Meterological Aspect Of Altimeters

Question 1

What does the rule ‘FROM HIGH TO LOW, LOOK OUT BELOW’ refer to?

Answer 1

The altimeter indicates high when flying from high pressure areas to low pressure areas without re-setting it.

This rule helps pilots remember to check for altitude discrepancies when transitioning between pressure zones.

Question 2

What does the rule ‘FROM WARM TO COLD, YOU’RE BEING BOLD’ imply?

Answer 2

The altimeter indicates high when flying from warm temperature areas to cold temperature areas without re-setting it.

This rule indicates that altitude readings may be misleading in temperature transitions.

Question 3

What happens to the altimeter when flying from cold temperatures to high temperatures?

Answer 3

The altimeter will yield an under-reading.

This can lead to unsafe flying conditions if not properly adjusted.

Question 4

What is pressure altitude?

Answer 4

The equivalent altitude in the standard atmosphere for a given pressure.

Pressure altitude is crucial for flight operations and performance calculations.

Question 5

How do you calculate pressure altitude?

Answer 5

Take the local altimeter setting, calculate the difference from 29.92” Hg, convert to feet, and add to airport elevation if the altimeter setting is lower than 29.92.

Alternatively, set the altimeter to 29.92 and read the indication.

Question 6

What is the pressure altitude for an altimeter setting of 29.62” Hg and airport elevation of 3,000 ft?

Answer 6

3,300 ft pressure altitude.

Calculation: 29.92 - 29.62 = +.30 = +300 ft; 300 + 3000 = 3,300 ft.

Question 7

What is the pressure altitude for an altimeter setting of 30.12” Hg and airport elevation of 1,500 ft?

Answer 7

1,300 ft pressure altitude.

Calculation: 29.92 - 30.12 = -20 = -200 ft; 1,500 - 200 = 1,300 ft.

Question 8

What is the pressure altitude for an altimeter setting of 29.91” Hg and airport elevation of 1,000 ft?

Answer 8

1,010 ft pressure altitude.

Calculation: 29.92 - 29.91 = 0.01” = +10 ft; 10 + 1,000 = 1,010 ft.

Question 9

What is density altitude (DA)?

Answer 9

Pressure altitude corrected for non-standard temperature.

High density altitude can negatively impact aircraft performance.

Question 10

What factors can increase density altitude?

Answer 10

• High airport elevation
• High ambient temperature
• High atmospheric humidity

These conditions can drastically reduce aircraft performance.

Question 11

How does temperature affect altimeter readings?

Answer 11

When air is colder than average, the altimeter reads higher than true altitude; when warmer, it reads lower.

This discrepancy must be accounted for during flight planning.