[Code of Federal Regulations]

[Title 14, Volume 1]

[Revised as of January 1, 2006]

From the U.S. Government Printing Office via GPO Access

[CITE: 14CFR31.47]



[Page 763]

 

                     TITLE 14--AERONAUTICS AND SPACE

 

CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION

 

PART 31_AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS--Table of Contents

 

                      Subpart D_Design Construction

 

Sec. 31.47  Burners.



    (a) If a burner is used to provide the lifting means, the system 

must be designed and installed so as not to create a fire hazard.

    (b) There must be shielding to protect parts adjacent to the burner 

flame, and the occupants, from heat effects.

    (c) There must be controls, instruments, 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 operation.

    (d) The burner system (including the burner unit, controls, fuel 

lines, fuel cells, regulators, control valves, and other related 

elements) must be substantiated by an endurance test of at least 40 

hours. Each element of the system must be installed and tested to 

simulate actual balloon installation and use.

    (1) The test program for 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 for 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 this section 

and minimum fuel pressure referenced 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 for 

each one minute cycle of at least 30 seconds; and

    (v) Fifteen hours of normal flight operation.

    (2) The test program for the secondary or backup operation of the 

burner must include six hours of operation with a burn time for each 

five minute cycle of one minute at an intermediate fuel pressure.

    (e) The test must also include at least three flameouts and 

restarts.

    (f) Each element of the system must be serviceable at the end of the 

test.



[Doc. No. 1437, 29 FR 8258, July 1, 1964, as amended by Amdt. 31-2, 30 

FR 3377, Mar. 13, 1965; Amdt. 31-7, 61 FR 18223, Apr. 24, 1996; 61 FR 

20877, May 8, 1996]