Aim To introduce the concepts and procedures used for visual navigation.

Navigation ProceduresATC Chapter 5

Aim

To introduce the concepts and procedures used for visual navigation

Objectives

1. Introduction and definitions2. State the method for map reading and

position fixes3. State the 1 in 60 rule and it’s use4. State the in flight work cycle5. Discuss applied navigation techniques

For the purposes of this Brief we are interested in the theory behind the dead reckoning navigation techniques you will use planning a flight and in flight.

Detailed information on how to plan a flight from a blank flight plan form through to submitting a flight plan to Air Services will be provided in later Briefings.

1. Introduction and Definitions

Definitions

Flight Planned Track (FPT) – The planned track to be flown

Track Made Good (TMG) – The actual path of the aircraft over the ground, this is a function of Heading and Wind Drift

Track Error (TE) – The angular deviation between the Flight Planned Track and the Track Made Good

TE

FPT

TMG

1. Introduction and Definitions

A B

Map (Chart) reading is the art of being able to relate the contours, colours and squiggles on a map to the real world passing beneath you.

1. Always orientate your map so the track is up, this means that features on your map should be in the same orientation in the outside world

Read from watch, to map, to ground2. Determine where you should be on your

map using time3. Seek features on your map in your

expected location4. Find them on the ground

Always start with large features working your way down to small

features5. When you get a positive fix mark it on

your map with a 4 figure time reference

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2. Map Reading and Position Fixes

Prominent FeaturesIdeally we want to use large, prominent features as reference points

Silos

Towns/Cities

Lakes/Rivers

Railway lines

Bridges

Large Highways

Hills/ Mountains

Aerodromes


Prominent FeaturesThings to avoid

Small Airfields

Dirt Roads

Homesteads


A Positive Fix - occurs when you can positively identify the position of the aircraft relative to the ground.

Examples include passing overhead or abeam an identified town or geographical feature.

Tracking Your Progress

Positive Fix

Positive Fix


A Position Line is defined as a line along which an aircraft is known to be at a particular time.Examples would be long narrow features such as roads, railway lines, coastlines. You know you are somewhere along the feature but do not have a Positive Fix.

Major Identified Road – Position Line

Tracking Your Progress

If you can identify a feature along the Position Line or another Position Line that intersects the Position Line then you can establish a Positive Fix.

Which aircraft have a positive fix?

1 2 3 4


During the pre-flight planning stage of your flight you should have a good look at your map and determine where you will be able to get a positive fix

When you arrive at your planned fix you need to assess if the aircraft is on track or not.

Tracking Your Progress3. 1 in 60 Rule

– mark this point with a perpendicular line with 1nm increments,

FPTTMG

Possible reasons for being off track:

• Actual wind is different to planned wind• Track has been incorrectly measured• Magnetic deviation has not been applied to the measured track• Incorrect HDG has been held• Diversion due weather or ATC

Once an off track assessment has been made we must do something about re-gaining the planned track or determine a HDG to hold to ensure we reach our destination.

The most common way to re-gain track or track to our destination is by using the 1 in 60 rule.

Tracking Your Progress3. 1 in 60 Rule

1 in 60The 1 in 60 rule is based on the assumption that 1nm subtends at an angle of 1⁰ at a distance of 60 nm.

In this case we can say we have a track error of 1⁰.

FPT

TMG1⁰

1 nm

60 nm

3. 1 in 60 Rule

1 in 60

Based on this principal we can say, for example, that if we are 5 nm off track in 60 nm we will have a track error of 5⁰.

5⁰5 nm

60 nm

3. 1 in 60 Rule

1 in 60

Or, for example, that if we are 5 nm off track in 30 nm we will have a track error of 10⁰.

10⁰ 5 nm

30 nm

3. 1 in 60 Rule

1 in 60

If we were on a flight from A to B and we simply adjusted our heading by our track error we would parallel our flight plan track, never making it to our destination.

Track Error

Distance Off

A B

Distance Travelled Distance To Go

3. 1 in 60 Rule

1 in 60In order to reach our destination we must also apply the 1 in 60 rule to the distance to go in order to determine our closing angle

Track ErrorDistance Off

A BDistance Travelled Distance To Go

Closing Angle

3. 1 in 60 Rule

1 in 601 in 60 calculations can be done quickly using mental arithmetic or using the flight computer.

When using the mental arithmetic method1. Divide distance travelled or distance to go into 602. Multiply the answer by the distance off track to get the track error or closing

angle3. Add the track error and closing angle to get heading change required4. Apply the heading change required to the original heading

When using the flight computer1. Set the distance off track on the outer scale against distance travelled or

distance to go on the inner scale2. Against the time index (60) on the inner scale read off the track error or

closing angle on the outer scale3. Add the track error and closing angle to get heading change required4. Apply the heading change required to the original heading

3. 1 in 60 Rule

1 in 60Example

8⁰

4 nm

A B30 nm 20 nm

16⁰

We are on a flight from A to B heading 090⁰. At our 1 in 60 point we determine we are 4 nm to the left of track. We have travelled 30 nm and have 20 nm to go.

1. Using the mental method we know 60 / 30 = 2 and 2 x 4 = 8, therefore our track error is 8⁰

2. We know 60 / 20 = 4 and 4 x 4 = 16, therefore our closing angle is 16⁰3. Our heading change required = track error + closing angle = 8 + 16 = 24⁰4. We are left of track so we must change heading to the right, therefore we

must add 24⁰ to our original heading. 090 + 24 = new heading 114⁰

3. 1 in 60 Rule

1 in 60Example

4⁰

A B84 nm 43 nm

We are on a flight from A to B heading 090⁰. At our 1 in 60 point we determine we are 5 nm to the left of track. We have travelled 84 nm and have 43 nm to go.

For this example we will use the flight computer1. Set the distance off track on the

outer scale against distance travelled on the inner scale.

2. Against the time index (60) on the inner scale read off the track error on the outer scale, 3.6⁰ which we can round up to 4⁰.

5 nm

3. 1 in 60 Rule

1 in 60Example

4⁰

A B84 nm 43 nm

7⁰

We are on a flight from A to B heading 090⁰. At our 1 in 60 point we wind we are 5 nm to the left of track. We have travelled 84 nm and have 43 nm to go.

3. Set the distance off track on the outer scale against distance to go on the inner scale.

4. Against the time index (60) on the inner scale read off the closing angle on the outer scale, 7⁰.

5 nm

3. 1 in 60 Rule

1 in 60Example

4⁰A B

84 nm 43 nm

7⁰

We are on a flight from A to B heading 090⁰. At our 1 in 60 point we wind we are 5 nm to the left of track. We have travelled 84 nm and have 43 nm to go.

5. Our heading change required = track error + closing angle = 4 + 7 = 11⁰6. We are left of track so we must change heading to the right, therefore we

must add 7⁰ to our original heading. 090 + 7 = new heading 097⁰

5 nm

3. 1 in 60 Rule

1 in 60Re-gaining track

A B

All of the 1 in 60 calculations we have looked at so far will take us from the off track position directly to a specific point.

In some cases this is not a viable option (CTA or Restricted airspace, weather, etc).

We will be required to re-gain our planned track.

Restricted Airspace

3. 1 in 60 Rule

1 in 60Re-gaining track

A B

The calculations required are the same as for the other 1 in 60’s we have looked at, however, instead of using the distance to the destination to determine the closing angle we will use the distance to the planned intercept point.

Once the planned track is intercepted alter heading by the closing angle to maintain the planned track.

Restricted Airspace

Distance flown Distance to fly

3. 1 in 60 Rule

The 1 in 60 point is also a good place to check our groundspeed and get a revised ETA for our destination.

The easiest way of doing this is using the flight computer. Refer to flight computer briefing.

We can also check our Groundspeed anytime we have 2 positive fixes.

Groundspeed3. 1 in 60 Rule

There are a number of items we need to monitor throughout our navigation exercises. Work Cycles ensure all items are checked on a regular basis allowing us to remain ‘ahead’ of the aircraft at all times.

A suggested Work Cycle for each leg of a flight is:

• Top of Climb Checks after Departing Airfield or Waypoint• CLEAROFFS• 1 in 60 Check and HDG/GS adjustment if necessary• CLEAROFFS• Brief and Plan for Arrival at Airfield or Waypoint• Top of Descent Checks

Where a leg is more than 30 minutes more frequent CLEAROFFS should be performed and after a HDG change due to a diversion or an Altitude change.

4. In-Flight Work Cycle

Work Cycle

Calculate burn, check on gauges, cross check on FMS

CLEAROFFS

ompass

ngine

og

adios/Nav aids

ltimetry

uel

rientation

AR time

orced landing

Flight log and plan are up to date

T’s and P’s, correct power setting set, mixture leaned

Frequencies set, standby stations tuned

Wind direction, visualize pattern, choose field

Location, mark on map

Amend as required

Compass and DI are aligned

Correct QNH, maintaining planned altitude, hemispherical, airspace

CLEAROFFS should be completed at least every 10 minutes in flight or after changing altitude or heading


The Flight Plan you prepare before flight is the basis for your Flight Log.Your Flight Log is a recording of in flight data you gather as the flight proceeds. In addition to the on ground calculated TK, HDG, GS, TI it includes• 1 in 60 Calculations - distance off track, HDG changes, GS changes• Time of arrival at - waypoints, 1 in 60 points, other checkpoints

Flight Log

FLIGHT LOG

POSITION TIME TI DIST

FLOWN G/S

HDG MAG

DIST OFF

NEW HDG

DIST TO FLY

ETI ETA PILOT NOTES

SPR 3 3 a/b Sedan 22 048 20 BLNCTN 3 2 a/b Mantng 23 115 27 ALWNA 3 4 Sandalwod 23 233 15 KRNDA 4 2 a/b Manum 31 281 25 WRR

• Diversions - start and destination points, TK, HDG, distances, time

• Fuel consumption - every 30 minutes against planned consumption

• SARTIME and SARTIME amendments


It is important to be able to work out a Top of Descent point to be able to arrive at your destination at a given altitude. This can be pre-planned but is often is calculated mid flight.

• For navigation flights we typically want to carry out a cruise descent at 500 feet per minute and around 110 Knots

• Divide the altitude to be lost by 500, this will give us the time for descent

• We will have a ground speed of around 2 nm per minute

• Time for descent x 2 = distance required for descent

Top of Descent Point

5. Applied Navigation Procedures

5. Applied Navigation ProceduresLow Level Navigation

Low level navigation should be avoided by thorough pre-flight planning. Unfortunately it is possible that the forecast may be different from the actual conditions and you may be forced to fly low level to maintain VMC.

Flight at low level can cause a number of problems including:• Obstacles• Poor visibility at low level• Visual illusions• Increased work load

If visibility is reduced establish the aircraft in the poor visibility configuration, 80 KTS and 10⁰ Flap.

Low level navigation should be used as a last resort. Consider an early diversion or if conditions become

extremely hazardous a PSL

Low Level Navigation Procedure1. Get a positive fix and record the time2. Select checkpoints along track3. Estimate the time you should reach each checkpoint.

We can estimate the time required by using a rule of thumb for the C172

• In light/moderate winds assume 120 knots or 2 nm per minute• In strong headwinds assume 90 knots or 1.5 nm per minute• In strong tailwinds assume 150 knots or 2.5 nm per minute

Note: A good trick here is to measure the width of your thumb. If, for example, your thumb is 6nm wide that will equate to around 3 minutes flight time at 2nm a minute (120kts groundspeed)

4. Record the time as you get to each checkpoint and revise estimates for the remaining points

5. If you find yourself off track apply the 1 in 60 ruleNote: During low level navigation it is acceptable to read from ground to map.


For example, we are on a flight from Blanchetown to Alawoona and are forced low level due weather.

1. Get a positive fix and mark the time on the map

2. Select checkpoints along the track. These should be visual features that we expect to see if we are maintaining track

3. Estimate the time you should reach each checkpoint.

4. Record the time as you get to each checkpoint and revise estimates for the remaining points

5. If we find ourselves off track apply the 1 in 60 rule

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Lost Procedure

If you become unaware of your position there is a natural tendency to panic. Keeping calm and apply the correct procedure to reorientate yourself.

1. Maintain present heading if able

2. Check:

• Read from watch, to map, to ground• Last positive fix and heading• DG and compass are aligned• Variation and 1 in 60 have been applied correctly• Tracks on map and flight plan correlate


Lost Procedure3. Climb to a higher altitude if able4. Conduct a square search pattern

1. Maintain present heading for 1 minute2. Turn 90⁰ and maintain the new heading for 1 minute3. Turn 90⁰ and maintain the new

heading for 2 minutes4. Turn 90⁰ and maintain the new

heading for 2 minutes5. Turn 90⁰ and maintain the new

heading for 3 minutes6. Continue applying technique

until position is determined


Lost Procedure

5. If you have applied the square search pattern and are still unaware of your position:

• Fly reciprocal heading to last positive fix if able• If a ground feature is identified track to it• Configure aircraft for max range• Contact centre and request assistance• Perform a PSL


DiversionsThere are a number of reason for a diversion including:

• Weather • Aircraft serviceability• Avoid controlled airspace• Avoid restricted/danger areas• Terrain clearance• Passenger requirements• Low fuel• Last light• Operational considerations

A number of these can be avoided by thorough pre-flight planning


Diversion Procedure

1. Find a positive fix and record the time2. Estimate heading required to diversion destination, fly

estimated heading3. Draw track on map, check for controlled or restricted airspace4. Measure track (remember variation) and distance, fly

measured track5. Apply wind to track to find required heading, fly the accurate

heading6. Choose 1 in 60 point7. Determine ETA, amend SAR time and flight plan as required8. Record all details on flight plan and flight log


Diversion ProcedureFor example we are on a flight from Alawoona to Karoonda, the weather is starting to deteriorate so we decide to divert to Murray Bridge.

1. Find a positive fix and record the time2. Estimate heading required to diversion destination, fly estimated heading3. Draw track on map, check for controlled or restricted airspace

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Diversion Procedure4. Measure track and distance, fly measured track5. Apply wind to track to find required heading, fly the accurate heading6. Chose 1 in 60 point7. Determine ETA, amend SAR time and flight plan as required8. Record all details on flight plan and flight log

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Maximum range is achieved when we can fly for the maximum distance from the available fuel.

Can be used when we are lost or when we are wanting to avoid intermediate stops for refuelling.

Maximum endurance is achieved when we can remain airborne for the maximum time from the available fuel.

Can be used when we need to hold before landing due weather or other reasons.

Consult you POH for recommended power settings for range and endurance.

This subject is covered in further detail in the Aircraft Operation , Performance and Planning CPL subject.

Flight for Maximum Range and Endurance


Questions?

Aim To introduce the concepts and procedures used for visual navigation.

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Transcript of Aim To introduce the concepts and procedures used for visual navigation.