De-icing and Anti-icing

Types of Fluids

• Type I
• minimum 80% glycol
• relatively low viscosity
• very limited anti-icing protection against re-freezing but does not protect against further accumulation
• Type II
• minimum 50% glycol
• high viscosity
• effective anti-icing
• for aircraft with Vr > 100 kts; shears off on take-off
• potential to lose effectiveness if improperly applied
• Type III
• properties between Type I and Type II
• for aircraft with Vr < 100 kts
• Type IV
• same fluid specifications as Type II, but longer holdover times
• dyed green to aid consistent application

Holdover Time

• the estimated time that the application of de-icing/anti-icing fluid will prevent the formation of frost, ice, or the accumulation of snow on treated surfaces of an aircraft
• begins when the final application of de-icing/anti-icing fluid commences, and expires when the fluid loses its effectiveness

Frozen Contaminants

Reference AIM AIR 2.12 Flight Operations in Winter

Factors affecting contamination and hold-over time:

• ambient temperature
• aircraft surface temperature
• de-icing / anti-icing fluid type, temperature and concentration
• relative humidity
• wind speed and direction

Cold-Soaking Phenomenon

• fuel temperature affects wing surface temperature
• cold-soaking at altitude means fuel in tanks may be much colder than ambient temperature after landing
• clear ice or frost may form on some aircraft on wing areas above fuel tanks, especially in conditions of high relative humidity

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

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!

2015: The Year of the ATPL

I'm not particularly one for making New Year's resolutions.  But this wintry weather in Montreal coincides with the beginning of the year and a few days off before starting work again, so it's a perfect time to start studying for my ATPL exams (which I plan to write by the end of March).  

Transport Canada has provided a lovely 46-page Study and Reference Guide for my reading pleasure... and who wouldn't want to spend their quiet evenings with a cup of hot chocolate, pouring through textbooks and notes in order to prepare for 7 hours worth of exams? (SARON, SAMRA, 80 questions/3.5 hours each, minimum pass mark 70%, but aiming for perfection!).  My plan is to provide highlights here, which will hopefully benefit others in the future.  

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A quick note about the name of this blog, 'Checklist'. That's essentially what the Study and Reference Guide is... a checklist to refer to, so we can verify we've covered everything.  And according to the CARs:

CAR 704.19 Checklist
(a) have a checklist and make it available
(b) use it

CAR 602.60 (2) further explains checklist requirements: basically it shall enable the aircraft to be operated in normal, abnormal and emergency conditions.

Sounds like a no-brainer right?  Yet, somehow, we still hear stories about pilots skipping steps because they think they can do them by memory.  Or worse: making up their own procedures.  

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The other portion of course is the 1500 TT requirement.  I'm roughly on track to achieve that by the end of the year.  And so it is my hope and goal that 2015 goes down in my book as the Year of the ATPL.  

Thanks for joining me... now sit back, relax, and enjoy the flight :)