[Federal Register Volume 59, Number 118 (Tuesday, June 21, 1994)] [Unknown Section] [Page 0] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 94-14678] [[Page Unknown]] [Federal Register: June 21, 1994] DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Emergency Locator Transmitters; Notice AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of technical standard order authorization withdrawal. ----------------------------------------------------------------------- SUMMARY: This notice withdraws each Technical Standard Order (TSO) C91 authorization to the extent that it allows the authorization holder to identify or mark emergency locator transmitters (ELT's) with ``TSO- C91),'' and sets a date for the termination of ELT's manufactured under TSO-C91. This withdrawal will ensure that future ELT's are produced under TSO-C91a, issued previously which requires a higher minimum operational performance standard for ELT's. EFFECTIVE DATES: For automatic ELT's December 19, 1994. For survival ELT's: June 21, 1996. FOR FURTHER INFORMATION CONTACT: Mr. Phil Akers, Technical Analysis Branch, AIR-120, Aircraft Engineering Division, Aircraft Certification Service, Federal Aviation Administration, 800 Independence Avenue SW., Washington, DC. 20591, Telephone (202) 267-9571. SUPPLEMENTARY INFORMATION: Background In April 1990, the FAA proposed that all future installations of Emergency Locator Transmitters (ELT's) use equipment approved under Technical Standard Order (TSO) C91a (55 FR 12316, April 2, 1990). The FAA also proposed the termination of the manufacture of TSO-C91 ELT's by withdrawing the TSO-C91 manufacturing authorizations. These actions were based on the known unsatisfactory performance of ELT's approved under TSO-C91. In April 1985, the FAA issued TSO-C91a, which provides an improved minimum operational performance standard (MOPS) for 121.5/243.0 MHz ELT's. In December 1992, the FAA issued TSO-C126, which provides a MOPS for 406 MHz ELT's. ELT's approved under either of these TSO's may be used to comply with the Federal Aviation Regulations for ELT's. Accordingly, this notice withdraws TSO-C91 to the extent that it authorizes the holder to mark ELT's with the designation ``TSO-C91.'' For automatic ELT's manufactured under TSO-C91, this cancellation is effective December 19, 1994. For survival ELT's manufactured under TSO- C91, this withdrawal is effective June 21, 1996. Issued in Washington, DC on June 10, 1994. Richard A. Kirsch, Acting Manager, Aircraft Engineering Division, Aircraft Certification Service. [FR Doc. 94-14678 Filed 6-20-94; 8:45 am] BILLING CODE 4910-13-M