After taking most of December and a good part of January off, winter has arrived at the virtual airport. I'm alone in the Pilot's Lounge because freezing rain is falling outside and those who were here realized flying was done for the day and went home. Naturally, because I've come back out here to do some research (I have to rewrite my column on flight in known icing conditions due to breaking news), the worst possible kind of icing is encasing the nearby world as I work. I'm beginning to wonder whether I'll be able to get into my car.
There are no two ways to slice it -- flying any kind of airplane in icing conditions is ugly. While it is not one of aviation's big killers, in-flight icing events claim about 10 to 20 lives annually and a few hundred pilots get to fervently wish they were on the ground rather than in flight. There is a good article in the January 2007 issue of IFR Magazine by Jane Garvey about icing accidents and statistics.
Even a little ice can be a big deal because it immediately screws up the carefully researched and designed contours of the wing, slowing the airplane and increasing stall speed, often dramatically. The majority of us fly airplanes that do not have much in the way of anti- and de-icing equipment. Therefore, when we fly in the winter and there are clouds about, those who have been around the block a few times tend to plot and scheme to minimize our time in the clouds because most of us have had the snot scared out of us once or twice by airframe icing.
It used to be that every once in a whiles someone would write an article claiming that in-flight icing wasn't all that bad and one could always go by just following some rule-of-thumb or other. That sort of jauntily optimistic sort of article came to a halt more than 20 years ago when the guy who wrote one such piece for FLYING magazine vanished with his Senator passenger in conditions of heavy icing during the time between when he wrote the piece and it appeared in the magazine. Nature has a funny way of making pronouncements of humans ironic.
Photo courtesy NASA Glenn Research Center
Pilots who are possessed of smarts as well as airplanes that are certified for flight into known icing conditions use the equipment on those airplanes to get out of the ice rather than continue to fly in the stuff. To get an idea of just how nasty in-flight icing can be and how puny our attempts to deal with it are -- despite the infusion of massive amounts of cash and engineering effort -- take a hard look at the Federal Aviation Regulations involved in certifying an airplane for flight in known icing. Anyone who has ever gone through that certification process will tell you that it is horrendously expensive, complicated and difficult. Yet, once all is said and done, an airplane that is certified for flight into known icing conditions has only demonstrated its ability to fly level in moderate icing for about 17 miles. That's not a heck of a long ways. And that is with boots or TKS, hot props, heated windshields, heated pitot tubes, a heated static source and other minor, but expensive gizmos. That is how bad "moderate" icing can be. Attempting to continue to fly in actual icing conditions rather than immediately seeking a way out can be one of the final mistakes a pilot ever makes.
A de-iced airplane still builds up ice on portions of the structure that are unprotected, which adds drag, and some weight. Pilots who fly "known icing" airplanes long ago learned to use the equipment aboard to get out of ice, not to press on in it. They will also tell you that should the icing conditions consist of freezing rain, all bets are off. Nothing -- absolutely nothing -- will give you any guarantee of more than very brief flight in freezing rain. There is a long-told story of a DC-2 en route into Chicago Municipal (now Midway) Airport in the late 1930s. At about the outer marker it encountered freezing rain. The crew elected to continue the approach as the airport was only about 5 miles away. They barely made it, floundering onto the runway at full power. This, in an airplane that had very similar de-icing equipment to what we have today and which was reputed to be a very good ice hauler. The report was that it had over 5 inches of ice on the leading edges of everything (the de-icing boots were simply overwhelmed). It took on the order of a half hour just to chip the ice off around the cabin door to let the occupants out.
If a "known icing" airplane only has to demonstrate the ability to carry on in ice for about 17 miles, what does that say about the abilities of an airplane with nothing more than a heated pitot tube and a defroster?
To answer an otherwise rhetorical question: An airplane that is not certified for flight into known icing conditions is not going to fly very long in moderate icing. However, and this is the big "however" because we are now entering the gray area of the real world of flight in icing conditions, that same airplane will not simply fall out of the sky upon brief exposure to rime or mixed icing. If that were not the case, almost every instrument-rated pilot in the northern part of the country would have to park his or her airplane for most of the winter.
Those who fly IFR where ice is a risk by and large have learned that if they enter a cloud when the temperature is between about +1 °C and -20 °C, they are probably going to pick up ice. Those with any common sense act accordingly. They do everything they can to minimize their exposure to ice. They know that if they have to enter a cloud, the worst icing will be near the top. They stay out of any clouds with vertical development because icing is worse in those than in clouds that lack such development. Around the Great Lakes they know that most days clouds will form layers and, if there is lake effect snow, the layers will usually be only a few thousand feet thick, tops are rarely above 10,000 feet and it is usually possible to find ice-free air between layers. They know that if they are in snow, outside of a cloud, that sort of visible moisture never causes airframe icing. They know that if they have to penetrate a cloud layer going up, they level off underneath it, accelerate to get the airplane going as fast as they can possibly make it go, then zoom climb through the layer. They never let the IAS get below 10 knots above Vy so that any ice they get is right on the leading edge and not down underneath where it can cause big problems. If descending through a layer, they do so fast. They avoid flying level in clouds, period.
In the real world pilots need to make use of their airplanes in winter. They do so, and most collect a small amount of ice in the process. They cannot afford to park their airplanes because there is a 2000-foot-thick layer of clouds starting at 2000 feet AGL, with clear skies above and there is some rime ice to be had in that layer of cloud. No, they go. They know how to go about it and they deal with that ice cautiously and safely. However, in doing so, they are probably in violation of the FARs.
Is it legal for us to fly a small, general aviation airplane into icing conditions? If the airplane has been specifically certified for flight into "known icing conditions" (and all three words are important to that phrase), it is legal. (As discussed above, it may not be safe.)
If the airplane has a Pilot Operating Handbook and has a limitation or prohibition against flight into known icing conditions, it is clearly not legal.
If the airplane was manufactured prior to about 1976 and has an Owner's Manual (as opposed to a Pilot Operating Handbook) and no Approved Flight Manual, that Owner's Manual probably does not say a word about operation in "known icing conditions," and to do so is probably, but not certainly, illegal. (There was also a period of time when the FAA did not formally certify airplanes for flight into known icing conditions, so whether such operation is legal or not on such things as a Beech 18 involves some serious homework.) There is a gap in the FARs on those airplanes, and it may be that flight into known icing conditions constitutes "careless and reckless" operation rather than operating contrary to the operating limitations of the airplane. The discussion on the legality of flight into icing conditions in those airplanes can get much longer than I'm in the mood to explore. Suffice to say it would make sense if one did not have to do in-depth research to find out if the airplane he or she wanted to fly was legal to fly into known icing conditions.
Photo courtesy NASA Glenn Research Center
From the standpoint of having to do research to find out what a regulation means, finding a definition of "known icing conditions" has meant digging into the case law where the NTSB has interpreted the FARs. The NTSB is charged with interpreting the FARs, and often does so when it makes rulings in the cases where the FAA seeks to suspend or revoke a pilot's certificate for violating a regulation. (The NTSB hears the cases the FAA brings against pilots). Finding those interpretations means reading what the NTSB has written in those cases. That takes some work.
Boiling down a lot of words in NTSB opinions, "known icing conditions" has been interpreted by the NTSB to be airspace in which pilots have reported ice or there is a forecast of at least a "chance of icing." That interpretation is overly conservative, but it is what pilots have lived with for years. They did their flight planning so as to stay out of clouds in the areas where there was a "chance" of icing conditions, unless the temperature was below -20 °C, or to keep their exposure to clouds to a minimum knowing that they were probably operating illegally but safely when they planned to make a brief foray through some clouds.
Even with the overly conservative definition by the NTSB, time and experience came to show that there was a balancing factor out there that kept all of us pilots who sometimes spent 30 seconds zipping through a layer of cloud and picking up a bit of rime ice from getting our certificates suspended. That was that the FAA took a pragmatic view of aviating and did not pursue violation actions against pilots for intentional flight into known icing conditions in an airplane that wasn't approved for it unless the pilot managed to prang the airplane or otherwise screw up enough to bring himself to the FAA's attention. Even then cooler heads at the FAA realized that education was a far better way to deal with a wayward pilot and often directed offenders to its excellent remedial training program rather than hit them with violations.
Things weren't perfect, but they weren't bad with that status quo. The "known icing condition" definition was about as close as one could get to black and white in the gray area of forecasting icing conditions. Another good thing was that the definition worked well as the new, increasingly sophisticated icing forecasts became available. Pilots could get cross-sections of the atmosphere and have a pretty good idea as to the locations and altitudes where they might be at risk of airframe icing during a planned trip, thus the areas of a "chance of icing in clouds and precipitation" became less gigantic and more realistic, allowing pilots to make good preflight planning decisions. Pilots honestly passed on pilot reports of icing knowing that doing so would not put them at risk of an enforcement action. They made use of their non-de-iced airplanes throughout the winter, even around the Great Lakes, where weeks may pass without viewing the sun due to persistent layers of clouds. Better still, pilots did not try to scud run under a thin cloud deck, a far more risky, but legal operation, rather than whistling up through that deck, catching a trace of ice and then having it sublimate off as they made their trip in the sunshine. Had the FAA ever tried to strictly enforce the NTSB definition of flight in known icing conditions, they would have caused a lot of deaths as pilots chose to scud run rather than risk their tickets with that trip through the cloud layer.
Then some enterprising pilot wrote to the New York Regional Counsel of the FAA asking for a definition of "known icing conditions." That has lead to a real mess.
As an aviation attorney, I'm hesitant to ever ask the FAA to define a regulation that has a lot of gray area because when someone tries to draw black-and-white demarcation lines, especially if that someone doesn't fly regularly in the real world, the results can be (and often are) very unpleasant. The results can make the challenges of dealing with the gray areas of the previous years look very attractive.
Yes, I know that there are those pilots who want to world to be black and white and get very paranoid when faced with the real world consisting of shades of gray. They should be treated gently and kept away from implements that are capable of creating letters to FAA lawyers asking for interpretations of regulations.
The lead attorney for the New York region responded with a letter that said known icing conditions included areas of "high relative humidity."
That was a first.
If you look at the FAA's own, very good, book on weather, Aviation Weather For Pilots and Flight Operations Personnel (you can download it from that link) and turn to Chapter 10, you find a lot of information on in-flight icing. Nowhere does it mention anything about high relative humidity. None of the FAA publications regarding in-flight icing mentions high relative humidity as a factor. It's because you have to be in visible moisture to get ice. While that is indeed high relative humidity (100%), adding "high relative humidity" as a factor to be considered in determining whether one's proposed flight will be in an area of known icing was ludicrous unless the author had gone on to define "high relative humidity" as 100% humidity. Being that any other definition is inconsistent with the visible moisture requirement of airframe icing, a rational person would logically assume that the author simply erred and forgot to mention that "high relative humidity" is 100% humidity.
The upshot is that despite many aviation groups calling for the FAA to withdraw the opinion letter, and despite the letter probably having no legal effect outside the New York Region of the FAA, the letter is sitting there like the proverbial elephant in the kitchen. It still has a lot of people worried. (As of this writing it has been reported that the FAA is withdrawing the letter, yet the FAA has not issued a formal withdrawal.)
First, it's impossible to comply with the regulation as interpreted by the New York region's letter: There is no weather forecast information available to pilots that provides relative humidity. Thus, an FAA attorney created a standard that is absolutely impossible for pilots to meet when conducting preflight planning. Stupid? You bet.
The chief pilot of one Part 135 charter operation told me that some of his pilots are now refusing to fly any of the airplanes that are not approved for flight into known icing conditions at all if the temperature will be below freezing. That is because, despite not being in the New York region, they are fearful that the new opinion letter will be used against them and they cannot get a forecast of relative humidity. Should an FAA inspector take a dislike to them, it would be easy for that inspector to start a certificate action against them for flight into known icing conditions, even on a clear day.
A silly over-reaction? Not to anyone who has ever dealt with a bureaucracy that has the power to issue arbitrary interpretations of the law and members of it who are willing to use those interpretations to persecute people they do not like. Remember, it was two rogue FAA inspectors who didn't like Bob Hoover and used an interpretation of the regulations to ground him.
The irony of the entire situation is that there are now more powerful icing forecast tools available to pilots than ever before. Yet, one region of the FAA chose to ignore all of the exciting new technology and hang the interpretation on the one bit of meteorological information a pilot cannot obtain when planning a flight. (A shrink would have a field day with the thought process leading to that result.) That attorney enlarged the definition of "known icing conditions" in a manner that did nothing to improve flight safety, erased the safety improvement available from new scientific data and caused pilots to either park their airplanes when they could be flown safely or fly in fear and keep their mouths closed if they get ice and not give PIREPS to warn others of its presence.
By ignoring technology and adding the undefined "high relative humidity" to the definition of "known icing conditions" the New York region provided no guidance to pilots. All it did was to give FAA attorneys more ammunition when they bring a violation action against a pilot. In my opinion, that was the reason for the letter -- not to improve flight safety, but to make the job of the FAA attorneys easier.
In my opinion, the action by the New York regional counsel was just plain wrong on two levels. It is my understanding that the FAA's mission is flight safety. Issuing an interpretation of a regulation that is geared to make it easier for FAA attorneys to convict pilots while diminishing flight safety is, as I look at it, unethical.
To make matters worse, not only did the New York letter do nothing to help pilots make safe flight planning decisions, there was, and is, no consensus as to whether the letter was or is even binding on pilots. For months pilots could not get a straight answer from the FAA as to whether they must comply with it. When individual FAA inspectors were called to ask whether the letter was actually policy and if so, for what regions, the answers I have got were that: 1) they didn't know; 2) they thought they had to follow it in the New York region; 3) they had to follow it everywhere; 4) it didn't matter at all because it was just a letter to one pilot; and 5) that it didn't matter because the FAA had withdrawn the letter with an internal memo that was not for publication.
It's scary when you ask the FAA for guidance on the interpretation of a regulation that has made the meaning of the regulation more confusing and you can't get it, especially when you are still on the hook for compliance with that regulation.
In my opinion, the only sensible thing for the FAA to do was to withdraw the letter and repudiate it. I hope the news reports and the information I've received from FAA employees are correct. In fact, I hope that by the time this column appears the FAA will have publicly repudiated the letter. It is time to return to the status quo of many years: Known icing conditions are in areas at altitudes where pilots have reported ice or there is a forecast of a chance of icing. While it is overly conservative, the new icing forecasts are much less scattershot than in the past and the "chance of" areas more realistic, thus allowing pilots to make informed decisions about planned flights.
Further, the FAA should continue its recognition that pilots can punch up or down through layers of cloud and acquire a little bit of airframe ice without placing the flight at risk -- and that it's often far safer to climb up through 2000 feet of cloud and light icing to operate in the clear air on top than to try and scud-run under the clouds to avoid being momentarily illegal by going through them. Under the long-time status quo, the FAA had more than adequate tools to pursue pilots for inappropriate operation in known icing conditions, and the pilot community knew it.
Until the New York region issued its opinion letter last summer, things were going pretty well when it came to appropriate operations in known icing conditions and how the FAA responded to it. The system wasn't broken. The New York region's "fix" didn't work. Let's hope it's gone.
See you next month.
Want to read more from Rick Durden? Check out the rest of his columns.