Navigation practice test

About how much shorter is the Earth from pole to pole than across the equator?

• 230 NM
• 23 NM
• 2.3 NM
• It is longer

Answer: 23 NM. 23 NM: a compression of about 1/300, or 0.3 %.

What is the graticule?

• Only the equator and Greenwich
• The net of meridians and parallels on a map or globe
• The scale bar on a chart
• The circles round the poles

Answer: The net of meridians and parallels on a map or globe. The net of meridians and parallels drawn on a map or a globe.

A great circle has its northern vertex at 55°N 100°W. Where is its southern vertex?

• 55°S 080°E
• 55°S 100°W
• 35°S 080°E
• 55°N 080°E

Answer: 55°S 080°E. Swap N for S, and move the longitude 180°: −100 + 180 = +80, so 55°S 080°E.

Flying east from that northern vertex, where does it first cross the equator, and on what track?

• 010°W, track 145°
• 170°E, track 145°
• 010°W, track 215°
• 080°E, track 035°

Answer: 010°W, track 145°. From 100°W, walking 90° east counts down towards Greenwich: 100 − 90 = 010°W. Going downhill the track turns south by 55°: 090° + 55° = 145°.

Flying west from the same northern vertex instead?

• 170°E, track 215°
• 170°E, track 145°
• 010°W, track 215°
• 170°W, track 035°

Answer: 170°E, track 215°. From 100°W, walking 90° west: 80° takes you to 180, 10° more into the east numbers: 170°E. Flying west the track starts at 270° and turns south by 55°: 270° − 55° = 215°.

A model of the Earth has an equatorial radius of 6 378 km and a compression of 1/298. What is its polar radius?

• 6 399.4 km
• 6 356.6 km
• 6 378.0 km
• 6 335.2 km

Answer: 6 356.6 km. 6 378 ÷ 298 = 21.4, and 6 378 − 21.4 = 6 356.6 km.

What is the change of longitude between 170°E and 165°W?

Which of these is a great circle and also a parallel of latitude?

• The equator
• The Arctic Circle
• The prime meridian
• The parallel of 45°N

Answer: The equator. The equator: a parallel whose centre is the Earth's centre.

Dynamic pressure is…

• Pitot − static
• Pitot + static
• Static − pitot
• Static only

Answer: Pitot − static. Pitot minus static.

Pitot and drain blocked. In a descent the ASI…

• Under-reads
• Over-reads
• Reads correctly
• Freezes

Answer: Under-reads. PUD: pitot blocked under-reads in descent.

Static blocked. In a climb the ASI…

• Under-reads
• Over-reads
• Reads zero
• Is unaffected

Answer: Under-reads. The opposite of SOD: under-reads in a climb.

Using the alternate static source, the altimeter…

• Over-reads slightly
• Under-reads slightly
• Freezes
• Reads zero

Answer: Over-reads slightly. Cabin pressure is a little lower: it over-reads slightly.

On an aircraft with a static port on each side, the static lines are…

• Cross-coupled
• Kept apart
• Joined to the pitot lines
• Not used

Answer: Cross-coupled. Cross-coupled, left and right.

300 kHz is the line between…

• LF and MF
• MF and HF
• HF and VHF
• VHF and UHF

Answer: LF and MF. LF and MF.

A DME works in which band?

• UHF
• VHF
• MF
• SHF

Answer: UHF. UHF, 962–1 213 MHz.

A wave 75 cm long is in which band?

• UHF
• VHF
• SHF
• HF

Answer: UHF. 300 ÷ 0.75 = 400 MHz: UHF.

Which aid works on 75 MHz?

• Marker beacons
• VOR
• ILS glide path
• NDB

Answer: Marker beacons. Marker beacons.

Weather radar works in which band?

• SHF
• UHF
• VHF
• EHF

Answer: SHF. SHF, 9 375 MHz.