Emergency Locator Transmitter (ELT)

Reference AIM SAR 3.0

Categories of ELTs

• A or AD: automatic ejectable or automatic deployable
• F or AF: fixed or automatic fixed
• AP: automatic portable
• P: personal
• W or S: water-activated or survival

CAR 605.38 ELT

• relevance to ATPL: large multi-engine turbojet airplanes engaged in air transport service with passengers require two ELTs (type W or S) when operating over water at a distance from land which requires life rafts (recall CAR 602.63 for life raft requirements)

CAR 605.39 Use of ELTs

• you can operate without a serviceable ELT if it is removed and repaired ASAP and the aircraft is placarded.
• ELT must be replaced within 10 days for 704 and 705 (30 days for everyone else)
• if you require 2 ELTs and they are both unserviceable: repair and replace the first ASAP, 10 days grace for the second

CAR 605.40 ELT Activation

• the only reason an ELT should be activated is in the event of an emergency, or testing (5 seconds only during the first 5 minutes of any hour)
• in the event of inadvertent activation, advise ATC / FSS / aerodrome and switch off

Note from AIM SAR 3.8: Unlike traditional 121.5/243 MHz ELTS, 406 MHz ELTs and their associated cockpit remote switch should be tested in accordance with the manufacturer's instructions only.

Pilot Response to Signals - notify nearest ATS:

• position, altitude and time first heard and contact lost
• ELT signal strength and did it cease suddenly or fade

Downed Aircraft Procedures:

• switch ELT on ASAP and do not cycle or switch off until positively located
• raising ELT from ground level to 8 ft may increase range by 20-40%
• if in an uninhabited area, stay with aircraft and ELT (more visible than people), have smoke/flares/signal fires read to attract SAR

Air Traffic Surveillance

Reference AIM COM 7.0

Recall: RADAR = RAdio Detection and Ranging (i.e. what's out there, which direction, and how far away?)

Primary Returns

• computes target positions by determining range and azimuth of reflected radio frequency energy
• passive - does not rely on info from aircraft
• uses:
• TSR (terminal surveillance radar) - short range (80 NM) to complement SSR
• PAR (Precision Approach Radar) - approach aid
• ASDE (Airport Surface Detection Equipment) - high def for aircraft and vehicles on manoeuvring areas
• Weather Radar - monitor hazardous weather conditions

Secondary Returns

• determines aircraft range by measuring the interval between transmitting an interrogation to and receiving a reply from an airborne transponder
• uses:
• enroute control - long range (200 NM)
• terminal control - in conjunction with PSR

ADS-B (Automatic Dependent Surveillance - Broadcast)

• uses aircraft avionics, satellites and/or ground infrastructure to relay a range of aircraft parameters to ATC
• automatic (no external stimulus required) but dependent (relies on aircraft avionics)

Canadian Domestic Routes

Reference AIM RAC 12.6

Use of Preferred Routes

• provides planning guidance, minimizes route changes, more efficient
• strongly encouraged, but not mandatory
• published in CFS

RNAV Routes

• Q-routes: high-level
• T-routes: low-level controlled 
• upward from 2200 AGL
• 10 NM each side of centre with MOCA protection 6 NM each side of centre
• L-routes: low-level uncontrolled
• MOCA protection 6 NM each side of centre
• Magnetic Reference Bearing published in SDA (reference only; RNAV systems will fly true course)

Position Reporting on Random Routes in NCA

• north-south: every 5 degrees of latitude with whole/half degree of longitude
• east-west (south of 75N): whole/half degrees of latitude with each 10 degrees of longitude
• east west (north of 75 N): whole/half degrees of latitude with each 20 degrees of longitude
• and of course, as requested by ATS

CMNPS = Canadian Minimum Navigation Performance Specifications (Reference AIM RAC 12.5)

• Laterally this includes the ACA, NCA, and a small portion of the SCA
• Vertical dimensions are FL330 to FL410

Polar Routes (Reference AIM RAC 12.6.7)

• aircraft need CMNPS certification
• must file designated polar fixes on the Achorage/Russian border but are otherwise random in Canadian airspace
• routing should be filed with a fix every 5 degrees of latitude

Transoceanic Flights

GOTA, RVSM, CMNPS, SLOP... it looks like we're having Alphabet soup for lunch!

CAR 602.39 Transoceanic Flights
If you want to fly a single engine aircraft or multi-engine that cannot maintain flight in the event of an engine failure over the high seas:

• pilot needs an instrument rating
• aircraft equipped as per CAR 605.18 + HF radio + hypothermia protection for each person on board
• sufficient fuel as per CAR 602.88 + additional 10%

Reference AIM RAC 11.0 North Atlantic Operations and ICAO NAT Doc 007

NAT MNPS = North Atlantic Minimum Navigation Performance Specifications

• compliance with NAT MNPS airspace is required by all aircraft operating between 
• FL285 and FL420 AND
• between 27 N and the North Pole AND
• Oceanic Control Areas: Reykjavik, Gander, New York, Shanwick, Santa Maria
• aircraft must be equipped with two fully functioning long range navigation systems (LRNS).  A LRNS may be one of the following:
• one Inertial Navigation System (INS)
• one Global Navigation Satellite System (GNSS)
• one navigation system using the inputs from one or more Inertial Reference System (IRS) or any other sensor system complying with the MNPS requirement.
• for eastbound and westbound traffic
• south of 70 N, the planned tracks shall be defined at each half or whole degree of latitude and each 10 degrees of longitude
• north of 70 N, the planned tracks shall be defined at latitudes expressed in degrees/minutes and each 20 degrees of longitude
• for northbound and southbound traffic
• the planned tracks shall be defined at latitudes spaced at 5 degrees and whole degrees of longitude

Traffic Alert and Collision Avoidance System (TCAS)

Reference AIM RAC 12.16

TCAS uses transponder interrogation and return signals to determine if aircraft around you pose a threat.  In order to detect these aircraft, they must be equipped with an operating Mode A, C, or S transponder.  Note: Mode A transponders will provide range and bearing only - no altitude info.

TCAS I provides TAs only.  
TCAS II provides TAs and RAs.

Some notes:

• Traffic Advisories (TAs) and Resolution Advisories (RAs) are only provided in the vertical plane (azimuth information is not reliably accurate)
• pilots should only alter their flight in the event of a RA (not a TA).  
• notify ATC ASAP of any deviation from your clearance.  Also notify them when you are clear of the conflict and returning to the cleared altitude
• See also CAR 602.31 (3) and (4) Compliance with ATC instructions and clearances

AIM RAC 12.16.6 (a) "Although TCAS will never be a complete substitute for a good lookout, good situational awareness and proper radio procedures, it has been proven to be a valuable tool in providing information on potential collision hazards."

Inertial Navigation Systems (INS)

Basic Principle: measures acceleration against time to determine speed and direction

How: uses accelerometers, in a gimbal assembly, to sense all vertical and horizontal accelerations to provide position and steering information.

Information Provided:

• steering information to autopilot
• aircraft attitude information for flight instruments
• antenna stabilization for airborne weather radar
• horizontal navigation data

GPS Approaches

Recall the basic operation of GPS: it triangulates your position by measuring distances from satellites by precise timing of radio signals.  4 satellites are required to obtain a 3D position fix. 

Reference AIM COM 3.14

GPS approaches are generally more efficient because they allow pilots to bypass procedure turns and proceed directly to the FAF.   GPS approaches must be retrieved from a current avionics database.  Pilot-generated waypoints are not approved for approach procedures.  There are two types of GPS approaches: stand-alone and overlay.

Stand-Alone

• approach design is usually based on a 'T' pattern 
• charted as "RNAV (GPS) RWY XX"

Overlay

• the underlying navaids do not have to be monitored
• you can use the GPS when the traditional navaid is out of service

There is always the requirement for a RAIM check (for +/- 15 minutes of the ETA) Without it, you have no assurance of the accuracy of the GPS position!

If you want to take credit for a GPS approach at an alternate aerodrome (AIM COM 3.14.12):

• there must be a usable approach at the planned destination which is served by a functioning traditional aid
• the published LNAV minima are the lowest landing limits for which credit may be taken when determining alternate weather minima requirements (not LNAV/VNAV or LPV)
• approach-level RAIM must be available at the ETA for the alternate
• periodically during the flight, and at least once before the mid-point of the flight to the destination, verify that approach-level RAIM is expected to be available at the planned alternate at the ETA

Note: There are GPS and WAAS NOTAM files which can advise of outages / failures

Wind

Reference ACWM Chapters 5 and 11

Wind is the result of changes in pressure gradient.

• flows from High to Low 
• steeper gradient = stronger wind

Coriolis Effect

• the deflection of wind caused by the Earth's rotation
• varies from zero at equator to maximum strength at poles

Curvature Effect

• when isobars are curved, air moves in an arc >> centrifugal force
• the pressure gradient around lows is generally stronger than around highs

Friction

• As you climb from the surface to 3000 feet, the wind veers (clockwise change in direction) and increases.
• As you descend from 3000 feet to the surface, the wind backs (counterclockwise change in direction) and decreases.
• We must also keep in mind that land and water create different amounts of friction.  There is less friction over water, so wind would blow at less of an angle across isobars and at faster speeds. 

Squalls and Gusts

• characteristics of turbulent flight conditions
• Gusts >> rapid peaks and lulls
• Squalls >> sudden increase lasting for a minute or more, then a decrease

Diurnal Effects

• surface winds are usually stronger and gustier during the day
• Sea Breeze during the day (higher pressure over water than land)
• Land Breeze at night

Topographical Effects

• hilly and mountainous terrain can contribute to mechanical turbulence
• Anabatic winds flow upslope during the day when mountain slops facing the sun are heated
• Katabatic winds flow downslope
• warm = Chinook wind, warms at DALR
• cold = glacier wind, cooling by underlying ice

Wind Shear

• increased performance (headwind) >> airspeed increases
• encountering increased performance on glideslope >> would have to reduce power to recapture glidepath, then increase power to maintain due to stronger headwind
• decreased performance (tailwind) >> airspeed decreases

Atmospheric Pressure

Pressure Measurements

• Inches of mercury (Hg) >> for altimetry
• Hectopascals (hPa) and millibars (mb) >> for weather map analysis
• measured using a barometer (digital or aneroid type)

METARs give both an altimeter setting and a sea level pressure.  What's the difference?

• Station Pressure
• measured at the airport; the weight of the air above the station
• Altimeter Setting
• station level pressure reduced to MSL assuming ISA conditions
• MSL Pressure
• station pressure reduced to MSL using the average surface temperature for the last 12 hours
• useful in weather map analysis when patterns across different observation stations must be compared

And just for fun, here's 'Under Pressure' by Queen:

Pressure Levels

In my January 2 post about the Earth's atmosphere, I said "some things you just have to memorize" with regards to which pressures correspond to which levels of the ICAO standard atmosphere.  As it turns out, memorization is not required if you have a CX-2 flight computer (and possibly others, but this is the one I have)!   Here's how:

• press 'FLIGHT'
• select (1) Altitude
• select (3) Std Atmos
• enter the altitude
• read the OAT, as well as pressure in "Hg and mb!

Small wins :)

Lapse Rates and Stability

Adiabatic Processes

• no heat is added or removed from air
• rising air >> lower pressure >> expands >> temperature decreases
• sinking air >> higher pressure >> compresses >> temperature increases

Lapse Rates

• Dry Adiabatic Lapse Rate (DALR): 3 C / 1000 ft
• Saturated Adiabatic Lapse Rate (SALR): 1.5 C / 1000 ft
• Average: 2 C / 1000 ft

• Environmental Lapse Rate (ELR): indicates the temperature of the surrounding air; comparison to lapse rate of air parcel determines if it is stable or unstable
• shallow lapse rate compared to SALR: absolute stability
• lapse rate between DALR and SALR: conditional instability
• steeper lapse rate than DALR: absolute instability

Characteristics of Stable Air

• sustained low visibility (i.e. haze layers, drizzle, fog)
• continuous precipitation
• strato-form clouds (layers)
• steady winds

Characteristics of Unstable Air

• good visibility
• showery precipitation
• cumulo-form clouds (vertical development)
• gusty winds

DO YOU KNOW... why rising saturated air cool less rapidly than rising unsaturated air?

• heat is released during the condensation of water vapour

Fuel Requirements

Fuel is probably one of the highest costs associated with the operation of an aircraft, so it makes sense that operators are always looking for ways to be more fuel efficient.  Extra fuel also means extra weight, which could otherwise be designated to paying passengers or cargo.  That being said, we know there are legal requirements for the minimum fuel on-board to cover various 'what if' scenarios.  

CAR 602.88 Fuel Requirements (General)

• Day VFR: destination + 30 min at cruise
• Night VFR: destination + 45 min at cruise

• IFR (prop)
• destination, approach, missed approach, alternate + 45 min
• if no alternate: destination, approach, missed approach + 45 min
• IFR (jet)
• destination, approach, missed approach, alternate + 30 min
• if no alternate: destination, approach, missed approach + 30 min

• All aircraft also need enough fuel to provide for:
• taxi, foreseeable delays prior to take-off
• weather
• foreseeable traffic delays
• loss of cabin pressure
• loss of engine at critical point
• any other foreseeable delays

CAR 704.20 Fuel Requirements (Commuter)
In addition to above,

• IFR
• descent to lower of single-engine service ceiling or 10000
• cruise at lower altitude to suitable aerodrome
• approach, missed approach
• hold for 30 min at 1500 AAE

CAR 705.25 Fuel Requirements (Airline)

• VFR: destination + 45 min at cruise

• IFR
• over designated routes / areas: destination + 5%
• descent to lower of single-engine service ceiling or 10000
• cruise at lower altitude to suitable aerodrome
• approach, missed approach
• hold for 30 min at 1500 AAE

Practical Meteorology

Practical Meteorology is all about applying all that meteorological theory to actual weather observations and forecasts.  There were a couple things I'd forgotten.   For example, with cloud layers, anything with 5/8 (broken) coverage or greater constitutes a ceiling.  This is not true if the it is a surface based layer, such as fog or snow.  In this case, the coverage must bee 8/8 to be considered a ceiling.  

Also, there are some charts that I don't use on a daily basis, because they cover much larger areas than I need on my regular runs between Montreal and Toronto.  When doing my practice questions, I was getting questions with regards to issuing and validity times wrong, so I knew it was time to consult the AIM.  

Prognosis = Forecast
Analysis = Observation

Reference AIM MET 3.2.1 Aviation Forecasts and Charts

Significant Weather Forecast - PROG Chart

• prepared 4 times daily, based on 00Z and 12Z data
• issued 12 hours prior to validity time (00, 06, 12, 18Z)
• specific flight level range (i.e. 700 - 400 MB = FL100 - FL240; also FL250-630)
• indicate surface positions of lows, highs, and any significant weather (thunderstorms, turbulence, mountain waves, etc)
• a forecast area of turbulence implies a 50% probability of encountering turbulence somewhere within the depicted area
• jet streams are depicted when the core speed is forecast to attain 80 knots or more

Upper Level Forecast - PROG Chart

• issued 4 times daily, 12 hours before the validity times of 00, 06, 12, 18Z
• applicable FL240, FL340, FL390, FL450
• depicts forecast wind and temperatures for the chart level

Reference AIM MET 3.2.3 Weather Charts

Surface Weather Chart

• observed at 00, 06, 12, 18Z
• issued 2-3 hours after observation
• pressure patterns from surface up to 3000 ft
• surface location of fronts, precipitation, obstructions to vision

Upper Level Chart - ANAL

• observed at 00 and 12Z
• issued over 3 hours after observation
• show reported atmospheric conditions at the pressure levels, such as wind speed/direction, temperatures, moisture content
• the contours or altitude gradient can be considered as the slope of the pressure surface

Airborne Weather Radar

It's been said that thunderstorms are among the most deadly hazards faced by pilots.  It's one thing to 'see and avoid' them when you're in VMC.  But what if you're flying in cloud and/or at night?

CAR 704.64 Airborne Thunderstorm Detection and Weather Radar Equipment (Commuter)
Needed if you have passengers in IMC when thunderstorms are expected along route.


CAR 705.70 Weather Radar Equipment (Airline)
Needed if you have passengers in IMC when thunderstorms are expected along route.

Recall: RADAR = RAdio Detection and Ranging (i.e. what's out there, which direction, and how far away?).  Azimuth scan for horizontal; tilt control for vertical.

Things to remember:

• rain provides the greatest radar echo intensity
• drop size determines radar echo intensity to a much greater extent than drop number
• "hooks" and "fingers" identify areas of hail and turbulence
• when thunderstorms contour on radar displays, they should be avoided by at least 20 NM
• when flying in moderate rain, the most important key to a more informative radar display is the use of the tilt control
• tilt the antenna beam to scan the middle/lower area of a CB
• attenuation is a loss of effectiveness due to the presence of large amounts of precipitation between the radar antenna and target storm cells

Notes about lightning detection system:

• displays electrical activity associated with a storm or line of storms
• does not detect the presence or intensity of precipitation
• able to detect electrical activity from cells that are located behind mountainous terrain

The probability of lightning strikes occurring to aircraft flying within a thunderstorm area is greatest when operating at altitudes where temperatures are between -5 and +5 C.

Critical Point

Also known as... should we return to our point of departure or continue to our destination after an engine failure, if there is no suitable alternate nearby?

Info you need:

• total distance (D)
• reduced (OEI) groundspeed home (RH)
• reduced (OEI) groundspeed out (RO)

For calculating groundspeeds, you need:

• track
• true airspeed
• wind direction and speed

And for calculating the time to the CP, you need

• AEO groundspeed out (GO)

**************************************

Formulae:

• Distance to CP = (D x RH) / (RO + RH)
• Time to CP = DCP / GO

**************************************

An increase in the tailwind component:

• decreases RH
• increases RO
• moves distance to CP closer to point of departure
• decreases time to CP

Instrument Landing System (ILS)

Reference AIM COM 3.12

Localizer

• valid and reliable signal coverage 35 degrees on either side of front course centre line up to 10 NM from transmitter
• 10 degrees up to 18 NM from transmitter for front and back courses
• 3-letter identifier
• starts with 'I' if aligned within 3 degrees of runway heading
• starts with 'X' if more than 3 degrees
• CDI needle deflection is 2.5 degrees from centre to full-scale

Glideslope

• beam depth is 1.4 degrees (0.7 above and below)
• standard glidepath is 3 degrees

Backcourse - Localizer only

• beware of reverse sensing!
• with an HSI, the track bar must be selected to the outbound course on localizer back course approaches in order to obtain positive track bar sensing

VHF Omnidirectional Range (VOR)

How does it work?

• it depends upon a phase difference between two signals transmitted simultaneously from a ground station
• position sensitive, NOT azimuth (i.e. no matter what direction you are facing, your instruments will give you the same VOR information about your position)
• line of sight: reception distance = 1.23 x sqrt(altitude above station)

Components:

• Omni Bearing Selector (OBS) >> select radials "FROM top, TO bottom"
• Course Deviation Indicator (CDI needle) >> centre to full scale is 10 degrees
• TO / FROM indicator >> directional ambiguity when crossing a radial 90 degrees from what is set on OBS

Tolerances:

• airway radials maintained by TC within +/- 3 degrees
• VOR checkpoint +/- 4 degrees
• dual VOR check +/- 4 degrees on ground or in air
• visual check over landmark +/- 6 degrees

To calculate distance (NM) from station:

• (groundspeed x time in minutes) / degrees of bearing change

How High Are We, REALLY?

True Altitude was something that always seemed to trip us up in ground school, but it's not actually that difficult.  In fact, if you read the instructions on your E6B, you're already more than half-way there!

True Altitude is particularly important when there are abnormally cold temperatures.  Usually the scenarios presented involve leveling off at a MEA, flying over a ridge, and realizing that you don't have nearly the amount of altitude clearance as you might have expected because it's -40. 

4 simple steps:

1. set air temperature over pressure altitude (make sure you're using the correct side!)
2. read true altitude over calibrated altitude scale (calibrated = planned - height of altimeter source)
3. add result of (2.) to height of altimeter source
4. subtract height of ridge to get ridge clearance

I'm tagging this both SAMRA and SARON because it fits in both Meteorology and Flight Operations.  So it could come up anywhere!

Things I'd Forgotten

Over the past week, I went through 171 'General Meteorology' practice questions... I got 150 (87.7%) of them right.  So there are obviously a few things that I'd forgotten since studying for my IATRA a couple years ago.  A few examples:

Terminology

• Overrunning: condition existing when an air mass is in motion aloft above another air mass of greater density at the surface.  This process that results in expansional cooling, subsequent condensation and formation of cloud. Example: warm air ascending the surface of a warm front. 
• Altimeter Setting: station level pressure reduced to MSL assuming ISA conditions
• Land breeze: blow from land to water during the night
• Stationary front: a frontal zone separating two different air masses, neither of which is strong enough to replace the other
• Riming: the growth of a descending ice particle as it collides with nearby water droplets which then freeze onto the particle

Location of Supercooled Water Droplets:

• in unstable air: lower levels of cloud where temperatures are only a few degrees below freezing
• in stable air: amount of supercooled water increases with height when temperatures are not far below freezing

Microbusts:

• The shaft of a microburst is normally about 2.2 nm wide or less at the surface.
• Downdrafts associated with a microbust could be as strong as 6000 ft / min

Mountain Waves:

• Rotor clouds are normally centred beneath the standing lenticular cloud (i.e. below each wave crest)
• The most powerful rotor is located under the first wave crest

Upper-Air Contour Charts:

• The wind blows along the contours in the same way that the 2000 ft wind blows along the surface isobars (parallel to the height contours, with lower heights on the left)
• the closer the contours, the stronger the wind; and if the height contours are curved, then centrifugal force acts on the wind

And other random facts:

• Snow grains: imply that freezing drizzle is present aloft.
• The vertical extent of CAT associated with a jet stream will be greatest on the low pressure, cold air mass side of the jet stream core.

I'll plan to cover some of these topics in more detail soon!  It's a good thing I like Meteorology... hopefully I'll still be this enthusiastic when I come back to Radio Nav :)

Air Masses

It is bitterly cold tonight, and one of the top news stories this week has been the weather across the entire country.  

Reference ACWM Chapter 6

Definitions:

• Air mass: a body of air whose temperature and humidity characteristics are uniform in the horizontal.
• Source region: a large area of land or ocean of relatively uniform characteristics and above which an air mass can form.
• Front: a transition zone between two air masses

Classification of Air Masses:

• Continental Arctic (cA)
• Maritime Arctic (mA)
• Continental Polar (cP)
• Maritime Polar (mP)
• Continental Tropical (cT)
• Maritime Tropical (mT)

Canadian Air Masses: cA, mA, mP, mT

Air masses may be modified as they migrate from their source regions.

• cold air (i.e. cA) moving south over the Lake Ontario in the winter becomes unstable since it is warmed from below, contributing to snow showers in Buffalo / south shores.
• warm air (i.e. mT) moving north over the Great Lakes in the spring becomes more stable since it is being cooled from below, contributing to stratus cloud, drizzle and fog over the north shores

POP QUIZ!

A south-westerly flow of Maritime Tropical air moving over the Labrador Current would produce what kind of fog?