Speed, Position Reference And Altimetry

Question 1

Define knot

Answer 1

Nautical mile per hour. 1 knot is equal to 1 minute of latitude

Question 2

Define ground speed, indicated airspeed, calibrated, equivalent and true airspeed.

Answer 2

GS - TAS of aircraft corrected for headwind/tailwind
IAS - on ASI, amount of air molecules moving through the wings
CAS - IAS after correcting for position and instrument errors
EAS - CAS after corrected for compressibility error. Exists when TAS > 250kts
TAS - EAS after correct density error or actual airspeed of aircraft through the air.

Question 3

Explain how TAS is affected by changes in pressure altitude, air temp and density.

Answer 3

Pressure:
- Difference between TAS & IAS as pressure changes, as altitude increase, pressure decreases then the gap between IAS and TAS increases.

With a constant TAS and a gain in altitude, IAS will decrease.
With a constant IAS and a gain in altitude, TAS will increase.

Temperature:
- warm air less dense, flying through warm air will give an increase in TAS if IAS remains constant.

Density - the higher you fly the higher the difference between TAS and IAS due to reduction in density.

Question 4

Speed provided by GNSS and intertial system is what?

Answer 4

INS (Inertial reference system) receives GPS data. Blends GPS data with INS data to receive optimum position. Vertically and horizontally.

Speed provide = GS

Question 5

Define waypoint and what are the two types.

Answer 5

Location/fix which can be entered into a GPS

A specified geographical location used to define an area navigation route or the flight path of an aircraft employing area navigation (IFR).

Fly-by waypoint: a waypoint which requires turn anticipation to allow a tangential interception of the next segment of a route or procedure

Flyover waypoint: a waypoint at which a turn is initiated in order to join the next segment of a route or procedure.

Question 6

Describe and apply position reference methods:

Place/bearing/distance

Latitude and longitude

Answer 6

Place - e.g overhead NZCH, object bears 170R at 32nm

Lat/long - s43 29 22 E172 32 04

Question 7

Locate a position on a chart from NDB given magnetic direction to and distance from and the three types:

Answer 7

ADF points to an NDB

3 types
Fixed card- north always at top.
Rotatable card - Like a DI, always what you set
RMI - aligns to your heading

HDG + RB = BRG TO

Question 8

From VOR given radial & DME distance, locate a position on chart

Answer 8

Radials:

Originate at the VOR
Magnetic direction away from the VOR
360º for each VOR

DME
Consists of DME ground station and airborne component, straight line distance (slant range) - use Pythagoras

Question 9

Define Indicated altitude, True altitude, Pressure altitude, flight level, QNE, density altitude, transition level/layer/altitude, QNH and QFE

Answer 9

Indicated altitude - altitude on altimeter, corrected for position, instrument error, set by QNH
True - indicated altitude corrected for temp error, for airspace not ground
Pressure altitude - altitude where pressure is located according to ISA
Flight level - FL16
QNE - vertical distance when 1013hPa set on altimeter
Density altitude - PA corrected by density, DA = PA + 120 x (OAT - ISA)
Transition layer - when descending through Transition level set QNH on sub-scale, when climbing through Transition altitude, set 1013 on sub-scale
QNH - local mean sea level
QFE - vertical distance from specified datum height above that level

Question 10

Explain and apply the VFR table of cursing levels below and above transition

Answer 10

NOSE: North = 270-089ºM South = 090 - 269ºM

Below transition layer: Fly an altitude (QNH)
Above transition layer: Flight at flight level (QNE)

Lowest causing level is 3000ft, always add 1000ft above highest terrain. And 500ft for VFR levels and 1000ft for IFR.

Question 11

Explain how true altitude and indicated altitudes are affected by changes in air pressure and air temperature.

Answer 11

Altimeter is calibrated with ISA conditions, but atmosphere varies with pressure and temperature. Depends on what pressure is set on subscale.

Question 12

Explain how true and indicated altitude are related when using flight levels.

Answer 12

When flying on a lower then 1013.2 day altimeter will over read.

Flying on a higher then 1013.2 day altimeter will under read.

High - low, read high be low
Low to high, read low be high.

Question 13

Define Local Mean Time (LMT)

Answer 13

Actual time on a selected meridian of longitude, set by the sun. All points along a meridian have the same LMT

Question 14

Calculate the LMT

Answer 14

UTC +/- LMT
Add if going East
Subtract if going West

Longitude 
360º = 24 hours
15º = 1 hr
1º = 4min
15’ = 1min
1’ = 4sec

Question 15

Convert between LMT, UTC, NZST, NZDT

Answer 15

LMT - time on a given meridian of longitude
UTC - time at Greenwich, 0º
NZST = UTC +12
NZDT = UTC +13