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Aircraft can cause rain or snow

David Parker Brown of the AirlineReporter blog and Discovery News have both noted an interesting phenomena – aircraft can punch holes through clouds causing it to rain. According to Discovery News, droplets in many clouds exist in a supercooled state. In fact, they can be as cold as -34 degrees C (-35 degrees F) and yet remain in a liquid form. When an aircraft cruises through, it can cause a quick drop in temperature and this freezes the droplets. Hence, the cloud is now populated by ice crystals and as droplets begin condensing around them in a chain reaction, a hole of blue sky appears where there was once a white cloud and the water and ice falls to earth.

Apparently though, not all aircraft that fly through clouds can seed them and generally speaking, there’s a "goldilocks" set of conditions that must be met. These conditions include clouds that are too high in the atmosphere, are too cold and may already be frozen. On the other hand, low clouds are warmer and hence an aircraft’s disturbance won’t produce ice. Moreover, Turboprop aircraft are better than jets for producing seeding effects because they often fly at the right altitude to encounter clouds with supercooled droplets plus they generate thrust by pushing fairly large amounts of air (as opposed to heated jet exhaust) that cools in their wakes.

So just how much potential is there for “plane seeding?” According to a new study in Bulletin of the American Meteorological Society, 7.8% of Earth is covered in clouds ripe for "plane seeding” but its important to also note that aircraft cannot alter global weather patterns (although they may impact weather patterns in a very localized area). In some instances though, planes flying through a cloud can also create "canal clouds" that can be many miles long and even visible from satellites.

Hence and if you find that your home or street has rain or snow while your neighbors do not, perhaps it was inadvertently caused by “plane seeding.”

Improve your landings with Jacobson Flare

Both pilots and flight instructors alike need to always be open to new ideas in order to become better and safer pilots. Moreover, performing a proper and safe landing is one of the more difficult tasks faced by both new and experienced pilots.

Hence, a recent post by John Ewing for Aviation Mentor is well worth reading because he describes a landing technique that a student, one with an inconsistent landing performance, had introduced him to after he found it on the internet. The technique is known as Jacobson Flare. According to John:

Jacobson uses the pilot’s Eye-to-Wheel Height (or EWH, based on the aircraft type), the pilot’s offset from the main landing gear (also based on aircraft type), the airplane’s approach angle (usually 3 or 4 degrees), and simple geometry to determine visual references on the runway surface where the pilot can aim and begin the landing flare.

After downloading and reading the material, John then had the opportunity to try out the technique with another instructor who on her first landing, mentioned that she had to suppress some of her normal landing instincts. However, her landing was very good and her second landing was even better and just about perfect. The next day, John and another instructor tried the technique again with the same performance results. Finally, John’s student with the inconsistent landing performance tried the technique and had nearly the same results.

Towards the end of his post, John concluded that:

It’s my considered opinion that pilots who learn to apply Jacobson’s techniques can make consistently good landings, provided they know how to configure their aircraft and fly a stable approach at the appropriate airspeed. Pilots still have to develop and maintain a feel for their aircraft and learn how to handle crosswinds and gusty conditions, but Jacobson’s procedure is very useful. And when you haven’t flown in several weeks or it’s your first landing in a new-to-you aircraft type, Jacobson’s approach gives you something on which to hang your hat.

However, John noted that there still is not much data for using the technique with newer aircraft and hence he is putting together a spreadsheet of measurements for some of the aircraft that he flies. Moreover, he noted that its also wise to have a flight instructor along before performing a new technique with your aircraft.

Amazing futuristic aircraft designs

If you are an aviation futurist, check out this really cool website called Octuri.com that was developed by Laurent Barrou, an interior designer for an aircraft manufacturer in Toulouse, France. Laurent has allowed his imagination to run wild and has come up with futuristic designs for a seaplane-convertible yacht, a sailboat airplane and a honeymoon space shuttle plus an innovative plane propulsion system. His website also includes the interior layouts of his novel aircraft concepts plus he recently exhibited his flying yacht and sailing aircraft concepts at the Air & Space Museum in Paris.

Given that we have seen a flying car about to go into production plus a solar powered aircraft in the prototype stage, maybe one day we will see a flying yacht designed for those who are both boating and aviation enthusiasts!

The British unveil the world’s first unmanned stealth fighter jet

The Daily Mail has reported that the British Ministry of Defense (MOD) has unveiled Britain’s first unmanned stealth fighter jet – the Taranis. The £142.5 million prototype aircraft, which was developed by BEA and named after the Celtic god of thunder, is about the same size as a Hawk jet or a light aircraft and its also equipped with stealth technology and an ‘autonomous’ artificial intelligence system.

The Taranis prototype will test the possibility of developing the world’s first ever autonomous stealthy Unmanned Combat Air Vehicle (UCAV) which could ultimately replace the Tornado and be used to carry bombs and missiles to strike targets at long ranges and even on other continents. Otherwise, the aircraft will primarily carry out intelligence, surveillance and reconnaissance missions while its crew remains safely on the ground.

Gerald Howarth, the Minister for International Security Strategy, noted that the Taranis is a trailblazing project for the British defense and aviation industries. In fact, he was quoted as saying that the aircraft is:

The first of its kind in the UK, it reflects the best of our nation’s advanced design and technology skills and is a leading programme on the global stage. ‘Taranis shows the UK’s advanced engineering, research, technology and innovation sector at its world-beating best.

If you want to learn more about the Taranis, the Daily Mail Article also includes a great video report detailing the aircraft’s capabilities.

Everything you ever wanted to know about airport runways

Devesh Agarwal, the blogger behind the Bangalore Aviation blog, has written a great two part series detailing everything you ever wanted to know about airport runways. Devesh began the series by covering runway numbers, correct pronunciation, number of runways, runway orientation, runway lengths and widths in part one and then common measurements, runway sections, runway lighting, Precision Approach Path Indicators (PAPIs), runway construction, Pavement Classification Numbers (PCNs) and Aircraft Classification Numbers (ACNs) in part two.

Some of the more interesting facts about runways mentioned by Devesh included:

The runway area marked with yellow V shapes, which are also referred to as overrun areas or stopways, are the blast pads and these areas are often constructed before the start of a runway in order to reduce the erosion of earth caused by the jet blast that is produced by large planes when they power up for take-off.
Runways must be extremely strong and most modern runways are constructed using concrete while in areas that are not susceptible to freezing weather, post-tensioned concrete will allow for thinner slabs.
Runways are numbered between 01 and 36 and this number indicates the runway’s heading. Since on a compass north is 360°, east is 90° south is 180° and west is 270°, you cannot have a runway numbered zero.
Runway orientations are actually decided based on the historical winds and wind directions. However and if the winds are more variable in direction and the airport is big enough to financially justify the investment, several runways may be built in different directions.
A typical runway is 10,000 feet but the largest runway in the world is the 11,917 meter (39,098 ft) long and 274 meter (899 ft) wide lake bed runway 17-35 at Edwards Air Force Base in California where the Space Shuttle lands.

After reading Devesh’s entire series, you will definitely know everything you had ever wanted to know about runways.

Using your hand rather than your head

A student is taking his second lesson. His instructor tells him to keep the altimeter needles aligned to indicate 5,500 feet. As the aircraft slowly descends, the student pilot keeps his hand on the altimeter setting knob, constantly changing it to keep… 5,500 feet indicated.