The bulletin
Text extracted from the PDF.
SPECIAL
AIRWORTHINESS
INFORMATION
BULLETIN
AIRCRAFT CERTIFICATION SERVICE 800 INDEPENDENCE AVENUE, S.W.
WASHINGTON, DC 20591
U.S. Department of Transportation Federal Aviation Administration
No. ACE-99-14 December 31, 1998
Published by: FAA, AFS-610, P.O. Box 26460, Oklahoma City, OK 73125 This is issued for informational purposes only and any recommendation for corrective action is not mandatory.
Introduction The purpose of this Special Airworthiness Information Bulletin (SAIB) is to inform owne rs/operators of aircraft equipped with BFGoodrich Avionics Systems, Inc. (BFGoodrich) SKYWATCH SKY497 Traffic Advisory System (TAS) with a top-mounted antenna of an Alternative Method of Compliance (AMOC) to Federal Aviation Administration (FAA) Airworthiness Directive (AD) 98-25-02.
Background AD 98-25-02 was issued based on 11 reports of internal component failure of BFGoodrich SKYWATCH SKY497 installations with a top-mounted antenna. When this failu re occurs, the antenna configuration changes from top to bottom mount which causes the target indicator to appear on the wrong side of the aircraft; e.g., the actual target is at the 9 o’clock position relative to the airc raft but the SKY497 display shows the ta rget at the 3 o’clock position. This condition, if not corrected, could result in the pilot making an incorrect initial maneuver based on the displayed information while trying to visually acquire the aircraft.
1. AD 98-25-02 requires incorporating information from BFGoodrich Service Bulletin #78A, dated October 21, 1998, into the airplane flight manual (AFM) of the applicable aircraft to verify the correct antenna configuration each time the aircraft is powered-up. If th e antenna configuration is in correct, the SKY497 must be removed from service.
2. BFGoodrich has released software version 1.5 for the SKY497 system that stores the antenna configuration during the system installation and displays a “SKY497 Failed” message and disables the system if the antenna configuration changes. The FAA approved the installation of software version 1.5 as an AMOC for AD 98-25-02 in a letter dated December 9, 1998.
3. BFGoodrich is currently working to determine the cause of the internal component failure, and plans to release a hardware change in early 1999 as terminating action to the AD.
Recommendation
1. The FAA recommends the installation of SKYWATCH SKY497 software version 1.5.
a. For new units or units returned to the BFGoodric h for service, installation of software version 1.5 is approved as an AMOC to AD 98-25-02.
b. For units currently in the field, installation of software version 1.5 per the instructions in Service Bulletin SB #79, dated November 25, 1998, is approved as an AMOC to AD 98-25-02.
For Further Information Contact:
Ms. Brenda Ocker, Aerospace Engineer, FAA, Chicago Aircraft Certification O ffice, 2300 East Devon Avenue, Des Plaines, IL 60018; telephone: (847) 294-7126; facsimile: (847) 294-7834.