The bulletin
Text extracted from the PDF.
FAA Aviation Safety
SPECIAL AIRWORTHINESS
INFORMATION BULLETIN SAIB: CE-10-22 SUBJ: Navigation Date: March 26, 2010 This is information only. Recommendations aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin advises you of an airworthiness concern regarding all modification levels of Honeywell GNS Series Navigation Systems: GNS_XLS PRNAV, part number (P/N) 17960-0103-XXX; GNS_XLS Enhanced PRNAV, P/N 17960-0204-XXX; and GNS_XL PRNAV, P/N 18355-0102-0XXX.
The FAA has completed a full review of this issue. At this time, the 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
Honeywell has recently discovered a software anomaly in their GNS Navigation Systems. This anomaly may affect the area navigation (RNAV) procedures, which contain RF (Radius-to-a-Fix) legs. If an RNAV procedure containing RF legs is loaded into the flight plan with the navigation system being used to fly the full procedure, the GNS system could fail to capture and fly the RF leg curved path and continue past the waypoint on an undetermined track line.
It should be noted that the GNS PRNAV systems are not approved for RNAV Required Navigation Performance (RNP) procedures. Honeywell Service Information Letter (Publication Number D201003000024) has been issued.
Recommendations
After reviewing the above data, we recommend that you adhere to the following:
1. Do not load any approach or departure procedure listed in Table 3 of the above-referenced Service Information Letter.
2. Do not load any approach or departure procedure listed as Special Aircraft & Aircrew Authorization Required or Special Authorization Required printed on the aeronautical chart.
3. Do not load any approach or departure procedure requiring RF capability.
4. Refer to the above-referenced Service Information Letter for additional guidance.
The Honeywell website also provides information on this subject and can be accessed at:
https://portal.honeywell.com/wps/portal/aero
Select the following in order:
¾ Support ¾ Technical Publications ¾ Safety/Certification Related Documents ¾ SIL GNS_XLS_RF Leg Approaches
2 For Further Information Contact
Albert Ma, Aerospace Engineer, FAA Wichita Aircraft Certification Office, Mid-Continent Airport 1801 Airport Rd., Wichita, KS 67209; phone: (316) 946-4151; fax: (316) 946-4107; e-mail:
albert.ma@faa.gov.