High Altitude Flight Planning October 4, 2006 Audio required make sure your volume is tuned up!
Introduction While high altitude flight planning can present different challenges than low altitude flight planning, the process is still the same. This section is designed to provide you with a basic review of flight planning, and is advisory in nature only. Be sure to consider all aspects when planning a flight in the high altitude environment.
Some things to think about Pilot and Aircraft Limitations and Capabilities Choosing Your Route Weather Considerations In Flight Considerations
Pilot & Aircraft Capabilities Understand your capabilities and limitations Understand your aircraft’s capabilities and limitations.
Planning Your Route Direct Victor Airways Jet Routes Preferred Routing http://www.fly.faa.gov Flight Planning Software Flight Star AOPA fltplan.com DUATS
IFR Charts Low En-route charts Provides navigational information below FL180 Depicts the following: Victor airways VHF Radio aids Military training routes Reporting points Special use airspace High En-route Provides navigational information above FL180 Depicts the following: Jet routes VHF Radio aids Selected airports Reporting points Special use airspace
Planning Your Altitude When choosing an altitude take in account: Am I IFR rated, current and proficient? If not flight must be below 18,000ft MSL Distance of flight Winds Cloud bases and tops Freezing levels and icing potential Terrain Oxygen availability
91.159 VFR Cruising Altitude or Flight Level Sec. 91.159 When operating at or below 18,000 feet MSL but above 3,000 AGL On a magnetic course of zero degrees through 179 degrees, any odd altitude (such as 3,500, 5,500, or 7,500); or On a magnetic course of 180 degrees through 359 degrees, any even altitude (such as 4,500, 6,500, or 8,500).
§ 91.179 IFR cruising flight level. When operating at or above 18,000 feet MSL but below flight level 250, and— On a magnetic course of zero degrees through 179 degrees, any odd flight level (such as 190, 210, or 230); or On a magnetic course of 180 degrees through 359 degrees, any even flight level (such as 180, 200, or 220).
Each person operating an aircraft in Class A airspace must conduct that operation under instrument flight rules (IFR) and in compliance with the following: (a)Clearance (b)Communications (c)Transponder requirement (d)ATC authorizations Remember to set your altimeter to 29.92 at 18,000 ft MSL. Remember to re-set your altimeter when descending below 18,000 ft MSL §91.135 Class A Operations
Special Use Airspace Prohibited All aircraft are prohibited Restricted IFR traffic is allowed if not active IFR traffic is allowed if altitude restrictions have been issued MOA IFR traffic may be cleared through, if IFR separation can be provided ADIZ Operations inside of an ADIZ must be on an DVFR or IFR flight plan in order to take place TFR Check appropriate NOTAMS during flight planning, restrictions may very. FSS or www.faa.gov
Weather Considerations Sources of weather information Flight Service Station 800-WX-BRIEF DUATS http://www.duats.com DUAT http://www.duat.com AOPA http://www.aopa.org/flight_planner/intro.html Aviation Weather Center http://adds.aviationweather.noaa.gov
High Altitude Weather Pressure Systems Knowing why position is important when flight planning Convective Activity Includes discussion on interpreting weather radar Icing What’s different about high altitude ice Jetstreams Refer to winds aloft charts for planning purposes CAT Can be found in areas of strong converging winds
Pressure Systems In the Northern Hemisphere Eastbound Fly North of a High, South of a Low Westbound Fly North of a Low, south of a high H
Convective Activity Avoid Cells by 20NM when the tops are above FL200 20/20 Rule 20+20 = 40 (40NM is the distance you should maintain between cells.) Gradients Avoid radar returns. General Radar Interpretation Guidelines If radar depicts the cell as red with yellow and green edges the whole cell should be considered red Thunderstorms present dangers which are not readily detectable by the radar such as turbulence, tornadoes, ice, and dry hail Weather can change faster than the update times of XM weather.
Icing Consider all factors of weather before making a go/no go decision when dealing with icing potential! Icing at High altitudes usually forms in the tops of tall cumulus clouds and in cirrus clouds Clouds over the mountains usually have more ice because of the added lifting motion Freezing levels PIC Concerns Where am I going to encounter ice? How can I get out of ice? Where are my MEAs in relation to the freezing level? Exit icing ASAP and inform ATC
Jet Streams Can be a factor in your Turbo Cirrus Result of large pressure gradients created by significant temperature changes over a short distance CAT is associated with the Jet Stream CAT risk increases if two jet streams converge General Jet Stream Rules Avoid during westbound flights, use on eastbound Jet streams can be depicted on winds aloft charts as areas of converging strong winds in excess of 60 kt
CAT (Clear Air Turbulence) Turbulence without clouds CAT generally forms when contrasting air masses converge Mountain Waves and strong low pressures aloft can create CAT CAT can be encountered in places where there seems to be no reason Strong winds can carry turbulent air away from its source (This is why you always should wear seatbelts even in what you presume to be smooth air) CAT is difficult to forecast because it gives no visual warning and winds can carry it away from its source PIREP’s and ATC are good current sources for CAT reports MSP UUA /OV MSP045020/TM 1636/FLUNKN/TP B757/SK TOPS 110/TB MOD- SEV UP TO 190/RM DURC RAP UUA /OV RCA/TM 1630/FL200/TP SR22/TB SVR FOR 1 MIN/RM WESTBND
Observation Considerations Terminal Aerodrome Forecast (TAF) METAR Most cover conditions below 12,000 AGL Special weather observation PIREP
In Flight Considerations Some things to think about in flight Changes in weather Changes in routing Do we have enough fuel to meet reserves and personal minimums? What is our oxygen status?
Time and Distance to Descend Descent planning in Garmin GNS-430 Vertical navigation page Alternate Method Example Cruise at FL200 Cross GEP VOR at 12,000 Need to lose 8,000 Descend at 1000 fpm (consider passenger comfort) consider any crossing restrictions from ATC Start descent 8 minutes out from GEP VOR Refer to POH supplement for fuel consumption.
Planning Summary Know the route(s) and get the big weather picture using local media sources, the internet and FSS Get a thorough preflight briefing with an emphasis on the position of weather systems, winds aloft, and convective activity Anticipate routing changes due to weather or ATC delays Planning is the same, just additional factors and considerations. If in doubt you should be on the ground and not in the air.
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