Lately it feels all I do is study for an exam. But we are almost done with the IR theory. It’s just one more week until holidays! These past couple of weeks we’ve finished Radio Navigation and the Bonanza theory. We have done two more exams, on Radio Navigation as well as Instruments. And we have been introduced to the mighty Bonanza.
In Radio Navigation we went through the workings of radio navigation equipment like ADF, DME, VOR as well as GPS, on a more detailed level than before. To start off we learned about antennas, radio propagation theory and radar principles. We learned about the operation principles of the radio nav aids and the factors affecting their accuracy. Depending on the frequency they operate on, different factors affect the range and cause errors or reduce accuracy.
The range of the equipment operating on very high frequencies (VHF), like VOR (108.0-117.95 MHz) and VHF radio (118-136.975 MHz), is based on the line-of-sight principle. The high frequency radio waves act the same way as light, that is to say that they don’t bend with the curving of the Earth’s surface, but travel in a straight line, to the horizon. Depending on how high the transmitting station and the aircraft are, there’s a formula to calculate the maximum distance the transmission can be heard from. This is called the radio horizon and it limits VHF transmission range to less than 160 km (100 Nm). Also, the VHF frequencies travel through the ionosphere and are lost in space, where as frequencies below 30 MHz are reflected back to Earth. This is called skywave propagation. The lower frequencies can therefore be utilized to accomplish a longer transmitting range and can be used for long distance communication. For example the communication system that is used on trans-oceanic flights operates on the HF frequencies below 30 MHz. The HF communication systems are mandatory on trans-oceanic flights.
This week we had a few lessons on the Garmin GNS 430W aviation GPS, which is installed in our Bonanzas. We also got to practise it with a computer simulator program to get familiar with the menus, different views and the input methods. I think some more practise will be useful in addition to those couple of hours to master the system in flight. Luckily the software can be downloaded for free from Garmin website. I’m a type of person who is always interested in new technology and computers and software. For me it was pretty cool to program a flightplan and then see how the plane flies it. I’m looking forward to the even more sophisticated systems on the Phenom jet later on. Right now though I’m looking forward to the IR flight training, which will start in January. It’ll be great to combine all that we have learned this fall into a complete flight.
As the IR flight training is getting closer we had Bonanza FDT (Flight Deck Training) this week. It was nice to sit in the Bonanza and inspect all the instruments and what not. We did a pre-flight check on the plane, went through all the gear, opened every lid and just saw how everything works, where the first aid kit and fire extinguisher are, how the doors and windows open and tried the emergency exit, the window, as well as a rapid exit from the backseat through the back door. Our Bonanzas have 4 seats but could be fitted with 6. In our operations 4 is enough and more seats would take away from the maximum fuel because of their weight. The school flights are usually flown in student pairs plus the teacher.
The week ended unexpectedly. The winterstorm Seija had caused a power outage at the school on Friday morning and we arrived at a pitch dark school. Mind you, the building is in the woods so it was really dark out there once the car lights were turned off. We got in nevertheless, and actually had a lesson in the dark. But we were supposed to have the Bonanza exam and since all our exams are done on the computer, it was not possible. We waited for for a couple of hours for the power to come back, but it didn’t. It was time to start the weekend early. The exam awaits on Monday morning.