What criteria for FIKI?
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bob_albertson
Pre-takeoff checklist
It's a certification process.... They follow already established parameters. Manufacturers may choose to "add safety factors" to the criteria, but just look in parts 23 and 25 to view the certification standards. Be prepared for a lot of looking up of new terms and a quick read of AC 91-74 will help with understanding some of the other criteria.
It is important to understand some parts of the certification process so that pilots also understand the limitations of their aircraft. This is probably the most forgotten detail with planes certified for FIKI.
Bob
gismo
Touchdown! Greaser!
There's also a substantial testing requirement. AFaIK, the design requirements are about safety (can't adversely affect the operation of the aircraft), reliability, and performance expectations. But even a design that meets all the specified requirements must go through a series of inflight testing which normally involves flying behind another airplane spraying water at an altitude where the OAT is below 0°C.
bob_albertson
Pre-takeoff checklist
I haven't looked for a while... I thought the flight tests were included in the part 23/25 certification standards? They have limits for how many microns the droplets should be, and I thought that is where the flight tests came in -- to test the water particle size to aircraft performance standards?
I haven't stayed in a Holiday in for several weeks and I stopped taking Ginkgo about a year ago
bbchien
Touchdown! Greaser!
I can't find the document, but the spray boom behind the C130 has to deliver a sepctrum of droplets averaging 40u in size but up to 100u in the spread. The exposure is 10 minutes between -2 and -10 IIRC. The a/c must reamain controllable- be able to climb, turn, descend, following the 130.
This is from an icing engineer who has passed away but was on Lifeline's board ?(C. Dan Cichy).
This is from an icing engineer who has passed away but was on Lifeline's board ?(C. Dan Cichy).
bob_albertson
Pre-takeoff checklist
Oh, that temp spread is right in the sweet spot for severe icing encounters too. The part that always made me stop and think was when the NASA videos started warning that no testing has been done for SLD events.... as far as certification standards. So every time your windshield suddenly ices over and the ice cap on the spinner goes behind the icing limit line - in a matter of seconds -- You've just become a test pilot for your plane.
Avoiding SLD events is one of my big motivations for trying to always read up on icing. I'm glad NASA took a subject that's potentially complicated for even meteorologist, and made it a bit easier for pilots to understand. Although, the host sure does really grab your attention and draw you in with his ever exciting voice and dramatic segways
dell30rb
Final Approach
hey now, what is SLD?
bob_albertson
Pre-takeoff checklist
Supercooled Large Droplets. It's like going through a car wash when the water and collecting surface are between -5 to -10 C, compared to using a mist spray to wash your car.
Think sudden clear ice, up to 1/4" thick in a matter of seconds. That is the possible side to a severe SLD event.
Check out AC 91-74 on the FAA's website. You can open it as a PDF and search "SLD" if you don't want to read the entire AC.
The part that always surprised me is that a "large drop" is about the size of a human hair
. A rain drop looks like Jupiter next to our moon when you compare a large drop of 50 microns (IIRC) to the average rain drop size.Bob
bob_albertson
Pre-takeoff checklist
Never Fails, outstanding information that's easy to understand and even better than any aviation weather book that I've read. Even the Jeppesen book could take some notes from you Sir, not all pilots need a book made for a meteorologist, but most aviation weather books treat it like that. So much non-pertinent information, and information that can't be easily applied unless you have the book to help you recall the information
.This is why I am a member of your website, and as a professional pilot I find that understanding your office is just as important as knowing the paperwork (ie. the flying and rules). So much to be learned from you.... Would you ever write an aviation weather book for pilots?
Skylane81E
Final Approach
And Scott brings up a good point on the certified ice protection. Even the "escape" de/anti-ice goodies haven't been proven.
Skylane81E
Final Approach
Yep, better than noting but only so long as you fully understand the limitations of non FIKI equipment.
bob_albertson
Pre-takeoff checklist
Not unless an individual has made a "gee-whiz" type of data sheet listing them. For the most part you have to check with each manufacturer to see which models offer some form of ice protection. Don't confuse those offering TKS with the ability to remain in icing conditions. TKS buys you time to exit the icing conditions - not forge ahead.
The plane I fly has the ability to remain in certain icing conditions (as could be required for approach and landing), but like I mentioned above knowing the limitations on the system is vital (which is gleaned from knowing what the plane has been certified for). Still, the best tactic is to exit the icing conditions by going up or down.... even with that convective activity can throw rain outward from the cell --- two nights ago we were getting icing while flying above a cell, we were in visible moisture (i.e. it was wet snow) with no clouds above us and none in front of us
.... kinda cool really. Either way, I guess my real point is that just because a plane has been certified for FIKI doesn't mean it has been certified to STAY in icing conditions. IIRC, Dr. Bruce's 10 minutes is what the certification standard is for part 25 aircraft... I don't remember what it is for part 23. Bob
bob_albertson
Pre-takeoff checklist
The unavoidable stuff can be a bit unnerving too. We all gain interest in things through our own experiences, sometimes. I started to want to learn more about icing conditions right after I had what, at the time, was a mind blowing encounter for me. I was going on my first IFR cross country as a newly minted IR pilot, and doing it single pilot. Check of the weather (with the old FSS - pre Lockmart) and the briefer said the night looked great for getting some actual - no airmets for icing and no pireps for icing either. The area forecast looked good and the temps were all well above the freezing level for the layer I wanted to spend my time flying in.
About half way to Texarkana (Hot Springs to Texarkana flight), I saw ice was on the windscreen and I started losing the pitot/static instruments shortly after that. I told center and they said they couldn't get me lower, so I told them I WAS descending because of icing and he cleared me down without either of us declaring. A short time after exiting the conditions all was normal again, but what I found out in the end was that I had an encounter with a very mild SLD event. The temps were above what the freezing should have been, but I also learned that not all OATs on the older Cessnas are all that accurate
. That started the hankering to learn "how not to do that again"
Skylane81E
Final Approach
Sounds like my ice encounter. I was vfr and had just crossed overtop of a small frontal system at 11,000msl where it was in the upper teens oat. Shortly after that I dropped under a small area of verga and despite being in the upper 30s the plane was still freezing so it stuck, in a hurry. Didn't last as the temp was warm and warming as I continued to decend.
I imagine that I'm in a small group of pilots to collect ice in above freezing vfr.
I imagine that I'm in a small group of pilots to collect ice in above freezing vfr.
Ted
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You need to look at the specifics of each system and what it consists of. A true FIKI aircraft has a lot of extra goodies, plus it's been tested. Those are nice comforts to have. Things like the stall warning heaters, heated fuel vents to prevent fuel starvation from ice accretion, etc.
The incidental systems still have their merits, though. In a number of cases (typically on older aircraft with boots), the major parts used on the incidental are the same as on the FIKI systems. They just typically won't have all the goodies of a FIKI plane. I find the planes with prop anti-ice but no boots to be humorous. Funnier still, I saw a plane with wing boots but no tail boots.
The reality of icing is that you end up being something of a test pilot every time you fly your aircraft, FIKI or not, into icing. Each ice encounter is going to be different. Furthermore, you have certain aircraft that just do not lend themselves well to flight in icing (think Cirrus, Lancair, anything with a hot wing), and certain aircraft that handle it very well (think Aztec, or anything with a big, fat, slow wing). What's important is that you know the limitations of your equipment firstly. Keep your head about you, have a good plan with good outs, execute them accordingly, and be willing to change the plan when appropriate. Hand fly the airplane so that it can tell you how it's responding to this particular ice situation. And get out of there.
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Bob Gardner
Not unless an individual has made a "gee-whiz" type of data sheet listing them. For the most part you have to check with each manufacturer to see which models offer some form of ice protection. Don't confuse those offering TKS with the ability to remain in icing conditions. TKS buys you time to exit the icing conditions - not forge ahead.
The plane I fly has the ability to remain in certain icing conditions (as could be required for approach and landing), but like I mentioned above knowing the limitations on the system is vital (which is gleaned from knowing what the plane has been certified for). Still, the best tactic is to exit the icing conditions by going up or down.... even with that convective activity can throw rain outward from the cell --- two nights ago we were getting icing while flying above a cell, we were in visible moisture (i.e. it was wet snow) with no clouds above us and none in front of us
Bob
Part 23 incorporates the icing appendix to Part 25 by reference...there are no separate standards for Part 23.
I'm relying on memory here, but IIRC Appendix C to Part 25 says that if you stay in a stratus layer for more than 17 miles or in an area of convection for more than 3.8 miles you have exceeded the standards for FIKI and are now a test pilot. As others have noted, FIKI does not permit a pilot to remain in icing conditions, it just buys time to exit those conditions.
Many, many years ago the Assistant Administrator for Regulations and Certification used to participate in an online forum and I got to know him through that medium. When I met him in person, I asked him the age-old question: If I am flying a non-FIKI airplane and encounter icing conditions, should I make a pilot report, or am I setting myself up for a violation? His reply was that I was required to report any unanticipated weather conditions but I would get a violation only if I did not take immediate steps to get out of the icing conditions.
Bob Gardner
Dave Siciliano
Final Approach
Yep, gotta watch flying in that Viagra! Can lead to some hard decisions.
Best,
Dave
gismo
Touchdown! Greaser!
Especially if you crash as a result.
straightwingedjetsrule
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Not sure I could agree with the bolded parts. My hot wings (mmm hot wings sound delicious) handles ice just fine if the dern'd operator (this guy) can remember to use it as anti-icing and not de-icing. On the other hand, I can think of a plane with a big, fat, slow wing that I have no desire to fly in ice if I can do anything to avoid it (Caravan).
Ted
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Scott got the reasoning for my statements. But our new friend is correct, it is not a 100% rule. I'm also looking more at piston aircraft, not getting into the various turbines and jets out there.
I would rather fly an Aztec with boots (but not certified FIKI) in ice over a Cirrus with certified FIKI TKS any day.
But if given the choice, sure, I'd take a Lear or a Gulfstream first.
Ted
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Point taken, but the Aztec's wing will also carry a LOT of ice, including runback. The Cirrus... not so much.
Skylane81E
Final Approach
Performance can be your best anti ice tool.
Ted
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Yes. The 310 has some advantages over the Aztec with its 300 HP engines instead of the 250. If I had my druthers, I'd put 421 engines (GTSIO-520s @ 375 HP a side) in the 310. Then add speed brakes. Altitude change? Yeah, we could do that.
Morne
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I'd like to drill down on this thought for a moment, especially in light of Ted's remarks about twins:
Is this why something like the old C-337 (inline pair of 210hp engines) is not a good candidate for FIKI?
Conversely, the Aerostar 600 series (pair of 290hp engines) might be a better FIKI candidate?
I can only imagine what a Beech Twin Bonanza E50 (pair of supercharged 340hp engines) could do.
Skylane81E
Final Approach
Well you can get a 337 FIKI. Thing with the centerline engine is that structural ice shed by other parts of the airplane can get into the pusher engine/prop.
But on the performance factor it's the ability to get the hell out of the ice before it drags you down.
But on the performance factor it's the ability to get the hell out of the ice before it drags you down.
Ted
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I've got no experience with the Skymasters, but I would expect them to be a less than optimal aircraft for icing due to the lower power (not sure about the weight). Although that's not much different than Senecas. Never flown a Seneca, either, but that is the minimum aircraft I'd want to venture into icing with. Aerostars aren't great candidates due to their hot wing design, but the power does help them out.
What I don't like about the Cirrus for ice is its hotter wing design, and relatively low performance. Yes, TKS has its advantages over traditional boots, but also has disadvantages.
The 310 isn't great in icing, but it does well enough with it. Like I said, in the 310 I fly, the power is what really helps it. Turbos would be better still.
straightwingedjetsrule
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Morne
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Morne
Can somebody clue me in as to what "hot" is being discussed here?Oh THAT is what you meant by "hot" wing. Then yes, I definitely agree!
Ted
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Oh THAT is what you meant by "hot" wing. Then yes, I definitely agree!
Ok good!
Many jets have "hot wings" whereby bleed air is used to heat the leading edges of the wings. Very nice, because ice shouldn't even form in the first place on them.
Skylane81E
Final Approach
Yes. The 310 has some advantages over the Aztec with its 300 HP engines instead of the 250. If I had my druthers, I'd put 421 engines (GTSIO-520s @ 375 HP a side) in the 310. Then add speed brakes. Altitude change? Yeah, we could do that.
BTW that 310 sounds like a blast.
It's only money, just go big with a pair of PT6s!
Morne
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Morne
The Aerostar 600-series is a piston twin, not a jet. Hence, I am still lost.
Ted
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That's what I thought! I think I could do it reasonably enough on cost, provided some of my assumptions regarding the base airframe are correct (big assumption). Might have to put together an STC proposal and talk to my ACO.
It's only money, just go big with a pair of PT6s!
If I went turbine I'd probably go TPE-331-5. However, with only 140 gallons of fuel, even 421 engines would necessitate adding some wing-locker tanks to get reasonable range. Going turbine, I'd barely make it off the ground before declaring fuel emergency. That's the problem that the turbine Dukes have.
Ted
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There are two definitions of "hot" with respect to wings.
1) Aerostar 600: Has a "hot" wing design. High aspect ratio. Builds up ice quicker, and is more adversely affected by having that ice build up. Aerostar, Lancair are both examples of piston aircraft with "hot" wing designs.
2) Most jets: Use bleed air to prevent ice from forming on the wings. The bleed air is hot, and makes the wings hot.
RotorAndWing
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The 337 actually does well in ice. Never had problems with ice getting into the rear prop.
The front prop is electrically heated and the rear prop uses heat from the engine for anti-ice.
As previously posted the best defense is to minimize your time in icing.
Morne
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Morne
Thanks for clearing that up!
Skylane81E
Final Approach
Yep, just ice ingestion is an issue conventional twins don't have to worry about
Skylane81E
Final Approach
Just tow a drop tank, Germans played with trailers in WWII
But the piston engine is a better option
straightwingedjetsrule
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Garrets are louder, so by definition they are "better".
Ted
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