unit, controls, fuel lines, fuel cells, regulators, control valves, and other related elements) must be sub-stantiated by an endurance test of at least 40 hours. Each element of the sys-tem must be installed and tested to simulate actual balloon installation and use. (1) The test program fo
46、r the main blast valve operation of the burner must include: (i) Five hours at the maximum fuel pressure for which approval is sought, with a burn time for each one minute cycle of three to ten seconds. The burn time must be established so that each burner is subjected to the maximum thermal shock f
47、or temperature affected elements; (ii) Seven and one-half hours at an intermediate fuel pressure, with a burn time for each one minute cycle of three to ten seconds. An intermediate fuel pressure is 40 to 60 percent of the range between the maximum fuel pressure referenced in paragraph (d)(1)(i) of
48、this section and minimum fuel pressure ref-erenced in paragraph (d)(1)(iii); (iii) Six hours and fifteen minutes at the minimum fuel pressure for which approval is sought, with a burn time for each one minute cycle of three to ten seconds; (iv) Fifteen minutes of operation on vapor, with a burn time
49、 for each one minute cycle of at least 30 seconds; and (v) Fifteen hours of normal flight op-eration. (2) The test program for the sec-ondary or backup operation of the burner must include six hours of oper-ation with a burn time for each five minute cycle of one minute at an inter-mediate fuel pressure. (e) The test must also include at least three flameouts and restarts. VerDate Mar2010 14
