Altimetry

Question 1

What does QNH mean?

Answer 1

A/C height above Mean Sea Level (MSL)

Question 2

What does QNE mean?

Answer 2

A/C height above ISA standard pressure level of 1013.25 hPa

Question 3

What is QFE?

Answer 3

Field elevation

Question 4

When is QNH set on the altimeter in Australia?

Answer 4

When flying under 10,000 feet

Question 5

When is QNE set on the altimeter in Australia?

Answer 5

When flying above 10,000 feet

Question 6

When flying from an area of higher to low pressure, what will occur on the altimeter ?

Answer 6

Altimeter will report an altitude higher than the actual setting.

Question 7

What must area QNH forecasts be within any low level point within or on the boundary of the appropriate area during the period of validity of the forecast?

Answer 7

5 hPa

Question 8

What must the Area QNH not differ from between any adjoining area?

Answer 8

5 hPa

Question 9

What altitude would a 5 hPa difference give?

Answer 9

5 * 30 = 150 feet.

Question 10

With an accurate QNH set, what should the primary altimeter indication read within airfield elevation?

Answer 10

1) within 100 feet of the published airfield elevation

2) within 110 feet if the elevation exceeds 3300 ft

Question 11

At what FL are VFR altimeters permitted up to?

Answer 11

FL200

Question 12

With an accurate QNH set, what is the deviation allowed from the altimeter to the airfield elevation?

Answer 12

1) Should read nominated elevation to within 60 feet.

2) If an altimeter has an error in excess of 75 ft, the altimeter is to be considered unserviceable.

Question 13

What altitudes should VFR aircraft be flying at if travelling on magnetic track 000 through to 179?

Answer 13

Odd thousands of feet + 500 feet.

Question 14

What altitudes should VFR aircraft be flying at if travelling on magnetic track 180 through 359?

Answer 14

Even thousands of feet + 500 feet.

Question 15

What altitudes should IFR aircraft be flying at if travelling on magnetic track 000 through to 179?

Answer 15

Odd thousands of feet

Question 16

What altitudes should IFR aircraft be flying at if travelling on magnetic track 180 through 359?

Answer 16

Even thousands of feet

Question 17

What is Transition Altitude (TA)?

Answer 17

• This is the published height AMSL at which pilots climbing to their cruising level change their barometric altimeter datum from QNH to QNE.
• In Australia, this is 1013.25 hPa

Question 18

What is the Transition Level (TL)?

Answer 18

• The lowest flight level available for use above the TA

- Varies from FL110 to FL125 depending on QNH

Question 19

What is the Transition Layer ?

Answer 19

• The airspace between the TA and the TL.

- A minimum of 1000 feet

Question 20

On ascent, when should pilots switch to 1013.25?

Answer 20

When passing above 10,000 feet.

Question 21

On descent, when should pilots switch to local QNH?

Answer 21

When first entering the transition layer.

Question 22

What is pressure altitude?

Answer 22

Altitude at which the altimeter sub scale is 1013.25 hPa

Question 23

What is density altitude?

Answer 23

Pressure altitude taking into account temperature deviation from ISA as well.

Question 24

Are flights within the transition layer allowed?

Answer 24

No, except for ascent and descent.