Cold Temperature

Question 1

What is the issue with cold temperatures and altimeters?

When is this error at its worst?

Answer 1

Cold (-30*C or less) cause altimeters to over read so there is reduced terrain clearance. However, any temperature below ISA will result in the true altitude to be lower than indicated.
The error becomes worse the higher in altitude you are.

Question 2

What temperature do temperature corrections apply?

Answer 2

0*C or less, or the temperature is less than the AD minimum temperature.

Question 3

Can you change barometric reference settings to fix?

Answer 3

No

Question 4

Should you apply under radar control?

Answer 4

Not to ATC assigned FL/ALT

Question 5

Does it apply to QNH/QNE/QFE?

What altitudes shall it be applied to?

Answer 5

Only QNH/QFE.

Min departure, enroute, approach, MA and MDA/DA. Must advise ATC.

Question 6

How is the correction determined?

Answer 6

“Height above altimeter reference source” is min alt to be flown - barometric ref setting (ele).
Is rounded to the nearest 100ft increment for MDA/DA.

Question 7

When are you in icing conditions (cruise)?

Answer 7

In cloud with visibility of 1600m or less AND
TAT 10C or less, or SAT -40C or greater OR

Visually confirmed ice build up

SAT is static air temp (OAT)
TAT is SAT + kinetic heating

Question 8

When are you in icing conditions (ground)?

Answer 8

OAT 10*C or less AND

• 1600m vis OR
• Standing water