WO5 - Pressure

Question 1

Define Atmospheric Pressure

Answer 1

Force per unit of area exerted by the atmosphere as a consequence of its weight, and thus equal to the weight of a vertical column of air of unit area, extending from the level in question to the outer limit of the atmosphere.

Question 2

Define Station Pressure

Answer 2

The atmospheric pressure at the station elevation

Question 3

What are the 4 conditions of the ICAO standard atmosphere?

Answer 3

Air is a perfectly dry gas
Pressure at Sea Level is 29.92 Inches of Mercury, or 1013.2 hPa
Temperature at sea level is 15 degrees C
Temperature decreases at a rate of 1.98 degrees C / 1000 feet.

Question 4

How is Mean Sea Level Pressure calculated?

Answer 4

Use the “Reduction of Station Pressure to Sea Level” table, using the mean temperature between now and T-12.

Question 5

What is the unit of measurement used when reading the barometer?

Answer 5

hectopascals (hPa)

Question 6

What is the name of the type of barometer now in use?

Answer 6

Vaisala Digital Barometer

Question 7

What other important information is displayed on the digital barometer, besides the pressure?

Answer 7

Error code of each transducer

Question 8

How long (minimum) can that batteries in the digital barometer power supply last in the event of a power failure?

Answer 8

48 hours

Question 9

How often is the output updated for the pressure displayed on the digital barometer?

Answer 9

once every second

Question 10

Code E001 is displayed on the bottom right of the digital barometer. What does this mean?

Answer 10

One transducer has an error, reading is still usable.

Question 11

Code E101 is displayed on the bottom right of the digital barometer. What does this mean?

Answer 11

Two transducers have errors, the reading shall not be used. Report as MISSING

Question 12

How is missing information coded on the 2322?

Answer 12

M

Question 13

For table “Station Pressure” which “bulb” temperature do we use?

Answer 13

Dry Bulb

Question 14

For MSL Pressure table, how often is the reduction calculated?

Answer 14

every 3 hours

Question 15

How many digits are required in columns 33,41,39?

Answer 15

3

Question 16

When must an entry be made in Column 1 of the 2322 regarding the use of tables?

Answer 16

If tables are used at a site that has a data entry screen that computes pressure, an entry for each time tables are used. (Entry also required on 2325)