The bulletin
Text extracted from the PDF.
FAA Aviation Safety
SPECIAL AIRWORTHINESS
INFORMATION BULLETIN SAIB: CE-11-38 SUBJ: Emergency Equipment; RESCUE 406(S) Emergency Locator Transmitter Date: June 3, 2011 This is information only. Recommendations aren’t mandatory.
Introduction
The Special Airworthiness Information Bulletin (SAIB) advises you, owners and operators of a potential failure mode of Honeywell’s RESCU 406(S) Emergency Locator Transmitter (ELT) with Part Numbers (P/Ns) 11513241-1, 1151324-1Mxxx, 1153046-1Mxxx, 1152892-1Mxxx, 1152890-1Mxxx, 1152794-1Mxxx.
At the time this SAIB is issued, the airworthiness concern is not an unsafe condition that would warrant airworthiness directive (AD) action under Title 14 of the Code of Federal Regulations (14 CFR) part 39.
Background
Honeywell has determined that the RESCU 406(S) ELT may fail to transmit the 406 MHz signal at the required frequency and with the required digital message due to improper grounding of the cover to the internal frame of the ELT. Transmission on the international Distress Frequency 121.5MHz and the Military Distress Frequency 243 MHz is unaffected by this issue.
The improper grounding is due to Room Temperature Vulcanizing (RTV) inside the cover, which may interfere with the electrical bonding between the cover assembly and the frame assembly. The cover is secured to the frame using screws and non-conductive washers. This situation is not detected in the factory’s acceptance test procedure or the subsequent return to service tests because the use of the antenna simulator provides additional grounding which circumvents the improper grounding cause by the RTV.
Honeywell has provided Service Bulletin 1151324-25-39, dated July 14, 2009, which if complied with will allow the ELT to properly transmit the 406 MHz signal.
Recommendations
The FAA recommends that all owners and operators comply with the actions outlined in Honeywell’s Service Bulletin 1151324-25-39, dated July 14, 2009.
For Further Information Contact
Assata Dessaline, Aerospace Engineer, Avionics and Electrical Branch, ANE-172, FAA, New York Aircraft Certification Office,1600 Stewart Avenue, Suite 410, Westbury, New York 11590; phone:
(516) 228-7301; fax: (516) 794-5531; e-mail: Assata.dessaline@faa.gov.
For Related Service Information Contact Honeywell ASCa Inc, 3333 Unity Drive, Mississauga, Ontario, Canada L5L 3S6; phone: (800) 601- 3099 (Toll Free U.S.A/ Canada), (602) 365-3099 (International Direct).