Archive for February, 2009|Monthly archive page

Pilot Error May Have Caused Crash Near Buffalo

Most images on this site enlarge with left clicks

Most images on this site enlarge with left clicks

What so many have been reluctant to say – probably being extra cautious because nothing is certain at this time – was finally printed in yesterday’s Wall Street Journal.  In my first posting about this terrible aircraft accident I suggested that if icing was indeed the problem – the accident should never have occurred.  Now – it is beginning to look as though the “reaction” to icing might have been incorrect causing the aircraft to immediately stall.

Please be mindful of the fact that the investigation of this accident is still in a very early stage.  Here is a link to the WSJ article:

http://online.wsj.com/article/SB123492905826906821.html

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RECORD LOWS COMING FOR PARTS OF FLORIDA

Left clicks enlarge most images on this site

Left clicks enlarge most images on this site

RECORD LOWS ARE EXPECTED FOR PARTS OF FLORIDA ON FRIDAY NIGHT AND SATURDAY MORNING.  I AM EXPECTING BELOW FREEZING WEATHER WHERE I LIVE IN NORTHEAST CITRUS COUNTY.  PLEASE GO TO THE FOLLOWING SITE FOR MORE DETAILS:

http://www.srh.noaa.gov/images/tbw/pdf/TopNews/RecordColdFeb21.pdf

THIS POST AND THE LINK ABOVE ARE TIME SENSITIVE.

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Icing Once Again Is Primary Suspect in Bombardier Dash 8 Q400 Crash

bombardier_dash-8-4001

The cause of last Thursday’s terrible airplane crash near Buffalo, New York may never be know for sure.  In any case, such investigations take many months.  There was a brief period of time when there were some significant doubts as to the role of icing in the accident – partly due to the embryonic stage of the investigation hindered by the complexities of carefully sorting debris of the aircraft and the house from the remains of the victims.  What a difficult job that must be.

Yesterday and today there have been more indications that icing was responsible.  If anything accurate can be said about the nature of the environment which produces icing conditions it is that it is fickle.  Just as the surface has its own micro-climatology, so do clouds.  It appears to me that the plane that crashed must have entered an icing environment which might have been severe.  There is also a possibility of some form of mechanical and/or instrument failure.  The final determination could very well point to a combination of unfortunate happenings.

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ICING AS PART OF THE HYDROLOGIC CYCLE – SOME BASICS

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TWO SEPARATE LEFT CLICKS TO ENLARGE

THE HYDROLOGIC CYCLE, A CLASSICAL TOPIC

IN NATURAL SCIENCE COURSES

I’ve taught the hydrologic cycle many times in geology, meteorology, physical oceanography and environmental science classes.  It’s always been a pleasure but I’ve never had enough time.  All of these were college courses and in almost every case the text book covered the subject adequately.  However, the manner in which water moves and changes in our natural environment is so very interesting that a few pages in a text with a traditional drawing and an hour lecture from me simply does not do the subject justice.  Water is such a remarkable compound – I can’t find the words to explain how very interesting it is and how mysterious it can be at times considering the amount of scientific attention it has received through the years.  There is still so much to learn.

So, it is with excitement that I look forward to a 6-hour course that I am scheduled to teach in May to the Senior Institute enrollees at Central Florida Community College.  In 37 years of full-time college teaching (and 4 years part-time) I never had the opportunity to devote so much time to the subject.  The method I intend to use is my own “idea” but surely it has been done before – that is, to follow water step-by-step as it goes from one phase or one environment to the next.  My presentation won’t be a journey without side trips and backtracking.  There are multiple manners in which water can transform and/or move with interesting little anomalies along the way.  With 6 hours to utilize I will be able to discuss aspects that were only fleetingly mentioned in my previous hour-long presentations e.g.: Capillary action, deposition, glacial calving, influent groundwater movement, juvenile water, super-cooled droplets, and much more.

SUPERCOOLED CLOUD DROPLETS AND ICING

I feel fairly certain that some people who read this have had the experience of having rain freeze upon impact with their vehicle’s windshield.  Some would assume that the freezing occurs because the windshield is so very cold.  That is usually not the case.  Instead, the liquid droplets were probably at a temperature well below “freezing” and the impact with the windshield itself triggered the instant freezing.  Hopefully, the “defrosting” vents can keep the windshield warm enough so that the ice can be quickly cleared.  Now, imagine what it must be like if the surfaces being iced are the windshield and wings of your aircraft in flight – as well as other aircraft surfaces (e.g. propellers, fuselage, horizontal stabilizers)!

Today, February 15, 2009, the mere thought of super-cooled droplets hauntingly reminds me that in addition to the marvelous beauty of water’s multifaceted journeys and transitions through our natural environment, there are some insidious elements that can become deadly in this modern world.  Of course, I’m thinking specifically of the recent terrible aircraft accident responsible for 50 fatalities near Buffalo, New York.

PURE SPECULATION

For a short while since the accident it appeared that icing might have been the culprit or perhaps a contributing factor in causing the aircraft to make its sudden rapid descent (apparently almost immediately after the application of flaps).  At the time other aircraft in the vicinity were reporting icing.  HOWEVER, AT THE TIME OF THIS WRITING, NEWS RELEASES HAVE INDICATED THAT THE NATIONAL TRANSPORTATION SAFETY BOARD CLAIMS THAT ICING APPEARS NOT TO HAVE BEEN A FACTOR. The changing of the airfoil’s shape upon flap engagement might have triggered the rapid descent – an apparent stall leading to a flat spin.  That would indicate either insufficient air speed at the time of flap deployment or some type of catastrophic failure.   SINCE MANY AVIATION ACCIDENTS HAVE BEEN CAUSED BY ICING – AND IT WILL REMAIN A PROBLEM FOR AIRCRAFT FOR A LONG TIME TO COME, I SHALL CONTINUE.

When icing was being blamed, I suspected that some critical errors might have been made in the cockpit.  At best, my notions were intuitive – or, on the other end of the spectrum, unfair during such an early stage in the investigation.  Nevertheless, a surprising amount of information has been made available during this embryonic phase – partly due to the fact that the flight recorders are advanced models and they were in very good shape.  There is no need for me to dwell on factors that can cause a plane to become unstable when icing occurs – suffice it to say that airfoils lose “lift efficiency” quickly when ice buildup changes their shape and of course the weight of the ice accumulation can also be a huge factor.  I do not know what kind of air speed indicators are installed on that type of aircraft but I do know that icing can cause false readings on some types.  Icing can also cause problems at air intakes and oil cooler intakes of some aircraft.

glls-labeled-bw4BUT WHY DOES THE PHENOMENON OCCUR

IN THE FIRST PLACE?

The cause of the icing is a surprise to most people.  Though icing can occur on a plane’s very cold surface when it descends into “warm” clouds whose temperatures are above freezing, the vast amount of problematic icing occurs when the liquid droplets themselves are below what we traditionally consider freezing temperature.  These droplets consist of what is called supercooled liquid water (SLW).  Water in cloud droplets can get as cold as about negative 40 degrees Celsius (which is the same as negative 40 Fahrenheit) without freezing.

When liquid water freezes (box 3 to 4 in the illustration above) the water molecules align in a crystalline fashion.  But in order to do so they need one of two things:  1) either a freezing nuclei whose surface acts as a template to initially “show” the molecules how to (or trigger the molecules to) line up, or 2) some molecules themselves must be jolted (or jiggled) such that for at least an instant they are arranged so they can act as a template or model for the rest to follow.  The likelihood of such alignment occurring in undisturbed droplets is slim.  This would not be true of most fresh water at the surface, such as in lakes because there are microscopically-sized particles available in the water to act as templates.  On the other hand, water that has condensed and remains in the air is very “clean” by comparison.

An aircraft flying though supercooled cloud droplets causes considerable rapid stirring to set the stages for freezing upon impact with that aircraft – just as supercooled raindrops freeze upon impact with trees and suspended wires in those notorious, damaging ice storms.

VIDEO DEMONSTRATIONS

The first three links below show convincing demonstrations of liquid water freezing as a result of hexagonal ice crystal seeding.  The ice crystals provide the template which “shows” the liquid water what to do in order to become solid.  In the third example when the water freezes and builds up a small mound on the wooden post, I suspect that the split second ideal alignment of some water molecules (while pouring) provoked the freezing.

http://www.youtube.com/watch?v=Xe8vJrIvDQM

http://www.youtube.com/watch?v=gGpNhBPYNfs

http://www.youtube.com/watch?v=4g1BDpU7ZQo

In this 4th example you will see that a jolt causing a sloshing of the water in the small amount of air space at the top of the bottle allows for enough water movement so that for an instant a hexagonal orientation occurs among some molecules causing a very rapid “follow the leader” freezing all the way down to the bottom of the bottle.

http://www.youtube.com/watch?v=DpiUZI_3o8s

Just as condensation and deposition give off heat, freezing is also exothermic.  This is probably why some of the water remains in the liquid state.  If the SLW is not very much colder than “freezing” temperature, the heat given off during freezing will cause the remaining liquid to acquire enough heat to teeter over to the liquid side.

Use the search term “supercooled water” on YouTube.com and you will find many other video demonstrations.

WHEN WATER FREEZES IT EXPANDS, BECOMING LESS DENSE.  THIS EXPLAINS WHY SOLID WATER FLOATS UPON LIQUID WATER.

If you compare box 3 and 4 in the illustration in this post, you will see why water expands and becomes less dense upon freezing.  To establish the hexagonal grid necessary for ice, the molecules can’t be as close together as they were when they were in the cold liquid stage.

Information on supercooled liquid water would have eventually been posted here if the Continental Express Flight 3407 disaster had not occurred.  It is regrettable that the accident played a role in my posting this information at this time.  I offer my sympathy to all who have broken hearts over the loss of a loved one and all others adversely effected.

Finally, the information in this post about SLW and icing merely scratches the surface compared to that which is known.  But, that which is not understood is formidable.

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Braided Streams and Close Marriages

braided-stream-leone
Image made available by Yann Arthus-Bertrand

There is a particular type of stream described as braided due to its interesting flow pattern.  The water in each of the river’s sub-channels carries a high sediment load on a low incline.  As the stream’s velocity slows the water becomes overloaded with sediment – not having enough energy to carry the amount it could handle at the higher velocity.  The result is that the alluvial sediment gets deposited in the river bed to the degree that the water must eventually turn to flow where there is less obstruction – following the path of least resistance.  It happens again, over and over, as the water works its way downstream.   The sub-channels crisscross making a braided flow pattern.

I’ve always felt that this is a good analogy for a good, close marriage.  Each partner flows along independent of the other – but near.  They travel in the same general direction with the same goal (in the river’s case, base level which is sea level).  Each partner has some space but the other is accessed easily.  At certain times, they join and for a while become as one.  These might be times of joy, crises, working together, and physical /spiritual intimacy.

The image above shows an aerial view of a braided portion of the Leone River in Argentina carrying very fine, powdery glacial flour.

© Tonie A. Toney 2-3-2008

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FLORIDA – THE SUNSHINE STATE!

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LEFT CLICK TO ENLARGE

It’s expected to get down into the high teens in the morning in my part of Florida (halfway between Inverness and Dunnellon at 28.97 degrees North latitude) and down to a warm 45 degrees where I used to live in Florida (Homestead at 25.46 degrees North latitude).  But even though the temperature here is going to be less than half what it will be down there – the “atmosphere” here is 100 times as serene.  I’ll take serenity and cold over helter-skelter and “not as cold” any old day.

God bless my friends who are stuck down there in that foreign county – even the ones who don’t even realize they are stuck.  As for me – being back in the country of my birth and the county I served honorably while in the Air Force – the good old U.S of A. is a tremendous relief.  In spite of all of our problems today, this is still the greatest country in the world!

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Hard Freeze Over Much of Florida Is Due

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LEFT CLICK TO ENLARGE

I recommend that Florida residents who are concerned about tonight’s temperature consult your local media for the forecast in your specific area.  On line you can go to http://www.weather.gov/ and at the small white rectangle near the top-left – type in your location or even easier, your 5 digit zip.

The image above shows an almost cloudless Florida earlier today.  It is covered by a frigid Arctic air mass.  The air is very dry and relatively clean.  There is not much water vapor within it to intercept outgoing infrared; the colder the air, the less energy is available to keep water in the vapor state.  During the daylight hours the incoming solar radiation exceeds the outgoing infrared but of course at night there will be no incoming solar radiation while terrestrial infrared continues to flow outward.  Therefore, it will get even colder.

Some folks in my neighborhood have wells.  Freezing at or near well sites is not uncommon.  It happened to one of my neighbors during a recent cold spell but fortunately there was no damage.  Since water expands by about 9% when it freezes, considerable damage can occur.  I run an extension cord out to my well and place a shop lamp on the surface and throw some sheets over the pump and plumbing fixtures to help hold in the heat from the 60 Watt light bulb.  In the several freezing episodes during the 43 months I’ve lived in this part of Florida, that method has worked for me without fail.  SEE IMAGE BELOW.

A neighbor suggested to me that a slow drip at a faucet inside will also help to prevent a line closure from freezing.  I have not tried that.

After tonight a slow warming trend is expected but this is probably not the last of this season’s cold episodes.

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LEFT CLICK TO ENLARGE


YET MORE COLDNESS FOR FLORIDA!

Two independent left clicks will enlarge
Two independent left clicks will enlarge

This seems almost like an instant replay!  We Floridians are again playing host to a couple of surges of cold air.  Florida is once again cloudless and the cold air is relatively dry –  therefore the state can’t count on much of a greenhouse effect to slow the loss of heat from the surface.

My neighborhood in northeast Citrus County, Florida can expect freezing temperatures on Wednesday and Thursday morning – and perhaps Friday morning.  As is so often the case, the fickle microclimatology of a neighborhood can be manifested by a wider-than-expected range of low (and high) temperatures.  For example, during a luncheon today a neighbor reminded me that by virtue of his property being on about the highest ground in the neighborhood, his low temperatures end up being not quite as low as those in other parts of the neighborhood.  This is not always the case but it happens the majority of times because on those cold, marginal mornings when the synoptic pressure gradient is weak, the coldest (and therefore densest) air tends to spill downward into the lower vicinities.

My wife and I have given up on covering our ornamentals – deciding a while ago to allow “survival of the fittest” to kick in.  But – many of my neighbors have already covered some of their plants.

This is not a mean-spirited criticism but it is a huge paradox to me that so many will go out of their way to protect a plant that isn’t meant to grow here yet some think nothing of killing a native species of harmless snake that dares to stray on to their property.  I understand the fear – but not the lethal reaction.

If you are “up north” reading this, I imagine that you’d love to be enjoying our temperatures down here.  Everything is relative, is it not?  For example.  I took my daily 3-mile walk earlier today wearing a light-weight sweater over a T-shirt and at the half-way mark the sweater came off!  It has been a delightful day for early February – that’s for sure.

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