n Wind Drift

Introductory Statement n one must be able to accurately compute a High Altitude Release Point (HARP) to successfully land into a selected areas using High Altitude, Low Opening (HALO) or a High Altitude High Opening (HAHO) techniques.

Terminal Learning Objective n Given actual or forecasted wind directions, velocities, and a Desired Impact Point (DIP), Compute and Plot a High Altitude Release Point (HARP) for a High Altitude, Low Opening (HALO) and High Altitude, High Opening (HAHO)

First Enabling Objective: n Given wind directions, velocities and a Desired Impact Point (DIP), Compute a HARP for a Free-Fall.

Jumpmaster considerations n Prevailing or forecasted wind data. n Terrain. n Aircraft routes.

Requirements for Wind drift Computations n Obtain Wind Data. n Analyze Wind Data. n Separate the data. n Compute numerical values. n Apply formula. n Convert. n Plot.

Obtain Wind data n Weather information is also available through the National Weather Service located at large International Airports. n Should be used within a 100 NM radius of your DIP. n Wind direction is given in TRUE degrees. n Wind direction is direction winds are coming from. n Wind speed is given in KNOTS.

Obtain Wind data con’t n If Winds are forecasted wind, use only 50% to 75% of provided data. n Use a satellite over-flight, Scout airplane or a Ground unit to ensure accurate weather.

Obtain Wind data con’t n For HALO operations, wind readings (direction and velocity) are recorded every: – 1,000’ for canopy drift. – 2,000’ for Free-Fall Drift.

Obtain Wind data con’t n The forward throw distance used for a HALO is: – 300 meters for a fixed wing aircraft with exit speeds above 120 knots. – 150 meters for aircraft with exits speeds below 120 knots.

Analyze Wind data n Analyze the wind data for: –Time and location of wind data. –Dog legs. –Erroneous winds. –Incompatible winds.

Separate the data n Separate the wind data: –Draw a line between the surface and 1,000’ –Draw a line between 4,000’ and 6,000’ (canopy drift).

Wind drift problem #1 HALO AltDirVel FFD average dir = ____  ____ = ____ T/G vel = ____  ____ = ____ kts vel = ____  ____ = ____ kts CD average dir = ____  ____ = ____T/G CD average dir = ____  ____ = ____T/G vel = ____  ____ = ____kts vel = ____  ____ = ____kts Sur235 8

Compute the Numerical Values

Compute the numerical values n Average wind direction: –total the azimuth and divide by the number of reading used. n Average wind velocity: –total the wind velocities and divide by the number of reading used.

Compute the numerical values n Round up or down for HALO. –.0 to.4 Round down –.5 to.9 Round up n NOTE: Round up or Down for direction and velocity only, NOT FOR DISTANCE

Wind drift problem #1 HALO AltDirVel FFD average dir = ____  ____ = ____ T vel = ____  ____ = ____ kts vel = ____  ____ = ____ kts CD average dir = ____  ____ = ____T CD average dir = ____  ____ = ____T vel = ____  ____ = ____kts vel = ____  ____ = ____kts Sur235 8

Wind drift problem #1 HALO AltDirVel FFD average dir = 1195  4 =298.7/ vel = 55  4 = 13.7/14 kts vel = 55  4 = 13.7/14 kts CD average dir = 1000  4 = 250 degs T CD average dir = 1000  4 = 250 degs T vel = 28  4 = 7 kts vel = 28  4 = 7 kts Sur235 8

Apply the Formula n The formula used to determine the Free-Fall and Canopy drift is: D = K A V

Apply the formula Con’t n D = Distance (in meters of drift). n K = Constant n 25 for Canopy drift n 3 for Free - Fall drift. n A = Altitude in thousands of feet. n V = Velocity (average wind speed in knots).

Apply the formula Con’t n To determine the distance (in meters) for canopy drift: –K x A x V = ____ –25 x 4 x 7 = degs T n To determine the distance (in meters) for Free-Fall drift: –K x A x V = ____ –3 x 8 x 14 = degs T

Wind drift problem #1 HALO AltDirVel FFD average dir = 1195  4 =298.7/ vel = 55  4 = 13.7/14 kts vel = 55  4 = 13.7/14 kts CD average dir = 1000  4 = 250 degs T CD average dir = 1000  4 = 250 degs T vel = 28  4 = 7 kts vel = 28  4 = 7 kts Sur235 8

Second Enabling Objective n Given the average wind directions, velocities, and a DIP, COMPUTE and PLOT a HARP (within meters) for a Free-Fall

Convert n Update the GM angle (G / T / M). –Grid to magnetic n Correctly plot the DIP. n Convert heading, ACCORDINGLY. n Plot from the DIP and work upwards towards the aircraft. n Zero on the protractor is pointing north.

Plotting the HARP Con’t n Center the protractor on the DIP. n Locate and mark the computed azimuth. n Draw a reference line from the DIP along the azimuth mark. n Measure the canopy drift distance on the azimuth line from the DIP. n The OP is at the end of the measured distance.

DIP 249 degs G Opening Point Plotting the Opening point

Plotting the HARP Con’t n Plot the Free-Fall drift. n Place the protractor on the OP. n Mark the desired azimuth. n Draw a line from the OP to the mark. n Measure the Free-Fall drift distance on the azimuth line from the OP. n This is the Preliminary Release Point (PRP).

DIP OP Plotting the Preliminary Release Point 298 degs G PRP

Plotting the HARP Con’t n To plot the HARP. n Center the protractor on the PRP. n Mark the back azimuth of the A/C track. n Measure three hundred (300) meters from the PRP along the back azimuth of the A/C track. n This is the HALO HARP.

DIP OP Plotting the High Altitude Release Point PRP 015 degs G HARP A/C track 195 degs G

Fourth Enabling Objective n Given wind directions, velocities and a Desired Impact Point (DIP), Compute and Plot a High Altitude Release Point (HARP) Dog Leg for a free fall.

Erroneous n Erroneous winds are defined as one ninety (90) degree change in a single altitude. (Erroneous winds will be disregarded for computation)

AltDirVel Sur25010 HALO Erroneous Winds

DOG LEG n Dog Legs are wind phenomena which can occur in HALO and HAHO operations. n A dog leg is a situation when the wind directions changes ninety (90) degrees or more for any two consecutive direction readings.

Dog Legs con’t n Two or more ninety (90) degree changes will require a separate computation and plot for the recorded wind data at a given altitude. n With a Dog Leg computation, a separate plot is required for each computation.

HALO Dog Leg AltDirVel Sur25010

DIP OP Plotting the High Altitude Release Point “Dog Leg” PRP 015 degs G HARP A/C track 195 degs G Canopy Dog Leg

DIP OP Plotting the High Altitude Release Point “Dog Leg” PRP 015 degs G HARP A/C track 195 degs G Free-Fall Dog Leg

Fifth Enabling Objective n Given wind directions, velocities, and a DIP, Compute and average incompatible wind direction data for a free fall.

Incompatible Winds con’t n Winds out of the North. n Determine and identify incompatible winds. n Add 360 to each incompatible wind direction record. n Average the wind data. n If the average is greater then 360, subtract 360 to get the correct direction.

360 degs N E 090 degs 270 degs W Winds Add 360

Incompatible Wind Range Fan 315 degs degs Add

Incompatible Winds #1 AltDirVel Sur06510

Incompatible Winds #2 AltDirVel Sur06510

Incompatible Winds #3 AltDirVel Sur06510

Incompatible Winds #4 AltDirVel Sur13010

Third Enabling Objective n Given wind directions, velocities and a Desired Impact Point (DIP), COMPUTE and PLOT a High Altitude Release Point (HARP) (within 500 meters) for a HAHO

HAHO Wind Drift n HAHO HARP computations are divided into four steps: –Record the average wind data. –Compute the Mean Average wind direction, speed and maximum distance. –Plot the Mean average wind Line and max.... distance (PRP). –Calculate the Jumper’s magnetic heading.

Record the wind data n Directions, velocities are recorded every 1,000’ from surface to 10,000’ AGL. n Wind data above 10,000’ is recorded every 2,000’ to A/C exit altitude. n If using civilian weather information the wind data is given every 3,000’. This will work but will not be as accurate.

Compute direction, speed and distance n The following HAHO formula is used to determine the distance a ram-air parachute will glide from a given altitude. n D = (A - SF) ( V) K

Compute direction, speed and distance con’t n D = The distance in Nautical Miles (NM) a ram-air parachute will glide (drift) from the PRP to the DIP. n This is the unknown which the Jumpmaster and/or A/C Navigator will determine through the use of this formula.

Compute direction, speed and distance con’t n A = The altitude in thousands of feet AGL at which the parachutist will exit the aircraft. n SF = Safety factor is a minimum value of two (2), but can be increased for team’s experience level.

Compute direction, speed and distance con’t n 20.8 = Is the maximum speed in knots of a RAPS parachute.

Compute direction, speed and distance con’t n V = The average wind velocity from 1,000’ AGL to the exit or deployment altitude AGL. n K = The constant or K-Factor for the three types and sizes of RAPS parachute was determined by testing and computer analysis of the glide and descent rates.

Compute direction, speed and distance con’t n The values for the K-factor are as follows: –K-48 = Large high glide RAPS (MT1-X, MC-4, MC-5). –K-60 = Medium glide RAPS (MT1-S, Unit III). –K-66 = Small low-glide RAPS (MT-1, PD230)

Compute direction, speed and distance con’t n Note: Jumpmaster always use the K-factor or Constant for the lowest performance parachutes to be used on that airborne operation. Should one have and accompanying bundle on the mission, the HARP should be computed for the bundle canopy or personnel canopies which ever has a larger K-factor.

Compute direction, speed and distance con’t n Average wind direction: –Total the wind directions and divide by the number of readings used. –Convert from True to Grid. n Average wind velocity: –Total the wind velocities and divide by the number of readings used.

Compute the numerical values n Round up or down for HAHO. –.0 to.4 Round down –.5 to.9 Round up n Only move one (1) decimal point (5.4) for distance and do not round up/down. n NOTE: Round up or Down for direction and velocity only, NOT FOR DISTANCE

Wind drift problem #1. (HAHO) AltDirVel average dir = ____  ____ = ____ degs T vel = ____  ____ = ____ kts vel = ____  ____ = ____ kts

Wind drift problem #1. (HAHO) AltDirVel average dir = 445  11 = 040 degs T vel = 174  11 = 16 kts vel = 174  11 = 16 kts convert True to Grid convert True to Grid = 039 degs Grid = 039 degs Grid

Compute direction, speed and distance con’t n The distance of the HAHO wind drift formula will be in Nautical Miles (NM) and may be converted to Kilometers (KM). n To convert NMs to KMs, multiply the NMs by 1.85 to get KMs. n 4.3 NMs X 1.85 = 7.9 KMs. n Pilots and Navigators use NM’s.

Compute the DKAV n n D = (A - SF) ( Vel) K n n D = (12 - 2) ( ) 48 n n D = (10) (36.8) 48

Compute the DKAV n  n D = 368  48 = 7.6 NMs n n 7.6 NMs x 1.85 = 14.0 KMs

Plotting the PRP n To Plot the PRP on the map: –Convert the average wind direction from True to Grid. –From the DIP, using the protractor mark and draw a line in the direction calculated. –Mark off the calculated distance, this your PRP.

DIP winds 039 degs g 16 kts PRP 7.6 NM 14 KM Plotting the PRP

Plotting the HARP n The Forward Throw (FT) is 300 meters back into the A/C track plus the Jumper Dispersion (JD). n Jumper dispersion is half (1/2) the jumpers, multiplied by 50 meters. –12  2 = 6 x 50 = 300 meters (JD) meters (FT) = 600 meters.

Plotting the HARP n From the PRP : –Plot the sum of the forward throw and the jumper dispersion back into the direction of flight. n Same as HALO except with adding the Jumper dispersion.

DIP winds 039 degs g 16 kts Plotting the HARP PRP HAR P A/C track

Calculate Magnetic heading n It is vital the the magnetic heading from the PRP to the DIP be computed and dispersed to the entire HAHO Team along with the following additional information:

Calculate Magnetic heading n Average wind direction and velocity. n Aircraft Track. n High Altitude Release Point (HARP) n PRP and distance traveled. n Magnetic Heading to the DIP. n Desired Impact Point (DIP).

Calculate Magnetic heading n Draw a line from the PRP to the DIP, mark the bearing and convert accordingly.

DIP winds 039 degs 16 kts = 219 degs G = 208 degs M Plotting the Magnetic Compass Heading HAR P A/C track PRP Compass heading 208 degs Mag.

Wind drift problem #1. (HAHO) AltDirVel average dir = 445  11 = 040 degs T vel = 174  11 = 16 kts vel = 174  11 = 16 kts Convert True to Grid Convert True to Grid = 039 degs Grid = 039 degs Grid Compass Heading ? Compass Heading ?

Wind drift problem #1. (HAHO) AltDirVel average dir = 445  11 = 040 degs T vel = 174  11 = 16 kts vel = 174  11 = 16 kts Convert True to Grid Convert True to Grid = 039 degs Grid = 039 degs Grid Compass Heading: Compass Heading: = = 208 degs M = = 208 degs M

Wind Drift Problem #2 HAHO AltitudeDirectionVelocity 20, True30 Knots 18, , , , , , , , , , , , , , Surface190 5

Wind Drift Problem #3 AltitudeDirectionVelocity 12, True30 Knots 10, , , , , , , , , , Surface295 5

Fourth Enabling Objective con’t n Given wind directions, velocities and a Desired Impact Point (DIP), Compute and Plot a High Altitude Release Point (HARP) Dog Leg for a free fall.

DOG LEGS n Dog Legs are wind phenomena which can occur in HALO and HAHO operations. n A dog leg is a situation when the wind directions changes ninety (90) degrees or more for any two consecutive direction readings.

Dog Legs con’t n Two or more ninety (90) degree changes will require a separate computation and plot for the recorded wind data at a given altitude. n With a Dog Leg computation, a separate plot is required for each computation. n Use 1/2 of SF for each Dog Leg. n If more than two(2) Dog Legs, use 1/2 SF for the 1st two legs and no SF for additional legs.

HAHO Dog Leg AltDirVel Sur210 8

HAHO Dog Leg AltDirVel Sur210 8

Calculate Dog Leg Magnetic heading n Average the two (or more) leg(s) by drawing a line from the PRP to your DIP and mark your heading and convert accordingly. n Your jumpers will follow a curved path and not a straight path. They will still remain on the compass heading which you plotted.

DIP 1st Dog Leg C-PRP 2nd Dog Leg HARP A/C track Dog Leg Compass Heading Course Over Ground

Erroneous Winds n Erroneous winds are defined as one ninety (90) degree change in a single altitude. (Erroneous winds will be disregarded for computation)

Fifth Enabling Objective n Given wind directions, velocities, and a DIP, Compute and average incompatible wind direction data for a HAHO HARP.

Incompatible Winds con’t n Winds out of the North. n Determine and identify incompatible winds. n Add 360 to each incompatible wind direction record. n Average the wind data. n If the average is greater then 360, subtract 360 to get the correct direction.

Incompatible Winds HAHO AltDirVel Sur06510

Select the Release Cone n The Release Cone is a given distance that a canopy will travel from a certain altitude without the help of winds. n The MC-4/MC-5 RAPS will travel 4.3 NMs/7.9 KMs from 12,000’ with a SF of two (2).

Select the Release Cone n The formula to determine the Release Cone radius is: n Release Cone distance = (A - SF) (20.8) K n RC = (12 - 2) x (20.8) 48

Select the Release Cone n Here are some examples of some RC’s: –10,000’ = 3.4 NM / 6.4 km –12,000’ = 4.3 NM / 7.9 km –15,000’ = 5.6 NM / 10.3 km –18,000’ = 6.9 NM / 12.7 km –21,000’ = 8.2 NM / 15.1 km –24,000’ = 9.5 NM / 17.5 km

Plot the Release Cone n Calculate and plot the Mean average wind direction and distance (PRP). n From the PRP, come back along the mean average wind line the RC distance-radius and make a mark. n From that mark draw the RC.

Average winds 16 kts. Dist. = 7.6 nm / 14 km (PRP) RC distance = 4.3 NMs PRP HAR P A/C track Release Cone Release cone Radius 4.3 nm

Analyze the Release Cone and PRP n Analyze the Release Cone and PRP for obstacles: –Mountains. –Man made obstacles. –Rivers - Lakes. –Air Routes, etc. n Select the most tactical PRP within the RC and this will be your Selected adjusted PRP.

Summary Statement n The objective of this block of instruction was to enable you to CALCULATE, COMPUTE and PLOT a HALO and HAHO HARP. n Success and safety must: – have the most current wind data available. – make accurate computations.