Property of Lear Siegler

0° WIND EFFECT VARIATION DEVIATION Property of Lear Sielger

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) 3-04.240 Property of Lear Siegler

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 Property of Lear Siegler

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 Property of Lear Siegler

The correction applied to prevent DRIFT CORRECTION wind 270° The correction applied to prevent drifting off course. Property of Lear Siegler

Property of Lear Siegler DRIFT CORRECTION NOT APPLIED wind 270° Headwind = No Drift Property of Lear Siegler

Left Crosswind = Right Drift DRIFT CORRECTION NOT APPLIED Left Crosswind = Right Drift Actual Flight Path True Course wind 270° Property of Lear Siegler

Left Crosswind = Right Drift DRIFT CORRECTION NOT APPLIED Left Crosswind = Right Drift Actual Flight Path True Course wind 270° Property of Lear Siegler

Right Crosswind = Left Drift DRIFT CORRECTION NOT APPLIED Right Crosswind = Left Drift Actual Flight Path wind 270° True Course Property of Lear Siegler

Right Crosswind = Left Drift DRIFT CORRECTION NOT APPLIED Right Crosswind = Left Drift Actual Flight Path wind 270° True Course Property of Lear Siegler

Property of Lear Siegler DRIFT CORRECTION NOT APPLIED wind 270° Tailwind = No Drift Property of Lear Siegler

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

RIGHT DRIFT CORRECTION IS ADDED TO TC TC = 360° DC = 10° RIGHT TC = 360° DC = 10°R 360° + 10° = 010° Property of Lear Siegler

TRUE HEADING The angle measured clockwise from true north to the nose of the aircraft. TC +/- DC = TH WIND 360 TH DC TC Property of Lear Siegler

Property of Lear Siegler Questions? Property of Lear Siegler

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 Property of Lear Siegler

TRACK THE ACTUAL FLIGHT PATH OVER THE GROUND, MEASURED CLOCKWISE FROM TRUE NORTH TN TR Property of Lear Siegler

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 Property of Lear Siegler

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 Property of Lear Siegler

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 Property of Lear Siegler

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 Property of Lear Siegler

Types of Airspeed Indicated Airspeed (IAS) - the airspeed read directly from the airspeed indicator. IAS is not affected by wind. Property of Lear Siegler

Types of Airspeed Calibrated Airspeed (CAS) - indicated airspeed corrected for instrument installation error. CAS is not affected by the wind. Property of Lear Siegler

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 Property of Lear Siegler

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 92 KTS WIND SPEED - 10 KTS GROUND SPEED = 82 KTS Property of Lear Siegler

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 92 KTS WIND SPEED + 10 KTS GROUND SPEED = 102 KTS Property of Lear Siegler

GROUND SPEED Headwinds - winds +/- 90° of the aircraft nose reduce ground speed. TAS minus wind velocity. Property of Lear Siegler

GROUND SPEED Tailwinds - winds +/- 90° of the aircraft tail increase ground speed. TAS plus wind velocity. Property of Lear Siegler

Property of Lear Siegler Questions? Property of Lear Siegler

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 Property of Lear Siegler

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. Property of Lear Siegler

Property of Lear Siegler H 1. Draw the true course. Property of Lear Siegler

2. Determine wind direction in relation to the true course. Property of Lear Siegler

TAS because of headwind. TC +/- DC = TH 232° + 9°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. Property of Lear Siegler

Fly from Skelly AHP, 31° 18’ N, 86° 07’ W to Crenshaw Memorial, 31° 51’ N, 86° 36’ W. The wind is 20015 and the DC is 12 Property of Lear Siegler

Property of Lear Siegler Questions? Property of Lear Siegler

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 1-240 and the Student Handout Property of Lear Siegler

The angular difference between VARIATION The angular difference between true north (TN) and magnetic north (MN). TN MN Property of Lear Seigler

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. Property of Lear Seigler

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. Property of Lear Siegler

0° AGONIC LINE A line connecting points of zero degree variation. There is only one agonic line in the United States. Property of Lear Siegler

0° 30’ W 1° W 1° 30’ W ISOGONIC LINES Lines connecting points of equal magnetic variation. Property of Lear Siegler

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

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

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

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

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 Property of Lear Siegler

MH = 010°, compass is pointing 10° west of TN. Added 10° in order to fly to TN. MN TN Property of Lear Siegler

0° 30’ W 1° W 1° 30’ W APPLYING VARIATION Find mid-point of TC, apply nearest whole degree of variation. A B Property of Lear Siegler

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 Property of Lear Siegler

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 Property of Lear Siegler

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

Property of Lear Siegler Questions? Property of Lear Siegler

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 1-240 and the Student Handout Property of Lear Siegler

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

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

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

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°

Plan a flight from Lowe AHP 31° 21’ N, 85° 45’W to Brewton airport winds 270°/15kts. DC is 9 degrees. Property of Lear Siegler

SOLUTION 1. Draw course line and measure TC. TC 256°

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

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

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°

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°

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°

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°

For light background reading: FM 3-04.240, Chapter 1, Paragraph 1-35 through 1-41 and Chapter 6, paragraph 6-1 through 6-7

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

Property of Lear Siegler