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The Thunderstorm Threat General Aviation News

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The Thunderstorm Threat

By ED BROTAK

With the onset of warmer weather, pilots face the increased risk of encountering thunderstorms.

Although more common in the warmer months, thunderstorms can occur even in the winter, especially in the southern states. It’s estimated that 100,000 thunderstorms occur in the U.S. each year. Some locations in southwest Florida have 100 storms a year, but thunderstorms do occur in all 50 states.

Thunderstorms are most common in the late afternoon, but can occur at any time of the day.

Technically called convective cells, a thunderstorm can cover an area from 200 to 1,000 square miles. Storms can range in height from 10,000 feet to over 60,000 feet. Individual cells can last from less than a half hour to many hours.

THE DIFFERENT TYPES OF THUNDERSTORMS

There are different types of thunderstorms that develop under different conditions. “Air mass thunderstorms” typically develop in the late afternoon and evening due to the heat of the day. Development tends to be random, but they are more numerous over mountainous terrain. Although relatively weak, they can still pose problems and should be avoided. Fortunately, air mass thunderstorms tend to be slow moving.

Dr. Ed Brotak

A greater threat is posed by organized convection. These are stronger storms that often move quickly, up to 60 mph. They are often associated with fronts, especially ahead of cold fronts.

“Squall lines” form when convective cells develop in a line in response to prevailing atmospheric conditions. The line can extend for tens or even hundreds of miles. Although there are breaks between the cells, circumnavigation or remaining on the ground until the line passes is strongly recommended. Individual storms will die out only to be replaced by new cells, with the whole system lasting for hours.

MINIMIZING THE DANGER

It’s a good time to review the risks thunderstorms pose to aviators and what you can do to minimize the danger.

Many things are happening inside a thunderstorm cloud (cumulonimbus) that they pose a wide variety of threats to aircraft.

Lightning can certainly do some structural damage and affect electrical equipment inside a plane.

Hail, which can grow to the size of softballs, can damage windshields and the exterior of the aircraft. The occurrence of hail indicates sub-freezing temperatures at some height in the cloud.

Even with the warmth of summer, towering thunderstorm clouds easily reach and exceed the freezing level. This also means super-cooled water and the risk of icing is present.

One of the more subtle threats thunderstorms produce is erroneous aneroid altimeter readings due to the rapid pressure changes the storm induces. Readings may be off by 100 feet.

But by far the greatest risk is turbulence. Updrafts and downdrafts within the storm can easily reach 50 mph (73.3 feet per second) and can reach 100 mph (146.6 feet per second). Planes can literally be torn to pieces by the turbulence generated between the up drafts and down drafts.

Even if there is no structural damage to the aircraft, loss of control is a distinct possibility.

And obviously within the cloud, IMC exist and the risk of Controlled Flight into Terrain (CFIT), especially in uneven terrain, is great.

Movement and turbulence of a maturing thunderstorm (FAA graphic).

And keep in mind that convection can develop very quickly. What was VMC everywhere can quickly contain areas of IMC.

TROUBLE ALL AROUND

Dangerous weather conditions are not limited to within the storm cloud itself.

Turbulence above the cloud top can extend upwards for thousands of feet.

Interestingly, the massive core of the storm can actually act as a solid impediment to the prevailing winds, almost like a mountain. Clear Air Turbulence (CAT) can be produced in the air flow downwind of the storm and extend tens of miles.

Beneath the storm cloud base, conditions can also be treacherous. Blinding rain and even hail can extend to the ground. IMC conditions are common.

Extreme downdrafts, called downbursts or microbursts, can occur even without precipitation. Once these downdrafts hit the ground, they can spread out, sometimes for tens of miles, producing strong, shifting winds that can exceed 100 mph, and the dreaded wind shear.

Microbusts can product destructive winds greater than 100 kts. (FAA graphic)

BE PREPARED

Before you start your flight, your preflight weather check, including TAFs and FAs, should highlight any convective problems.

Particularly note any CONVECTIVE SIGMETS, forecasts that warn of dangerous flying conditions due to convection in the next two hours.

But keep in mind, it is impossible to predict exactly when and where thunderstorms will develop in advance. And convection can develop rapidly, sometimes in a matter of minutes.

Closer to takeoff, you can check the latest METARs and PIREPS to see if convection has been reported.

Weather radar is the best tool for locating and tracking thunderstorms. The heavy rainfall rates associated with convection are well depicted as areas of yellow, red, or even purple if hail is present.

Movement and changes in intensity can be determined by tracking storms over time.

Major terminals are well covered by land-based radar. Terminal Doppler Weather Radar can detect thunderstorms and even wind shear near an airport. Larger airports also have specialized wind shear monitoring equipment for the runways. Smaller GA airports are often not as well equipped.

IT’S UP TO YOU

It’s up to the pilot to determine thunderstorm risk. Fortunately with today’s technology, a variety of weather radar products are readily available over the Internet and there are even apps for smartphones.

Always check the time on any radar display you’re checking. Delays due to processing are common. The radar image you’re looking at could be up to 20 minutes old. In fast developing convective situations, that could be crucial.

If your aircraft is equipped with radar, it can be extremely helpful in convective situations. Current radar data is always available, allowing you to detect significant convection 300 nm away.

Source: The Thunderstorm Threat — General Aviation News

When Is a Non Precision Approach a Better Choice Than a Precision Approach Bold Method

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primary

When you’re picking an approach at your destination, you usually go for the precision approaches first. But is there ever a time when shooting a non-precision is better?
There can be, depending the ceiling, visibility, turbulence, ice, and how soon you want to get out of the clouds. But any time you choose a non-precision approach over a precision, you’re also taking on more workload, and opening yourself up to the possibility of a mistake while descending on the approach.
Seeing The Runway Sooner
Let’s look at this example in Olympia, WA. Runway 17 is in use. The visibility is 10SM, and the ceilings are overcast at 700′.
Looking at available approaches, the ILS to 17 is your first pick. But like most ILS approaches, you can also shoot a localizer only approach to runway 17 using this chart.olm-ils
What’s the difference? The ILS gets you down to 218′ above touchdown, and the LOC, which is a non-precision approach, gets you down to 433′ above touchdown.
Since the ceiling is 700′ overcast, both approaches with get you out of the clouds with no problem. But if you fly a localizer only approach, it can get you out of the clouds sooner, depending on your descent rate. Why would you want to do that? It can give you more time to visually orient yourself with the runway and surrounding area. And if you’re getting beat up by turbulence or picking up ice, it can give you, and your passengers, some added relief.
How Much Time Will You Spend In The Soup?
Let’s start with the ILS to 17. If you’re flying a 90 knot approach speed on a 3 degree glideslope, you’ll need to descend at roughly 450 feet-per-minute (FPM) to maintain the glideslope.There’s a pretty easy rule-of-thumb to figure that descent rate out. Divide your ground speed by 2, then add a 0 to the end. So if you take 90 knots / 2, you get 45. Add a zero to the end, and you get 450 FPM.
On this approach, glide slope intercept is at 2400′ MSL. Since TDZE is 207′ MSL, that means you’re roughly 2200′ above the touchdown zone when you intercept glideslope. And since the ceilings are 700′ overcast, you’ll need to descend roughly 1500′ before you break out of the clouds.
That means if you’re descending at 450 FPM on the ILS, it will take you roughly 3 minutes and 20 seconds before you break out of the clouds.
What If You Fly The LOC Only?
Now lets look at the LOC only approach. You know that the MDA of 640′ MSL (433′ above TDZE) is still easily going to get you out of the clouds. And if you increase your descent rate even slightly, it can get you out of the clouds sooner.When you cross the FAF, if you start a descent at 600 FPM, which is still a very reasonable descent rate, it will take you about 2 minutes and 30 seconds before you break out of the clouds. That’s 50 seconds sooner than shooting the ILS.

precision-vs-nonprecision-chart
non-precision
Making The Best Choice For Your Approach

In almost all cases, using a precision approach is the best choice. That’s especially true in low visibility. Following the glideslope on a precision approach means you know you’re at the right place, at the right time, all the way to DA/DH.

But if you want to get yourself out of the clouds to get oriented with the runway and surrounding area a little early, or if you’re trying to get yourself out of the clouds when there’s turbulence or ice, using a non-precision can do that for you. Just make sure you’re flying a stable descent, you’re ready to level off at MDA, and you’re prepared to make a stable descent from MDA to touchdown.

 ALL THANKS TO BOTDMETHOD FOR SHARING THIS WITH US

DA42 MPP Geostar

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All-in-one solution for Geo Survey and Mapping

Diamond Aircraft, known for the most efficient aircraft in the industry and state-of-the-art remote sensing solutions, puts another Diamond in the sky. For the first time, the new DA42 GEOSTAR enables collecting laser-scanning and photo-grammetry data during one single flight. The GEOSTAR is particularly suited for surveying cities, land areas, critical infrastructure (such as pipelines), glaciers or snow fields, but also for mapping damages caused through natural disasters.

Source: DA42 MPP Geostar

AIRBUS Adverse Weather Operations Windshear Awareness

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via AIRBUS Adverse Weather Operations Windshear Awareness — Egyptianaviators

KEY  FACTOR : 

Flight crew awareness and alertness are key factors in the successful application of windshear avoidance and escape / recovery techniques. This Flight Briefing Note provides an overview of operational recommendations and training guidelines for aircraft operation in forecast or suspected windshear or downburst conditions.

REAL DATA : 

Adverse wind conditions (i.e., strong cross winds, tailwind and windshear) are involved in more than 30 percent of approach-and-landing accidents and in 15 percent of events involving CFIT. Windshear is the primary causal factor in 4 percent of approach-and-landing accidents and is the ninth cause of fatalities.

Defining Windshear : 

Windshear is defined as a sudden change of wind velocity and/or direction.
Windshear occurs in all directions, but for convenience, it is measured along vertical and horizontal axis, thus becoming vertical and horizontal windshear:

Vertical windshear: − Variations of the horizontal wind component along the vertical axis, resulting in turbulence that may affect the aircraft airspeed when climbing or descending through the windshear layer − Variations of the wind component of 20 kt per 1000 ft to 30 kt per 1000 ft are typical values, but a vertical windshear may reach up to 10 kt per 100 ft.
 Horizontal windshear: − Variations of the wind component along the horizontal axis (e.g., decreasing headwind or increasing tailwind, or a shift from a headwind to a tailwind) − Variations of wind component may reach up to 100 kt per nautical mile.
Windshear conditions usually are associated with the following weather situations:

• Jet streams • Mountain waves • Frontal surfaces • Thunderstorms and convective clouds • Microbursts.

MICROBURSTS:

 Microbursts combine two distinct threats to aviation safety :cof

• The downburst part, resulting in strong downdrafts (reaching up to 6000 ft/mn of vertical velocity) •

The outburst part, resulting in large horizontal windshear and wind component shift from headwind to tailwind (horizontal winds may reach up to 45 kt).

Windshear and Aircraft Performance :

Headwind gust instantaneously increases the aircraft speed and thus tends to make the aircraft fly above intended path and/or accelerate ( item 1).

. A downdraft affects both the aircraft Angle-Of-Attack (AOA), that increases, and the aircraft path since it makes the aircraft sink ( item 2).

Tailwind gust instantaneously decreases the aircraft speed and thus tends to make the aircraft fly below intended path and/or decelerate ( item 3).

NOTE: 
Windshears associated to jet streams, mountain waves and frontal surfaces usually occur at altitudes that do not present the same risk than microbursts, which occur closer to the ground.

KEY FACTOR : Flight crew awareness and alertness are key factors in the successful application of windshear avoidance and escape / recovery techniques. This Flight Briefing Note provides an overview of operational recommendations and training guidelines for aircraft operation in forecast or suspected windshear or downburst conditions. REAL DATA : Adverse wind conditions (i.e., strong […]

via AIRBUS Adverse Weather Operations Windshear Awareness — Egyptianaviators

The 7 Hardest Parts About Becoming A Private Pilot 

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Everyone knows that crosswind landings are usually challenging for student pilots. But beyond landings (and money!), there’s a lot about learning to fly that can be pretty tough. Here’s what you should be ready for.

The 7 Hardest Parts About Becoming A Private Pilot

By Swayne Martin

Everyone knows that crosswind landings are usually challenging for student pilots. But beyond landings (and money!), there’s a lot about learning to fly that can be pretty tough. Here’s what you should be ready for…

1) Aircraft Systems
One of the toughest topics for private pilot students is aircraft systems. As less and less people grow up working on cars or around machinery, there’s diminishing knowledge behind what makes that engine turn.Want to know more about the systems and equipment in your aircraft? Dig into your POH and read section 7. Better yet, find a local A&P at your airport and have them walk you through a few systems with the cowling off. Getting hands-on with the equipment behind closed panels is a great way to learn how your airplane flies.

2) The National Airspace System
It’s more than identifying lines of airspace on a sectional chart. You’ll need to know what weather minimums exist at different altitudes (day and night), what your equipment requirements are, and what your communication requirements are.
We can help – give our National Airspace System course a try.

3) Learning Regulations
There are hundreds of FAA Regulations that govern how, where, and when you can fly. Some of them can be pretty confusing. As a student pilot, you’re just as responsible for adhering to the FARs as any fully certificated pilot. Keep yourself out of trouble and learn those regs!

4) Aerodynamics
A huge part of learning to fly is understanding the physics behind how it all works. But how can a strong foundation of aerodynamics save your life? One simple example is the lift to drag ratio for your airplane. At L/D max, or the best lift to drag ratio, you’ll find an approximate best glide speed.

5) Decoding Textual Weather
Whether it’s a METAR or PIREP, it’s your responsibility as a pilot to maintain your skills for decoding textual weather.
Need a refresher? Give our Aviation Weather Products course a try.

6) “Radio Talk”
Learning how to actively listen for your callsign in busy airspace with dozens of airplanes on-frequency is tough. Adding that to learning the correct verbiage provides quite the task for brand new student pilots. Here are some things you shouldn’t say over the radio.

7) Getting Into “School Mode”
First and foremost, getting your brain into a “school mode” can be tough, especially if you haven’t sat in a formal classroom setting in years. Learning to fly is undoubtedly fun, but there’s also a lot of work outside the cockpit.

Microlight Trikes Active Recreation by GleBB

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Travel and active recreation. Photo outdoors. Series « Travel, nature and active recreation». Landscape. The natural lighting. via 500px http://ift.tt/2jIMd2B

via Popular on 500px : Microlight trikes _ active recreation by GleBB — Photo Snapping

Why Jet Lag Is Worse than You Think

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If you’re traveling cross-country to run a race or participate in a sporting event, you may want to prepare for the time change in advance. A new study of professional baseball players shows that jet lag doesn’t just affect mental performance—it can also affect physical performance, as well. The authors say their findings can have implications for all types of athletes, and they offer strategies for lessening the impact.

The new study, published in Proceedings of the National Academy of Sciences from researchers at Northwestern University, looked at Major League Baseball data from more than 40,000 games spanning 20 years, including teams’ travel schedules and players’ performance in hitting, running, pitching and more.

Traveling two or more time zones before a game affected play in subtle but detectible ways, the authors found. For example, teams from eastern states who had just returned home from a game out west tended to have fewer stolen bases, doubles and triples, and were subject to more double plays, than those who hadn’t traveled as recently.

Pitchers from both home and away teams also gave up more home runs after traveling eastward. The effects are enough to erase a team’s home-field advantage, the authors say. They speculate that jet lag may have even played a role in Game 6 of the 2016 National Championship Series, in which the home-team Chicago Cubs scored five runs off the visiting Los Angeles Dodgers’ ace pitcher, Clayton Kershaw.

The effects of west-to-east travel were stronger than those of east-to-west travel, supporting the argument that they are due to the body’s circadian clock—not just time on an airplane or scheduling issues in general, says Dr. Ravi Allada, associate director of Northwestern’s Center for Sleep and Circadian Biology.

The study isn’t the first to show that jet lag can impact athletic performance. Allada says the new findings add to the evidence that jet lag isn’t just all in one’s head. “We know, based on studies in animals and humans, that when you misalign your internal biological clock with your external environment, there can be a lot of consequences in terms of health,” Allada says. “And the circadian clock is present in muscle cells, too, so it makes sense that one might see an impairment in muscle activity or muscle efficiency, as a result of this misalignment.”

Based on these findings, Allada recommends that baseball teams send their starting pitchers to games across the country a day or two early, when possible, so that their internal clocks can adjust to the local environment.

Similar advice could also apply to anyone traveling for athletic events—especially eastward—he adds, like runners going to a destination marathon or adventure race. That also includes people who have been away and are heading home for an event: an aspect of jet lag that people don’t often think about, says Allada.

“The rule of thumb is that the body clock can shift about one hour a day, so if you’re traveling across three time zones, you’d want to ideally give yourself three days to adjust,” he says.

If your schedule won’t allow for an earlier trip, he recommends faking it for a few days by trying to wake up and go to bed according to the time-zone of your event, even while you’re still at home. If you’re traveling west-to-east, exposing yourself to bright light earlier in the morning can help, as well.

Allada says there’s not yet a lot of research to back up the effectiveness of these strategies, but he believes they could benefit anyone looking to optimize their performance. “That’s something we’d love to study in the future,” he says, “to work with athletes and see if these interventions actually have real impacts.”

via Why Jet Lag Is Worse than You Think — TIME

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