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► Complete line 1 of the flight navigation log; Positions "A" to "B". What is the HDG° (M) and ETA?
Given:
TIME - 1015
COURSE/TRACK T - 270
W/V - 050/40
HDG (T) - ?
VAR - 7E
HDG (M) - ?
CAS/MACH - 210
FL - 180
OAT - -20°C
TAS - ?
GS - ?
DISTANCE - 300
TIME - ?
ETA - ?
Step 1) Find the TAS
On your navigation computer align the OAT with the pressure altitude (-20°C against 18 000ft in our case)
Look up CAS (210) on the inner scale and find TAS (278kts) on outer scale
(If a Mach number was given, you'll only need the OAT, place this under the Mach Number index , read mach number on inner scale and find TAS on the outer scale)
Step 2) Find Groundspeed and drift
On the wind side of your navigation computer put the track/course on top (270°) and set the wind so it comes from 50°.
Slide the scale up/down so that the windspeed 40kts intersects with the TAS line of 278kts.
At that point of intersection look at the vertical lines to find your drift (5° LEFT) and groundspeed is shown inside the circle (310kts)
Step 3) True and magnetic heading
True course + 5° DRIFT LEFT (drift left = wind and heading to the right) = 275° TH
275° True heading - 7° VAR = 268° MH
Step 4) Find time
Distance (300) / Speed (310kts) = 59 minutes
Start time was 10:15 so ETA will be 11:14
Given:
TIME - 1015
COURSE/TRACK T - 270
W/V - 050/40
HDG (T) - ?
VAR - 7E
HDG (M) - ?
CAS/MACH - 210
FL - 180
OAT - -20°C
TAS - ?
GS - ?
DISTANCE - 300
TIME - ?
ETA - ?
Step 1) Find the TAS
On your navigation computer align the OAT with the pressure altitude (-20°C against 18 000ft in our case)
Look up CAS (210) on the inner scale and find TAS (278kts) on outer scale
(If a Mach number was given, you'll only need the OAT, place this under the Mach Number index , read mach number on inner scale and find TAS on the outer scale)
Step 2) Find Groundspeed and drift
On the wind side of your navigation computer put the track/course on top (270°) and set the wind so it comes from 50°.
Slide the scale up/down so that the windspeed 40kts intersects with the TAS line of 278kts.
At that point of intersection look at the vertical lines to find your drift (5° LEFT) and groundspeed is shown inside the circle (310kts)
Step 3) True and magnetic heading
True course + 5° DRIFT LEFT (drift left = wind and heading to the right) = 275° TH
275° True heading - 7° VAR = 268° MH
Step 4) Find time
Distance (300) / Speed (310kts) = 59 minutes
Start time was 10:15 so ETA will be 11:14
