MSA - SSA - MOA - OMA SECTION 8

Question 1

How are MSA /SSA figures quoted?

Answer 1

Rounded up to next hundred feet excluding last two zeros.

Question 2

What is bandwidth for MSA’s on CIRRUS plans?

Answer 2

20nm either side of track - min 2000ft obstacle clearance.

Question 3

What is minimum MSA on CIRRUS plan?

Answer 3

Minimum MSA on CIRRUS plan is 2000ft.

Question 4

Where do you find your MSA if operating off the CIRRUS flight plan?

Answer 4

MSA for operating off flight plan route is obtained from the LIDO en-route chart.

Question 5

On aerodrome related charts what does the MSA figure represent.

Answer 5

MSA on an aerodrome related chart represents the safe altitude around a NAV station or aerodrome reference point. Generally 25nm unless otherwise shown on the chart.

Question 6

What is TAA - Terminal Arrival Altitude?

Answer 6

In the case of an RNAV approach the MSA may be replaced by TAA which is based on one of the procedure fixes.

Question 7

On aerodrome related charts what obstacle clearance is given by MSAs or TAAs?

Answer 7

MSA and TAA are used for airport navigation and provide 1000ft - 300m obstacle clearance down to the intermediate approach segment.

Question 8

Where are MSA critical points and escape procedures published?

Answer 8

MSA critical points and escape procedures are published in the performance manual.

Question 9

When a route is in airspace that has TERRAIN DRIFTDOWN CRITICAL AREA, where is this notified?

Answer 9

CIRRUS will have an ‘airspace note’ if a route is through airspace that has TERRAIN DRIFTDOWN CRITICAL AREA.

Question 10

If the CIRRUS is annotated with a ‘TERRAIN DRIFTDOWN CRITICAL AREA’ what must you do?

Answer 10

If the CIRRUS is annotated with a ‘TERRAIN DRIFTDOWN CRITICAL AREA’ the performance manual must be consulted to check applicability and procedures.

Question 11

If a driftdown escape route is applicable to your flight - where is the route entered?

Answer 11

The driftdown escape route should be entered into the FMC route 2 prior to reaching the start of the escape route.

Question 12

What does the bandwidth and vertical clearance MSA at the MSA critical point take account of?

Answer 12

The bandwidth and vertical clearance MSA at the MSA critical point takes account of drift-down in the event of engine failure based on the aircrafts ability to continue flight to the diversion airfield.

Question 13

What clearance does the driftdown escape route ensure?

Answer 13

The driftdown escape route ensures to clear all terrain and obstructions within 10nm either side of the escape route by 2000ft. If a turn is required exceeding 10nm the greater distance should be assumed.

10nm either side - 2000ft

Question 14

What clearance does the driftdown escape route on an aircraft with an RNP less than 5nm ensure?

Answer 14

The driftdown escape route on an aircraft with an RNP of less than 5nm ensures to clear all terrain and obstructions within 5nm either side of the escape route by 2000ft. If a turn is required exceeding 10nm the greater distance should be assumed.

RNP - 5nm either side - 2000ft

Question 15

What is the minimum operating altitude - MOA?

OM A 8.11.1

Answer 15

The MOA is the minimum altitude at which a flight may be planned or operated.

At night - relevant MSA,SSA or Radar cleared Altitude.

By day - VMC 500ft above all obstacles

Radar clearance is based on 1000’ clearance ± 5nm

Question 16

What is the minimum clearance for a radar cleared altitude?

Answer 16

Minimum clearance provided by radar cleared altitudes is 1000ft within bandwidth of +- 5nm.

However if there is any doubt to aircrafts position then MSA/SSA

Question 17

What corrections can be made to the MOA?

Answer 17

Strong wind adjustment - When the wind speed at MSA/SSA greater than 50kts.

Cold temperature Altimeter correction - altimeter over reads in cold temperatures

Question 18

Does an ATC clearance guarantee terrain or obstruction clearance?

Answer 18

No - the crew must maintain awareness of controlling MSA and if unable to ascertain position must climb above the controlling MSA.

Question 19

What actions should be taken when cleared below MSA?

Answer 19

Pilot flying will announce ‘Clearance below MSA’

Pilot monitoring will respond ‘MSA of xxxx’ and will state justification to continue descent below MSA.

Question 20

IMC flight below MSA based on a single nav aid should be avoided but if no other independent aid is available to cross check position what precautions should be taken?

Answer 20

Any discrepancy between expected and displayed values must be resolved to continue approach.

Question 21

If conducting an approach based on a single nav aid when descent to SSA permitted.

Answer 21

Descent to SSA is permitted when aircraft is within 25nm of the aerodrome and within appropriate quadrant- consideration must be given to SSA’s in adjacent quadrants.

Or

Descent to radar cleared altitudes is permitted when under positive radar control.

Question 22

If conducting an approach based on a single nav aid and at SSA and either within 25nm or under positive radar control when further descent permitted?

Answer 22

If on a single nav aid approach at SSA and either within 25nm or under positive radar control when further descent is permitted using a published approach procedure or in accordance with VMC flight below MSA rules - OMA 8.13.3.c

Question 23

When is flight below MSA in VMC permitted?

Answer 23

Upon reaching SSA sufficient visual reference is continuously maintained.

Day - ensure clearances from obstacles along track

Night - line of sight is line of flight - flight is directly towards identifiable lit area - generally the runway AND distance can be checked against height by means of radio or radar aids.

Question 24

If in VMC flight below MSA and visual reference is lost what action must be taken?

Answer 24

If below MSA and visual reference is lost the aircraft must be climbed to MSA/SSA as appropriate.

Question 25

What is the maximum rate of descent when descending below 3000ft above the MSA/SSA

Answer 25

When descending below 3000ft above the MSA/SSA the maximum rate of descent is 3000fpm.

3000fpm within 3000ft of MSA.

Question 26

Cold temperature Altimeter Correction

OMA 8.13.4.a

Answer 26

When surface temperature is less than ISA -25 deg, add the values derived from cold weather calculator App to the published procedure altitudes at the Final Approach Fix and the MDA/DA to ensure adequate obstacle clearance

Question 27

What temperature should the iPad calculators app used?

Answer 27

temps below ISA-25°C