Magnetic Variation – CAT II and III Operations PANC/PAFA OSWG

1. Magnetic Variation – CAT II and III Operations PANC/PAFAOSWG Presented by: John Swigart Date: March 18, 2015

2. Overview • Magnetic Variation 101 • Airplane Systems, Airports, IAP Designs • MagVar Tables Explained • Course Steering • Safety Effects if Airport & Airplane MagVar disagree • Anchorage ILS Example • Procedure Updates… • Moving forward

3. Magnetic Variation 101 Difference between local bearing to the True pole vs the Magnetic pole • Defined: Magnetic Bearing = True -- Magnetic Variation (MV) • Variation • Differs across the Earth • Is greatest near the Poles • Earth’s magnetic field changes over timeMagnetic variation can, too • Extremes: Max D near poles 1o in ~3 years, Minimum in Asia ~2o/century • NOAA updates its magnetic Earth model every 5 years • Mag & True references are each appropriate & useful • Largest effects in Alaska, Arctic Canada & Russia, Greenland, Iceland, Antarctica • Airplanes, airports, databases and Earth ideally should agree • This is technically & organizationally harder than it looks

4. Airplane Systems, Airports, IAP Designs Air Navigation is a blend of True and Magnetic references • Most transport airplanes (with inertial) measure True and calculate Magnetic. Then they use both. • They do not include Magnetic sensors in nav solutions. • Don’t need to because they have inertials (IRS, IRU, ADIRU, etc) • They could, but would introduce other, even bigger errors • Global Nav, and most computers, work in True references • Magnetic values are converted from databases and for displays • Exceptions • Many RJs, turboprops & older jets rely on AHRS. They only measure magnetic. • Modern Standby systems measure magnetic. Those are independent, separate. • Most charts, runways, facility references & Navaids use Magnetic references • Instrument Approach Procedures, charts and airports use Magnetic references • Therefore they must all be updated as the Earth’s magnetic field moves • Always a challenge to reconcile the differences When it all works, it works very well, if all players understand limitations and obligations

5. MagVar Tables Explained On airplanes with Inertials • Variation is looked up in a “MagVar Table,” a 2-D database of: MagVar = f(Lat, Long) • Magnetic is calculated as a sum of True minus Variation • If the variation is wrong, then the calculated Magnetic will be wrong • MagVar Tables are stored in the Inertial Reference Unit & FMC • Data are intended for at least 10 years • Accurate enough for much longer at most locations • Data embedded in Complex Hardware • Avionics OEMs update their tables every 5 or 10 years (usually) • Production incorporations are routine. (Usually) • Perfect match among airplanes, airports & Earth is instantaneous, perishable • Retrofit • Updates can require sending the IRU in for chip change & new part mark • FMC and newest ADIRU can be loaded in field • Done via Service bulletin, on condition, not required • Many airplanes are flying with 30 year old MagVar tables and have no issues in their niche ops • Some airplanes and operations require 1o MagVar accuracy, especially for CAT III • 2008 AD against Airbus due to similar symptoms • Airports, charts, nav data and airplanes can each have errors • FAA data and OEMs’ MagVar will adjust, but at different schedules • Updates can anticipate future MagVar values • Facilities do as needed, possibly working ahead

6. Course Steering • Crew normally enters Magnetic course into the MCP, taken from the IAP chart • Autopilot will construct a reference path in space • Autopilot takes MCP Magnetic selection, adds MagVar from the inertial, builds a True course line, and commands that. • If MagVar is wrong, then the commanded course diverges from local magnetic • Navaids or visual references make large errors apparent. Small errors less so. • On ILS, the autopilot computes steering commands using a blend of ILS and Inertial • Biased to the ILS. A/P uses Inertial to stabilize, compensate for wind & turbulence, and to avoid chasing passing distortions in the LOC signal. VOR is similar. • Important to the late stages of Autoland • Specifics vary greatly by airplane type (blending schemes and error sensitivities) • Systems can tolerate some nav source discrepancies • Tolerance varies by airplane type and by operation • Differences between the LOC and the Inertial/Autopilot paths • Include MagVar errors, LOC distortion and errors, charting resolution, some FTE • When Inertial Reference and the Localizer are in conflict • The autopilot tries to obey both. Trouble occurs when they disagree too much. • Bulk of the issue appears during capture • When any autopilot cannot reconcile its inputs, it gives the airplane back to the crew. This is good.

7. Safety Effects if Airport & Airplane MagVar disagree • IRU will cause an error when flying a commanded course • ILS, far away (usual symptom) • Missed capture • Try again, or try something else • Missed approach • Annoying, expensive, generally not dangerous • ILS close in (less likely) • Poor or unstabilized approach dynamics • Misalignment with the physical runway when trying to capture. • On an ADF procedure • Course misalignment. Misleading, especially while outbound. • HSI/RDMI are correct • Escape from TERPS area if unnoticed. • Potentially hazardous

8. 4o bearing error ~7900 ft offset Anchorage, ILS Runway 7R Example At the IF (ELIAS,) 18.6 NM from Rwy, 4o bias from using 2005 MagVar table with 2015 Epoch will compute a 7900 ft overshoot. At the threshold, that diff between constructed path and LOC is 900 ft. Constructed Path to the Runwayif using 21o from 2005 MagVar table “TrueConstructed” = Magnetic + 21o • 2005 was 090oT = 069o + 21o • 2010 was 092oT = 071o + 21o • late 2011 was 092oT = 071o + 21o • In Feb 2012 became 094oT = 073o + 21o • June 2012 will be 092oT = 071o + 21o • In 2015 the intent will be 090oT = 073o + 17o (presuming operators have updated their tables) • True Runway Bearing is 090o • Magnetic Bearing • 2005 was 069oM, MV was 21o • 2010 was 071oM, MV was 19o • 2012 is 071.5oM, MV is 18.5o • 2015 will be, 073oM, with MV 17o • By 2020 the Rwy might become 8R

9. Anchorage/ Fairbanks NOTAMs • Original NOTAM issued 12 April 2012 • Prohibits CAT II, CAT III ops at Anchorage in 747, 757, 767, 777, MD-11 • 737 is OK. Different A/P & guidance architecture. • Airbus may have issues at some point if procedure is not updated to ICAO standards. • Boeing issued an Operators Updated Message (MOM) Fall of 2015 • Describes issues in detail • Now includes B747-800 • Will have AFM requirements • Must update to 2015 tables – requires new NOTAM

10. ANCHORAGE (PANC) Procedure Update • Anchorage ILS procedures will be updated by Fall 2015 • 18 E value interim will be applied. • Interim value brings procedure close to ICAO standard . • Accommodates magnetic referenced systems. • Buys more time for operators to update systems. • Will be updated to 17 E in 2018 (ICAO Standard). • Boeing aircraft with 2005 and newer magvar tables will still be able to operate normally…..until 2018. • Airbus is good to go. • Current NOTAM will suffice.

11. Fairbanks (PAFA) Procedure Update • Fairbanks ILS procedures will be updated by December 2015 • 18 E value will be applied. • Interim value was investigated – no fix is possible to accommodate Boeing aircraft with 2005 and previous tables (aircraft will not be in compliance regardless of making no change or updating the procedure). • Boeing aircraft identified in latest MOM will be required to have 2015 magvar tables installed/ updated (2005 and previous magvar tables will not be compatible after procedure update). • AFM will be updated to reflect requirement…..drives airworthiness. • Updated NOTAM will be issued to reflect changes and add more aircraft to list (aircraft affected by procedure update). • Airbus may have issues….we’ll keep you updated.

12. Moving Forward….CAT II / III Ops • IRU MagVar tables….update….update….update! • Operators should have MagVar tables adequate for their locale worldwide. • Must update all aircraft operating into PAFA by Fall 0f 2015. • Must update all aircraft operating into PANC date TBD in 2018. • Honeywell can only accommodate 50 IRU units per month….3 per aircraft and potentially 1200 aircraft affected. • Reference above….get a plan in place now…2018 will be here soon. • AFS-410 updating OpSpec C059 and C060 combo to include requirements that will address database updating for operators that utilize procedures at ANC and FAI. • MMEL will be affected so plan accordingly…..AFM requirements. • Update will enable FAA to delete NOTAM

13. Moving Forward…. • IRU MagVar tables….update….update….update! • Honeywell can only accommodate 50 IRU units per month….3 per aircraft and potentially 1200 aircraft affected. • Reference above….get a plan in place now…2018 will be here soon. • AFS-410 updating OpSpec C059 and C060 combo to include requirements that will address database updating for operators that utilize procedures at ANC and FAI. • MMEL will be affected so plan accordingly…..AFM requirements

14. Thank you