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VOLUME 24

NUMBER 35

Washington, Thursday, February 19, 1959

of negative pressure on the aircraft skin.
Positive pressure can be added by con necting another vent to a ram -air scoop Chapter I Civil Aeronautics Board elsewhere on the aircraft surface. An acceptable alternative would be to locate Federal Aviation Agency the battery in a compartment through Supp. 12
which sufficient ventilating air naturally PART 18 MAINTENANCE, REPAIR, flows during flight in such a manner th at AND ALTERATION OF AIRFRAMES, the hydrogen gas is dumped overboard.
POWERPLANTS, PROPELLERS, AND Certain nickel-cadmium batteries are so designed th at the hydrogen generated APPLIANCES
within the cell during charging is chemi Storage Battery Installations and Cir cally recombined. If it can be demon strated th at no hydrogen is emitted cuit Protection Devices during any probable charging condition The Federal Aviation Agency policy the probability of over-voltage on the contained in 18.30-12 captioned Elec charging system should also be investi trical systems is amended by adding a gated, such nickel-cadmium batteries new paragraph j regarding circuit need not be ventilated for the purpose of protection and a new paragraph k re explosion prevention.
garding installation of all commercial ii Noxious fu m es. When charging storage batteries. This supplement re fates are excessive, the electrolyte may vises 18.30-12 b 1 i to prescribe boil to the extent th at fumes containing frequent checks of the draining and droplets of the electrolyte are emitted venting provisions for the battery or through the cell vents. These fumes battery container.
may become noxious to crew and passen 1.
Insert a new 18.30-12j to readgers. Closed ventilating systems in as follows:
which the battery is enclosed and vented 1 8 .3 0 12 Electrical systems FAA pol as described in subdivision i of this subparagraph dispose of any caustic or icies which apply to 1 8 .3 0 .
noxious gases which may be emitted by

the battery in flight. When the battery j S torage battery installations 1 is not case-enclosed, but rather located B attery installation hazards an d m eans in a ventilated compartment in the air o f prevention i Explosion. Electro craft, the ventilating air should be di chemical action in all commercial air rected away from passengers and crew.
craft storage batteries lead-acid, iii E lectrolyte corrosion. Electro nickel-cadmium, and silver-zinc gener lyte spillage or leakage may result in ates hydrogen. I f this hydrogen is re serious corrosion of nearby structure or leased to the surrounding atmosphere, control elements. Both sulphuric acid an explosive hydrogen-air mixture may and potassium hydroxide are actively accumulate. Each battery cell generates corrosive. Electrolyte may be spilled approximately 7 cc. of hydrogen gas during ground servicing, leaked when Ha per ampere-minute as the battery cell case rupture occurs, or sprayed from nears full charge. Four percent concen cell vents due to excessive charging rates.
tration of hydrogen in air is violently A generally satisfactory solution for the explosive. To provide a margin of safety, leakage problem is to place the battery in the concentration of this gas should be a case which can contain the total kept below one percent by ventilation quantity of electrolyte, or which is pro which is effective during all flight vided with an overboard drain. All case regimes. The ventilation air flow should and drain surfaces which will come in be sufficient to cope with any probable contact with electrolyte should be treated charging condition, including those to prevent corrosion effects. Sprayed which could result from any malfunction electrolyte is normally disposed of by the ih the charging system. An acceptable provisions for closed ventilation. If the method of achieving the necessary ven battery is not case-enclosed, structural tilation is to enclose the battery in a case parts near the battery which may be a fwhich is vented by connection to a point Continued on next page
Title 14 CIVIL AVIATION

CONTENTS
Agricultural Marketing Service
Pase
Rules and regulations:
Okra, frozen; U.S. standards for grades; correction___________

1288

Agricultural Research Service Rules and regulations:
Bollworm, pink; administrative instructions exempting cer tain articles from specified requirements______________ _

1288

Agriculture Department S ee Agricultural Marketing Serv ice; Agricultural Research Serv ice; Commodity Exchange Au thority.

Alien Property Office Notices:
Unknown nationals of Bulgaria;
vesting orders 3 documents _ 1297, 1298

Civil Aeronautics Board Notices:
Hearings, etc.:
Frontier Airlines, In c________
Northeastern States area in vestigation _______________
Jap an Airlines Co., L td .____
Rules and regulations:
Airframes, powerplants, propel lers, and appliances; mainte nance, repair and alteration;
storage battery installations and circuit protection de vices _______________________

1292
1292
1292

1279

Commerce Department S ee also Foreign Commerce Bu reau; National B u r e a u of Standards.
Notices :
Vander Heide, Joh n S .; state ment of change in financial interests________________

1292

Commodity Exchange Authority Rules and regulations:
Simultaneous buying and sell ing orders of different prin cipals ____

1288

Defense Department Rules and regulations:
Military colleges in Reserve Of ficers Training Corps pro grams; subsistence and uni form commutation rates for enrolled members___ 4 --------1279

1289