STATION PRESSURE

Station pressure is the actual atmospheric pressure at the elevation of the observing station. It is, in other words, the actual weight of a column of air extending up from the station level to the outer limit of the atmosphere. The value is determined directly from the mercury barometer at the observing station.

For example: The weight of the atmosphere decreases with altitude, the atmospheric pressure reading at a station at 5.000 feet elevation will be less than that at a station at 1,000 feet and still less than that at a station at sea level.

MEAN SEA LEVEL PRESSURE

Anabatic Winds – These Winds are upslope winds driven by warmer surface temperatures on a mountain slope than the surrounding air column.

Katabatic Winds – Katabatic winds are downslope winds created when the mountain surface is colder than the surrounding air and creates a downslope wind. At night as the sides of the hills or mountains cool, the air in contact with them tends to become denser and blows down the slope into the valley.

This one is pure memorization. Under International Standard Atmosphere (ISA) conditions, the tropopause has the following characteristics:

Height: Approximately 36,000 feet above sea level.

Temperature: Around -56.5°C

Explanation:

The ISA provides a baseline for atmospheric conditions, assuming average conditions at sea level with a temperature of 15°C (59°F) and a pressure of 1013.25 hPa (29.92 inHg). The tropopause under ISA conditions represents the point where the temperature ceases to decrease with altitude and remains relatively constant or begins to slightly increase in the stratosphere above.

The upper charts are actually issued four times daily; valid 00Z, 06Z, 12Z, 18Z.

Inertial navigation is a self-contained navigation technique in which measurements provided by accelerometers and gyroscopes are used to track the position and orientation of an object relative to a known starting point.

In a VOR, full scale deflection is 10°.

In an ILS, full scale deflection in the localiser is 2.5°.

In an ILS, full scale deflection in the glidepath is 0.7°. 

Remember you can only get to half full scale deflection before you must initiate a go around.

Reference: AIM COM 4.7

Precipitation-induced fog is caused by the addition of moisture to the air through evaporation of rain or drizzle. This type of fog is associated mostly with warm fronts and is sometimes known as frontal fog.

AIM COM 4.7 Distance Measuring Equipment (DME) 

The DME slant range error is the greatest when the airplane is at a high altitude close to or over the ground station. Moreover, slant range error also affects groundspeed and time-to-staion displays when you are close to the station.

AIM COM 4.8 TACTICAL AIR NAVIGATION (TACAN)

Tactical air navigation aid (TACAN) is a navigation aid (NAVAID) used primarily by the military for en route, non-precision approaches (NPAs) and other military applications. It provides azimuth in the form of radials and slant distance in nautical miles (NM) from the ground station. The system operates in the ultrahigh frequency (UHF) range with the frequencies identified by channel number.

TACAN users may obtain distance information from a distance measuring equipment (DME)  that is paired with the VHF omnidirectional range (VOR). This TACAN paired channel number is published in the Canada Flight Supplement (CFS) for every VOR/DME facility.

CAUTION:
Only DME information is being received by the TACAN avionics. Any apparent radial information obtained through the TACAN avionics from a VOR/DME facility can only be false signals.

AIM COM 5.3.1 Aircraft-Based Augmentation System (ABAS)

RAIM and FDE functions in current IFR-certified avionics are considered ABAS. RAIM can provide the integrity for the en route, terminal, and NPA phases of flight. FDE improves the continuity of operation in the event of a satellite failure and can support primary-means oceanic operations.

RAIM uses extra satellites in view to compare solutions and detect problems. It usually takes four satellites to compute a navigation solution, and a minimum of 5 for RAIM to function. The availability of RAIM is a function of the number of visible satellites and their geometry. It is complicated by the movement of satellites relative to a coverage area and temporary satellite outages resulting from scheduled maintenance or failures.

If the number of satellites in view and their geometry do not support the applicable alert limit (2 NM en route, 1 NM terminal and 0.3 NM NPA), RAIM is unable to guarantee the integrity of the position solution. (Note that this does not imply a satellite malfunction.) In this case, the RAIM function in the avionics will alert the pilot, but will continue providing a navigation solution. Except in cases of emergency, pilots must discontinue using GNSS for IFR navigation when such an alert occurs.

A second type of RAIM alert occurs when the avionics detects a satellite range error (typically caused by a satellite malfunction) that may cause an accuracy degradation that exceeds the alert limit for the current phase of flight. When this occurs, the avionics alerts the pilot and denies navigation guidance by displaying red flags on the HSI or CDI. Continued flight using GNSS is then not possible until the satellite is flagged as unhealthy by the control centre, or normal satellite operation is restored.

Some avionics go beyond basic RAIM by having an FDE feature that allows the avionics to detect which satellite is faulty, and then to exclude it from the navigation solution. FDE requires a minimum of 6 satellites with good geometry to function. It has the advantage of allowing continued navigation in the presence of a satellite malfunction.

Most first generation avionics do not have FDE and were designed when GPS had a feature called SA that deliberately degraded accuracy. SA has since been discontinued, and new generation SBAS-capable receivers (TSO-C145a/C146a) account for SA being terminated. These receivers experience a higher RAIM availability, even in the absence of SBAS messages, and also have FDE capability.

STATION PRESSURE

Station pressure is the actual atmospheric pressure at the elevation of the observing station. It is, in other words, the actual weight of a column of air extending up from the station level to the outer limit of the atmosphere. The value is determined directly from the mercury barometer at the observing station.

For example: The weight of the atmosphere decreases with altitude, the atmospheric pressure reading at a station at 5.000 feet elevation will be less than that at a station at 1,000 feet and still less than that at a station at sea level.

MEAN SEA LEVEL PRESSURE

Up to 10 NM: 35 degrees either side of centreline

Between 10 NM to 18 NM: 10 degrees either side of centreline

NDB Intercepts inbound Formula:

300° + 050° = 350° 

6.2 SIGMET ISSUANCE CRITERIA

Significant meteorological information (SIGMET) is issued in response to the following criteria (the abbreviations are shown in all capital letters):

(a) Thunderstorms:

(i) Frequent (FRQ TS);

(ii) Frequent with hail (FRQ TSGR);

(iii) Frequent with hail and possible tornado/waterspout (FRQ TSGR POSS +FC);

(iv) Frequent with hail and tornado/waterspout (FRQ TSGR +FC);

(v) Squall line (SQLN TS);

(vi) Squall line with hail (SQLN TSGR);

(vii) Squall line with possible tornado/waterspout (SQLN TSGR POSS +FC);

(viii) Squall line with tornado/waterspout (SQLN TSGR +FC);

(b) Severe turbulence (SEV TURB);
(c) Severe icing (SEV ICE);
(d) Severe icing due to freezing rain (SEV ICE [FZRA]);

(e) Severe mountain wave (SEV MTW);
(f) Low-level wind shear (L LVL WS);
(g) Heavy dust storm (HVY DS);
(h) Heavy sandstorm (HVY SS);
(i) Radioactive cloud (RDOACT CLD);
(j) Volcanic ash (VA);
(k) Tropical cyclone (TC).

TC AIM Air 2.8

If you enter a thunderstorm:

(a)  Concentrate on your instruments; looking outside increases the danger of temporary blindness from lightning.

(b)  Don’t change power settings; maintain the settings for turbulence penetration airspeed.

(c)  Don’t attempt to keep a constant rigid altitude; let the aircraft “ride the waves”. Manoeuvres in trying to maintain constant

850 mb (5 000')

700 mb (10 000')

500 mb (18 000')

250 mb (34 000')

850 mb (5 000')

700 mb (10 000')

500 mb (18 000')

250 mb (34 000')

2°C/100 ft = 14,000 x 2° = 28 degrees

Standard temperature is 15°C-28 = -13°C

VOT Signal:

With a VOT, you can check the VOR accuracy from your plane before takeoff. So what is a VOT? It's an approved VOR test signal, and it's located on an airport. Not all airports have VOTs, so you'll need to check the chart supplement to see if your airport has one. If your airport does have a VOT, here's what to do:

1. Tune your VOR to the VOT signal.
2. Set the course selector to 0 degrees, and the track indicator should be centered.
3. The TO-FROM indicator should read FROM.
4. Next, set the course selector to 180 degrees
5. The TO-FROM indicator should read TO, and the track bar should then be centered.
6. The maximum indicated bearing error is plus or minus 4 degrees.