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Icing, Layers, Certification, and Smarts


M016576

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It's that time of the year again: ICING SEASON!

I've been trolling PoA and the major brand B forums... like many of you do... always looking for insight that maybe I haven't considered in relation to the hazards and techniques in General Aviation, and I had a thought cross my mind in relation to icing (obviously the hot topic for the winter months, to those of us in the northern latitudes).

Before I go further, a little about my experience, to help keep this thread in perspective: I'm coming from a background of 16 years as a military pilot in high performance jets and over 20 years of total flying experience.  That equates to about 4000 hours total time, with approximately 600 hours of general aviation time (ATP rated), and of that 4000 hours, about 500 hours of IMC time (actual).  I've owned two mooney's over the past 8 years, my current Mooney is a missile with the inadvertent TKS system.

I've flown in icing. I've flown in icing conditions. I've flown in icing conditions where there was no ice, and I've flown in areas where no ice was forecast, and picked it up.  It seems like most of the IFR rated folks around here that have done much hard IFR time in the winter month up north have probably done and seen the same.

WAAAAAYYYYY back during my instrument ground school, in Pensacola, we learned that +5c to -40C with visible moisture could yield icing.  I've found that to be accurate... as that temperature range certainly yields the conditions necessary for icing to exist.  Practical application, though, of flight in clouds between that temperature bracket has proven to me, that ice only forms the minority of time that I'm in clouds between that temperature range- so there's more to it than just temperature and visible moisture (as we all know).

1.  I hear a lot about people with TKS systems saying "I use this system to punch through a layer and get on top."  I use my TKS system for the same application.  The question becomes- what exactly is the legal difference between the inadvertent and FIKI TKS system in punching through a layer with a known out on either side (above / below)? 

2.  Here's an even better question for those more weather knowledgeable than me- the type of cloud that could form as a defined layer through which one could "punch through"- could it house significant ice to overwhelm such a system (fiki or not... as they both have the same coverage on a mooney)?

here are my answers before I open it up to the crowd for discussion!

1- If you're using the system to "punch through layers to get on top," then the issue is mainly are there PIREPS of icing on departure (ie known icing conditions).  If that's the case, then you shouldn't transit the layer in an inadvertent system (legally), even if you know that the layer is "transit-able."  This could become a different situation on approach into a field, however.  If icing was not forecast at your destination, and you are above a known, defined layer of clouds that are below freezing with the inadvertent system, descending through that layer would not be illegal, unless there is some form of information that tells you that icing exists.  But what if you know you can get below the icing layer (a pirep states the cloud layer is 1500' thick, with light rime, and was made by a M20M 5 minutes prior to your arrival in the terminal area, and that the field is calling VFR... just a widespread overcast stratus layer)- so your intention isn't to fly continuously in the icing layer, but just to transit through it to a known, non-ice area?  would that pirep (seemingly benign) force you to an alternate, or could you legally justify punching through the layer?  (answering questions with questions- perfect for stimulating conversation!).

2. My answer here is yes, layered clouds could house more ice than a fiki system could handle- unless you know via PIREP where the tops are and calculate climb rate vs accumulation vs shed capability.  I don't think there are many of us, FIKI or not, that would launch into clouds 200'-FL280 with known moderate ice, and plan to fly continuously in those conditions in a single engine piston GA aircraft (Although I'm SURE someone will post a story of how they do that regularly).  Where would you draw the line as a FIKI mooney owner, on cloud conditions and what you would and would not launch in. 

Again, these questions are meant to stimulate conversation, and are hypothetical in nature, but allow us to chair fly some situations on the board, and in our minds, that are more ambiguous that the icing circulars draw out in black and white.  After hearing what some of the piston twin folk say, from brands P and B, as well as the parachute wielding brand C single engine folks, I figure I'd get some insight from the smarter, more handsome, cooler and more interesting Mooney folks!

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M,

Did you search first?  I like the seasonal conversation.  So, allow me to start...

Fiki vs non-FIKI.... primary function is identical.  Secondary function for reliability and useability are night and day... extra back-up systems and lights to improve functionality...

The volume and coverage are both limited, so punching through a layer is prudent.  Hanging out for the hours of flight in icing would be a horrendous idea...  minimizing exposure is key.

There are areas around the country that are known for the worst types of ice clouds.  Lake effect and Pacific NW effect seem to be places where an ocean of water can be lofted above and move 1000miles...

There are weather products available to help avoid icing and know where icing Starts and ends...

Icing comes in different types of threats.  Additional weight. Loss of lift. Loss of visibility, And, Loss of thrust.  Consider these when looking how well your system protects your plane.

Hope that helps give you some guidance.  I know this stuff is here, because, it's not in my POH.  (Wish it was)

Best regards,

-a-

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my bravo is fiki equipped.That being said ,whether or not the plane is inadvertent vs fiki only matters to the Ntsb investigator staring at the smoking hole in the ground.Both systems work well in my 7 years using the tks.And yes my primary use is to punch through icing layers.Only once or twice have I stupidly plowed on ,going through stratus cell after stratus cell almost exhausting my entire 6 gal supply.My wife ,wasn't to happy on a couple of those flights,she was cold up high and the Bravo heater was coping with oat of -37.I just didn't believe stratus clouds at that temp could contain that much ice.I maid my moderate rime ice report with chattering teeth .I know know to avoid "pink"nexrad cells over the high southern Sierra s.I guess my pireps generate known ice conditions.I only report what I see.

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24 minutes ago, thinwing said:

my bravo is fiki equipped.That being said ,whether or not the plane is inadvertent vs fiki only matters to the Ntsb investigator staring at the smoking hole in the ground.Both systems work well in my 7 years using the tks.And yes my primary use is to punch through icing layers.Only once or twice have I stupidly plowed on ,going through stratus cell after stratus cell almost exhausting my entire 6 gal supply.My wife ,wasn't to happy on a couple of those flights,she was cold up high and the Bravo heater was coping with oat of -37.I just didn't believe stratus clouds at that temp could contain that much ice.I maid my moderate rime ice report with chattering teeth .I know know to avoid "pink"nexrad cells over the high southern Sierra s.I guess my pireps generate known ice conditions.I only report what I see.

Outstanding point about the report, one I never even considered- would anyone pick up ice and NOT report it for fear of violation??  If I see even the faintest traces of ice, in my jet or mooney, I'm quick to report it- who knows what type of aircraft could be coming next, and how you may be able to help them with first hand knowledge along the way.  I've never really considered that I might be violated because I'm picking up ice. I guess I'm more of the "cooperate to survive" mentality regarding ATC instead of "they're out to get me."

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17 minutes ago, carusoam said:

M,

Did you search first?  I like the seasonal conversation.  So, allow me to start...

Fiki vs non-FIKI.... primary function is identical.  Secondary function for reliability and useability are night and day... extra back-up systems and lights to improve functionality...

The volume and coverage are both limited, so punching through a layer is prudent.  Hanging out for the hours of flight in icing would be a horrendous idea...  minimizing exposure is key.

There are areas around the country that are known for the worst types of ice clouds.  Lake effect and Pacific NW effect seem to be places where an ocean of water can be lofted above and move 1000miles...

There are weather products available to help avoid icing and know where icing Starts and ends...

Icing comes in different types of threats.  Additional weight. Loss of lift. Loss of visibility, And, Loss of thrust.  Consider these when looking how well your system protects your plane.

Hope that helps give you some guidance.  I know this stuff is here, because, it's not in my POH.  (Wish it was)

Best regards,

-a-

A-  I'm aware of other threads covering similar icing concerns- but I hadn't seen one that delved into what we all consider "a layer" before- so I decided to start this one as a seasonal tabletop discussion.  If it seems too redundant, I'll gladly abandon it, but I think there is value here that is nuanced enough and hasn't been discussed before, or recently.

and the real piece here is like you mention: this info isn't in a POH, or even really an icing circular or regulation- they are all designed with significant warning to allow for minimal liability while sufficiently vague to allow for flexibility.  But flexibility can possibly be just enough rope.... so I am always interested to see what other pilots are doing.  There's a great thread from last winter where a FIKI Baron pilot detailed his icing experience over a flight.  He said he was in Moderate ice for significant periods of time... from the pictures it looked more like light to me- based on the spinners and nose and the amount of time he spent airborne in the conditions.  I would not have launched in my mooney, though based on the described conditions (400' blowing snow, - temps at the surface, clouds up to fl200- same weather at destination).  But it's a pretty great thread, for those of you on beechtalk- I recommend a visit- search for baron fiki ice.

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Since both your questions are about the LEGAL elements I will not dwell on the system capabilities.

The FAA has issued a letter on this subject (attached) that basically allows a pilot to launch into any kind of weather legally i.e. forecast or even reported icing does not prevent GA pilots from flying. The FAA terms "icing" or "known Icing" to be the formation of ice on your air frame. In MY VIEW, the FAA has conveniently positioned themselves in a way to not prevent a pilot from flying but still holding them legally in violation IF the flight encounters actual icing.

Regardless, it would seem that "inadvertent" icing that does not result in an emergency or accident will be ignored by the FAA.

090126icing.pdf

p.s. I am not an attorney and I did not stay in a Holiday Inn last night. View my post with the appropriate cautions.

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BT also has a really strong weather guru in their community...

I wonder.... if he became the weather guru before or after purchasing the B...:)

A good grasp of weather knowledge and prediction skills comes with the IR territory.  Thunderstorms and icing are incredibly important to have a complete grasp on.  And all the instruments to go with it...

Best regards,

-a-

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42 minutes ago, Cruiser said:

Since both your questions are about the LEGAL elements I will not dwell on the system capabilities.

The FAA has issued a letter on this subject (attached) that basically allows a pilot to launch into any kind of weather legally i.e. forecast or even reported icing does not prevent GA pilots from flying. The FAA terms "icing" or "known Icing" to be the formation of ice on your air frame. In MY VIEW, the FAA has conveniently positioned themselves in a way to not prevent a pilot from flying but still holding them legally in violation IF the flight encounters actual icing.

Regardless, it would seem that "inadvertent" icing that does not result in an emergency or accident will be ignored by the FAA.

090126icing.pdf

p.s. I am not an attorney and I did not stay in a Holiday Inn last night. View my post with the appropriate cautions.

I would agree with your assessment based on the Bell letter.  But that in turn goes back to the question on the table- would you legally need a FIKI system to continue through a known layer (if you start picking up ice) to achieve a known on top or out of icing condition? Or should you have to descend back out of the conditions.., or should you have just stayed in the FBO sipping coffee :P

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27 minutes ago, carusoam said:

BT also has a really strong weather guru in their community...

I wonder.... if he became the weather guru before or after purchasing the B...:)

A good grasp of weather knowledge and prediction skills comes with the IR territory.  Thunderstorms and icing are incredibly important to have a complete grasp on.  And all the instruments to go with it...

Best regards,

-a-

The BT weather guru certainly enjoys his Skew-T diagrams!

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The bell letter is nice...

1) it requires being a lawyer to interpret...

2) a weather expert to apply it

3) a systems engineer to know how to apply it to your specific aircraft.

4) a PIC to behave in the proper manner.

The way I (a PP with aged IR) understand this is simple...

If there are known icing conditions in front of you, it would be best to avoid them, unless you have a FIKI system.

With a FIKI system, That allows you some flexibility to transit the area of known icing, in the shortest possible way within the restrictions of your aircraft.  The shortest possible way is often higher or lower by a few thousand feet.  FIKI or not the get out of the icing is the same... take the shortest or best route...

Check to see if your pitot heat and your stall warning device heater are both working.  Having an ice coating on the wings will change it's lifting capability.  This could significantly change the stall speed and behavior.  

Is your stall vane heated? Is your prop heated?

Best regards,

-a-

 

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There are no airplane cops that will pull you over if you have ice on your plane. If you have some kind of incident or declare an emergency, you better have your preflight ducks in a row proving that there was no forecast or reported icing.

i would fear the ice more than the Feds.

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Hopefully the reporting of pireps will increase, I'm glad you report icing on every encounter. On my many flight in the northeast I only wish there would be more pireps even if stated negative ice at 12000 ft., temp. -7, I often ask if there are any pireps, last month between Cleveland & Detroit, Cleveland control asked me to provide them a pirep. Also it was mentioned moderate icing where it was felt to be light icing. We should know the difference when reporting conditions it could mean the difference between diverting or carrying on therefore the report should be standard.

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2 hours ago, Danb said:

Hopefully the reporting of pireps will increase, I'm glad you report icing on every encounter. On my many flight in the northeast I only wish there would be more pireps even if stated negative ice at 12000 ft., temp. -7, I often ask if there are any pireps, last month between Cleveland & Detroit, Cleveland control asked me to provide them a pirep. Also it was mentioned moderate icing where it was felt to be light icing. We should know the difference when reporting conditions it could mean the difference between diverting or carrying on therefore the report should be standard.

I think the system is standardized in what equals what, but pilot experience and hardware vary, thus the pirep does have an element of the subjective.

the difference, as I understand it, isn't the amount of ice on the airplane, rather the rate at which it is accumulating.  Thus, a 1 hour moderate ice encounter *should* yield 1-3 inches of ice on an unprotected wing surface.  I've heard pilots call 1 inch of ice in 10 minutes moderate, and 1 inch in an hour and change light.  Neither are technically wrong...

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