February 2016 Issue
Elliot Seguin and Justin Gillen brief before an early morning time to climb test sortie. (Photo: Tim Adams)
Radio communication is a huge part of flying, and a lot of effort has been made to improve its efficiency. In fast-paced situations like high-risk flight, test radio communication becomes even more important. The best radioman I know is retired Scaled Composites test pilot Doug Shane. His ability to calmly, clearly communicate while subtly letting you know both that you can do it and you really need to do it, is one of the reasons he has had so many awesome opportunities.
I remember a particularly hairy first flight of a strangely shaped homebuilt here at Mojave. I had the privilege of watching and listening to Doug chase the test aircraft in his Long-EZ as the pilot limped around the pattern with a serious primary control problem. It was really impressive. Like so many skills that make all the difference in flight test, the trick is creating opportunities to practice those skills ahead of time so that we can be proficient when those skills are needed.
Andy Chiavetta and Elliot Seguin perform last chance checks before the fastest time to climb to 3000 meters by a piston-powered airplane in the record books.
Mojave Records Week
The first record attempt of the 2015 Mojave Records Week was on Tuesday, April 14. The record I was attempting to break was the C1c time to climb to 3000 meters (9842.52 feet). The time to beat was three minutes and nine seconds, set in a pressurized Cessna 210 in 1984 by Wilhelm Heller in Bonn, Germany.
Conditions were very good for a late-morning attempt, not too hot and very windy (35 mph winds and 55° F), and Lynn Farnsworth’s Aerochia-prepared Super Legacy was ready to go. After waiting on the runway for 60 seconds to be sure we got a good GPS fix, I set 200 horsepower while holding the brakes. This is the most power that the tires can reliably hold, and setting it allows the propeller governor and fuel pump to come up to speed and pressure. It also dramatically reduces the risk the engine will stumble when you rapidly apply full power and ADI (anti-detonation injection). Once the engine was stabilized, I checked engine indications one last time, opened the throttle butterfly, released the brakes, and switched on the cylinder spray water and ADI.
The airplane’s first movement would be caught by the GPS and officially start the clock for the record. On an Aerochia Super Legacy, once the throttle is open, the power is controlled by the aftermarket pneumatic wastegates that regulate the turbochargers, and therefore the manifold pressure. At last chance I had set the wastegates to give me just over 500 hp once I opened the throttle. On race gas, 500 hp is the most power we run without ADI (which takes a few seconds to pressurize). The next seconds were spent focused on the engine monitor on the far left side of the panel, specifically the indicated manifold pressure and fuel flow. Comparing these values is the quickest way to manage fuel/air mixture on Race 44.
Lynn Farnsworth’s Aerochia Super Legacy breaks ground for a 3-km closed-course speed record. (Photo: Blake Brown)
The stock Continental mechanical fuel controller has trouble keeping up at these higher power settings and needs to be trimmed using the mixture knob. I got lucky, or all the testing paid off, but the mixture was very close and after turning on the spray water and the anti detonation methanol injection, I was able to crank more power into the wastegates. For the record attempt we lowered rotation speed to 85 KIAS without flaps (we found in testing the flaps took too long to retract) and as soon as the airplane was airborne, I dumped the nose and selected gear up, watching the airspeed build toward VY of 125 KIAS. The hydraulic pump typically turns off about the time I get VY, so when I found the airplane at VY and the pump still running, I knew it had been a good start. We reached 1000 feet in 20 seconds. The fastest start we had ever done previously was 42 seconds; the improvement was due to the wind and the aggressive rotation speed. With the airplane stable and headed uphill, I broadened my scan off the HSI and went back to watching the engine. Head temperatures confirmed the spray water was functioning and exhaust temperatures confirmed the mixture was close. Things looked good; and since Lynn and Andy Chiavetta had cleared me to run more power, I used the wastegate regulator to roll that power in, adjusting the mixture accordingly. At 3800 feet agl (1/3 of the way to the top), I got a call from Justin Gillen who was with Andy and the crew on the ground watching the attempt. His voice was familiar and calm, and he said one word: “Smoke.”
Elliot Seguin holds an aggressive pitch angle in Miss Karen II, an Aerochia-prepared Super Legacy, on the fastest time to climb to 3000 meters by a piston-powered airplane in the record books—120 seconds, set at the 2015 Mojave Experimental Fly-In.
The biggest concern through all of the testing had been monitoring the air/fuel mixture of the engine. Therefore I assumed the smoke call was intended to mean thick black exhaust that related to rich mixture. I had been watching the mixture and was pretty confident that it was right, but I trusted Justin and Andy, so I reached up, leaned the mixture and went back to adding boost. Justin called again, “Smoke, you are smoking.”
I could hear Andy in the background, and he sounded alarmed. Andy’s concern snapped me out of record mode, and I started thinking about all the kinds of smoke—particularly the ones that ruin a day. I called back, “Do you want me to abort?”
“Abort, abort, abort,” Justin said.
In a modern control room environment, the majority of conversations happen independent of the crew. The team on the ground is watching what is going on and communicating it to the test conductor, who decides what to communicate to the crew and how. In this case the crew on the ground included Andy, the builder of the airplane and designer of its systems; Lynn, the owner of the airplane who has more time in it than anybody; and Justin, the flight test engineer who had been focused on preparing for this record exclusively for the last two months.
Holding the radio, Justin had the responsibilities of a test conductor without the authority to censor the rest of the team. The result was all of the control room coms were transmitted, and there was a significant reduction in efficiency.
After the abort call at 4500 feet agl, I started my emergency abort checklist. I pulled the throttle back to idle, turned off the ADI, confirmed the spray water was still on, and rolled the airplane into a split S back toward the airport. The deceleration was impressive. “Glitter One copies—knock it off, going Runway 30.”
With the sudden and significant change in available bandwidth, I looked around the cockpit for clues about what had just happened. The midday sun, which had been washing out the cockpit, was now blocked by the raised right wing and the contrast made it hard to tell if there was smoke in the cockpit. Is that really smoke in the cockpit? With all that had already happened, I decided it was relatively low cost to act as though there was smoke in the cockpit. I reached behind the ADI tank and turned Lynn’s A-14 diluter-demand oxygen regulator to emergency (100% oxygen) and called to the ground, “Glitter One has smoke in the cockpit.”
Dave responded from the Mojave tower: “Glitter One, clear to land Runway 30.”
On an SFO (simulated flameout) in the Super Legacy, I typically use 2500 feet agl for high key, so at 4000 feet I had more than enough energy to glide back to the airport. With the time pressures of a potential fire, I elected to go direct to low key (2000 feet agl) and extend the gear early. Touchdown was a relief, and as I rolled out, the Mojave Airport fire trucks were waiting for me at the edge of the runway; Donald McMullin’s truck with the crew wasn’t far behind them. Before I could get the engine shut down, Andy approached and quickly disappeared beneath the wing to inspect; he returned with an oily hand. I was sure we were done for the week and wasn’t sure how to feel about that.
Andy Chiavetta in his element, inspecting the engine on Miss Karen II between record attempts at the 2015 Mojave Experimental Fly-In. (Photo: Zac Adams)
It turned out the airplane had started streaming white smoke almost immediately after I broke ground, and the entire crew had seen it. The acceleration due to the high power setting (the highest ever run on takeoff in a Super Legacy) and all the turbulence from the wind had pushed the oil up the back of the crankcase where it had gotten whipped up by the crank, then blown overboard via the hot exhaust. The belly was covered with oil but only half a quart was missing. To fix it for the rest of the records, Andy separated the crankcase breather from the hot exhaust so that if it vented, it wouldn’t smoke. We repeated the record two days later and broke it by over a minute, eventually setting four records in three days, including two 3-km closed-course speed records, without another failed attempt.
I walked away from this, my 28th forced landing, fascinated by another lesson in how to communicate during flight test. The idea that telling the pilot he is smoking in this particular situation may have no value, and could actually be a distraction, fascinates me.
SpaceShip Two pilot Mark Stucky describes the initial smoke call as a descriptive call, rather than a directive call. Justin, Andy, and I decided after this flight that during this type of fast-paced test, descriptive calls have no place on the radio and should be saved for “control room” type conversations. Of course, the idea that Justin should have said nothing when he saw the airplane smoking until there was an associated directive call is what makes the whole thing absolutely fascinating and an important lesson about an awesome occupation. This is good work that we do—cold and unforgiving—but good.
The Aerochia team after a hard-fought week of record setting at the 2015 Mojave Experimental Fly-In. (Photo: Drew Seguin)
Elliot Seguin is a homebuilder, engineer, and test pilot based at the Mojave Civilian Flight Test Center in California. He is a member of the Society of Experimental Test Pilots and each year he competes in Wasabi, the IF1 racer he designed, at the Reno National Championship Air Races. He is also a Test Pilot for Aerochia Performance Aircraft and is a project engineer and flight test engineer at Scaled Composites, founded by Burt Rutan.
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