15.3 Grid Navigation
In the event of any major failure of the FMS the crew could use the last airplane position to plot a track to the desired destination, measure the track and distance and navigate by Mental DR till suitable Navigation Aids are available. At any point on track the true heading/track could be measured while aligning the protractor along the meridian at the place. The True heading/track would change by an amount equal to the meridian convergence at any other place. The crew could also use the formula to calculate the true track/heading at any point .
GRID TRACK= TRUE TRACK + LONG WEST
-LONG EAST

Since the ND displays GRID headings beyond 70° N latitude these could be used to maintain single heading to the destination.
Issue I 28.08.2007 Rev.0

 极地运行手册 POLAR OPERATIONS MANUAL

CHAPTER 15 GRID NAVIGATION AND PLOTTING PAGE 15-2
Issue I 28.08.2007 Rev.0

CHAPTER 16 MINIMUM EQUIPMENT LIST  PAGE 16-1

16.  Minimum Equipment List
16.1  The following items must be operational for north polar operations. For ETOPS flights, all MEL restrictions for 180-minute operations shall be applicable.
(1)  Fuel quantity indicating system (FQIS) (to include fuel tank temperature indicating system);

(2)  Auxiliary power unit (APU) -for two-engine airplanes (including electrical and pneumatic supply to its designed capability);

(3)  Autothrottle system;

(4)  Autopilot; and

(5)  Communication system(s) relied on by the flightcrew to satisfy the requirement for effective communication capability.

16.2  Long-range Flightcrew Requirements : The crew requirements would be as per DGCA CAR Section 7, Series J Part III dated 27 July 2007.
16.3  Dispatch and Crewmember Considerations during Solar Flare Activity. The operator must be aware of the content of AC 120-52, Radiation Exposure of Air Carrier Crewmembers, and provide crewmember training as stated in AC 120-61, Crewmember Training on In-Flight Radiation Exposure.