Down to Earth

Lets start with the sad truth: It had been a month and a half since I last flew the RV-10. Meanwhile, my husband, the builder, had installed a radical new update to the Grand Rapids Technologies Avionics Horizon I EFIS boxes, and figured out how to get them to fly laterally coupled approaches with the autopilot, in both synthetic approach and ILS/LOC mode.

I know, I know, who wants to do that? Why bother when it is easy enough to drive the airplane right onto the white line extending from the runway centerline on the multifunction display (MFD) and fly the classic ILS needles to the decision altitude and look up?

Thats how this homebuilding thing works. Once you’ve built your masterpiece and have it flying, its hard to resist the temptation to continue tinkering.

Experience Counts

The impulse overcame us after wed flown a terrific 6000-mile trip to the West Coast that showed us what we didn’t know about the airplane and what we ought to do to tweak it. Seriously, youd think wed just be satisfied that we got nearly 17 nautical mpg (rounding up to 20 statute mpg) over the course of the trip, and made it there and back in less than 28 hours of flying time.

Prompting from the GRT to climb, with the flight director engaged.

Youd also think wed be content to see the autopilot fly the beautifully programmed flight plans, rounding the corners, and wed thrill watching the lines on the MFD flip from white to magenta on each leg. Surely wed be giddy to be able to pull up and then fly a SID (standard instrument departure) out of busy Class B airspace with a click and a button push, or to execute a GPS approach to a satellite airport with the best fuel in the area without fumbling at the boxes.

But we knew we could do better. Within a week of coming home, wed adjusted the fuel flows into two cylinders (with fuel-injector sleeves available from Airflow Performance) to bring them to within 0.2 gph of each other and ensure that all cylinders peaked and ebbed together. It worked! Now the airplane runs much smoother lean-of-peak (LOP), and our effective flight range with 60 gallons of 100LL on board is extended comfortably from 3.5 hours (with reserve) to 4.5 (with reserve). Fuel flows at altitudes of 7000 to 9000 feet AGL are comfortably 11 gph, while producing true airspeeds of about 165 knots at 55% power. When you are flying 3000-mile trips, every stop you don’t have to make for fuel saves time and money. Flying LOP does both, and keeps the engine cool, which is critical for long engine life.

That was a month ago. We knew that Grand Rapids had added some neat functions to the Horizon I EFIS from our conversations with the company’s owner, Greg Toman, last spring at Sun n Fun. Now it was time to download them, put them on a USB stick and plug them into the airplanes EFIS boxes. A snap.

Teacher Becomes the Student

Learning to fly the new settings will take longer. My retired airline-captain builder has already mastered the system of soft-key followed by knob push followed by switch flip followed by another soft-key punch, but I am behind the curve. It didn’t help that I have limited experience following the V-bars of a flight director system, nor that I skipped items on my checklist, feeling pressured to try out the boxes new tricks.


The flight instructor in me should have known better. The combination of rushing and a caffeine-free frontal cortex left me at 65% power, 178 knots and 3000 feet headed west (over open water, fortunately) with my copilot/builder (also a flight instructor) shouting, Turn the autopilot on, slow down and make some decisions-NOW!

A synthetic approach (fly-through boxes) set up for the authors home field.

If Id been the flight instructor, I probably would have shared his ire, so there’s no one to blame but myself. I did what he said, clicked the autopilot track and altitude buttons on, pulled the power and mixture back to slow things down and took a moment to gather my thoughts.

Thats what I needed. A little prompting soon had me pulling up a synthetic approach for our home airport and coupling it to the autopilot (softkey, scroll, punch enter with the knob, flip autopilot switch, then back to the heading knob to set the intercept, repeat softkey, scroll, set Decision Altitude, set Missed Approach Altitude, knob punch…).

Flying the V-bars with the heading bug isn’t rocket science, either-once everything is set up. But if you think you can pull up the flight director without setting up the boxes, you are mistaken. If I learned anything about our systems capabilities today it is this: Do not use advanced options if you don’t absolutely know how to set them up. Incorrect setups will confuse you and possibly distract you from your primary task, flying the airplane.

We put in the Grand Rapids Horizon I boxes so that wed have a capable IFR aircraft for those times when we need one. But it is only so if the pilots are capable of flying it IFR properly, and that means I have to learn every possible way my new machine can ply the airspace I fly through, and learn each procedure well.

My plan is to study some more, go over my checklists, use them, and then set up another training session in the airplane with the builder, now my teacher. Ill get up early before my next flight and prime my frontal cortex with a little caffeine and the proper mental attitude, and see how it goes. Once I finally do master it, I will not let those skills atrophy. Until a decent Horizon I simulation program is available (Greg Toman, are you reading this?), Ill have to fly my airplane more often. But, hey, isn’t that what we built it for?