The Joys Of Flight Testing

Trouble was, the airplane wasn't even close to being ready. It had only about 30 hours of flight testing logged and still had a number of squawks. There seemed little chance we could make it to Paris before the impound date, two days before the show opened. After that date, we couldn't be admitted to our exhibit space.

Ed Swearingen, the brilliant but volatile designer, had made it clear we would be there on time. Bill Lear had been Swearingen's mentor, and like Lear, Swearingen felt most corporate jets of the time were larger than they needed to be, and their sheer size and large equivalent flat-plate area reduced their potential performance. Swearingen believed business jets should be fast and long-ranged, with strong climb and tall altitude capability.

Pascarell had been flying the number-one prototype for two months and had encountered a variety of problems that aren't at all unusual for high-performance jets. One of those squawks was a runaway pitch trim. Pascarell had the elevator trim run away twice during early flights, and one of those had been at FL470 directly over San Antonio. Accordingly, Carl had placed a large, bright red tie wrap around the overhead elevator trim circuit breaker so he could identify it quickly at the first hint of a pitch runaway.

I took a short familiarization ride with Carl in the prototype jet the afternoon I arrived and we climbed to FL450. The prototype was fully painted outside, but like many test articles, it had no upholstery inside other than seats for the flight crew.

Carl commented that the coffin corner between stall and Mach buffet wasn't that critical on the SJ-30, but he didn't want to get anywhere near overspeed or stall at extreme altitude where the air is so thin that recovery might be a problem.

Another squawk was our long-range navigation systems. We had two VLF/Omega nav receivers onboard, and by the time I arrived, the day before we were scheduled to leave for Paris, the airplane had already burned up three sets of the exotic low-frequency nav systems. Swearingen's engineers had tried several tricks to keep the VLF/Omegas cool, and they thought they had the problem solved. I hoped so, as that would be our only source of precise navigation on the ocean crossing.

Somehow, miraculously, we launched on time the following morning for the leg from San Antonio to Bangor, Maine. Flying light, with only two pilots and full fuel, the SJ-30 was a rocket ship in climb, high-jumping to FL410 in just under 30 minutes. We settled in for what we hoped would be an easy leg to Bangor.

No such luck, as it turned out. Within an hour, both VLF/Omegas had failed again and we were reduced to the VHF system for our IFR flight diagonally across the country.

Then, as we were approaching Memphis, we were startled by a loud bang from the back of the aircraft. We scanned the instruments and immediately spotted both hydraulic gauges losing pressure.

All the plumbing for the hydraulics was located behind the aft cabin bulkhead, so I unbuckled and made my way aft past the bare metal walls to the access port: a simple, improvised Velcro® panel. I separated the access panel and shined a flashlight into the darkness.

There was red hydraulic fluid spattered all over the back of the airplane. I went forward, tapped Carl on the shoulder and told him both hydraulic systems had just self-destructed. I looked at the two hydraulic pressure gauges, and they were both showing 0 pressure.

Carl had been talking to ATC as I was checking the hydraulics, and he suggested I take my seat, as we'd be orbiting to burn off fuel for several hours. We also got Ed Swearingen and the engineering staff on the com link to offer suggestions. I knew we had a pneumatic blow-down system for emergency gear extension, but neither Carl nor I had much faith that it would work. Pascarell went over the blow-down procedure with Ed three times, all the while shaking his head.

We gradually descended to 5,500 feet above the Memphis airport, held our breath and popped the emergency bottle. Sure enough, there was a soft "phtttt", and we got the nosegear and right main green lights.

We flew by the tower twice, and they suggested that all three wheels looked down, but the left main obviously wasn't locked. Memphis had closed the west side of the airport for us, and with the equipment in place, we lined up for the approach.

As we crossed the airport fence, I took a quick look at the hydraulic pressure gauges, and one of the needles seemed to be ticking slightly.

I punched the pump, and watched the left gear light suddenly glow green about two seconds before Carl simultaneously shut down the engines and touched down. We rolled out normally, happy to be chased by fire engines and ambulances that now had nothing to do.

We'll never know if a little shot of residual hydraulic pressure did the trick, the gear was down all the time but the microswitch was inhibited by a speck of dirt, or if the hot, turbulent air near the ground helped lock the left gear in place.

And we didn't care. The SJ-30 prototype was still in one piece, and that was all that mattered.

An hour after our pseudo-emergency, a Lear 36 from San Antonio arrived with a full team of mechanics and an entirely new hydraulic system. Carl and I were taken to the airport hotel and showed up the next morning to find the crew had worked all night, replaced everything, hopped back into the Learjet and flown home. The SJ-30's hydraulics were totally rejuvenated, and we were ready for the rest of the trip.

We departed Memphis and headed northeast for Bangor once again. The Williams FJ-44-2 engines were running perfectly, and the airplane zipped along at .80 Mach, scoring about 440 knots. We landed at Bangor, checked in with customs and continued to Goose Bay for the overnight.

The next morning, we launched for Narsarsuaq, Greenland, 680 nm across the Labrador Sea. It was June and the Far North was luxuriating in clear skies and warm weather, even offering a slight push as we drifted up toward 60 degrees North.

The SJ-30 drew a crowd at every stop, as no one outside of San Antonio had seen the airplane. It was a comparatively small jet, and several pilots were interested in all the details. We didn't really need to stop for fuel in Narsarsuaq, but the universal rule on the North Atlantic is the only time you can have too much fuel is if you're on fire.

One nice feature of the SJ-30 was the airplane's 12 psi differential pressurization system. This allowed us to fly with the cabin at sea level when we were lofting nearly eight miles above the ocean. It was apparent that Ed Swearingen had succeeded at creating exactly what he'd wanted---a fast, high-altitude, long-range corporate jet that could fly high and fast with everyone breathing oxygen-rich, sea-level air. Max operating altitude was eventually approved for 49,000 feet, but we flew no higher than FL410 on our trip to France.

Reykjavik was our next stop after Greenland, and we elected to RON and continue on the final 1,200 nm leg to Paris the following day. We landed at Le Bourget six hours before the curfew.

During the show, I hiked over to the American Pavilion and contacted Tim Casey, aviation products manager of a new avionics company named Garmin to see if they had anything that could provide accurate GPS position information for the trip home. At the time, the 24-satellite NavStar constellation was only about half complete and wouldn't be certified for another four years, but Garmin's Casey dropped by the Swearingen Chalet at the conclusion of the show and left me a beta version of his company's first product, a portable GPS called the GPS 100 AVD.

We didn't receive continuous readouts on the Garmin GPS, but there were enough to keep ATC happy.

In the next three days, we flew the $80 million Swearingen SJ-30 prototype jet 5,000 miles back to San Antonio with a $900 portable GPS Velcro®-ed to the top of the panel.

As of January 1, 2016, Senior Editor Bill Cox has logged 15,100 flight hours in 321 types of aircraft. He also holds 28 world city-to-city speed records, has made 211 international delivery flights, and owns and flies a LoPresti Mooney. You can email Bill at flybillcox@aol.com.