74-20-10 LEIGH SYSTEMS: Amendment 39-1976 as amended by Amendment 39-2038, 39-2732, and 39-3000 is further amended by Amendment 39-3104. Emergency Locator Transmitter Leigh Systems Sharc 7 Series. Applies to all Leigh Systems Sharc 7 Emergency Locator Transmitters Serial Numbers all through 163500 equipped with lithium batteries. \n\n\tCompliance required as indicated. \n\n\tAs a result of chemical corrosion resulting in either failure of the Emergency Locator Transmitter (ELT) to operate or inadvertent activation, jamming the emergency frequencies of 121.5 MHz and 243.0 MHz accomplish the following: \n\n\tWithin the next 90 days and thereafter at each additional 60 day interval after the effective date of this Airworthiness Directive, accomplish the following: \n\n\t1.\tDeleted. \n\n\t2.\tConduct a visual inspection for evidence of corrosion in accordance with photo reproduction which is part of Leigh System's Service Bulletin No. 003A, dated May 15, 1974, or equivalent inspections approved by Chief, Engineering and Manufacturing Branch, FAA Eastern Region. \n\n\t3.\tIf no corrosion is found, prior to reinstalling, determine ELT transmits properly. ELT transmissions are authorized in the first five minutes of any hour or at other times if coordinated with the nearest FAA Tower or Flight Service Station for a total of three audio sweeps (Ref. FAA Advisory Circular 00-35A or 20-81). \n\n\t4.\tIf corrosion is found or if the ELT does not transmit properly, replace with an approved serviceable unit which has been inspected in accordance with paragraph 2; or replace with another TSO approved unit, prior to the next flight except that a ferry flight may be conducted in accordance with FAR 91.52(e)(2). \n\n\tNOTE: ELT's equipped with lithium batteries may be identified by inspecting the identification tags. Units marked in the weight range of 1.5 to 2.0 lbs. are lithium batteries. \n\n\tAmendment 39-1976 was effective October 1, 1974. \n\n\tAmendment 39-2038 was effective December 9, 1974. Amendment 39-2732 was effective September 29, 1976. \n\n\tAmendment 39-3000 was effective August 10, 1977. \n\n\tThis Amendment 39-3104 is effective December 30, 1977.