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Schlagwort: all things technical



I bought a text book in order to prepare for the CVFR rating. I have always loved good text books. I know, that’s a bit weird, but I like to follow a well organized stream of thoughts on a specific topic.

CVFR is a very specific topic. Controlled Visual Flight Rule is a part of the qualifications of a private pilot. The rating will enable me to fly in controlled airspace and with guidance by ATC.

The big thing about CVFR however, is learning to make better use of the instruments and to use radio navigation.

VOR stations are the back bone of radio navigation. VOR is short for “VHF omnidirectional radio range”. The idea is very close to the idea of a light house. The VOR indicator in the cockpit shows me the bearing to the VOR station.

The VOR stations are marked on my aviation map. If I know That my relative bearing to the station is 090, I know that it is at 90° to the right. So I know that if I draw a line at 90° from the staion, my position would be somewhere on this line (called a radial, by the way).

This information alone is enough to get a pretty good idea about my position if combined with other VFR navigation skills (“this looks like the lake on the map”). At night or above the clouds however, I would need a second VOR station in order to do a triangulation. If I know that I am on radial 90° of station A and radial 200° of station B, I can draw two lines on my map and the point at which they meet is going to be my position.

Still with me? Great!

I have been taught to use the VOR from my first lesson for the private pilot on. My instructor knew that I was going to go for the CVFR rating eventually.

Today he means it. The flight preparation today is longer than usual. We have a very detailed flight plan. Up to the north and climbing up into the controlled air space over the city. Then a flight from the VOR in Löwenberg, via Tegel Airport to the VOR in Fürstenwalte. North to south over the big city.

I call ATC after take-off and anounce our big plan. After a bit they call back with bad news. The weather is bad, the airspace is full and they don’t need a green horn who needs extra attention. No clearance for me today.

Plan B is to clear the controlled airspace to the north and then climb to 7.500 feet and do our drills there. The day is rainy and other small aircraft ask for advice and divert right and left. My instructor is not impressed by a bit of rain on the screen and before long we are above the grey clouds. I close the vent as the stream of outside air is getting quite cold. The instructor hands me the IFR cap “Put this on”.

An IFR cap is a plastic visor that blocks the view to the outside. After I put it on, I can only see the instruments. What a difference!

Steady as she goes

The first task at hand is to hold course and altitude. The air up here is calm but I still need a lot of concentration for the task. After a bit, the instructor tells me to start going right and left, 10 degrees from the course. After this works, he pulls the flaps lever. Kilo Sierra slows down because of the added drag and climbs at the same time because of the increase in lift. I counter the movement and fight to keep the altitude.

Radio Navigation

The instructor seems to believe that I will not fall out of the sky. So we start with navigation. He tells me to fly to the Fürstenwalde VOR station. We had set the frequency before, so all I have to do now is turn the bearing indicator of the VOR receiver until the course deviation indicator is in the middle and the direction flag shows “To”.

The bearing to the station is 179, so I turn right onto the new course. After a few minutes, the instructor tells me to sink. We go down to 5.500 feet, 3.500 feet, then 2.000 feet. Finally I contact Strausberg and ask for QDM. That is the magnetic heading to the station. The controller on the tower can determine my relative bearing to him.

The heading to the airport is 250. So I turn right until I have 250 locked and ask again. 260 now. The runway is 270, so we are getting very close. The instructor tells me to sink to 1.000 feet and take off the cap. The runway is directly in front of me, I am on long final – wow!

After we are back on the ground and done with the de-briefing, I walk to the train station. There is a light drizzle and I enjoy the rain on my face. My head is pounding from the concentration, I’m exhausted but I feel great nontheless.

To be continued…


(originally posted on October 7, 2012 by tilbo at aloft.blog.com/vor/)



I am outside on the street watching PIA flight 785 from Islamabad’s Benazir Bhutto Airport fly over Berlin enrout to London Heathrow. It is a Boeing 777-300ER traveling at 36.000 feet at over 400 knots per hour.

I looked at the contrails and the mighty iPhone did the rest. Thanks to ADS-B.

FlightRadar24.com gathers ADS-B-information form thousands of aircraft all over the world and projects them on a map in real time. If this is combined with the location service of the iPhone (it knows where it is, sometimes better than me…), the contrails in the sky become a particular airliner. Magic if I ever saw it!

So what is ADS-B?

In the sky it is very important to know where you are. Aviation at large has that one figured out pretty good. Maps, VOR, GPS, Radar controllers and more high-tech systems like inertia navigation have pretty much taken care of position awareness.

The problem is, figuring our where everybody else is!

Mid-air collisions are rare but the more devastating when they happen. And they are surprisingly difficult to avoid. The sky is very large and aircraft are very fast. Even more so if two of them are moving towards each other. Even in perfect visual conditions, it can be hard to see oncoming traffic in time. Let alone at night or in the clouds.

Because of that, Airliners have had a collision avoidance system for years. The standard is called TCAS (Traffic Alert and Collision Avoidance System) and it is very cool. Traffic will not only be displayed in the cockpit. The respective TCAS-systems of two airliners will actually talk to each other, determine the best way to avoid any close calls and make recommendations for actions to resolve a possible conflict, to their flight crews.

ADS-B is TCAS for the rest of us. The remarkable thing is that it basically combines parts of the existing infrastructure to create a valuable, additional service.

ADS-B is a communication standard which utilizes the transponder (identification transmitter) of a general aviation aircraft and feeds the location information from the on-board GPS into it. Genius! So now my transponder sends out “this is me” plus “this is where I am”. All of a sudden, I can receive the transponder information of other aircraft around me and display their positions on my GPS screen. And since the technical step is relatively small, many pilots are upgrading their hardware to ADS-B capability.

Additional services, like weather information, is also broadcasted via ADS-B and can also be displayed on the GPS screen. This makes the system even more popular.

I look up to the sky again and I wonder again, where the jet above my head is heading for. I might check, or maybe I will just dream for a moment.

To be continued…


(originally posted on June 18, 2012 by tilbo at aloft.blog.com/ads-b/)

RE: when in doubt, don’t!

RE: when in doubt, don’t!

It was the exhaust manifold!

It was cracked, hence the sound. This may or may not have been a safety issue – but it is a good feeling that I did not imagine the rough sound.

To be continued…


(originally posted on September 21, 2011 by tilbo at aloft.blog.com/re-when-in-doubt-dont/)

Dry run

Dry run

We start moving and I hit the start button on the timer. The preset time for the first leg of our trip starts counting down. It will start flashing and beeping once the previously calculated time is up.

I have a pretty fancy flight timer. It is a very specialized stop watch. It has a fuel timer, it can time up to 12 legs of a flight and it has a clock in my local time as well as in UTC. The Universal Time Coordinated is the international aviation time. All flight plans all over the world use UTC and UTC only. This is very important to avoid misunderstandings on trips across time zones.

The fuel timer is also very important. Obviously you don’t want to run out of fuel. But there is more: many airplanes have several tanks. They are not always used at the same time. The reason for that can be weight and balance or fuel overflow. So it is important to remember to change tanks as this is very easy to forget. The fuel timer is a count down timer. As soon as it reaches zero, it starts counting up again as well as giving its warning message. So the pilot knows how long it has been since he should have changed the tanks.

The count down of leg #1 is up and I get a beep. For every part of my trip (leg) I calculate the time that I will approximately need to complete it. As air is a dynamic medium and winds are changing, this is not an exact science. But the leg timer alerts me that I should be getting close to my next way point. It is a good idea to make sure now that I know where I am and that I am prepared for the change of course.

The change is completed. I turn the big, friendly knob on the timer and the D2 leg appears (Destination 2). I hit the start button again. The second leg is longer and I get my morning paper out. The timer starts beeping once more right as the train approaches my stop. Nobody pays attention to the guy with the funny looking stop watch. They have all seen worse things than a flight timer dry run on the subway. I love the big city!

To be continued…


(Originally posted on March 8, 2011 by tilbo at aloft.blog.com/dry-run/)