Saturday, February 28, 2009

Penelope Pilot Project article in AOPA

I can't help it, I need to toot my own horn. Or rather Penelope's. I am at the Women in Aviation conference and noticed the traffic really picked up at the Girls With Wings booth. Turned out that AOPA online magazine had put the word out about the Penelope Pilot Project. I think it's a wonderful article and I hope you all will support the program!

Penelope Pilot encourages girls to take to the sky
By Sarah Brown

Aisles of toys and books are dedicated to transporting young girls to a land of fairy tales and princesses, but one organization is launching a character this spring that encourages them to aim for the sky.

The Penelope Pilot Project, part of the organization Girls With Wings, is designed to capture the imagination of girls with the character Penelope Pilot, a commercial airline pilot. The project will feature a series of books about Penelope and her friends, along with the characters’ dolls.

“Instead of encouraging our girls to wait for their knights in shining armor, how about encouraging them to explore the night in their shiny airplane?” reads the Ohio-based business’s Web site.

Girls With Wings, a public awareness and e-commerce project, organizes events and activities to introduce girls to aviation-related careers. Its Web site bears the slogan, “Girls need flight plans, not fairy tales!” and sells a range of products centered on the theme, “Yes, Girls Can Fly!”

The Penelope program is sponsored by Flight Plan Magazine, a publication for women in aviation that is also launching this spring. The first issue will feature a “character form” of Penelope, a thin foam image that girls can take to airshows and other aviation-related events. They can upload pictures of themselves with the character to

Penelope will make her first cross-country journey in April, when she rides along with ultralight pilot Arty Trost in Trost’s 1984 Maxair Drifter from Oregon to Lakeland, Fla., for Sun ’n Fun.
Lynda Meeks, the founder of Girls With Wings, said she has written a picture book about Penelope that she expects to be out before the EAA AirVenture convention in late July. Girls With Wings will have a booth at the Wisconsin airshow.

Meeks, a private airline pilot, said she started the company about five years ago after she looked for a baby gift for a friend of hers—also a pilot—who was expecting a girl. She could find no aviation-themed products for girls, so she started embroidering airplanes on items herself.
“I thought it was a bigger issue that we weren’t celebrating women in aviation as we should,” she said. She made it her mission to use women in aviation to educate and inspire young girls.

Susan Pruitt, editor of Flight Plan Magazine, contacted Meeks about the Penelope Pilot Project after her daughter found the Girls With Wings Web site. Meeks said the launch of the magazine and the Penelope project are coinciding nicely, and Pruitt has taken the lead on developing a doll. Meeks hopes to develop nine characters in the project, encompassing all aspects of aviation.

Wednesday, February 25, 2009

Women in Aviation Conference 2009

If you are going to go to the Women in Aviation Conference in Atlanta this weekend, please stop by the Girls With Wings booth and say "Hi!"

We will be recruiting volunteers for the Girls With Wings Mission: Encouraging more girls to have an interest in aviation.

We will also once again be interviewing women in all fields of aviation to find out what they do and why they love it. The video will be posted on the Girls With Wings website!

Hope to see you there,

Lynda Meeks

Founder, Girls With Wings™

"Our mission is to encourage girls to have wings no matter what they may dream."

***Sign up for our eZine***

Saturday, February 21, 2009

X14, pt 2; or PAPI and VASI

Yesterday started telling you about x14, an airport in La Belle, Florida, USA . I searched "airport identifiers" and got distracted by figuring out how different airport IDs originated. I covered Large, Medium and Small hub airports and their IDs, but left it up to you, the reader, to research the IDs for smaller airports.

So just real quick, here is what an Location Identifier is (from Wikipedia). The ones that we are most familiar with (such as the ones in yesterday's post) are the International Air Transport Association sets of 3-letter IATA identifiers which are used for airline operations, baggage routing, and ticketing. There is no specific organization scheme to IATA identifiers; typically they take on the abbreviation of the airport or city such as MNL for Manila Ninoy Aquino Airport. (I tried to find something that said what those long sticky labels meant, but they're really just bar codes printed on machine like the one left. On the one pictured, DCA means Washington, DC, and CO 158 is the flight number from Continental. Pic from Airline Lost Your Luggage! Now What?)

In the United States, the IATA identifier usually equals the FAA identifier, but this is not always the case. A prominent example is Sawyer International Airport, Michigan, which uses the FAA identifier SAW and the IATA identifier MQT.

Aviation professionals usually use The International Civil Aviation Organization 4-letter location indicators. These are used by air traffic control agencies to identify airports and by weather agencies to produce METAR weather reports. The first letter indicates the region: K for conterminous United States, C for Canada, E for northern Europe, R for the Asian Far East, and Y for Australia. The remainder of the identifiers are established at the national level. Examples of ICAO location indicators are RPLL for Manila Ninoy Aquino Airport and KCEF for Westover Joint Air Reserve Base.

The Federal Aviation Administration identifier is a three-letter or four-letter alphanumeric code identifying United States airports. They were developed in the 1960s, replacing an old system that relied on plain language, teletype station identifiers, and weather reporting codes. For nearly all major airports, the letters are alphabetic three-letter codes, such as SFO for San Francisco International Airport. Minor airfields typically have a mix of alphabetic and numeric codes, such as 8N2 for Skydive Chicago Airport and 0 B5 for Turners Falls Airport. Private airfields have a four-letter identifier, such as 1CA9 for Los Angeles County Fire Department Heliport.

So to get back on topic, the captain and I were pretty surprised when we got assigned a trip to X14; we had to look it up to find out where it was! Then we had the hardest time picking out the airport until we were nearly on top of it. X14 is an airport that is "uncontrolled." There is no tower controlling traffic, so the ATC service remotely located will ask a pilot when she has the "airport in sight." When she does, ATC will clear the crew to proceed on their own. The crew then makes radio calls announcing their arrival to anyone operating at the airport (it would be a whole other post to talk about these operations - let me know the interest level).

Although there are airport diagrams to give guidance to pilots taxiing around an unfamiliar airport guidance, they sometimes just depict buildings, and it can be pretty confusing to know where to park. To the left is a picture of our airplane's nose. As you can see, we were lucky. There is actually a sign saying "Fuel." That's a big clue!

It was a tight squeeze as we taxied on to this ramp and did a 180 turn to end up right here
on the end of the tarmac with our nose pointed back towards the taxiway. If personnel are available to "marshal" or direct you in, it helps, but a lot of times at smaller airports you're on your own!

Pulling back from the view a little bit, you can see more of the airport. If you look to the right from the fuel sign, across the taxiway there is a sign that just looks like a black rectangle. Then just to the right of that are four lights in the ground in a row. These are called PAPI lights, or Precision Approach Path Indicator lights.

According to the AIM: The precision approach path indicator (PAPI) uses light units similar to the VASI (be patient...) but are installed in a single row of either two or four light units. These systems have an effective visual range of about 5 miles during the day and up to 20 miles at night. The row of light units is normally installed on the left side of the runway and the glide path indications are as depicted.

VASI, or
Visual Approach Slope Indicator, is a system of lights so arranged to provide visual descent guidance information during the approach to a runway. These lights are visible from 3-5 miles during the day and up to 20 miles or more at night. The visual glide path of the VASI provides safe obstruction clearance within plus or minus 10 degrees of the extended runway centerline and to 4 NM from the runway threshold. Descent, using the VASI, should not be initiated until the aircraft is visually aligned with the runway.


X14, doesn't that sound like a super powerful cleaning agent? Or a secret service agent? Actually it's also the identifier for La Belle Municipal Airport in La Belle, Florida, USA.

You probably know the identifier for the city you live in; for example, mine is CLE for Cleveland. Some airports are lucky that way, in that the identifier is recognizable such as SLC or Salt Lake City. Others don't bear any resemblance to the city they are located in, like LGA. This is an airport in New York City, but the airport is
named for Fiorello H. La Guardia, the former mayor who built it. Then there are airports like SDF, which is Louisville, KY. Do you know where the SDF comes from?

Turns out that these "odd" airport names usually have a story and I will share with you now some of the identifiers that aren't immediately apparent.

Lists come from Airport Codes. Definitions from Wikipedia. All Primary Airports are further designated as large hubs, medium hubs, small hubs, or nonhubs, based on their share of total U.S. passenger boardings during the previous calendar year.

Large Hubat least 1%
Medium Hub0.25% to 0.99%
Small Hub0.05% to 0.249%
NonHubless than 0.05%


Cincinnati airport's code, CVG, comes from the nearest major city at the time of its opening, Covington, Kentucky.

Washington's IAD is named after John Foster Dulles, United States Secretary of State under Dwight D. Eisenhower.

Orlando's airport code MCO stands for the airport's former name, McCoy Air Force Base, a Strategic Air Command (SAC) installation named for Colonel Michael Norman Wright McCoy, USAF, commander of the 321st Bombardment Wing at the then-Pinecastle Air Force Base.


Kansas City is known was originally named Mid-Continent International Airport, hence MCI.

New Orleans is was originally named after daredevil aviator John Moisant, who died in an airplane crash on this land (which was devoted to farming at the time) in 1910. Though its IATA code MSY was derived from Moisant Stock Yards, it is now known as Louis Armstrong International Airport.

Kahului on the island of Maui is OGG. The airport code pays homage to aviation pioneer Bertram J. Hogg who worked for what is now Hawaiian Airlines flying aircraft ranging from 8-passenger Sikorsky S-38 amphibians to Douglas DC-3s and DC-9s into the late 1960s.

The Ft Myers, FL, designator RSW was originally assigned for "Regional South-West" (for Southwest Florida Regional Airport)

Now, SDF, in Louisville KY: Standiford Field was built by the Army Corps of Engineers in 1941 on a parcel of land south of Louisville that was found not to have flooded during the Ohio River flood of 1937. It was named for Dr. Elisha David Standiford, a local businessman and politician, who was active in transportation issues and owned part of the land.

Orange County's airport is also called the John Wayne Airport and is an airport in an unincorporated area in Orange County, California, with its mailing address in Santa Ana, hence the SNA code.


ABE is in Lehigh Valley, PA, but was formerly Allentown-Bethlehem-Easton International Airport.

Spokane's GAG was known as Sunset Field before 1941, it was purchased from the county by the Department of Defense and renamed Geiger Field after Major Harold Geiger, an Army aviator.

The Newport News/Williamsburg International Airport airport was originally named Patrick Henry Airport. It was assigned the designator PHF, representing Patrick Henry Field.

In Knoxville, TN, their airport, TYS, is a joint civil-military public airport serving the Knoxville The airport is named for United States Navy pilot Charles McGhee Tyson, lost on patrol in World War I.[2]The airport also serves as the home of McGhee Tyson Air National Guard Base, an air base134th Air Refueling Wing (134 ARW) of the Tennessee Air National Guard. for the

Last, but not least, is XNA, Northwest Arkansas Regional Airport located in Highfill, Arkansas, near Bentonville, Rogers, Fayetteville, Springdale, and Siloam Springs, Arkansas. It is commonly referred to by its IATA code, which is incorporated in the airport's logo as "Fly XNA". They apparently got whatever letters were left, and decided to make the best of it!

I'll let you look at the list of Non-Hub airports, which process more than ten thousand (10000) but less than 0.05 percent of revenue passenger boardings annually, whether or not in scheduled service. See if you can find more interesting stories and make your comments below!

Monday, February 16, 2009

PST, EST, UTC, GMT, and Zulu

This morning I awoke around 5:30a.m., as I usually do, except that it was 5:30 Pacific Standard Time (PST), in California instead of my home time zone: Eastern Standard Time. That meant it was really 8:30am, or 1330Z (Zulu), or Coordinated Universal Time (UTC) or Greenwich Mean Time (GMT). If I would have awakened this late at home, I would have felt like I had slept most of the day away. I was somewhat comforted by the fact that I was on duty til 11pm PST, which is 0700Z (or UTC or GMT) or 2am EST. Confused yet?

The truth is, my watch is set to EST, though I can press a button and see UTC time. UTC is the time system used in aviation, referred to as Zulu. Weather forecastings, flight plans, air traffic control clearances, and maps all use UTC to avoid confusion about time zones and daylight saving time. The UTC time zone is sometimes denoted by the letter Z – a reference to the equivalent nautical time zone (GMT), which has been denoted by a Z since about 1950. Since the NATO phonetic alphabet and amateur radio word for Z is "Zulu", UTC is sometimes known as Zulu time. This is especially true in aviation, where Zulu is the universal standard. This ensures all pilots regardless of location are using the same 24-hour clock, thus avoiding confusion when flying between time zones.

EST is UTC+5, which is pretty easy math. But then try this delimma: According to my tripsheet, I am expected to take off from Des Moines at 10am, making a 2 1/2 hour flight to Pheonix, but the passenger is 45 minutes late and we won't expect to take off for another 30 minutes by the time we settle the passenger, get the engines started, taxi out and take off. Upon his arrival my passenger asks me what time we will now arrive in the local time so he can have his driver pick him up. I look at my watch and I see 11:45am EST. The time shown on my paperwork is out the window due to the delays. What should I tell him?

So the answer to the above can be a nightmare. If it's 11:45am EST, subtract an hour for CST, but add 30 minutes ground time. Then add 2 1/2 hours for flight time and then adjust it to the new time zone of your destination. We have to convert to Pheonix local time, which is MST. But not always. They don't observe Daylight Saving Time (DST), so, darnit, should I subtract 1, 2, or 3 hours? (Don't forget, the passenger is expecting you to have a ready answer - you destroy your credibility if you can't come up with the answer ASAP!)

Another wrinkle to consider when you're adding and subtracting:

Arizona does not observe Daylight Saving Time (March through November). They do not "spring Forward" in Phoenix -- they always stay on Mountain Standard Time. During Daylight Saving Time (DST) most of Arizona is at the same time as California (Pacific Daylight Time or PDT). On the first Sunday in November, when DST ends, most everyone else in the country "falls back" or sets their clock back one hour. They do not. From that first Sunday in November through the second Sunday in March they are one hour ahead of those states on Pacific Standard Time, like California and Nevada; one hour behind states in the Central Time zone, such as Texas and Illinois; and only two hours behind those states on Eastern Time, such as New York and Florida.

So, depending on the time of year, let's say today, we don't have to worry about AZ not switching to DST, so they are still MST, which means just an hour behind CST. Whew! It is somewhat easier to do all of this math in Zulu time and then just convert at the end. MST is UTC - 7.

Of course there will always be some confusion no matter how big the timezone difference. I was on an Army flight out of England years ago and the passengers waited for the crew for an hour. The General was looking at the Local time in London to determine when to show for his flight. Because they also have daylight savings, Local time was not the same as Zulu time (which determined when we showed for our flight). We briefly tried to explain the difference, and then just decided to say, Yes, sir," and move on.

Anyway, I just find it easier to keep my body clock on Eastern time no matter where I am. The most I am going to be "off" is three hours when I go to the West Coast, which means I get up really early according to their clocks. Staying up late like I had to do the last two nights in a row becomes more of a challenge. Caffeine can be a short term solution, but I don't recommend it for long. One may be awake, but not necessarily alert.

The medical community usually advises people to go to bed and get up at the same time every day.

"Sleep is a homeostatic process [a system where our bodies regulate automatically based on our daily patterns]," says Sonia Ancoli-Israel, Ph.D., a professor of psychiatry at the University of California at San Diego and a spokesperson for the National Sleep Foundation. "If you sleep in, it might affect your ability to fall asleep the next night, since you have to be awake for a certain amount of time before you'll be sleepy enough to go to sleep again."

This is not always possible on the road. For example, I woke up at 3am EST to start this tour, because I had an early morning airline flight to go to pick up my airplane. We immediately started flying west, which means each day we were getting progressively later "start times." Later in the sense that a 7am flight on the west coast is, according to my body clock, a 10am flight. Since we pilots can work a 14 hr duty day, a 7am PST start means theoretically we could be working until midnight (EST). I'm not usually up this late.

But today we are flying back to the east coast, which means there is a chance that I may have to get up early for a flight EST. But like I said, today I "slept in" til 6:30am PST. If tomorrow morning I have to wake up at 6:30am EST, that is virtually 3:30am PST, which is what I've been working off of the last 3 mornings and so will be an adjustment. Is this all making sense?

The result of this, as you may know, is commonly referred to as jetlag. Add to this a disjointed work/eat/sleep schedule, in unfamiliar beds in noisy hotels, and fatigue becomes a factor pretty quickly. An article on Pilot Fatigue written by Dr Samuel Strauss.

“Circadian rhythms” are physiological and behavioral processes, such as sleep/wake, digestion, hormone secretion, and activity, that oscillate on a 25 hour basis. Each rhythm has a peak and a low point during every day/night cycle. Time cues, called “zeitgebers,” keep the circadian “clock” set to the appropriate time of day. Common zeitgebers include daylight, meals and work/rest schedules. If the circadian clock is moved to a different schedule, for example when crossing time zones or changing from a day work shift to a night shift, the resulting “sleep phase shift” requires a certain amount of time to adjust to the new schedule. This amount of time depends on the number of hours the schedule is shifted, and the direction of the shift. During this transition, the circadian rhythm disruption or “jet lag” can produce effects similar to those of sleep loss.

Transmeridian flights in excess of three time zones can result in significant circadian rhythm disruption. When flying in a westerly direction the pilot’s day is lengthened. When flying east, against the direction of the sun, the pilot’s day is shortened. Thus the physiological time and local time can vary by several hours. Symptoms of jet lag are usually worse when flying from west to east as the day is artificially shortened. It takes about one day for every time zone crossed to recover from jet lag. When circadian disruption and sleep loss occur together, the adverse effects of each are compounded (3).

I blogged about this previously in 10 hour turns, in which I discussed a flight crew that had fallen asleep and overshot their destination. According to Dr. Strauss, "many of the unique characteristics of the flight deck environment make pilots particularly susceptible to fatigue."

Contributing aircraft environmental factors include movement restriction, variable airflow, low barometric pressure and humidity, noise, and vibration. In commercial aircraft, hands on flying has been mostly replaced by greater demands on the flight crew to perform vigilant monitoring of multiple flight systems. Research has demonstrated that monotonous vigilance tasks decreased alertness by 80% in one hour (4). This phenomenon is often referred to as “boredom fatigue.”

So what can we do? We can't always stay in our own time zone. The company won't make a profit if they don't get the crews to fly for more than a couple of hours a day, causing pilots to lose their jobs and end up moving back in with their parents. Tragic. So Dr. Strauss lists some countermeasures:

Research has shown that several countermeasures for fatigue are effective in improving alertness and performance. Long naps, 3-4 hours, can significantly restore alertness for 12-15 hours. Short or “power” naps of 10-30 minutes can help restore alertness for 3-4 hours. Allow 15-20 minutes after awakening to become fully alert before assuming aircrew duties (7,12,17).

Other countermeasures include:

Eat high protein meals (avoid high fat and high carbohydrate foods)
Drink plenty of fluids especially water
Caffeine can help counteract noticeable fatigue symptoms if awake for 18 hours or less
Rotate flight tasks and converse with other crewmembers and keep the flight deck temperature cool
Move / stretch in the seat, and periodically get up to walk around the aircraft if possible
Gradually shift times for sleep, meals, and exercise to adjust to a new time zone (19)

On that note, I think I'll go down to the hotel restaurant for lunch. Oops, what time is it? I mean breakfast.

Wednesday, February 11, 2009

Smoke in the Cockpit

I got the idea for this post after Julie, a Civil Air Patrol 2nd Lieutenant and Girl With Wings, told her fellow twitterers about investigating a report of smoke with an electrical smell at her current place of employment. Julie, who also wants to be a flight attendant, said that she would raise the alarm if she were to smell such a thing in an airplane. See, she is a safety minded crewmember already!

So I wanted to blog about why smoke in the cockpit is such a big deal. From the King Air to the Citation X, every multi engine airplane I've flown has had oxygen masks and goggles, for use during the unlikely event that smoke is generated during flight (fortunately, in-flight fires are rather rare, in comparison to other causes of airline accidents. Read about some of the more notable ones). The Citation X I fly has an additional safety feature, an EVAS. Since my employer is listed on The EVAS website, I can be assured I'm not giving anything away here.

EVAS stands for Emergency Vision Assurance System and is contained in a box located along the wall next to our pilot seats. For someone taller than me, it is in a position where they might hit their elbow. But it needs to be handy. The reason that one would be interested in spending the extra money on this system is that goggles are fine for keeping the smoke out of your eyes, but your range of vision is now limited to the goggles. If the cockpit is filled with smoke, the goggles will not allow you to see through it to the instruments, much less out of the window, making it very difficult to land under this emergency situation.

Since there seems to be no pictures available, I found a good description of the equipment in an article entitled, "Orders for Emergency Vision Equipment Pouring in After Report of "Smoke in the Cockpit" From Swissair Flight 111"

The device, known as the Emergency Vision Assurance System (EVAS), physically displaces smoke in the cockpit by inflating a clear plastic bubble, and keeps it gently inflated through a pump and filter system. The bubble is tailored to fit the cockpit layout of each specific aircraft. It presses against the instrument panel and the windscreen. Pilots can see vital instruments and out the front of the plane by pressing their goggles against the inflated bubble.
The Swissair 111 accident was the subject of a National Geographic program. A clip on YouTube shows the seriousness of the situation: The entire series, though (5 parts), is on YouTube. The most important lesson for pilots to take away from this type of disaster is to never delay landing if smoke is detected. Hesitation may save lives. Lessons learned, courtesy of the International Aviation Safety Association:
When the primary flight displays failed, the crew had to adjust to small standby instruments, which added to the workload (AW&ST Jan. 7, 2002, p. 43). Gradually overcome with heat and fumes, the pilots lost situational awareness, and the MD-11 crashed into the sea at 10:31 p.m. The report notes that although the crew recognized the necessity for a diversion, they did not believe the threat to the aircraft was sufficient to declare an emergency or initiate an emergency descent profile. The report notes that from the time the peculiar odor was detected, "the time required to complete an approach and landing to Halifax . . . would have exceeded time available before the fire-related conditions in the cockpit would have precluded a safe landing."
The driving principal behind development of the EVAS is this fact: At least 1230 lives have been lost in air crashes where smoke and pilots inability to see their instruments was cited as the primary cause. You can see a video of this device in action: Sorry, there are no pictures of it for me to attach!
If you are not a pilot, what can you take away from this? Well, the Miracle Landing on the Hudson, as it's being called, was fortunate that it happened during the day, in clear conditions. Passengers need to be aware that an emergency egression from an airplane may very well be executed in a dark, smoky cabin, that may even be upside down. Please pay attention to the inflight safety briefing. Julie and her fellow flight attendants will appreciate it!

Basic Aerodynamics

Do you twitter? One of the people I follow is a flight instructor who posts quiz questions each evening. Last night he asked: what is the imaginary straight line between the leading edge of an airfoil and the trailing edge? I think I learned this in my fixed wing transition back in 1995, so the first word that came to mind was "camber." I responded quickly, because I could only gain by being right (I had no points to lose, after all). But then again, I was wrong and so probably lost credibility points as a professional pilot.

Truth is, I don't think about camber lines, or chord lines (which was the correct answer) when I'm flying. One of the things I try to stress in my presentations to youth groups is that if there is something you really want to do in life you will be more inclined to push yourself thru those undesirable study subjects to be able to get there. You can't be a doctor without studying biology, but chances are unlikely you'll dissect another frog. This is a building block of eventual knowledge.

So, having been shamed by my incorrect answer, I have followed a link that another helpful flight instructor provided to refresh my knowledge on Airfoil Geometry. I will make this quick and painless, I promise.

See that little diagram to the left on this illustration? This term will come up again. That is showing the Angle of attack (AOA, α, Greek letter alpha) is a term used in aerodynamics to describe the angle between the chord line of an airfoil and the vector representing the relative motion between the airfoil and the air. It can be described as the angle between where the chord line of the airfoil is pointing and where the incoming air is going .

The caption for the diagram above is: NACA 4 digit and 5 digit airfoils were created by superimposing a simple meanline shape with a thickness distribution that was obtained by fitting a couple of popular airfoils of the time: y = ±(t/0.2) * (.2969*x0.5 - .126*x - .3537*x2 + .2843*x3 - .1015*x4) The camberline of 4-digit sections was defined as a parabola from the leading edge to the position of maximum camber, then another parabola back to the trailing edge.

Yeah, that doesn't help me either. I need a Wikipedia definition! So let's start with just talking about what an airfoil is. Simply put, an airfoil is the shape of a wing or blade (of a propeller, rotor or turbine) or sail as seen in cross-section.

Here is some Airfoil terminology:
The mean camber line is a line drawn midway between the upper and lower surfaces.
The chord line is a straight line connecting the leading and trailing edges of the airfoil, at the ends of the mean camber line.
The chord is the length of the chord line and is the characteristic dimension of the airfoil section.
The maximum thickness and the location of maximum thickness are expressed as a percentage of the chord.
For symmetrical airfoils both mean camber line and chord line pass from centre of gravity of the airfoil and they touch at leading and trailing edge of the airfoil.
The aerodynamic center is the chord wise length about which the pitching moment is independent of the lift coefficient and the angle of attack.
The center of pressure is the chord wise location about which the pitching moment is zero.

Just a little background from the same website above: "The earliest serious work on the development of airfoil sections began in the late 1800's. Although it was known that flat plates would produce lift when set at an angle of incidence, some suspected that shapes with curvature, that more closely resembled bird wings would produce more lift or do so more efficiently." Imagine your hand outside of the car window. The resultant wind from you moving with the car strikes your hand at an angle of incidence, depending on what at slant you hold your hand. If you're interested in more information, you can read more on airfoil development. It really is interesting. This is an online textbook, however and gets pretty in depth. If you would like to read it on your own, I'll see you back here next time. For those who want a cliff notes definitition, read on...

Your hand is like "Any object with an angle of attack in a moving fluid, such as a flat plate, a building, or the deck of a bridge, will generate an aerodynamic force (called lift) perpendicular to the flow. Aerofoils are more efficient lifting shapes, able to generate more lift (up to a point), and to generate lift with less drag." You may have heard how an airplane can stall. This is because "With increased angle of attack, lift increases in a roughly linear relation, called the slope of the lift curve. At about eighteen degrees this aerofoil stalls and lift falls off quickly beyond that." In other words, the airfoil stops producing lift and the airplane stops flying.

This last paragraph is what most pilots take away from the study of airfoils. If you don't know how this works, you may find yourself in trouble. I'll have to do a seperate entry about stalls. Stay tuned, and as always, let me know if I have been wrong/incomplete/unclear. Thanks!

Tuesday, February 10, 2009


This is a picture after I took my sister's family for a ride in a Cessna 172. From left is Emmett, Eli and then me (and it's a few years old). I learned to fly helicopters in the military and transitioned to multiengine fixed wing after getting only 30 flight hours in a 182. I did most of my flying in Germany, where all airspace is controlled, or in the US, always under an IFR flight plan. So, for me, flying a single engine airplane under VFR, with my family on board no less, was a little, shall we say, stressful?

Anyway, I include the picture because I wanted to talk about "Squelch." Say it enough times and it just sounds weird. Emmett, when he was young, was obsessed about my blush. So every time I'd visit, he'd watch me putting my makeup on and just keep saying, "Bluuuush." A tenuous link, but there it is.

Squelch has always been to me just a "SQ" button on airplane communications radios. If I tried to listen on a frequency of a transmitter that was some distance away, I could press this button and possibly hear earlier (assuming I'm traveling to it) but the frequency would have static as well. This comes in handy, btw, if you switch to a different radio and you want to make sure it's working and the volume is set adequately - press the squelch switch, hear a burst of static and then press switch again.

So, what am I doing, really? Here is the definition of carrier squelch from Wikipedia.

A simple carrier squelch or noise squelch operates strictly on the signal strength, such as when a television mutes the audio or blanks the video on "empty" channels, or when a walkie talkie mutes the audio when no signal is present. In some designs, the squelch threshold is preset. For example, television squelch settings are usually preset.

In devices such as radiotelephones (also known as two-way radios), the squelch can be adjusted with a knob, others have push buttons. This setting adjusts the threshold at which signals will open the audio channel. Backing off the control will turn on the audio, and the operator will hear white noise if there is no signal present. The usual operation is to adjust the control until the channel just shuts off - then only a small threshold signal is needed to turn on the speaker. However, if a weak signal is annoying, the operator can adjust the squelch to open only when stronger signals are received. If you hold the squelch open you will also get a lot of noise.

I am not kidding when it took me three times to understand all that. So, let me sum up: when I tune in a random frequency where nothing is being transmitted, I would just hear static - same as you would if you selected channel 3 on your TV and there's no Channel 3 TV station in your area (there may be one in the next town over - but not close enough for you to receive it). The TV blocks that static so you don't have to listen to it if you so chose to keep the tv on that channel.

The comm (short for communication) radios in my airplane do me a favor by shutting this static noise out as well when it "knows" there's nothing to hear. If I know that I just might be close enough to hear the station (because, let's face it, who's smarter? Me or the radio?). I can disable this feature so the radio will let me hear whatever's there. If I'm lucky, I'll hear the weather at my destination farther out than I would if I waited until I could hear it without adjusting the preset threshold.

Monday, February 09, 2009

Negative feedback!

The other day on my commercial flight home from a tour, every time the flight attendant tried to make an announcement, there was this painful screech. Luckily it was an RJ700 and the other FA at the front of the airplane finished the briefing on another microphone. This is an example of audio feedback, which occurs when a sound loop exists between an audio input (for example, a microphone or guitar pickup) and an audio output (for example, a loudspeaker).

Ha - you thought "negative feedback" meant someone had insulted my blog, didn't you?

This sometimes happens with a pilot's headset, or when a pilot tries to use the handmike. I'll be honest, I've never been sure how it happens and why - so I'm learning here too. It has never happened in the CE750, but in previous airplanes I just started flipping switches, going to headset, talking faster so I didn't transmit as long, etc.

It used to happen most often when I was talking with the handmike and listening over the overhead speakers, which you can see in the picture to the right - it's that white circle on the ceiling (although this is a CitX pic). BTW, the black squarish thing above my head is a sun shade that rotates down on that silver bar above the window, so it will slide around to where the sun is coming in. The handset is located in a bracket on the side of the yoke "stem," for lack of a better word. It looks just like the ones you see cops using in their squad cars; it's on a long coil and you push a button to transmit.

As you can see in the other picture, I've got the yoke right in front of me, and then there is a stand that goes into the floor between my feet. Some yokes go toward the front of the cockpit; some airplanes even use a joystick on the side of the cockpit on the armrest!

Getting back on subject. When I speak into the handset, the signal is received by the microphone and amplified and passed out of the loudspeaker. Then the sound from the loudspeaker can then be received by the microphone again, amplified further, and then passed out through the loudspeaker again. This is a good example of positive feedback. The frequency of the resulting sound is determined by resonant frequencies in the microphone, amplifier, and loudspeaker, the acoustics of the room, the directional pick-up and emission patterns of the microphone and loudspeaker, and the distance between them.

Most audio feedback results in a high-pitched squealing noise familiar to those who have listened to bands at house parties, and other locations where the sound setup is less than ideal — this usually occurs when live microphones are placed in the general direction of the output speakers. Since we can't change the location of the mike or the speaker, we can try to use the speaker on the opposite side of the cabin. Or go to headset!

This is about all I could find on the subject. I know feedback happens under other circumstances in the cockpit talking on the radios, so any "feedback" is appreciated!

Sunday, February 08, 2009

Kudos to the Wichita River Walk!

I stay at hotels quite a bit, and it is rare to find one that has running routes identified for the guests. Since I'm such a fanatic about trying to stay in shape on the road I talk about this quite a bit, so I will show you the standard that has been set.
Checking in to this hotel once previously, I asked for running routes. Imagine my delight when I was handed this pocket sized rigid card with running routes of various distances already mapped out (personal injury disclaimer included). Too bad it was near freezing and raining out that day. I decided to forego the run since I didn't want a resulting cold. But as mentioned in a previous post just a couple of days ago, the weather in Wichita was perfect.
Due to a time constraint, I thought I would do the 5.6mi route. But it was so nice out and the trail was so nice, I just kept on going. This was a well maintained - and clean - walk along side the river, past a reflecting pool of a (perhaps) museum, and through park like settings. At the turn around point, I was running by golf courses and playgrounds. THEN there was an recreated old West town.
  1. It was great! Imagine my surprise when trying to search for the Wichita River Walk on the internet that I could find nothing. I mean, what a treasure trove for Kansans. Sigh. So instead, I noticed the card was created by "Athletic Minded Traveler." On their website they have a list of about 75 cities with specific and reliable recommendations for:

Fitness-focused hotels
Fantastic health clubs
Running routes
Lap pools
Places to eat

Too bad you have to buy a subscription. If they post more cities up here, I would definitely consider signing up!

Saturday, February 07, 2009

A Day in the Life

I was sitting in the airport awaiting a flight to Denver to go to a 99s conference (this was year before last). THE NINETY-NINES, INC., is an international organization of licensed women pilots from 35 countries with currently over 5,500 members throughout the world. They are a non-profit, charitable membership corporation holding 501(c)(3) U.S. tax status. International Headquarters is located in Oklahoma City, Oklahoma. Although there are other female pilot organizations in various states and nations, virtually all women of achievement in aviation have been or are members of The Ninety-Nines.

If you're wondering why I am using such old pictures - it's because I forgot the cable to connect my camera to my laptop! I'm making do til I get home tonight.

Does anyone recognize this airport? All I remember is that the terminal was new, and that everywhere were floor to ceiling windows. The view on the ramp was incredible. There were kids with their noses pressed up against the glass, and adults were mostly sitting facing out to see the airport operations.

I thought it would be great to take these pictures in preparation for the Penelope Pilot book which talks about a commercial airline pilot getting ready for work. In these three pictures are just about everything a non-pilot illustrator would need to be able to accurately portray the scene. Plus, it's easy for me to forget that though I see this scene all the time, not everyone does. This little girl running around in front of me kept asking her parents what everything was. She was filled with curiousity.

Friday, February 06, 2009

Time of Useful Consciousness

Do you remember the tragic crash of Golfer Payne Stewart's airplane in 1999? The nation watched in disbelief as the Lear 35 with a two person crew and four passengers stopped communicating with ATC and flew on autopilot until it ran out of fuel and spiraled into the ground in South Dakota. Less than 15 minutes after its departure from MCO and somewhere in a climb from FL 230 to FL 390, contact with the pilots had been lost. A military airplane soon flew out to check on the airplane and that pilot said, "that he could not see inside the passenger section of the airplane because the windows seemed to be dark. Further, he stated that the entire right cockpit windshield was opaque, as if condensation or ice covered the inside. He also indicated that the left cockpit windshield was opaque, although several sections of the center of the windshield seemed to be only thinly covered by condensation or ice; a small rectangular section of the windshield was clear, with only a small section of the glare shield visible through this area."

The Cockpit Voice Recorder (CVR) captured "the sound of an engine winding down, followed by sounds similar to a stickshaker and an autopilot disconnect, can be heard on N47BA's cockpit voice recorder (CVR), which recorded the final 30 minutes of cruise flight. The CVR also captured the continuous activation of the cabin altitude aural warning, which ceased at 1212:26 CDT." Because this accident would not have occurred without both the loss of cabin pressure and the failure of the flight crew to receive supplemental oxygen, the Safety Board considered possible reasons for both of these key events in the accident sequence.
Because the crew was already at a high altitude when they were still communicating with ATC, the NTSB has determined that there was mostly likely not a slow depressurization; there are too many indications in the cockpit for the pilots not to recognize this situation: symptoms of hypoxia, cabin altitude warnings, etc. (Hypoxia is the physiological state of insufficient oxygen in the blood and body tissue and may ultimately cause impaired vision, judgment, or motor control; drowsiness; slurred speech; memory decrements; difficulty thinking; and loss of consciousness and death.)
Pressurized aircraft cabins allow physiologically safe environments to be maintained for flight crew and passengers during flight at physiologically deficient altitudes. At cruising altitudes, pressurized cabins of turbine-powered aircraft typically maintain a consistent environment equivalent to that of approximately 8,000 feet by directing engine bleed air into the cabin while simultaneously regulating the flow of air out of the cabin. The environmental equivalent altitude is referred to as "cabin altitude."

This aircraft was operating under Part 135 regulations which requires:
(2) Whenever a pressurized aircraft is operated at altitudes above 25,000 feet through 35,000 feet MSL, unless each pilot has an approved quick donning type oxygen mask -
(i) At least one pilot at the controls shall wear, secured and sealed, an oxygen mask that either supplies oxygen at all times or automatically supplies oxygen whenever the cabin pressure altitude exceeds 12,000 feet MSL; and
(ii) During that flight, each other pilot on flight deck duty shall have an oxygen mask, connected to an oxygen supply, located so as to allow immediate placing of the mask on the pilot's face sealed and secured for use.
(1) Whenever a pressurized aircraft is operated at altitudes above 35,000 feet MSL, at least one pilot at the controls shall wear, secured and sealed, an oxygen mask required by paragraph (b)(2)(i) of this section.
(2) If one pilot leaves a pilot duty station of an aircraft when operating at altitudes above 25,000 feet MSL, the remaining pilot at the controls shall put on and use an approved oxygen mask until the other pilot returns to the pilot duty station of the aircraft.
At left, I am demonstrating how the mask installed on a Citation X can deflect a stream of air to inflate the harness so it can be placed over the head (to operate properly, the pilot must remember to remove a headset). Releasing the levers will deflate the harness and secure the mask. It is a very tight fit, and not very comfortable, but for reasons explained in this post, a necessary evil. Pilots can communicate with each other and with ATC with a microphone integral to the mask, but it is not as clear as the ones in our headsets. Because of the tight fit, the mask presses against the face and makes talking difficult.

This is called "Time of Useful Consciousness," defined as the amount of time an individual is able to perform flying duties efficiently in an environment of inadequate oxygen supply. It is the period of time from the interruption of the oxygen supply or exposure to an oxygen-poor environment to the time when useful function is lost, and the individual is no longer capable of taking proper corrective and protective action. It is not the time to total unconsciousness. At the higher altitudes, the TUC becomes very short; considering this danger, the emphasis is on prevention rather than cure. In accordance with 14 CFR 25.1477(c)(2), flight crewmembers must be able to don the oxygen mask within 5 seconds for the mask to be considered quick donning. A TUC chart on Wikipedia displays TUC; for example, usually upon exposure to hypoxia at FL250, an average individual has a TUC of 3 to 5 minutes. A rapid decompression can reduce the TUC by up to 50 percent caused by the forced exhalation of the lungs during decompression and the extremely rapid rate of ascent.

In the NTSB review of the Payne Stewart accident, the FAA found that the Learjet Model 35/36 AFM did not have an emergency procedure requiring the flight crew to don oxygen masks immediately after the cabin altitude aural warning is activated. Because the AFM contains an abnormal procedure allowing the flight crew to troubleshoot the pressurization system before donning oxygen masks, the FAA noted that the flight crew may delay donning oxygen masks and become incapacitated.
If there had been a breach in the fuselage (even a small one that could not be visually detected by the in-flight observers) or a seal failure, the cabin could have depressurized gradually, rapidly, or even explosively. Research has shown that a period of as little as 8 seconds without supplemental oxygen following rapid depressurization to about 30,000 feet may cause a drop in oxygen saturation that can significantly impair cognitive functioning and increase the amount of time required to complete complex tasks. Prior problems with this aircraft's pressurization system had been addressed in the period before the accident. Full details in The entire NTSB transcript.

Thursday, February 05, 2009


One really great thing about Oshkosh is meeting all of the people there that are so enthusiastic about aviation. A lot of the visitors at the booth are dads, who ask me how they can encourage their daughters to be as enthusiastic about aviation as the rest of us there at the airshow. I mean, really, what's more interesting? A good view or a good book? As an avid reader myself, I can tell you sometimes it's a bit of a toss-up!

I have mentioned before that I didn't grow up wanting to be a pilot. I'm not sure as a kid what I would have done with the opportunity to fly in a small airplane even once, much less more often. I mean, by the time I started doing anything interesting, like jumping OUT of airplanes, I was already in college. My parents took us around the country in a little camper (yes, that's four kids and two parents in a Winnebago), and though it was a trial then, I look back with fondness and enjoy traveling to this day. I mean, who wants to hang out with your parents?? (This picture at right is of my dad and I standing in front of my airplane. I spent the night once in the town where he lives, so he got the nickel tour. His pictures are below and in an upcoming entry, too)

So I usually tell the dads to look for other kids their child's age. And for girls, find examples of women who are in aviation as well - so it doesn't look like a club just for middle aged men (Dads everywhere gasp - yeah, but we're *cool* middle aged men; we're pilots!). Ahem... Anyway. Here's a place to start: Girls With Wings Role Models. I, in fact, may even be a role model for my DAD. He hung out with me at the GWW booth last year again in Oshkosh and I think he's getting closer to getting a license himself. Something maybe a less intimidating than my ride.
And give it time, the girls will come around eventually. They may even secretly like it already - but it would be so uncool for them to let you know. At the very least, dads, you are giving your daughter the opportunity of a lifetime - to do something very few people get to experience. If they don't grow up to be a pilot themselves, you may give them the inspiration to do something else "out of the box." And for you dads (and moms, of course) who don't own an airplane or don't have a pilot's license, there are many resources out there to introduce your daughter to the world of aviation. Stay tuned to Girls With Wings for an announcement of an exciting new program for this very purpose!
p.s. Co-pilot Egg, shown in picture at right was also in picture at top.

Wednesday, February 04, 2009

The Latest Girls With Wings Newsletter

The Girls With Wings eZine is now available online. Read about this year's scholarship winner and upcoming events.

You can sign yourself up to receive it in your inbox on this page. Please use the forward link at the bottom of the newsletter and forward it to your friends!

Thanks for your support,
Lynda Meeks
Founder, Girls With Wings

Sunday, February 01, 2009

More info on winter ops

Yesterday I did a quick blog entry about a scenario when de-icing can be unsuccessful. The following pictures are from the same airport but the next morning. We walk into the FBO and see our airplane surrounded by the requisite equipment during winter operations. There's a plow clearing the ramp. BTW, ramps can get mighty slippery because of the prohibition against using salt around airplanes (salt is corosive). Some places put down sand, but that's of limited use and makes a mess! You may notice that the fuel truck parked here is plugged into an engine block heater. Not only was it snowy - it was cold, too!

So first, just like I did with my car, someone went out and brushed off the loose snow off the wings so that the de-icing fluid doesn't have to melt as much snow. This in itself has dangerous repurcussions, since there is a possibility that the airplane can tip backwards if the weight of the snow on the tail is too much. This happened to one of my company's airplanes when some pro-active FBO employees thought they would clean off the airplane before the crew arrived. The entire story was published is published in the local paper, Sun Valley Online.

But back to our aircraft (which thankfully stayed on all three gear assemblies until we required it to take flight). The FBO then brought up their deicing sprayer. Deicing fluids come in a variety of types, and are typically composed of ethylene glycol or propylene glycol, along with other ingredients such as thickening agents, wettening agents, corrosion inhibitors, and colored, UV-sensitive dye. Propylene Glycol is more common due to the fact it is less toxic than ethylene glycol. (Majority of this information is culminated in Wikipedia entries for de-icing fluid and de-icing.)

As I mentioned in yesterday's post, we were not able to depart the airport the night before because the snow was coming down faster than the FBO could remove it. This was immediately obvious to us because we could see the melted snow immediately refreezing. But the FAA has also published tables on how long de-icing fluids are effective based on certain conditions. You can see an example Hold Over Time (HOT) chart here.

Deicing fluid performance is measured by holdover time, which is the length of time an aircraft can wait after being treated prior to takeoff. Holdover time is influenced by the ambient temperature, wind, precipitation, humidity, aircraft skin temperature, and other factors. For Type I fluids, the holdover time is only about five to 15 minutes, so the aircraft must take off immediately or else wait to be deiced again. Type IV fluids generally provide a holdover time between 30 and 80 minutes.

This FBO only had TYPE 1 fluid, have a low viscosity, and are considered "unthickened". They provide only short term protection because they quickly flow off surfaces after use. They are typically sprayed on hot (130° - 180° F) at high pressure to remove snow, ice, and frost. Often they are dyed orange to aid in identification and application (You can see the orange snow in this picture).

Again, this is a de-icing fluid. Many FBOs also have other types of fluid. Deicing fluids containing thickeners (types II, III, and IV) are also known as anti-icing fluids, because they are used primarily to prevent icing from re-occurring after an initial deicing with a type I fluid (which was our problem the night before).

Type II fluids are "pseudoplastic", which means they contain a polymeric thickening agent to prevent their immediate flow off aircraft surfaces. Typically the fluid film will remain in place until the aircraft attains 100 knots or so, at which point the viscosity breaks down due to shear stress. The high speeds required for viscosity breakdown means that this type of fluid is useful only for larger aircraft. The use of type II fluids is diminishing in favour of type IV.

Type III fluids can be thought of as a compromise between type I and type II fluids. They are intended for use on slower aircraft, with a rotation speed of less than 100 knots. Type III fluids are gaining acceptance in the regional and business aviation markets.

Type IV fluids, commonly referred to as anti-icing fluids because an aircraft must first be deiced prior to a Type IV fluid application, meet the same viscosity specifications as type II fluids, but they provide a longer holdover time. They are typically dyed green to aid in the application of a consistent layer of fluid.

And Tracy left this comment after yesterday's post: The majority of the time we get de-iced twice. First they go over the whole plane with what is called Type I fluid. It is pretty much to wash off whatever accumulation is on the plane. Then they go over the wings and tail with a Type IV fluid that is thicker and sits on the surface, melting the snow/sleet that is still coming down. With two trucks working on it(one on each side of the plane), they completed a 747-400 in 25 minutes. Then we had a little over an hour to get airborne before the effect of the de-icing expired. That time limit is determined by the type of fluid, the rate the precip is falling and the outside air temperature.

De-Icing vs. Anti-Icing

When I got home yesterday, this was how my car looked. Pretty sad and lonely, huh? I had parked way out here on a monday morning, and on saturday there wasn't as much traffic at the train station. I tried to clean off my car, but the snow banks around the car were a pain to stand in. Finally I thought to pull my car forward out of the snowpile and finish clearing the windows. And, yes, it started like a champ. I am so grateful to have an 11 year old, yet reliable, car. I also am very grateful that a neighbor snuck over and plowed my driveway while I was gone. It took me an hour just to do some fine-tuning of removing the snow on the drive, I can't imagine how long it would have taken me if I had to do the whole driveway. These are some methods of de-icing (though some might argue it was actually de-snowing). Since it is going to be 40 degrees today, I am hoping the rest of the snow and ice on my driveway will melt.
This is the kind of de-icing most non-pilots have to deal with, unless they are being delayed when taxiing out for their commercial flight. All pilots at some point will have to deal with aircraft deicing since even any frost adhering to aircraft surfaces can cause a 30% decrease in lift. Secondly, chunks of ice that seperate from, say, the wing, can be deflected into the engine and cause damage. Additionally, any frozen liquids may interfere with flight control movement. It's a safety thing.
Aircraft are also cleaned of snow by shovels, brooms and chemical applications of De-icing fluid (more pictures tomorrow). The aircraft may also be pulled into a warm hangar or parked in the sun (if available, obviously).

Deicing isn't completely infallible, however. First of all, as I was told by an old salt when I was still a regional airline pilot years ago, the deicing fluid used on that Beech1900 was blown off the plane at 80kts (before rotation speed). So, if weather conditions are really bad, deicing may not allow airplanes to take off anyway for fear that the airplane will ice over again. Also, depending on the application methods and type of fluid used, the precipitation can refreeze within minutes. The rampers who apply deicing fluid may never get ahead of the precip. This happened to me recently at an airport in Ohio.
Note: there is a difference between DEicing and ANTIicing. Wikipedia's definition.

De-icing is the process of removing frozen contaminant, snow, ice, slush, from a surface.

Anti-icing is the process of protecting against the formation of frozen contaminant, snow, ice, slush on a surface.

Deicing can be accomplished by mechanical methods (scraping, pushing); through the application of heat; by use of chemicals, known as deicing fluids, designed to lower the freezing point of water (various salts, alcohols, glycols); or by a combination of these different techniques. Deicing fluids are always applied heated and diluted.

Anti-icing is accomplished by applying a protective layer, using a viscous fluid called anti-ice fluid, over a surface to absorb the contaminate.

All anti-ice fluids offer only limited protection, dependent upon frozen contaminant type and precipitation rate. A fluid has failed when it no longer can absorb the contaminant and it essentially becomes a contaminant itself. If it fails it must be washed from the surface using a deicing fluid.

This is a picture of the nose of the airplane. As you can see, there are frozen rivulets down the surface of the airplane. The FBO had a very small, low powered deicing spray system, which just melted the snow. By the time they got around the whole airplane, the water had refrozen. Since it was snowing so hard, they could have lapped the airplane many times trying to remove this fluid, because they had no anti-icing fluid. So we just canceled the trip and went in the morning. Tomorrow I will show more pictures of the deicing process.