Figure: North Pole, from Jeppesen Airway Manual AP(HI).
If you fly over the poles under 14 CFR 135, you need to understand everything written below about high latitude operations. It could very well be that you can't legally do what your airplane is physically capable of doing.
Flying over the poles under 14 CFR 91? You still need to understand this stuff, but you might not be prevented from doing something stupid. Me? I would make sure we had all our ducks in line first. What follows will help you do just that.
Think you know this stuff already? Here's a pop quiz: where are you more likely to encounter in-flight temperatures below -70°F at FL 450, at the North Pole or at the equator? If you said North Pole you are wrong.
What follows are quotes from the references listed below, with technique shown in blue:
[Advisory Circular 120-42B, ¶601.]
[Advisory Circular 91-70A, ¶ 3-6.w.] Navigation in Areas of Magnetic Unreliability (AMU). The FAA designates Canada's NCA and Arctic Control Area (ACA) as AMUs. Although Canadian publications sometimes refer to it as the area of compass unreliability, they are the same. The magnetic North Pole is at approximately 75°N 100°W and is slowly moving as it circles the true pole every 960 years. This is why we see current navigation charts occasionally changing an instrument landing system (ILS) course by 1°.
The worst magnetic compass performance is probably in the center of the Northern Control Area, home to the magnetic North Pole. This position creates a notch in the circle of magnetic unreliability, often called a "key hole." Charts should be checked for the presence of a "T" denoting the use of True Heading instead of Magnetic. Some aircraft automatically switch to True based on airway designation or latitude. The G450, for example, automatically switches above N73° or S60° latitude. More about this: G450 Procedures & Techniques / FMS: True/Magnetic Selection.
Figure: Southern, Northern, and Arctic Control Areas, from Transport Canada Aeronautical Information Manual, Figure 2.3.
What we used to call "polar ops" is now "high latitude operations." The definition depends on your source of information but can be summarized as follows:
[14 CFR 135, §135.98 Operations in the North Polar Area.] After February 15, 2008, no certificate holder may operate an aircraft in the region north of 78° N latitude (“North Polar Area”), other than intrastate operations wholly within the state of Alaska, unless authorized by the FAA. The certificate holder's operation specifications must include the following:
[FAA Order 8900, Volume 4, Chapter 1, §5, ¶4-102.E.] All approvals for operations into AMUs are granted by issuing OpSpec paragraph B040, Operations in Areas of Magnetic Unreliability, and by adding that area of en route operation to paragraph B050 of the standard OpSpecs. A checklist for operations in AMUs is available in the guidance subsystem in association with OpSpec paragraph B040.
Crews operating under 14 CFR 135 require operations specification approval (B040 and B050).
Crews operating under 14 CFR 91 should consider the many challenges involved and the potential safety risks illustrated below.
[Advisory Circular 135-42, Appendix 3, ¶3.f.] Certificate holders must have at least two cold weather anti-exposure suit(s) for the crewmembers on the airplane if outside coordination by a crewmember at a diversion airport with extreme climatic conditions is determined to be necessary. The certificate holder may be relieved of this requirement based on seasonal temperatures that would render the use of such suits unnecessary. This determination must be made with concurrence of the CHDO.
This isn't much of a list; you would be wise to consider adding the requirements of Advisory Circular 120-42B, which do not restrict 14 CFR 135 and 91, but offer sound operating practices.
[Advisory Circular 120-42B, ¶603.b.(5)]
[FAA Order 8900, Volume 4, Chapter 1, §5, ¶4-102.C.]
[Advisory Circular 135-42, Appendix 3, ¶3.c.] Before receiving approval to conduct polar operations, a certificate holder must review their MEL for such operations and should amend their MEL. The following systems and equipment should be addressed in the MEL based on specific needs applicable to this operation.
(1) Fuel Quantity Indicating System (to include a fuel tank temperature indicating system).
(2) Communication system(s) needed for effective communications by the flight crewmember while in flight.
(3) Expanded medical kit.
[Advisory Circular 135-42, Appendix 3, ¶3.e.] Before conducting polar operations, certificate holders must ensure that flight crewmembers are trained on any applicable passenger recovery plan used in this operation. Certificate holders should also ensure that flight crewmembers are trained on the following items, which should be included in a certificate holder's approved training programs:
(1) Atmospheric pressure at Field Elevation/Barometric pressure for Local Altimeter Setting and meter/feet conversion issues (flight crewmember training).
(2) Training requirements for fuel freeze (maintenance and flight crewmember training).
(3) General polar-specific training on weather patterns and aircraft system limitations (flight crewmember training).
4) Proper use of the cold weather anti-exposure suit, if required (flight crewmember training).
(5) Radiation exposure (see AC 120-61A, In-Flight Radiation Exposure).
[FAA Order 8900, Volume 4, Chapter 1, §5, ¶4-103.D.] The following must be in the approved training programs:
Figure: Arctic Radio VHF, from Jeppesen Airway Manual AP(HI).
There is some VHF radio coverage, denoted on en route charts.
Figure: Arctic HF / CPDLC Example, from Jeppesen Airway Manual AP(HI).
HF Frequencies and CPDLC addresses also appear on en route charts.
[FAA Order 8900, Volume 4, Chapter 1, §5, ¶4-103.B.(2)] High frequency (HF) voice has been considered the primary communications medium in the North Polar Area. However, other mediums may be used as a supplemental means in accordance with the applicable policy. For example, although HF voice remains primary for communications with Anchorage Center, in areas where there is satellite coverage, satellite communication (SATCOM) voice may be used as a back-up to communicate with ARINC Radio and in non-routine situations to establish direct pilot-controller voice communications.
I am told the HF quality is generally good, though signals may be impacted by solar activity. You may need to use either AM, USB or LSB to achieve the best clarity.
Figure: INMARSAT Line of Sight, from Eddie's Notes.
[FAA Order 8900, Volume 4, Chapter 1, §5, ¶4-103.B.(3)] In areas of satellite coverage, Controller-Pilot Data Link Communications (CPDLC) may be used for ATC communications, provided the ATS unit has an approved capability. In addition, provided the capability is approved, HF datalink may also be used to fulfill communications requirements with ATS units having the capability and with airline dispatch. Inspectors must ensure the operators meet the regulatory (14 CFR part 1) and policy requirements for long-range communication systems (LRCS). HF voice capability is always required.
[FAA Order 8900, Volume 4, Chapter 1, §5, ¶4-103.B.(4)] It is recognized that SATCOM may not be available for short periods during flight over the North Pole, particularly when operating on some designated polar routes. Communication capability with HF radios may also be affected during periods of solar flare activity. For each dispatched polar flight, the operator must take into consideration the predicted solar flare activity and its effect on communication capability.
[G450 Aircraft Operating Manual, §2B-21-40, ¶1.D.]
Because INMARSAT satellites are in geostationary orbits over the equator, the curvature of the earth limits their use at the poles. It is said that SATCOM is available for voice and datalink up to 82°N.
As in other remote areas, do not enter holding for lack of further clearance or radio contact at the FIR. Continue on your cleared route and altitude while trying pass a position report through the appropriate agency or a relay by another aircraft that you might raise on guard or on the air-to-air frequency 123.45 MHz. In the event of a total loss of communications, fly your flight plan. More about: Abnormal Procedures / Lost Communications.
Figure: Magnetic Variation Convergence Example, from Eddie's notes.
[FAA Order 8900, Volume 4, Chapter 1, §5, ¶4-102.]
The example chart illustrates the rapid change in magnetic heading over a relatively short distance.
Figure: True vs. Magnetic Example, from Jeppesen Airway Manual AP(HI).
Navigating near the poles presents several issues not found anywhere else in the world. Because of these issues, the only acceptable method of navigating through the NCA and high latitude region is through the use of long-range navigation systems using inertial and GPS based FMS systems referenced to True North only.
Other methods of navigation in the NCA are impractical or unreliable because of the inherent limitations of magnetic compasses near the magnetic and geographic North Poles, and because of the geometric problem caused by meridian convergence.
Some aircraft make the switch automatically by reference to latitude or airway, while for other the switch must be made manually. See G-450 FMS True/Magnetic Selection for more details.
Figure: GPS Satellite Line of Sight, from Eddie's notes.
Each GPS satellite traces a track over the earth from 55° North to 55° South every twelve hours. At their maximum latitudes they are actually "looking down" on the poles:
Of course you have no guarantee you will have at least one satellite that high in its orbit. In order to have line of sight on the pole, a satellite would have to be at least 39° latitude:
I've not found anything in writing that tells you there will always be at least four satellites above 39° North and 39° South, but it appears so. You should have a good GPS position at either pole. More about this: Procedures & Techniques / GPS.
Figure: Tropopause Height, from Geerts and Linacre.
The tropopause at the poles is lower than at the equator; that means the altitudes where most polar-capable aircraft cruise is warmer. Knowing this, altitude selection may not be straight forward. More about this: Basic Aerodynamics / Properties of the Atmosphere.
Figure: North Pole January Mean Temperatures, from Wikimedia Commons.
If a descent into lower altitudes is required, fuel freezing and other aircraft systems limitations can become issues. If an emergency landing is required, surface temperatures can be life threatening. See: Fuel Freezing, and Minimum Equipment List.
[Advisory Circular 135-42, Appendix 3, ¶3.c.] Fuel Freeze Strategy and Monitoring Requirements for Polar Operations. Certificate holders must develop a fuel freeze strategy and procedures for monitoring fuel freezing for operations in the North Polar Area. A fuel freeze analysis program in lieu of using the standard minimum fuel freeze temperatures for specific types of fuel may be used. In such cases, the certificate holder's fuel freeze analysis and monitoring program for the airplane fuel load must be acceptable to the FAA Administrator. The certificate holder should have procedures for determining the fuel freeze temperature of the actual fuel load on board the airplane. These procedures relative to determining the fuel freeze temperature and monitoring the actual temperature of the fuel on board should require appropriate levels of coordination between maintenance and the flight crewmember.
Should fuel temperatures approach the aircraft’s freezing limit you should consider:
Your flight planning vendor should provide a temperature chart to help you plan for these contingencies. Remember, any changes in flight level, speed or route must be coordinated with ATC.
For more on weather at high latitudes, see Weather / Arctic Weather.
Figure: Solar Flare, from Wikimedia Commons.
[Advisory Circular 120-61A, ¶6.] Radiation received on a lower-latitude flight will be lower because of the greater amount of radiation shielding provided by the earth's magnetic field. This shielding is maximum near the equator and gradually decreases to zero as one goes north or south. Radiation levels over the polar regions are about twice those over the equator at the same altitudes.
Flights in the Polar Region at typical business jet operating altitudes are well above the tropopause where much of the atmospheric protection from solar storms is lost, increasing crew and passenger exposure to solar radiation.
For example, one New York-Tokyo flight during a solar storm could expose the passengers and crew to the normal annual exposure (1mSv) of someone who remained on the surface. If an S4 solar storm is active or predicted, polar operations are generally considered not suitable at any altitude, while operations at FL310 or below are considered acceptable in S3 storm conditions.
Some flight plan vendors will include predicted solar activity for flights through the high latitude airspace. Additionally, Space Weather Now from the NOAA and spaceweather.com are useful when planning a polar flight.
Figure: Arctic Alternates, from Eddie's notes.
[Advisory Circular 135-42, Appendix 3, ¶3.a.] Before each flight, certificate holders must designate alternate airports that can be used in case an en route diversion is necessary. The airplane should have a reasonable assurance that the weather during periods when the certificate holder would need the services of the airport are within the operating limits of the airplane. The airplane should be able to make a safe landing and maneuver off the runway at the diversion airport. In addition, those airports identified for use during an en route diversion should be capable of protecting the safety of all personnel by allowing:
(1) Safe offload of passengers and crewmember during possible adverse weather conditions;
(2) Providing for the physiological needs of the passengers and crewmember until a safe evacuation is completed; and
(3) Safe extraction of passengers and crewmember as soon as possible (execution and completion of the recovery should be within 12 to 48 hours following landing).
[FAA Order 8900, Volume 4, Chapter 1, §5, ¶4-103.E.] Operators are expected to define a sufficient set of polar diversion alternate airports, such that one or more can be reasonably expected to be suitable and available in varying weather conditions (AC 120-42A, Extended Range Operation With Two-Engine Airplanes (ETOPS), provides additional guidance for two-engine airplanes).
[FAA Order 8900, Volume 4, Chapter 1, §5, ¶4-103.G.] A recovery plan is required that will be initiated in the event of an unplanned diversion. The recovery plan should address the care and safety of passengers and flight crew at the diversion airport and include the plan of operation to extract the passengers and flight crew from that airport.
The requirements for the passenger recovery plan are quite extensive and must be detailed for each airport listed as a possible alternate airport. More on this: Advisory Circular 135-42, Appendix 3, ¶3.b.
There aren't many airports with paved runways in the Arctic, and many of those do not have regular airline service or customs. If you are flying under 14 CFR 135 your Operations Specification approval will require a list of alternates and a plan for getting passengers from the alternates within 48 hours.
Portions of this page can be found in the book International Flight Operations, Part VIII, Chapter 23.
14 CFR 135, Title 14: Aeronautics and Space, Operating Requirements: Commuter and On Demand Operations and Rules Governing Persons on Board Such Aircraft, Federal Aviation Administration, Department of Transportation
Advisory Circular 91-70A, Oceanic and International Operations, 8/12/10, U.S. Department of Transportation
Advisory Circular 120-42B, Extended Operations (ETOPS and Polar Ops), 6/13/08, U.S. Department of Transportation
Advisory Circular 120-61A, In-flight Radiation Exposure, 7/6/06, U.S. Department of Transportation
Advisory Circular 135-42, Extended Operations (ETOPS) and Operations in the North Polar Area, 6/10/08, U.S. Department of Transportation
Joint Aviation Authorities JAR-OPS 1, Commercial Air Transportation (Aeroplanes), 10 May 2007
Jeppesen Airway Manuals, Arctic Polar / North Pacific High Altitude En Route Chart AP (HI) / NP (HI), 19 Sep 13
NAT Doc 001, Guidance and Information Material Concerning Air Navigation in the North Atlantic Region, Seventh Edition, January 2002.
The Height of the Tropopause, B. Geerts and E. Linacre, University of Wyoming, Atmospheric Science, 11/97.
Thousand-fold Rise in Polar Flights Hikes Radiation Risk, http://www.nasa.gov/centers/langley/science/polar-radiation.html, Michael Finneran, NASA Langley Research Center, 02.18.11