No CAT (sorry LLM!) approaches at ANC?
FROM: THE BOEING COMPANY
TO: Boeing Correspondence (MOM) [MESSAGE NUMBER:MOM-MOM-12-0240-01B] Multi Operator Message MESSAGE DATE: 12 Apr 2012 1659 US PACIFIC TIME / 12 Apr 2012 2359 GMT Enhanced Controls Required? No Summary Notes: This message is sent to all 747, 757, 767, 777 and MD-11 customers and respective Boeing Field Service Bases, Regional Directors and Airline Resident Representatives. CATEGORY: Flight Operations SERVICE REQUEST ID: 1-2175453884 ACCOUNT: Boeing Correspondence (MOM) DUE DATE: No Action Required PRODUCT TYPE: Flight Operations PRODUCT LINE: SEVERAL PRODUCT: 21 - Navigation/FMC/RNP ATA: SUBJECT: Information - Magnetic Variation Disagreement at Anchorage REFERENCES: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - SUMMARY: The FAA has issued a NOTAM prohibiting ILS approaches to Special Authorization (SA) Category I or Category II/III weather minima at Ted Stevens International Airport in Anchorage on all 747, 757, 767, 777 and MD-11 series airplanes because of potential autopilot flight director system (AFDS) behavior resulting from a difference between the published magnetic variation for PANC reflected in the latest FMC Navigation Database (NDB) and the magnetic variation from the airplanes' onboard inertial reference systems. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - DESCRIPTION: The FAA issued the following NOTAM for Anchorage (PANC) Airport on 12 April 2012: QUOTE: FDC 2/3535 ANC ..SPECIAL.. TED STEVENS INTERNATIONAL AIRPORT, ANCHORAGE, AK. DUE TO A DIFFERENCE BETWEEN THE ONBOARD MAGNETIC VARIATION (MAG VAR) DATA TABLES AND THE MAG VAR CURRENTLY PUBLISHED FOR THE AIRPORT, THE FOLLOWING SERIES AIRCRAFT ARE PROHIBITED FROM CONDUCTING ILS APPROACHES TO SA CAT I OR CAT II/III WEATHER MINIMA AT ANCHORAGE INTERNATIONAL AIRPORT (PANC); B-747, B-757, B-767, B-777, AND MD-11. THESE SERIES AIRCRAFT HAVE EXPERIENCED A SHIFT OF RUNWAY CENTERLINE PRESENTATION AND DEGRADED LOCALIZER TRACKING PERFORMANCE ON ILS APPROACHES. THIS ACTION IS BEING TAKEN TO MINIMIZE THE HAZARDS ASSOCIATED WITH DEGRADED LOCALIZER TRACKING PERFORMANCE OR COURSE PRESENTATION/DEVIATION DISCREPANCIES DURING APPROACH. PILOTS OF ANY AIRCRAFT EXPERIENCING ILS ANOMALIES ARE REQUESTED TO REPORT THEM TO PANC TOWER. FOR ADDITIONAL INFORMATION CONTACT THE NORTHWEST MOUNTAIN REGIONAL OPERATIONS CENTER AT 425-227-2000 OR [email protected] UNQUOTE The NOTAM has been issued because of reports of Autopilot Flight Director System (AFDS) behavior during instrument approaches at Anchorage. These reports include a shift of runway centerline presentation and degraded localizer tracking performance. Boeing and the FAA have determined that the reported AFDS behavior at Anchorage results from a difference between the published magnetic variation (MagVar) for PANC reflected in the latest FMC Navigation Database (NDB) and the MagVar value for PANC from the MagVar tables in the airplanes' onboard inertial reference systems (ADIRU/IRU). In November 2011, the published magnetic variation at PANC was changed to E19 degrees from its 2005 value of E21 degrees. At this time, the FMC NDBs were updated to the new value of E19 degrees. No approach issues were reported after the November 2011 change. In February 2012, the published magnetic variation at PANC was changed again to E17 degrees and the FMC NDBs were updated accordingly. Reports of anomalies during instrument approaches began following the NDB change to E17 degrees. The ADIRU/IRU MagVar tables on most of the affected airplanes are based on a 2005 or earlier model. From the 2005 MagVar tables, the magnetic variation for PANC is approximately E21 degrees, a difference of 4 degrees from the current FMC NDB value for PANC. The AFDS on most of the affected airplanes controls to a localizer deviation that is filtered with inertial data translated geometrically through the use of an adjusted final approach course. The final approach course can be adjusted for minor localizer beam misalignment, normal biases in inertial data, and differences in magnetic variation. The 4 degree difference between the magnetic variation in the ADIRU/IRU and the FMC NDB reduces the available margin to adjust for minor localizer beam misalignment and normal biases in inertial data. If these deviations combined with the known 4 degree difference exceed the system tolerance, the AFDS may exhibit degraded localizer tracking performance during instrument approache! s. All 737 series airplanes are not affected because of differences in the Autopilot Flight Director System design. All 787 airplanes have updated MagVar tables in the onboard earth reference system (ERS) and are not subject to this condition. Boeing is working in concert with the FAA on potential solutions to restore the capability of the affected airplanes to conduct ILS approaches to SA Category I and Category II/III weather minima at PANC as soon as possible, including a roll back of the NDB magnetic variation at PANC to E19 degrees to provide additional margin for the AFDS and the possibility of an early update of the ADIRU/IRU MagVar tables to the 2015 model. If you need further information regarding the subject or if copies of attachments (when referenced) are required, please access them by logging into MyBoeingFleet Service Requests. If you have further questions, you may contact the appropriate Airline Support Manager or call the BCA Operations Center at (206) 544-7500. |
I don't think FDX MD-11's have ever been authorized ILS (sa) approaches?
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Originally Posted by MaydayMark
(Post 1168743)
I don't think FDX MD-11's have ever been authorized ILS (sa) approaches?
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Originally Posted by MaydayMark
(Post 1168743)
I don't think FDX MD-11's have ever been authorized ILS (sa) approaches?
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Originally Posted by FoxHunter
(Post 1168869)
FOM 6.19 Authorized Landing Minimums
:eek: |
Originally Posted by FoxHunter
(Post 1168869)
FOM 6.19 Authorized Landing Minimums
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Originally Posted by Adlerdriver
(Post 1168858)
Regardless of that, we're still out of the Cat-2/3 business there until this gets fixed. At least it's not the dead of winter - although that a.m. fog bank can bring the vis down quite well.
fbh |
$$$$$$$$................The way we like it in ANC:D
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Since ANC is now a NOCAT airport, I can expense $25 every time I'm there? :D
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Originally Posted by FoxHunter
(Post 1168869)
FOM 6.19 Authorized Landing Minimums
FDX is not authorized SA Cat 1 approaches but can do any (Not RNAV (RNP) labeled "SAAAR") approach labeled "Special Aircrew and Aircraft Certification Required" approaches. FOM 6.29 |
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