Please find attached a Foreign State of Design Advisory document, endorsed by EASA.
This advisory document is also online at
https://ad.easa.europa.eu/ad/NE-17-26 .
Should you have any questions, please contact the Agency by e-mail at
[email protected] or by fax, No.: +49 221 89990 9515.
Safety Information Section Email:
[email protected]
EASA
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(Attachment is in Acrobat PDF format)
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FAA SPECIAL AIRWORTHINESS
Aviation Safety INFORMATION BULLETIN
SUBJ: NAVIGATION - Traffic Advisory System - Misleading Intruder SAIB: NE-17-26
Aircraft Vertical Trend Date: September 25, 2017
This is information only. Recommendations aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin alerts you, owners and operators of aircraft equipped
with an Avidyne TAS600A, TAS600, and 9900BX Traffic Advisory System (TAS) of an
airworthiness concern regarding the display of intruder aircraft vertical trend indications. At this
time, this airworthiness concern is not an unsafe condition that would warrant airworthiness directive
(AD) action under Title 14 of the Code of Federal Aviation Regulations (14 CFR) part 39.
Background
Avidyne has identified a defect in TAS units that may prevent the TAS from updating intruder
aircraft vertical trend when rapidly changing ownship altitude updates are received. This problem is
particularly pronounced when the TAS receives ownship altitude updates from an ARINC-429
altitude source providing 1 ft. resolution. However, there is the potential that the problem may be
observed regardless of the source of ownship altitude updates. This issue does not affect traffic
alerting because aircraft vertical trend is not used in the alerting algorithm. This issue also does not
affect intruder range, altitude, and bearing indications.
Avidyne has released Service Information Letter 606-00161-005, regarding this issue. Avidyne has
also released Service Bulletin (SB) 601-00185-009, which updates the software in the TAS600A
processor to provide a solution to this behavior. Avidyne does not plan to release a software update
to address this issue in TAS600 or 9900BX TAS series systems.
Recommendations
• The FAA recommends that owners and operators of TAS600 or 9900BX series TASs remain
aware that those TASs have a defect and that they cannot rely on the display of intruder
aircraft vertical trend indications.
• The FAA recommends that owners and operators of TAS600A series TASs remain aware that
those TASs have a defect and that they cannot rely on the intruder display of vertical trend
indications until the TAS600A series TAS has complied with Avidyne SB 601-00185-009.
For Further Information Contact
Nick Rediess, Aerospace Engineer, FAA, Boston ACO Branch, 1200 District Avenue, Burlington,
MA 01803; phone: 781-238-7159; email:
[email protected].
For Related Service Information Contact
Avidyne Corporation, 710 North Drive, Melbourne, FL 32934; phone: 888-723-7592, (Toll Free US)
or, 781-402-7592 (International Direct Dial); fax: 781-402-7599; Internet:
http://www.avidyne.com/support/index.asp.
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