N2468Z is Legal to Fly Anywhere and Carry Passengers

I took the last two test flights in N2468Z, my Bede BD-4C airplane, today. After landing, I made the official entry into the aircraft logbook.

Having made that entry, and signed it, my airplane has completed “phase 1 flight test.” I am now free to fly it anywhere (no longer restricted to a flight test area that is a 50 mile circle around Pittsfield-Penstone Airport). I am also free to carry passengers. After seven and a half years of help by family and friends, I can finally give thank-you airplane rides.

My final flight in “phase 1 flight test” was to determine the ceiling, the maximum height to which I could fly my airplane. I hoped that I could get the airplane up to 15,000 feet so I loaded up my oxygen tank and took off. Here is a photo of my MGL iEFIS screen as I climbed through 13,090 feet. Click to see it larger.

There is a ton of data on that screen but let me point out a few of the highlights.

Start by looking at the vertical “tape” (rectangle) on the right side of the screen. It shows that I am at 13,090 feet above sea level. However, it was hot today, 47 degrees Fahrenheit at that altitude. Hot air is less dense than cold air so, from a pure physics perspective, the airplane was actually flying through air the equivalent of 15,345 feet above sea level. You can see that number as “DA 15345ft” at the top of the vertical tape on the right side of the screen. I sought 15,000 feet and more than achieved that goal. After I took that photo, I continued the climb to 13,580 feet, approximately 15,800 feet density altitude.

Now look at the vertical tape on the left side of the screen. It shows an indicated airspeed of 89 knots (89 nautical miles per hour or 102 MPH as cars reckon speed in the USA or 161 KPH as cars go in most of the rest of the world). Cars measure speed by tracking how fast the wheels are turning but that does not work in an airplane. Instead, the airspeed indicator measures the amount of air passing through the pitot tube. Faster airplane equals more air. However, the air gets thinner (less dense) as the airplane goes higher and the effect is exacerbated by warm temperatures. Higher/hotter air equals less air. The result is that the indicated airspeed (IAS) is lower than the true airspeed (TAS). If you look underneath the 89, you will see “TAS 113kts”, showing a true airspeed of 113 knots, fully 27% faster. You will also see “GS 142kts” meaning that my ground speed was 142 knots (163 MPH), due to a nice tailwind.

Last, look near the bottom, center of the screen. You will see a box with four vertical green bars and, above the box, the label “CHT 367.” This shows the cylinder head temperatures of each of the four cylinders in my Lycoming IO-360 engine. The hottest cylinder (#3) is 367 degrees Fahrenheit. Despite the long climb, which puts a strain on the engine, this temperature is well within normal limits, not even close to the yellow line. To the right of the CHT, you can see that the oil temperature (OT) and oil pressure (OP) are also well within the green.

This completes the FAA-mandated phase 1 flight test but certainly does not indicate that all work on the airplane is done, nor is all testing finished. It does mean that Candy and I can finally get in the plane and go somewhere for the weekend. It also means that I can take friends up just to enjoy being in the sky. 😀