CA.I.F Performance and Limitations

Question 1

Describe the composition of the atmosphere.

Answer 1

78% nitrogen
21% oxygen
1% other gasses (helium, argon)

Question 2

What happens to air pressure as altitude increases?

Answer 2

The weight of the atmosphere decreases -1 inch of mercury per 1,000ft of altitude.

Question 3

If you stood outside the airport with a barometer and it shows 29.72, is that your altimeter setting?

Answer 3

No, you would have to ratio it down to sea level pressure.

Question 4

You fly into an area of lower pressure and forget to change to the local altimeter setting. Will you be flying above or below the altitude on your altimeter?

Answer 4

Below
(High to low, look out below)

Question 5

What is Pressure Altitude?

Answer 5

The height above the standard datum plane (SDP).

The elevation is sea level, and the pressure is 29.92

Question 6

What is pressure altitude used for?

Answer 6

Calculating performance (fuel burn, climb rates, true airspeed), and flying in the flight levels.

Question 7

How do you determine Pressure Altitude?

Answer 7

1) Set altimeter to 29.92 read the altitude
2) Subtract current altimeter setting from 29.92
Multiply the result by 1,000
Add the result to the field elevation if it’s positive, or subtract it if it’s negative

Question 8

What affects air density?

Answer 8

Pressure, temperature, humidity

Question 9

How would a higher density altitude contribute to a reduction in performance?

Answer 9

1) Less power, fewer molecules to combust in the engine
2) Less thrust, prop throwing back fewer molecules
3) Less lift, fewer molecules striking the wing

Question 10

How would you define “density altitude”?

Answer 10

Pressure altitude corrected for nonstandard temperature.

The altitude at which the plane feels like it’s flying.

Question 11

When would density altitude and indicated altitude be the same?

Answer 11

When temperature and pressure are standard.

Question 12

As temperature increases, what happens to density altitude?

Answer 12

DA increases

Question 13

How would a high density altitude affect performance during takeoff?

Answer 13

• Increase takeoff roll distance
• Reduced rate of climb
• Higher ground speed, but IAS would be the same

Question 14

How would density altitude affect the landing?

Answer 14

• Longer roll out
• Faster ground speed, but IAS would be the same

Question 15

How does density altitude affect true airspeed for any given indicated airspeed?

Answer 15

Higher the DA, higher the TAS in relation to IAS.

Question 16

As density altitude increases, what happens to IAS at which the plane stalls?

Answer 16

Stays the same. True Airspeed increases.

Question 17

Define Basic Empty Weight (BEW)

Answer 17

Standard empty weight, plus the weight of optional and special equipment installed. Includes full engine oil and hydraulic levels, plus unusable fuel.

*Think of BEW as the plane’s weight before we add bags, fuel, and people.

Question 18

Define Useful Load.

Answer 18

Max gross - BEW = Useful Load
Weight of pilot, passengers, bags, useable fuel and drainable oil.

Question 19

What are the standard weights for 1 gallon of AvGas, JetA, Oil, and Water?

Answer 19

AvGas: 6 lbs
JetA: 6.8 lbs
Oil: 7.5 lbs
Water: 8.3 lbs

Question 20

What are the maximum ramp, takeoff and landing weights in the 172S?

Answer 20

Max Ramp: 2558 lbs
Max TO: 2550 lbs
Max Landing: 2550 lbs

Question 21

Where is the datum located on the C172S?

Answer 21

Lower portion of the front face of the firewall.

Question 22

Define VNE.
What is it in the C172S?

Answer 22

Never Exceed Speed
163 KIAS

Question 23

Define VNO.
What is it in the C172S?

Answer 23

Maximum Structural Cruise Speed. Do not exceed unless in smooth air.
129 KIAS

Question 24

Define VA.
What is it on the C172S?

Answer 24

Design Maneuvering Speed: max speed at which the limit load can be imposed (by gusts or full deflection of the control surfaces) without causing structural damage.
2550lbs - 105 KIAS
2200lbs - 98 KIAS
1900lbs - 90 KIAS

Question 25

Define VFE.
What is it on the C172S?

Answer 25

Maximum Flap Extended Speed
Flaps 10º: 110 KIAS
10º-FULL: 85 KIAS

Question 26

What are some scenarios where you would slow below Va?

Answer 26

• Turbulence/gusty
  conditions.
• Setting up for high load maneuvers such as accelerated stalls.

Question 27

What is the formula for determining VA?

Answer 27

𝑉𝑎 @ 𝑀𝑎𝑥 𝐺𝑟𝑜𝑠𝑠 𝑊𝑒𝑖𝑔ℎ𝑡 X √(𝑌𝑜𝑢𝑟 𝑊𝑒𝑖𝑔ℎ𝑡 / 𝑀𝑎𝑥 𝐺𝑟𝑜𝑠𝑠 𝑊𝑒𝑖𝑔ℎ𝑡).

Question 28

What is the RPM limit for takeoff and continuous operation?

Answer 28

2700RPM

Question 29

What is the maximum number of occupants during a spin flight, and where must they be
seated?

Answer 29

Max 2, and the rear seat must not be occupied.

Question 30

What is the CG range in the C172S?

Answer 30

12 inches.

Question 31

What are your aircraft’s load limits in the Normal and Utility category?

Answer 31

Normal: +3.8 to -1.52.
Utility: +4.4 to -1.76.

Question 32

What is the definition of max demonstrated crosswind?

Answer 32

It is the crosswind
component for which adequate control of the aircraft during takeoff and landing was
actually demonstrated (using average abilities) during certification tests.

Question 33

What are the max demonstrated crosswind for takeoffs and landings?

Answer 33

TO & LDG w/ 0º-10º flaps: 20 kt. LDG w/ flaps FULL: 15 kt.

Question 34

Is it legal to takeoff when the crosswind exceeds Max Demonstrated Crosswind?

Answer 34

Yes, it’s not a limitation.

Question 35

If you had a strong headwind throughout your climb, how would you expect your time, fuel, and distance calculations to change?

Answer 35

Time and fuel should stay about the same, but the
distance would shorten.

Question 36

What exactly does your “total feet to clear 50 foot obstacle” calculation mean?

Answer 36

Starts at the point where you
clear the 50 ft. obstacle, ends where the plane comes to a stop.