Basic Search and Rescue Pattern Practice

Swimmer and survivor are hoisted about a USCG Dauphin helicopter

Discussion

Commence Search Point (CSP) – given as a Lat/Lon position, a Nav Aid fix such as cross radials from two VORs or a single VOR radial with DME, or an RNAV fix.  Easiest way to identify and fly to the CSP is using a flight planner such as FSNav where any of them can be entered and flown to directly.

Major/Minor Axis – basically defines the ‘box’ you will search.  Each pattern uses these somewhat differently to define the direction of the Legs and Spaces

Leg/Space – Defined as distances.  Using FSNav or other flight planning tools, these are easy to program.  After plotting in the CSP and heading for it, the SAR pilot can set up the pattern while enroute.  Without these tools, one is left with an E6B flight computer (circular slide rule), a ruler, and a map to lay out the search pattern.  Then you would fly it using a stopwatch, adjusting for wind direction and speed to keep a constant ground track and speed (whew!).   Leg is also called the Search Leg, and space is sometime referred to as the creep distance.

Altitude – Affects the visual distance you can see.  Between 500 – 1000 ft for helos and between 1000 – 2000 ft for fixed wing is normal. 

Track –  the general direction the search pattern should progress.

Airspeed – If the target is large, you can go faster, if it is small, you’ll need to go slow.  Also go slow if your crew is tired.  If you fly above 180 kts, the Spaces will need to be at least 5 NM.

Types of Basic SAR Patterns

Some Patterns are better for certain situations and aircraft types.  Further study will make the choices clearer; for now they will be assigned to you to fly and the parameters provided.  Click on the pattern title to see the graphical representation.

• Trackline – when the path of target is known, fly the path.  After reaching the CSP, fly the MAJOR AXIS first.  The multiple Trackline is used to bracket either side of the known path.

• Parallel – General pattern to cover large areas.  After reaching the CSP, fly the MAJOR AXIS first.

• Creep – When the probability of the target being at one end of the pattern or the other, this pattern covers large areas.  After reaching the CSP, fly the MAJOR AXIS first.

• Sector - Usually the first pattern flown upon reaching an assigned location.  This pattern may be commenced upon arrival if no other instructions have been received.  The first leg should be downwind, and default uses 10 NM legs.

SAR Pattern Practice Exercises

You can download the FSNav files for each of the situations below to help in this exercise.  SAR_Scenarios

Scenario 1 – Creep Pattern

After reaching the CSP, you will turn right to 125 for 10 NM, then left to 035 for 5 NM, then 305 for 10 NM, 035 for 5 NM, 125 for 10 NM, 035 for 5 NM, 305 for 10 NM, 035 for 5 NM, etc, etc.  Fly at least five Legs before stopping.

Scenario 2 – Parallel Pattern  

Again, reach the CSP and turn right to 180 for 10 NM, then 090 for 5 NM, then 000 for 10 NM, 090 for 5 NM, 180 for 10 NM, 090 for 5 NM, 000 for 10 NM, etc etc.  Fly at least four Legs.

Scenario 3 – Trackline Pattern

At the CSP, fly 40 NM heading 090.

Scenario 4 – Multi Trackline Pattern  

At the CSP, fly 40 NM heading 090, turn right 180 for 20 NM, then right again to 270 for 40 NM.  This pattern tracks along the course from scenario 3.

Scenario 5 – Sector Pattern  

After reaching the CSP and turn to 090 for 10 NM, then make each turn after a 10 NM leg is completed.  A little knowledge of basic triangle math will help (the sum of all angles in a triangle = 180 degrees).