Mental Math Shortcuts

Question 1

Mach to Miles Per Minute

Answer 1

.1 Mach equals 1 mile per minute

Question 2

Groundspeed to Miles Per Minute

Answer 2

Groundspeed divided by 60

Question 3

Distance to start Descent

Answer 3

Altitude to lose divided by 1000 times 3

Question 4

Required Descent Rate for 3 degrees

Answer 4

Groundspeed divided by 2 and add a zero to the end

Question 5

Specific Range

Answer 5

TAS/FF, mph/(lb./hr), NM/LB

Question 6

Specific Endurance

Answer 6

Flight Time/FF in lb./hr

Question 7

Specific Fuel Consumption

Answer 7

FF/Thrust (in lb./hr)

Question 8

Calculate VDP (with DME)

Answer 8

MDA (HAT) divided by 300 is the distance from the runway in miles

Question 9

Calculate VDP (with Time)

Answer 9

MDA (HAT) X 10% = Time before missed approach point

Question 10

Compute Descent Rate on an ILS

Answer 10

Groundspeed X 5 = VSI in feet per minute

Question 11

DME Radial Rule

Answer 11

At 60 DME each radial is 1 mile apart

Question 12

Standard Rate Turn Bank Angle

Answer 12

(TAS/10) X 1.5

Question 13

Turn Radius in Standard Rate Turn

Answer 13

TAS/200

Question 14

True Airspeed from Indicated Airspeed

Answer 14

IAS + (2%IAS X Altitude/1000)

Question 15

Crosswind correction

Answer 15

Xwind/(TAS/60) = degrees of heading correction

Question 16

Pounds to Gallons of fuel

Answer 16

Pounds / 10 times 1.5 = Gallons

Question 17

What are the crosswind components at wind angles of 90, 60, 45, and 30 degrees?

Answer 17

100%, 90%, 70%, 50%

Question 18

1” of Barometric pressure change equals how many feet?

Answer 18

1” = 1000’
Higher than 29.92, subtract correction amount
Lower than 29.92, add correction amount

Question 19

How do you determine ISA temperature at a given altitude?

Answer 19

Double the thousands, subtract 15 and change the sign.

Question 20

How do you calculate an equal time point distance?

Answer 20

(Total Distance X Return GS) / (Continue GS + Return GS)

Question 21

How do you calculate and equal time point Time?

Answer 21

Take ETP Distance / Continue GS = Hours

Question 22

How do you determine the time required for a standard rate turn given amount of degrees required to turn?

Answer 22

Degrees of turn / 3 = time in seconds

Question 23

How can you determine how many degrees off course you are?

Answer 23

(NM Off Course / Distance Flown) = (Degrees Off Course / 60)

Question 24

How do you determine the Distance to a VOR

Answer 24

(TAS X Minutes) / Degrees of Bearing Change

Question 25

How do you determine Minutes to a VOR

Answer 25

(60 X Minutes) / Degrees of Change

Question 26

How do you determine the required rate of descent?

Answer 26

Descent Angle X NM/Min

Question 27

How do you determine climb gradient?

Answer 27

Obstacle Height / NM distance = Ft/NM

Question 28

How do you determine % climb gradient?

Answer 28

Climb Gradient / 60 = % Gradient

Question 29

How do you find the rate of climb required with a gradient?

Answer 29

(TAS/60) X Climb Gradient = Ft/Min

% Gradient X Ground speed = Ft/Min

Question 30

One Minute of Latitude is how many NM?

Answer 30

1 NM

Question 31

How do you determine the bases of clouds?

Answer 31

(Temperature C / Dew point) X 400