Operating Altitudes Flashcards
- What clearances have you got at MSA/SSA?
Above 6000ft – 2000ft. Below 6000ft – 1000ft
What is the MSA Bandwidth on Cirrus?
With the introduction of LIDO 4D, MSA bandwidth has been reduced from 20nm to 10nm – so 20nm wide vs CIRRUS which was 40nm. OMA 8.2.9
For a/c capable of RNP 5 this bandwidth may be further reduced to 5nm any MSA/emergency turns constrictions permitting - for example when taking account of MSA critical points. See 8.2.9.c.
Between the aerodrome and the first fix, on take-off, and between the last fix and the aerodrome, on landing, the MSA relates to the direct track between the points. When transferring from CIRRUS to aerodrome documentation, care must be taken to ensure that any relevant MSAs are not infringed.
- What is the minimum MSA on Cirrus?
2000ft
What is the MSA referenced to between aerodrome and the first and last fixes?
A direct track between the fix and aerodrome.
- What Clearance does a background MSA on a LIDO en-route chart give you?
MGA represents lowest safe altitude which can be flown off-track. Uses same criteria as MSA. LIDO 1.6.2.11.1.6. Minimum Grid Altitude (MGA)
The MGA is calculated by rounding up the elevation of the highest obstruction within the respective grid area to the next 100ft and adding an increment of
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1000ft for terrain or obstructions up to 6000ft; or
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2000ft for terrain or obstructions above 6000ft.
Example:
ELEV of highest obstruction: 6345ft; rounded up = 6400ft + 2000ft buffer = 8400ft MGA
MGA is shown in hundreds of feet. Lowest indicated MGA is 2000ft.
This value is also provided for terrain and obstacles that would result in an MGA below 2000ft. Exception is over water areas where the MGA can be omitted.
How far from aerodrome do quadrant SSA extend and what margin of overlap is built in?
Out to 25nm and + 5nm quadrant overlap.
What clearance have you got and within what bandwidth on an MSA critical route?
8.2.9.c. 10nm either side of track by 2000ft which may be reduced to 5nm for RNP 5 capable aircraft. On such routes CIRRUS will be annotated by way of an ‘airspace note’ ‘TERRAIN DRIFTDOWN CRITICAL AREA’.
What clearance will a radar cleared altitude give you? In what bandwidth?
1000ft bandwidth 5nm either side of track. OMA 8.11.1
What are the minimum operating altitudes by Day and by Night?
Day VMC – 500ft above all obstacles.
Night/IMC – relevant MSA or Radar cleared Alt
What corrections are made to MSA in cold wx? What particular relevance is ISA-25 to PBN operations?
4% of ht per 10deg below ISA (use BA Calculators>Cold Wreather App).
Note: until ISA -25deg the app will not offer any correction. ISA -25 is the temperature at which, in the absence of specific temperature guidance on the chart, the vertical profile may no longer be flown using VNAV. At a sea level airfield that’s only -10!
- What corrections are made with strong winds?
When wind at MSA/SSA >50kts increase MOA by min 2000ft
If you are given a major detour off your planned route how do you calculate what the MSA’s are?
Appropriate chart/Radar vectoring plate/look out the window!
Define LIDO MOA?
Minimum Operating Altitude at which flight may be planned/operated taking into account min standards/a/c performance/weight/wx.
What section of OMA covers clearance below MSA?
Section 8.13
