1. Property of Lear Siegler

2. 0°
WIND EFFECT
VARIATION
DEVIATION
Property of Lear Sielger

3. Terminal Learning Objective
At the completion of this lesson the student will:
Action: Acting as a pilot, plan a flight
Condition: Given a VFR flight mission, required equipment, charts and publications
Standard: In Accordance With (IAW) Army Regulation (AR) 95-1, Federal Aviation Regulation (FAR) Part 91, and Field Manual (FM)
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4. Enabling Learning Objective (ELO) #1
Action: Solve for drift corrections necessary to maintain the true course
Condition: Given a True Course
Standard: IAW FM 1-240
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5. The proposed flight path measured clockwise from true north.
TRUE COURSE
The proposed flight path measured
clockwise from true north.
True North
(Meridian)
clockwise to
flight path
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6. The correction applied to prevent
DRIFT CORRECTION
wind 270°
The correction applied to prevent
drifting off course.
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7. Property of Lear Siegler
DRIFT CORRECTION
NOT APPLIED
wind 270°
Headwind = No Drift
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8. Left Crosswind = Right Drift
DRIFT CORRECTION
NOT APPLIED
Left Crosswind = Right Drift
Actual Flight Path
True Course
wind 270°
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9. Left Crosswind = Right Drift
DRIFT CORRECTION
NOT APPLIED
Left Crosswind = Right Drift
Actual Flight Path
True Course
wind 270°
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10. Right Crosswind = Left Drift
DRIFT CORRECTION
NOT APPLIED
Right Crosswind = Left Drift
Actual Flight Path
wind 270°
True Course
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11. Right Crosswind = Left Drift
DRIFT CORRECTION
NOT APPLIED
Right Crosswind = Left Drift
Actual Flight Path
wind 270°
True Course
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12. Property of Lear Siegler
DRIFT CORRECTION
NOT APPLIED
wind 270°
Tailwind = No Drift
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13. Property of Lear Siegler
LEFT DRIFT CORRECTION
IS SUBTRACTED FROM TC
TC = 360°
DC = 10°
LEFT
TC = 360°
DC = 10° L
360°
- 10°
= 350°
Property of Lear Siegler

14. RIGHT DRIFT CORRECTION
IS ADDED TO TC
TC = 360°
DC = 10°
RIGHT
TC = 360°
DC = 10°R
360°
+ 10°
= 010°
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15. TRUE HEADING The angle measured clockwise from
true north to the nose of the aircraft.
TC +/- DC = TH
WIND 360 TH DC TC
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16. Property of Lear Siegler
Questions?
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17. Enabling Learning Objective (ELO) #2
Action: Identify the effects of wind on an aircraft in flight
Condition: Given situational data
Standard: IAW FM 1-240
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18. TRACK THE ACTUAL FLIGHT PATH OVER THE GROUND,
MEASURED CLOCKWISE FROM TRUE NORTH TN TR
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19. DRIFT ANGLE THE ANGLE BETWEEN TRUE HEADING (TH) AND TRACK (TR)TC TH DC
WIND 360 DA TR
WIND IS MORE THAN PLANNING WINDS, DA > DC
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20. DRIFT ANGLE THE ANGLE BETWEEN TRUE HEADING (TH) AND TRACK (TR)TC TH DC
WIND 360 DA TR
WIND IS LESS THAN PLANNING WINDS, DA < DC
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21. HEADING (TH) AND TRACK (TR) WIND EQUAL TO PLANNING WINDS, DA = DC
DRIFT ANGLE
THE ANGLE BETWEEN TRUE
HEADING (TH) AND TRACK (TR)
WIND 360 TH DC
DA = DC TC
TR = TC
WIND EQUAL TO PLANNING WINDS, DA = DC
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22. TRACK EQUAL TRUE COURSE WHEN: 4. DRIFT CORRECTION IS CORRECT
1. NO WIND CONDITION
2. HEAD WIND CONDITION
3. TAIL WIND CONDITION
4. DRIFT CORRECTION IS CORRECT
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23. Types of Airspeed Indicated Airspeed (IAS) - the airspeed read
directly from the airspeed indicator.
IAS is not affected by wind.
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24. Types of Airspeed Calibrated Airspeed (CAS) - indicated airspeed
corrected for instrument installation error.
CAS is not affected by the wind.
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25. Types of Airspeed True Airspeed (TAS) - calibrated airspeed corrected
for error due to air density (altitude and temperature).
TAS is not affected by the wind.
4000’ PA, 7° C = 96 KTAS
1000’ PA, 13° C = 92 KTAS
90 KIAS
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26. GROUND SPEED Ground Speed - speed of the aircraft over the ground.
GS is TAS +/- wind speed. Used to calculate time
required to fly a certain distance.
TAS 92 KNOTS
AIRMASS MOVEMENT 10 KNOTS
TAS KTS
WIND SPEED KTS
GROUND SPEED = 82 KTS
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27. GROUND SPEED Ground Speed - speed of the aircraft over the ground.
GS is TAS +/- wind speed. Used to calculate time
required to fly a certain distance.
TAS 92 KNOTS
AIRMASS MOVEMENT 10 KNOTS
TAS KTS
WIND SPEED KTS
GROUND SPEED = 102 KTS
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28. GROUND SPEED Headwinds - winds +/- 90° of the aircraft nose reduce
ground speed. TAS minus wind velocity.
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29. GROUND SPEED Tailwinds - winds +/- 90° of the aircraft tail increase
ground speed. TAS plus wind velocity.
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30. Property of Lear Siegler
Questions?
Property of Lear Siegler

31. Enabling Learning Objective (ELO) #3
Action: Complete the wind effect components of the VFR flight log
Condition: Given situational data
Standard: IAW the Student Handout
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32. Transport a passenger from Hanchey AHP
31° 21’ N, 85° 40’ W to Sikes airport
30° 47’ N, 86° 31’ W. The wind is
260° / 20 kts and will require a 9° DC.
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33. Property of Lear SieglerH
1. Draw the true course.
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34. 2. Determine wind direction in relation to the true course.
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35. TAS because of headwind.
TC +/- DC = TH
232° °R = 241° H
WIND 260°
GS will be less than
TAS because of headwind.
3. Complete the wind component
part of the VFR flight log.
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36. Fly from Skelly AHP, 31° 18’ N, 86° 07’ W
to Crenshaw Memorial, 31° 51’ N, 86° 36’ W.
The wind is and the DC is 12
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37. Property of Lear Siegler
Questions?
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38. Enabling Learning Objective (ELO) #4
Action: Select the definition of magnetic variation, agonic and isogonic lines and their application
Condition: Given situational data
Standard: IAW Fm and the Student Handout
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39. The angular difference between
VARIATION
The angular difference between
true north (TN) and magnetic north (MN). TN MN
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40. The angular difference between
VARIATION
The angular difference between
true north (TN) and magnetic north (MN). TN MN
NOTE :
Magnetic north is moving,
therefore magnetic variation
changes from one chart
edition to another.
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41. AGONIC AND ISOGONIC LINES
0° 30’ W
1° W
1° 30’ W
AGONIC AND ISOGONIC LINES
Represented on sectional charts as
dashed magenta lines, numbered and
lettered, e.g. 1° W, in 1/2° (30’) increments.
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42. 0° AGONIC LINE A line connecting points of zero degree variation.
There is only one agonic line in the United States.
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43. 0° 30’ W 1° W 1° 30’ W ISOGONIC LINES
Lines connecting points of equal magnetic variation.
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44. Compass needle points east of TN and is subtracted. “EAST IS LEAST”
EASTERLY VARIATION
Compass needle points east of TN
and is subtracted. “EAST IS LEAST” TN MN
Property of Lear Siegler

45. TH = 360°, compass is pointing 10° east
of TN. Must subtract 10° in order to fly to TN.
TC +/- DC = TH +/- VAR = MH
360° + 0° = 360° - 10° = 350°
This example assumes a calm wind. TN MN
Property of Lear Siegler

46. MH = 350°, compass is pointing 10° east
of TN. Subtracted 10° in order to fly to TN. TN MN
Property of Lear Siegler

47. Compass needle points west of TN and is added. “WEST IS BEST”
WESTERLY VARIATION
Compass needle points west of TN
and is added. “WEST IS BEST” MN TN
Property of Lear Siegler

48. TH = 360°, compass is pointing 10° west
of TN. Must add 10° in order to fly to TN.
TC +/- DC = TH +/- VAR = MH
360° + 0° = 360° + 10° = 010°
This example assumes a calm wind. MN TN
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49. MH = 010°, compass is pointing 10° west
of TN. Added 10° in order to fly to TN. MN TN
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50. 0° 30’ W 1° W 1° 30’ W APPLYING VARIATION
Find mid-point of TC, apply nearest
whole degree of variation. A B
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51. 1° 30’ E 1° E 0° 30’ E 1. Find mid-point of course leg.B
1° 30’ E
1° E
0° 30’ E
1. Find mid-point of course leg.
2. Find nearest WHOLE
degree of variation. A
3. TC +/- DC = TH +/- VAR = MH
320° + 0° = 320° - 1° = 319°
EAST IS LEAST
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52. 0° 30’ W 1° W 1° 30’ W 1. Find mid-point of course leg.
2. Find nearest WHOLE degree of variation.
3. TC +/- DC = TH +/- VAR = MH
090° + 0° = 090° +1° = 091°
WEST IS BEST A B
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53. Now that you know how to figure out MH, the next
MAGNETIC HEADING
Now that you know how to figure out MH, the next
question is “What is it ?”
Magnetic Heading is measured from magnetic
north clockwise to the nose of the aircraft. MN MH
VAR
Property of Lear Seigler

54. Property of Lear Siegler
Questions?
Property of Lear Siegler

55. Enabling Learning Objective (ELO) #5
Action: Select the definition of deviation, use of the compass deviation card and completing VFR flight log
Condition: Given situational data
Standard: IAW Fm and the Student Handout
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56. Compass error caused by external magnetic
DEVIATION
Compass error caused by external magnetic
fields such as generators, radios, etc., causing
the compass needle to deviate from magnetic north.
Property of Lear Seigler

57. Compass error caused by external magnetic
DEVIATION
Compass error caused by external magnetic
fields such as generators, radios, etc., causing
the compass needle to deviate from magnetic north. MN N 3 33
No deviation,
Compass Heading (CH) =
Magnetic Heading (MH)
Property of Lear Seigler

58. Compass error caused by external magnetic
DEVIATION
Compass error caused by external magnetic
fields such as generators, radios, etc., causing
the compass needle to deviate from magnetic north. MN N 33
Deviation due to magnetic field caused by radio.
Compass Heading (CH)
no longer equals
Magnetic Heading (MH)
Property of Lear Seigler

59. DETERMINE AND APPLY DEVIATION
1. Determine MH, e.g. 010°.
2. Find number closest to
MH in the “to fly” column.
3. Find corresponding CH in
the “steer” column.
4. Apply difference (2°) to MH.
? Is difference + or - ?
TC +/- DC = TH +/- VAR = MH +/- DEV = CH
010° + 0° = 010° + 0° = 010° + 2° = 012°

60. Plan a flight from Lowe AHP 31° 21’ N, 85° 45’W to Brewton airport
winds 270°/15kts. DC is 9 degrees.
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61. SOLUTION
1. Draw course line and
measure TC. TC
256°

62. SOLUTION
1. Draw course line and
measure TC.
2. DC: 9°R or L.
TC +/- DC
256° + 9°

63. SOLUTION
1. Draw course line and
measure TC.
2. DC: 9°R.
3. Compute TH.
TC +/- DC = TH
256° + 9° = 265°

64. SOLUTION
1. Draw course line and
measure TC.
2. DC: 9°R.
3. Compute TH.
4. Add/subtract VAR.
TC +/- DC = TH +/- VAR
256° + 9° = 265° + 2°

65. SOLUTION
1. Draw course line and
measure TC.
2. DC: 9°R.
3. Compute TH.
4. Add/subtract VAR.
5. Compute MH.
TC +/- DC = TH +/- VAR = MH
256° + 9° = 265° + 2° = 267°

66. SOLUTION
1. Draw course line and
measure TC.
2. DC: 9°R.
3. Compute TH.
4. Add/subtract VAR.
5. Compute MH.
6. Add/subtract DEV.
TC +/- DC = TH +/- VAR = MH +/- DEV
256° + 9° = 265° + 2° = 267° + 2°

67. SOLUTION
1. Draw course line and
measure TC.
2. DC: 9°R.
3. Compute TH.
4. Add/subtract VAR.
5. Compute MH.
6. Add/subtract DEV.
7. Compute CH.
TC +/- DC = TH +/- VAR = MH +/- DEV = CH
256° + 9° = 265° + 2° = 267° + 2° = 269°

68. For light background reading:
FM , Chapter 1, Paragraph 1-35 through and Chapter 6, paragraph 6-1 through 6-7

69. Property of Lear Siegler
Questions?
End of Day 4
Property of Lear Siegler

70. Property of Lear Siegler