VFR Obstacle Clearance Requirements

Once again, there are various exceptions when it comes to minimum altitudes and distances, based on the operating context.  Let's see if we can make some sense of it all.

Except for the purpose of take-off or landing....

CAR 704.23 (Commuter)

• Day: must be at least 500 AGL and 500 feet horizontal from any obstacle
• Night: must be at least 1000 feet above any obstacle within 3 miles of route

CAR 705.32:  (Airline)

• Day: must be at least 1000 AGL and 1000 feet horizontal from any obstacle
• Night: must be at least 1000 feet above any obstacle within 5 miles of route (2000 feet in mountainous regions)

Black Boxes

The Flight Data and Cockpit Voice Recorders (so called 'black-boxes' even though they are actually orange) provide invaluable information to investigators as they try to piece together the sequence of events leading up to an accident.  

CAR 605.33 Flight Data Recorder and Cockpit Voice Recorder Requirements

• FDR: required for multi-engine turbine aircraft (see regulation for specifics and variations based on passenger configurations)
• CVR: required for multi-engine turbine aircraft configured for 6 or more passengers and two pilots

CAR 605.34 Use of Flight Data Recorders and Cockpit Voice Recorders

• Operation 
• FDR: continuously from take-off to landing
• CVR: continuously from application of electrical power prior to flight until removal of electrical power following flight
• Without a MEL, either the FDR or CVR may be unserviceable for up to 90 days after day of failure, as long as the other one is serviceable, and the date of failure is recorded in the aircraft technical records. 

Air Law Grab-Bag

Another random selection of Air Law trivia...

CAR 605.93 Technical Records - General
(4) Every person who brings into use a new volume of an existing technical record shall make the entries relating to the preceding volume that are necessary to ensure that an unbroken chronological record is maintained.

CAR 705.22 Operational Flight Plan

• PIC shall ensure a copy is left at a POD in accordance with procedures specified in COM
• airline shall keep a copy including any amendments for at least 90 days
• for commuters, the period is defined in the COM (CAR 704.17)
• if cruise segment is less than 30 minutes, may use an informal operational flight plan (CAR 725.22 and CAR 724.17)

CAR 705.94 Portable Oxygen

A 15 minute supply (with masks) must be available for each flight attendant on pressurized aircraft in airline operations above FL250. 

Reference AIM RAC 6.4.5

Along off-airways tracks, the airspace to be protected is 45 NM each side of that portion of the track which is beyond navigational and signal coverage range. 

Reference AIM RAC 8.1 IFR Enroute
If while on an IFR flight plan your ETA for a reporting point changes by more than 3 minutes, advise the appropriate ATS unit ASAP.

Manuals

CARs 704.122 and 705.136 Distribution of Company Operations Manual

• provide copies of appropriate sections to each crew member, ground operations and maintenance personnel
• alternatively place a copy in each aircraft
• each person with a copy must keep it up-to-date and accessible

CARs 704.123 and 705.137 Aircraft Operating Manual

• a copy must be on board each aircraft

CARs 704.124 and 705.138 Standard Operating Procedures

• required when aircraft is required to be operated by 2 or more pilots
• a copy must be on board each aircraft

For Airlines (705), AOMs and SOPs must be submitted to Minister. 

Routes in Uncontrolled Airspace

CAR 704.29 and CAR 705.37: No person shall, in uncontrolled airspace, conduct an IFR flight or a night VFR flight on a route other than an air route unless the air operator establishes the route in accordance with the Commercial Air Service Standards.

Related Standards CAR 724.29 and CAR 725.37:

• IFR MOCAs: minimum 2000 feet above highest obstacle within 10 miles of centreline
• Night VFR: minimum 1000 feet above highest obstacle within 3 miles of centreline

Aviation Occurences

Reference AIM GEN 3.3

Accidents:

• a person is killed or sustains serious injury
• on board
• direct contact with any part
• exposure to jet blast / rotor downwash / prop wash
• the aircraft sustains structural failure or damage which adversely affects the structural strength of the aircraft
• the aircraft is missing or inaccessible

Mandatory Reportable Incidents:
Incident for aircraft with MCTOW greater than 2250 kg or operating under Part VII where:

• engine fails or is shut-down as precautionary measure
• power train transmission gearbox malfunction
• smoke detected or fire occurs
• difficulties controlling aircraft (malfunction, weather, wake turbulence, vibration)
• aircraft fails to remain on runway, lands with gear retracted, drags a wingtip or engine pod
• crew incapacitation which poses a threat to safety
• depressurization requiring emergency descent
• fuel shortage requiring diversion or landing priority
• incorrect type or contaminated fuel
• collision, risk of collision, loss of separation
• emergency requiring priority handling or equipment on standby
• slung load released unintentionally or as precautionary measure
• dangerous good released in or from aircraft

How Far and How High?

There are so many different regulations that specify distances, heights, etc.  It's easy to get some of them mixed up.  So... time for a quiz to see which ones you know!  Questions here; answers and references in the links provided.

A low level airway is controlled airspace and extends from ________ AGL up to ___________. 
(Answer here)

A low level air-route is Class ___ airspace and extends from ____________ up to __________.
(Answer here)

A control zone normally has a _____ NM radius and the normal vertical extent is up to ______ AAE.
(Answer here)

When an aircraft is on a defense flight plan, the PIC shall revise the estimated time and point of entry/exit into the ADIZ if they vary by _____ minutes of _____ NM. 
(Answer here)

No person shall conduct a take-off in an aeroplane if the weight of the aeroplane is greater than the weight specified in the aircraft flight manual as allowing a net take-off flight path that clears all obstacles by at least ___ feet vertically or at least ___ feet horizontally within the aerodrome boundaries, and by at least ___ feet horizontally outside those boundaries.
(Answer here)

An airline operator may not operate an aeroplane at a weight which will not allow it to attain with any engine inoperative, a net flight path which has a positive slope at _____ feet above all terrain and obstructions within ___ NM on either side of the intended track. 
(Answer here)

The vertical dimensions of the Arctic Control Area (ACA) are FL____ and above.
The vertical dimensions of the Northern Control Area (NCA) are FL____ and above.
(Answer here)

The vertical dimensions of the Canadian Minimum Navigation Performance Specification Airspace (CMNPSA) within the Canadian Domestic Airspace (CDA) are FL___ to FL___.
(Answer here)

The vertical dimensions of RVSM airspace is FL___ to FL___ inclusive.
(Answer here)

The vertical dimensions of the North Atlantic Minimum Navigation Performance Specification Airspace (NAT MNPSA) are FL___ to FL___.
(Answer here)

Throughout the North Atlantic (NAT) Region, airspace at and above FL___ is Class __ airspace, while airspace below this level is Class __ airspace.
(Answer here)

An aircraft operating in the vicinity of an active forest fire should operate clear of the area by a minimum altitude of _____ AGL and a minimum distance of ___ NM.
(Answer here)

Altimeter Setting and Operating Procedures

Reference AIM RAC 2.11 and 2.12

ALTIMETER SETTING REGION

CAR 602.35 

• Departure: altimeter setting at aerodrome, or if not available the elevation of the aerodrome
• Enroute: altimeter setting of nearest station along route
• Arrival: altimeter setting at destination

STANDARD PRESSURE REGION

CAR 602.36

• Departure: altimeter setting at aerodrome, or if not available the elevation of the aerodrome
• Enroute: immediately prior to reaching the intended flight level, set 29.92
• Arrival: altimeter setting at destination
• Holding: once descending below lowest flight level of hold, altimeter setting at destination

TRANSITION BETWEEN REGIONS

CAR 602.37

• the simplest way to think about this is to always change the altimeter in the standard pressure region, whether it is a lateral or vertical transition

Air Law Potpourri

I went through some practice questions about Air Law this morning and it emphasized my need to study even more!  Here are some things I'd forgotten:

TRAINING

• Instrument Training
• CAR 425.21: with a CPL or ATPL, you may give a licensed pilot instrument training towards an IFR rating provided you have and instrument rating and:
• instructor rating OR
• 500 hours PIC of which 100 must be on the same group of aircraft used for training (and for Group 1, at least 10 hours on the type used for training)

AIRSPACE

• Class F Restricted
• CAR 601.04: A pilot may fly through an active area:
• if authorized by appropriate person
• if it doesn't pose hazard to aircraft
• if it doesn't jeopardize national security

• CAR 602.145: VFR Flight in ADIZ
• VFR flight within or into the ADIZ requires a Defense Flight Plan or Defense Flight Itinerary to be filed.
• Must revise time/point of entry if more than +/- 5 minutes or 20 NM.

AIRPORTS

• Take-off Alternates (i.e. weather is above take-off minima but below landing minima for that aerodrome):
• CAR 704.26 Commuter: if authorized on air operator certificate
• CAR 705.34 Airline: within 60 minutes with OEI (twin) or 120 minutes with OEI (three or four engines or ETOPS)

• Dispatch Limitations:
• CAR 704.49 and CAR 705.60: must be able to land at destination and alternate within
• Turbo-jets: 60% of landing distance available (LDA)
• Turbo-props: 70% of LDA
• must be suitable runway for aircraft and conditions, and can't take credit for more than 50% of anticipated headwind or less than 150% of tailwind
• CAR 704.50 and CAR 705.61: for turbo-jets, if wet runway expected, the calculated runway requirement must be increased by an additional 15%. (Can be less if AFM includes info, but not shorter than what is required by 704.49 / 705.60).

SYSTEMS

• Altitude Alerting System or Device
• CAR 605.36: required for turbo-jets, with these exceptions:
• MEL, or if no MEL, being ferried to location with device
• flight tests, PPCs, training
• if failure after TO, until it reaches location where it can be repaired

• GPWS
• CAR 605.37: required for 704 and 705 turbo-jets with MCTOW of more than 15000 kg (33069 lbs) and authorized to carry more than 10 passengers (exception - MEL). 

• Standby Attitude Indicator
• CAR 605.41: required for Part VII turbo-jets (some exceptions).  Required for Part VII turbo-props configured for 10 or more passengers.
• CAR 625.41: must be installed on turbojet aircraft, and operate for 30 minutes in the event of a complete electrical system malfunction

Personnel Requirements - Airline

CAR 705.103 Designation of PIC and SIC
Designated by air operator.

CAR 705.104 Flight Attendant Requirements
Discussed in another post.

CAR 705.106 Pilot Qualifications

• appropriate license, ratings, endorsements
• within past 90 days:
• 3 take-offs and landings at controls
• 5 sectors
• training requirements
• valid PPC
• valid line check or line indoc
• fulfilled operator's training
• exceptions: training or ferry flight or authorized on air operator certificate

CAR 705.107 Flight Engineer and Second Officer Qualifications
Here are the basics:

• appropriate license and endorsements
• check ride with operator, or 50 hours in past 6 months on type
• completed line indoc
• fulfilled operator's training

CAR 705.108 Crew Pairing
Based on combined experience.

CAR 705.111 Route and Aerodrome Qualifications
Must have been flight crew or observer along same route within the last 12 months or else have received training and demonstrated adequate knowledge.

CAR 705.113 Validity Period

• line check valid for 1 year
• PPC valid for 6 months (1 year if approved 6-month recurrent training completed)
• dispatcher competency check valid for 1 year
• if renewed within 90 days prior, new date is 6/12 months after old date
• validity can be extended up to 60 days

Personnel Requirements - Commuter

CAR 704.106 Minimum Crew (Commuter)
If you have 10 or more passengers, or are carrying passengers in IFR flight, two pilots are required.

CAR 704.107 Designation of PIC and SIC
Designated by air operator.

CAR 704.108 Flight Crew Member Qualifications
Here are the basics:

• appropriate license and ratings
• 3 take-offs and landings within the past 90 days
• valid PPC
• ground training complete
• exceptions: training or ferry flight or authorization on air operator certificate

Other important things:

• to fly IFR with passengers as PIC, you need at least 1200 TT
• to fly VFR as PIC, you need at least 500 TT
• to flight Night VFR with passengers as PIC, you need an instrument rating

CAR 704.109 Qualifications of Operational Control Personnel

• requires training and demonstration of knowledge
• 3 months recency requirement

CAR 704.110 Check Authority

CAR 704.111 Validity Period
PPCs are valid for one year.  They can be renewed up to 90 days prior with same expiration.  They can be extended for up to 60 days.

Radiocommunications

The key to this section is common sense and good airmanship (as with so many other parts of flying!).

CAR 602.136 Continuous Listening Watch

• maintain listening watch on appropriate frequency
• establish communication with appropriate ATC, FSS, etc. when required

CAR 602.137 Two-way Radio communication Failure in IFR Flight

• in controlled airspace:
• maintain listening watch on appropriate frequency
• squawk 7600
• attempt to contact other ATS facilities or aircraft to relay info
• if unable to make contact, comply with procedures in CAP / CFS (unless other procedures were given by ATC)

Reference also AIM RAC 6.3.2:

• if VMC, or if VMC is encountered, remain VFR and land as soon as practicable (not the same as 'as soon as possible' - use good judgement)
• if IMC:
• Route:
• route last assigned and acknowledged
• if being vectored, go directly to fix/route/airway specified in clearance
• if no assigned route, use advised/expected
• if no advised/expected, use what has filed on flight plan
• Altitude: use highest of:
• altitude last assigned and acknowledged
• minimum IFR altitude
• expected in a further clearance
• Descent and approach: commence descent at most recent time of:
• calculated ETA
• ETA last notified and acknowledged
• EAT last received and acknowledged
• if assigned a hold, commence approach at EAT or EFC
• if cleared for a STAR, proceed to FAF via
• published routing
• from radar vectors direct fix for straight-in or full procedure
• CLOSED RNAV STAR as published for straight-in
• OPEN RNAV STAR as published to DTW and then turn to FACF to intercept for straight-in

Reference AIM COM 5.15: As a last resort, PIC may attempt to contact ATS using conventional cellphone or satellite phone.

CAR 602.138 Two-way Radio communication Failure in VFR Flight

• in class B, C or D:
• leave airspace (by landing or else shortest route)
• squawk 7600
• inform ATC ASAP of actions taken

Reference also AIM RAC 4.4.8: if you are outside of class B, C, D, you may enter and land if there is no nearby suitable aerodrome available.  See NORDO arrival procedures in AIM RAC 4.4.5.

Formation, Aerobatics, and jumping out of a perfectly good airplane

I flew skydivers one summer.  It's hard to say it was a job... more like a volunteer position.  But I never jumped myself.  Oh yes, I think it would be fun and thrilling, but it's also quite risky and I was content to remain in the aircraft (especially since I was the pilot!)

CAR 602.25 Entering or Leaving an Aircraft in Flight

• need permission of PIC
• PIC shall not permit unless
• leaving using a parachute
• CAR 702.19 (helicopter ops)
• CAR 603.02 (special aviation event certificate) or CAR 603.67 (special flight operations certificate)

CAR 602.26 Parachute Descents

• prohibited in controlled airspace / air routes, and over built-up areas and open-air assemblies unless you have a special flight operations - parachuting certificate as per CAR 603.37

This takes us into the realm of airshows, and while they are not the only place where formation flight and aerobatics take place, this would be a good time to talk about such activities.  This is also covered in AIM RAC 1.11.

CAR 603.01 Certificate Requirements for Special Aviation Events

• cannot conduct a special aviation event unless you comply with the provisions of a special flight operations certificate - special aviation event

CAR 602.24 Formation Flight

• PICs must make arrangements beforehand
• if in a control zone, PICs must coordinate with ATC

CAR 602.27 Aerobatic Maneuvewrs - Prohibited Areas and Flight Conditions

• No person operating an aircraft shall conduct aerobatic manoeuvres
• over a built-up area or an open-air assembly of persons;
• in controlled airspace, except in accordance with a special flight operations certificate issued pursuant to section 603.67;
• when flight visibility is less than three miles; or
• below 2,000 feet AGL, except in accordance with a special flight operations certificate issued pursuant to section 603.02 or 603.67.

CAR 602.28 Aerobatic Maneuvers with Passengers

• PIC must have:
• at least 10 hours dual instruction conducting aerobatics or 20 hours conducting aerobatics
• at least 1 hour conducting aerobatics in the previous 6 months

Alcohol and Drugs

CAR 602.03 Alcohol and Drugs - Crew Members

• 8 hours bottle to throttle
• Zero tolerance for impaired flying

Alcohol consumption can increase the susceptibility of an individual to hypoxia.  Remember, there is no magic cure for removing alcohol from your bloodstream.  Such a reduction can only be attained over the passage of time.  

CAR 602.04 Alcohol and Drugs - Passengers

• cannot drink your own alcohol (must be served / provided by operator)
• operator must not serve if passenger is already impaired by drugs/alcohol to extent as to be a safety hazard
• operator must not allow a person with impaired faculties to board aircraft
• exception: passenger has been administered drug for medical reasons and is under supervision

Clean Aircraft Concept

Reference AIM AIR 2.12 Flight Operations in Winter

Wing contamination is serious business.  Ice with the thickness and texture of sandpaper on the surfaces of an aircraft could decrease lift by 30% and increase drag by 40%.  As ice accumulates on a wing, the stalling speed increases and the angle at which the wing will stall decreases.

Clean Aircraft Concept:

• refers to take-off being prohibited when frost, snow or ice is adhering to any critical surface of the aircraft

Critical Surfaces refers to:

• wings
• control surfaces
• propellers
• horizontal stabilizers
• vertical stabilizers
• upper surface of fuselage in the case of aircraft with rear-mounted engines

CAR 602.11 Aircraft Icing

• no person shall attempt to conduct a take-off in an aircraft that has frost, ice, or snow adhering to any of its critical surfaces
• exception: frost on underside of wing caused by cold-soaked fuel (refer to manufacturer's instructions)
• take-off in icing conditions
• Part 705: PIC (or person designated by operator) must inspect immediately prior to take-off (or operator has established aircraft inspection program)
• Part VII other than subpart 5: operator has established aircraft inspection program  
• report observed ice to PIC (or designated person) so they can inspect
• PIC must inform other crew members of intention to de-ice/anti-ice

Approach Bans

It seems that Approach Ban regulations are full of IFs ANDs and BUTs...  This is a classic example of there always being an exception to the rule!!

For some helpful examples, reference AIM RAC 9.19.2.

CAR 602.129 Approach Bans - General
(This does not apply to Part VII aircraft - see below)

• RVR minima for aeroplanes:
• if RVR A and B
• RVR A < 1200 ft and RVR < 600 ft
• if only RVR A or B
• either < 1200 ft
• If RVR is below minimums, you cannot continue an instrument approach in an IFR aircraft unless:
• aircraft has passed FAF (if no FAF, aircraft has intercepted final approach course)
• training flight and landing not intended
• RVR is fluctuating above and below
• ground visibility is reported as at least 1/4 mile
• PIC is conducting precision approach to CAT III minima
• (5) No PIC of an IFR aircraft shall commence a non-precision approach, an APV or a CAT I or CAT II precision approach to an airport where low-visibility procedures are in effect

CAR 602.130 Approach Bans - Category III

(This does not apply to Part VII aircraft - see below)

• (2) No person shall continue a CAT III precision approach in an IFR aircraft beyond the FAF inbound or, where there is no FAF, the point where the final approach course is intercepted, unless the RVR reported is equal to or greater than the minimum RVR specified in the Canada Air Pilot in respect of the runway or surface of intended approach for the instrument approach procedure conducted.

CAR 700.10 Approach Bans - Non Precision, APV, and CAT I Precision

• RVR minima change based on CAP advisory visibility, for example:
• CAP 1/2 (2600) >> RVR 3/8 (1600)
• CAP 3/4 (4000) >> RVR 5/8 (3000)
• CAP 1 (5000) >> RVR 3/4 (4000)
• If no RVR, use runway vis.  South of 60: if no runway vis, use ground vis. 
• If below minimums, you cannot continue a non-precision approach, an APV or a CAT I precision approach in an IFR aircraft unless:
• aircraft has passed FAF (if no FAF, aircraft has intercepted final approach course)
• training flight and landing not intended
• RVR is fluctuating above and below
• South of 60 with no RVR or runway vis: ground visibility is fluctuating above and below
• localized phenomenon affecting ground visibility
• approach is conducted in accordance with 703.41, 704.37, or 705.48
• exceptions made based on operator certificate, 2-crew ops, aircraft equipment (FD / AP), runway lighting, etc. 
• different tables:
• CAP 1/2 (2600) >> RVR 1/4 (1200)
• CAP 3/4 (4000) >> RVR 3/8 (2000)
• CAP 1 (5000) >> RVR 1/2 (2600)
• (4) No pilot-in-command of an IFR aircraft operated under this Part shall commence a non-precision approach, an APV or a CAT I precision approach to an airport where low-visibility procedures are in effect.

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

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."

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