Saturday, January 27, 2007
Pilots know their altitude because of the altimeter (abbreviated on the instrument as "alt"). The large number display is our altitude, which is the same as the pointer readout (currently sneaking below 40,000 feet). The knob in the lower left hand corner changes the numbers in the lower windows. Since the readout is 29.92, the 40,000 feet is not the reading above the ground but a standardized flight level (FL400).
Ok, so to explain. When pilots are getting ready to take off, they get an altimeter setting at the airport. This altimeter setting is adjusted for the temperature and pressure (for example, if there is a low pressure front moving through, it may be, say, 29.68 or alternatively a higher pressure indication of something like 30.13). Then the window will give us the altitude of the airport, like 791 feet in Cleveland. This is above the level of the sea, called Mean Sea Level (791ft MSL). That way, as you climb out and see 4791 feet, you know you're 4000 feet above the ground (or above ground level -- AGL).
This information is important when we are descending into an airport. We need to know exactly how far above the ground we are -- especially when we are in the clouds. When we do an instrument approach, the co-pilot will call out the airplane's altitude. For example, on an approach that takes us to within 200 feet above the ground, the copilot will think of 991 feet as the go-around point (using Cleveland again) and call out "1000 feet" when she reads 1991ft. Usually also 500, 300, 200, and 100 feet above this "decision altitude" are also called out. Sometimes the math is a pain, but it's very accurate.
When we level at say, 7000 feet MSL, we are given altimeter settings by air traffic control as we travel along. This keeps everyone consistently at their given altitude, regardless of the hills or valleys below us. At the higher altitudes, fluctuations would make this very confusing (and dangerous). So in the United States, we change to the standard altimeter setting 29.92. Now everyone is flying at Flight Levels but not necessarily the same as above mean sea level (MSL). Even though we're not flying at exactly 40,000 feet MSL, at least everyone is flying with the same margin of error. What's important here is that there is 1000 feet of separation between the aircraft!
Hopefully I have explained this well. For more information, Wikipedia has a good explanation of Flight Levels. http://en.wikipedia.org/wiki/Flight_level
Wednesday, January 24, 2007
This is what it looks like when ATC says "Options 525, you have crossing traffic at your 10 to 11 o'clock, 1000 feet above you." Can you see the black speck in the picture to the left?
We just so happen to be "in the clear" as opposed to "in the clouds," so we can actually see this traffic. If we couldn't we would rely on our TCAS to show us this traffic when we select the TRFC button (see the green light over this button?). Our TCAS shows this picture after the other aircraft passes over us:
See the diamond with the +10? This is saying that we have traffic 1000 feet above us. You can see by the display above the screen that we are at 19,000 feet above sea level, as opposed to just "above the ground." This distinction deserves a seperate discussion, so more on that later.
The pink line on this screen is the route we are flying. The reason the nose of the airplane is slightly off to the right is because we have a cross wind from our right. We are compensating for the push to the left the wind is giving us. If we pointed straight to our destination, we would go left to where we intended. It's like swimming across a river with a current. If we tried to swim straight across, we'd end up farther down the bank than we wanted. So we would swim slightly (or in proportion to the strength of the current) upstream so we could end up on the opposite bank exactly where we wanted.
See all of the orange numbers in the displays below the screen? Those are the radio frequencies we transmit on. More on these later, too!
Tuesday, January 23, 2007
Have you flown on one of these "puddle jumpers?" BTW, I don't like this term. It seems very disparaging of both the hardworking pilots and aircraft. Both propeller airplanes and their crews are overall very skilled and love their jobs, just like the commercial jet pilots.
Some people seated behind me were discussing why it was so dern loud while we were climbing out, but quieter when we were in cruise. Here is why:
A propeller is a device which transmits power by converting it into thrust for propulsion of a vehicle such as an aircraft, ship, or submarine though a fluid such as water or air, by rotating two or more twisted blades about a central shaft, in a manner analogous to rotating a screw through a solid. The blades of a propeller act as rotating wings, and produce force through application of both Bernoulli's principle and Newton's third law, generating a difference in pressure between the forward and rear surfaces of the airfoil-shaped blades.
Okay, so now that you know what a propeller does...
When rolling down the runway and climbing out to a safe (should an engine fail, an altitude to give you options to manuever back down for a safe landing), or cruising altitude, the props are set to give maximum lift. A consequence of this is maximum drag. Think of it like swimming laps in a pool. If you do your best crawlstroke, really grabbing at the water to move yourself forward, you will, but you'll tire yourself out. Better would be to do a more comfortable stroke, leaving energy to swim longer. It's a balance between energy and output.
So, it's most important to speed up and climb! despite the noise and wear and tear. When you reach cruising altitude, the propellers can be reduced in pitch and lessening the noise.
Ok, so that's pretty basic and doesn't give much real info. How about this more scientific explanation:
Changes to a propeller's efficiency are produced by a number of factors, notably adjustments to the helix angle, the angle between the resultant relative velocity and the blade rotation direction, and to blade pitch. Very small pitch and helix angles give a good performance against resistance but provide little thrust, while larger angles have the opposite effect. The best helix angle is when the blade is acting as wing producing much more lift than drag.
However due to the shape of the propeller, only part of the blade can actually be operating at peak efficiency. The outer part of the blade produces the most thrust and so the blade is positioned at a pitch that gives optimum angle to that portion. Since a large portion of the blade is therefore at an inefficient angle, the inboard ends of the blade are hidden by a streamlined spinner to reduce the resistance torque that would otherwise be created. (Actually, most propeller blades have been twisted, to compensate for this - lm)
Most propellers are fitted with mechanisms to allow variable pitch – coarse pitch for high speed flight and fine pitch for climbing or accelerating from lower speeds. Early pitch control settings were pilot operated and so limited to only three or so settings; later systems were automatic. Later still, variable pitch was replaced with the constant speed unit. In some aircraft the pilot can manually override the constant speed mechanism to reverse the blade pitch angle, and thus the thrust of the engine. This allows the aircraft to back up on its own, at unimproved airfields when aircraft tractors are unavailable. (Though most operators frown on their pilots doing this at any time -- it's too easy to rock the airplane back on its tail! - lm)
A constant-speed (also known as variable-pitch) propeller enables the pilot to set a desired propeller rpm (within a given allowable range). A propeller governor acts as an open-loop control system to vary propeller pitch angle (and therefore drag) as required to maintain the commanded rpm. In many aircraft this system is hydraulic, with engine oil serving as the hydraulic fluid. The purpose of varying propeller pitch angle with a variable pitch propeller is to maintain an optimal angle of attack (maximum lift to drag ratio) on the propeller blades as aircraft speed varies.
Most information from Wikipedia.
Sunday, January 21, 2007
Although like most everyone else I tanned my skin until my early 30s when I started seeing the effects of the sun damage (Genes don't help either). I no longer spend time out in the sun unprotected. But every time I feel like I'm cooking up there at 37,000 feet, I think, this can't be good for my skin either. In the mornings before I go fly I use sunscreen. But I wonder, does it just feel hotter, or is there something to be concerned about?
I know that the atmosphere is thinner, so certainly exposure to radiation is greater (some say 100 to 300 times). Does this mean more cancers in frequent fliers? What about melanoma from the sun?
I found this:
Category: Environmental & Background Radiation — Aircraft and Space Radiation
The following question was answered by an expert in the appropriate field:
Q: What are some of the risks or "worries" that someone may have if deciding to become an airplane pilot? I would appreciate it if the answer would be related to physics and radiation, rather than simply the risk of an accident.Robert J. Barish, PhD, CHP, DABR, DABMP, FAAPM
A: Since you've sent this question in to the Health Physics Society for an answer by an expert in radiation safety, I will assume that your question is primarily directed to the issue of the radiation risks encountered by flight crewmembers. In your question, you used the term "airplane pilot" rather than "airline pilot." If in fact you're asking about becoming a licensed pilot in the realm of "general aviation" rather than commercial flying, be assured that at the low altitudes used by private pilots in light aircraft the radiation risks are negligible.
For airline pilots, the situation is different. In both Europe and the United States, airline flight crewmembers have for years been considered radiation workers, although most US-based flight attendants and pilots are unaware of this classification. The acceptable radiation exposure for a radiation worker is substantially greater than that for a member of the general public—a factor of 50 times more in the United States, 20 times more in the European Union.
The rationale for this large difference is not only predicated on the difference between the acceptability of a radiation exposure to a compensated employee compared with an "innocent bystander," it also considers several other important areas of dissimilarity. Radiation workers must be at least 18 years old, while the public is composed of all age groups, including children who may be more susceptible to harm. Another factor is the availability of ongoing health monitoring for radiation workers. And there is the simple fact that radiation workers must willingly accept their increased levels of risk or seek other employment.
In this context, airline pilots receive exposures that are well within the accepted dose limits for occupational exposures, limits recommended by organizations such as the International Commission on Radiological Protection. Pilots flying high-altitude, high-latitude routes do receive exposures that put them in the top five percent of all radiation workers when ranked by dose. Even so, their exposures are generally no greater than half of the value which is permissible under the more strict European (compared with US) occupational standards.
For male and female pilots, the primary risk of many years of exposure at these levels is the possibility of a small increase, about 1%, in their lifetime risk of cancer. For female pilots, issues related to pregnancy may also apply (other answers on this site address those concerns). Although the presumed increase in cancer risk is small, it is the right of all flight crewmembers to make a choice about the personal acceptability of this risk based on sound scientific principles and educated decision making. If you become an airline pilot, you should insist that your employer provide the educational materials necessary for you to understand this issue thoroughly.
In an article in Plane & Pilot magazine: http://www.planeandpilotmag.com/content/pastissues/2001/sept/rising.html
There are other risks to flying then, in addition to the possibility of crashes or bad airline food. Definitely something to think about...
European studies have shown that pilots, flight attendants and frequent fliers have a higher incidence of various forms of cancer due to radiation exposure. The FAA agrees that airlines should provide information about radiation exposure to crewmembers, but a 1984 petition for rulemaking concerning radiation was denied.
The article also says that many studies have shown a large increase of melanoma in the pilot population over the general population, but the studies aren't clear yet whether it comes from the additional exposure during flying or from a pilot's lifestyle.
Saturday, January 20, 2007
From Wikipedia: A deicing boot is a device installed on aircraft surfaces to permit a mechanical deicing in flight. Such boots are generally installed on the leading edges of wings and control surfaces (e.g. horizontal and vertical stabilizer) as these areas are most likely to accumulate ice and any contamination could severely affect the aircraft's performance. A deicing boot consists of a thick rubber membrane that is installed over the surface. As atmospheric icing occurs and ice builds up, a pneumatic system inflates the boot with compressed air. This expansion in size cracks any ice that has accumulated, and this ice is then blown away by the airflow. The boots are then deflated to return the wing or surface to its optimal shape.
While deicing boots have undoubtedly saved many lives and have permitted flight into known icing conditions, it is important to note that they are unable to handle extremely severe icing. In these cases, ice can accumulate faster than the boots can shed it or, ice can accumulate on non-booted surfaces to the point where it weighs the aircraft down until it is overweight and no longer flyable.
Deicing boots are most commonly seen on medium-sized airliners and utility aircraft. Larger airliners and military jets tend to use heating systems that are installed underneath the wing's leading edge, keeping it constantly warm and preventing ice from forming.
Friday, January 19, 2007
She was a student of Wiley Post (a famous pilot from the early 1900s and supporter of women pilots), so you can see that website, www.wileypost.org for more info.
Thursday, January 18, 2007
These charted "jet" routes (there are also V-Victor airways at lower altitudes) connect various navigation aids around the world. They used to be between NDB (non directional beacons--like radio stations putting out a signal) and VORs (very high frequency omnidirectional receivers), but are more and more relying on GPS designated intersections.
Pilots usually use paper "maps" to navigate their way around (given permission by Air Traffic Controllers of course), produced by Jeppesen.
Jeppesen (formerly Jeppesen Sanderson, and still used today) is an American company that specialises in aeronautical charting and navigation services, flight planning, pilot supplies and aviation training. The company is a subsidiary of Boeing Commercial Airplanes. Jeppesen also publishes related software, some of which is used on its electronic flight bag product line.I can't readily find a picture on the net of the charts to show you what they look like. Let me know if you'd like me to get a hold of one and scan it so you can see what they look like....
The company was founded in 1934 by Elrey Borge Jeppesen, a pilot himself working for Varney Airlines, who was the first to make aeronautical charts for pilots to navigate in flight. The information he collected and the charts he drew were at first only for personal use, but fellow pilots quickly saw the benefits of using these charts and
Jeppesen started selling copies of his chart book for 10 dollars. Other pilots started to collect data on their own routes and handing this to Jeppesen for him to include in his navigation book.
United Airlines, the airline Jeppesen worked for in the late 1930s after Varney airlines had merged with several other companies to form United Airlines, was one of the first airlines to start using Jeppesen's charts. After a while the chart business started taking up so much of Jeppesen's time that he quit his job as a Captain and became dedicated to making charts.
Wednesday, January 17, 2007
Generally stratocumuli bring no precipitation or only drizzle / light rain or snow at best. However, these clouds are often seen at either the front or tail end of worse weather, so may indicate storms to come, in the form of thunderheads or gusty winds.
As you can see, there are several different ways clouds are formed.
But clouds can also be formed when two air masses below saturation point mix. Examples are breath on a cold day, aircraft contrails and Arctic sea smoke.
Also clouds are formed when air stays the same temperature but absorbs more water vapor into it until it reaches saturation point. This information from Wikipedia, Clouds.
The atmosphere can have several layers that are fairly well isolated from each other and can have separate dynamics, including lifting and convection, although convection above the lower level of the atmosphere is normally much weaker.The atmosphere also has a fairly complex temperature structure, so that temperature is increasing with height in some layers (thereby squelching the production of clouds) and decreasing with height in other layers (where clouds are more likely to form because air can more easily rise if heated some). Different characteristics of the air in the different levels can therefore produce different clouds or the same kind of cloud in the different layers, depending on the dynamics of the layer. Read all.
Tuesday, January 16, 2007
Friday, January 05, 2007
"You don't have to be a social scientist to see how, for every plastic vamp we allow to sashay through our kids' bedrooms, we are only encouraging a larger sexual trend to take root in their culture. From the boy-crazy characters in tween movies to the barely there costumes on Dancing with the Stars, sex has become something our kids are growing up with rather than growing into, and this uninvited tutoring is often occurring below the radar. "
"The battle is also escalating among the competing manufacturers themselves. AG Properties, which markets the more "wholesome" Holly Hobbie characters (sweet-faced kids, furry pets - you get the picture), recently commissioned a survey of 1,010 mothers with preteen daughters to determine how they feel about the army of sultry chickies invading their kids' playrooms. The results were nearly unanimous: 90% expressed a desire for a wider selection of dolls that were positive role models for young girls, while 85% said they are fed up with the "sexpot" playthings available."
"Like everything else with parenting, we need to be discriminating. For my money (literally), I remain a big fan of the American Girl doll line, if only because it has the audacity to teach little girls U.S. history instead of fashion tips."
Thursday, January 04, 2007
- Women In Aviation, International began in 1990 and was formally established in 1994 to encourage women to seek opportunities in aviation. According to the Federal Aviation Administration, of the nearly 700,000 active pilots in the United States, less than six percent are women and only slightly more than two percent ATP rated. Women account for only 2.13 percent of the more than 540,000 non-pilot aviation jobs in the United States.
- Women in Aviation, International is a nonprofit organization dedicated to the encouragement and advancement of women in all aviation career fields and interests. Our 7,000+ membership includes astronauts, corporate pilots, maintenance technicians, air traffic controllers, business owners, educators, journalists, flight attendants, high school and university students, air show performers, airport managers and many others.
- We provide year-round resources to assist women in aviation and to encourage young women to consider aviation as a career. WAI also offers educational outreach programs to educators, aviation industry members and young people nationally and internationally.
In addition, WAI promotes public understanding of the accomplishments and contributions of women in aviation. This includes historic notables such as Amelia Earhart, Bessie Coleman, Eileen Collins, Jeana Yeager and many others.
This organization has given me such a boost. In their most recent edition of their magazine, they have published a full page article on Girls With Wings. I hope it will translate into more sales to develop the GWW program, since I am getting more and more requests for GWW assistance. Click here to see the article.
Wednesday, January 03, 2007
It had been hypothesized that in regions such as the United States with heavy air traffic, contrails affected the weather, reducing solar heating during the day and radiation of heat during the night by increasing the albedo. The suspension of air travel for three days in the United States after September 11, 2001 provided an opportunity to test this hypothesis. Measurements did show that without contrails the local diurnal temperature range (difference of day and night temperatures) was about 1 degree Celsius higher than immediately before; however, it has also been suggested that this was due to unusually clear weather during the period.
So, for the best answer, we again ask the rocket scientists:
NASA scientists have found that cirrus clouds, formed by contrails from aircraft engine exhaust, are capable of increasing average surface temperatures enough to account for a warming trend in the United States that occurred between 1975 and 1994. According to Patrick Minnis, a senior research scientist at NASA’s Langley Research Center in Hampton, Va., there has been a one percent per decade increase in cirrus cloud cover over the United States, likely due to air traffic. Cirrus clouds exert a warming influence on the surface by allowing most of the Sun’s rays to pass through but then trapping some of the resulting heat emitted by the surface and lower atmosphere. Using a general circulation model, Minnis estimates that cirrus clouds from contrails increased the temperatures of the lower atmosphere by anywhere from 0.36 to 0.54°F per decade. Minnis’s results show good agreement with weather service data, which reveal that the temperature of the surface and lower atmosphere rose by almost 0.5°F per decade between 1975 and 1994.
This enhanced infrared image from the Moderate Resolution Imaging Spectroradiometer (MODIS), aboard NASA’s Terra satellite, shows widespread contrails over the southeastern United States during the morning of January 29, 2004. Such satellite data are critical for studying the effects of contrails. The crisscrossing white lines are contrails that form from planes flying in different directions at different altitudes. Each contrail spreads and moves with the wind. Contrails often form over large areas during winter and spring.
Tuesday, January 02, 2007
Last survey question: Why do you personally have an interest in the success of Girls With Wings? Choose as many as applicable.
Response in Percent followed by Response Total
I am a parent. 45% 27
I am an educator. 20% 12
I am a pilot and want to share the joy of flying with others. 51.7% 31
I am a female pilot and want to make the future of women in aviation better. 55% 33
I have a female family member or friend who is a pilot. 28.3% 17
I didn't even know there was such a thing as a female pilot. 0% 0
Other (please specify). 31.7% 19
1. Relative of mine is interested in learning to fly.
2. I was told I couldn't do it! I joined the Air Force, but never tried to get my commission and become a pilot. That was for guys! Your too pretty to worry about that stuff, I was told. Crap, I say! My daughter won't hear that stuff!
3. i am an 11 year old girl pilot
4. I have a niece
5. MCFI who has truly enjoyed teaching and seeing young pilots reach their goals.
6. I'm a future pilot.
7. I am also interested in increasing awareness for women in military aviation (and more specifically the 'fighter/jet' community). I am often amazed at how often people are surprised to hear that, as a woman, I fly for the Navy, especially in fighter-type aircraft. In addition, I am also amazed with how few woman there are in my community....I'd like that to change.
8. i am on my way to getting my license.
9. i am a teenager intrested in avaition
10. I am inspired by my daughter who wants to earn her pilots license.
11. Girls get caught up in the desire of boys and having kids without having self esteem and the desire to think for themselves. I want little girls to have goals and aspirations for themselves so that when they have kids they can pass of the great opportunities available.
12. Our organization is very active in STEM and promooting female career opportunities.
13. Girls to aspire to more in life then graduating from high school, getting married, and having kids. Not to say that that is a bad thing but we all need to live!
14. I have two nieces, one who I have regular contact with and she enjoys many of the things I do that her parents do not, besides, flying is cool and she wants to do cool stuff.
15. Our granddaughter thinks flying is wonderful and her brothers and male cousins say "girls can't fly" I think she is going to show them all up in a few years. At 4 1/2 she is already asking to fly the plane.
16. Women Fly?? "Another empty kitchen and proud of it!"
17. im a student who like to learn more about how women can do the same as men
18. Believe in girls achieving whatever they want to do - sky is no limit.
19. I've met too many people who didn't realize that "there was such a thing as a female pilot."
Total Respondents 60