Mass and Balance

Question 1

What does Basic Empty Mass not include?

Answer 1

Pilots and crew
Payload
Ballast
Usable fuel

Question 2

How does Empty Mass differ from Basic Empty Mass?

Answer 2

BEM includes full oil rather than undrainable oil

Question 3

BEM + items necessary for flight =

Answer 3

Operating Mass

Question 4

What fuel does Zero Fuel Mass include?

Answer 4

Unusable fuel

Question 5

What kind of mass is always greatest? Structural or performance?

Answer 5

Structural

Question 6

The lower of a maximum structural mass and performance-limited mass is called the…

Answer 6

Regulated mass

Question 7

Fuel gravity

Answer 7

0.72 Avgas

Question 8

Oil gravity

Answer 8

0.96 synthetic and 0.90 mineral

Question 9

1 USG equals how many pounds?

Answer 9

6lb

Question 10

Turning moment of a force depends on?

Answer 10

Size of the force
Moment arm (length)

Question 11

Turning moment equation

Answer 11

Force x Distance

Question 12

How is an Index Unit composed?

Answer 12

Mass.length (Pound.Inch)

Question 13

Is the Index Unit a mathematical unit?

Answer 13

No, it is a convenient figure

Question 14

1 Index Unit equals

Answer 14

1000 kg.mm

Question 15

The lift force of a tailplane depends upon its…?

Answer 15

Airspeed

Question 16

Forward CG affects stability how?

Answer 16

Stability is greater as tailplane has long moment arm

Question 17

Aft CG affects stability how?

Answer 17

Stability is less as tailplane has shorter moment arm

Question 18

Why are fuel tanks often designed to be near the CG?

Answer 18

As fuel is burnt, change in CG is kept to a minimum

Question 19

Normal category involves what max degree of bank?

Answer 19

60 degrees

Question 20

Utility category involves what range of bank degrees?

Answer 20

60 to 90 degrees

Question 21

What manouevre does utility category include that normal category doesn’t?

Answer 21

Spins

Question 22

What is the datum?

Answer 22

The point from which all items are measured

Question 23

When is the ‘+’ used for moment arms?

Answer 23

When mass is aft of the datum

Question 24

When is the ‘-‘ used for moment arms?

Answer 24

When mass is forward of the datum

Question 25

What elevator force is insufficient if CG is too far forward?

Answer 25

Nose-up force

Question 26

What elevator force is insufficient if CG is too far aft?

Answer 26

Nose-down force

Question 27

Longitudinal stability is reduced = very
sensitive to pitch control occurs when?

Answer 27

CG is too far aft

Question 28

How does CG movement affect glide range?

Answer 28

CG too far aft reduces glide range

Question 29

How does CG movement affect the flare?`

Answer 29

CG too far forward will mean not enough elevator nose-up force to flare

Question 30

Why does drag generally increase if CG is too far forward?

Answer 30

A large balancing download is required
from the tailplane, requiring large
elevators deflections increasing DRAG

Question 31

How is longitudinal stability affected if CG is too far forward?

Answer 31

Longitudinal stability increases

Question 32

How is stick force affected if CG is too far forward?

Answer 32

Slow to respond to stick inputs hence an
increase in stick force is required