(a)Requirement. Any person requesting authorization to establish a pilot brewing plant under this subpart shall execute and file a brewer's bond, Form 5130.22. A person may not begin operation of a pilot brewing plant until receiving notice from the appropriate TTB officer of the approval of the bond. Operations may continue only as long as an approved bond is in effect.(b)Penal sum. The penal sum of a bond covering the premises of a pilot brewing plant will be an amount equal to the potential tax liability of the maximum quantity of beer on hand, in transit to the plant, and unaccounted for at any one time, computed by multiplying the quantity of beer in barrels by the rate of tax in 26 U.S.C. 5051 . The penal sum of the bond (or total penal sum if original and strengthening bonds are filed) may not exceed $50,000 or be less than $500.(c)Conditions of bonds. The bond will be conditioned that the operator of the pilot brewing plant shall pay, or cause to be paid, to the United States according to the laws of the United States and the provisions of this part, the taxes, including penalties and interest for which the operator shall become liable, on all beer brewed, produced, or received on the premises.Sec. 4, Pub. L. 91-673, 84 Stat. 2057, as amended ( 26 U.S.C. 5417 )