Exclusive: Wired Test-Drives Boeing’s New 787 Dreamliner
- 6:15 am |
Even with the more traditional pilot input/feedback in the 787, the fly-by-wire system provides plenty of help to reduce pilot workload.
At the most simple level, and common to other fly-by-wire aircraft, there’s no back pressure on the yoke needed during a turn. In most aircraft without fly-by-wire, the pilot must pull back on the stick or yoke a small amount to compensate for the vertical component of lift from the wings that is lost when the plane is in a bank. When “hand-flying” the 787 the pilot simply turns the yoke and the computer inputs the correct amount of elevator to maintain the same altitude.
Simple, yet new to those not accustomed to flying via computer.
“Watch your altitude,” comes the gentle reminder from Neville. During my time at the controls making S-turns over the Midwest, there is a little altitude gain during many of the turns. Old habits die hard.
Simulating the loss of power in an engine is a far more impressive demonstration of fly-by-wire technology, and something I get to experience first-hand.
For pilots learning to fly a twin-engine aircraft, much of the time is spent learning how to deal with the loss of an engine. During critical phases of flight such as take-off or landing, losing an engine demands immediate action and dramatically increases the pilot workload. Even in other modern fly-by-wire airliners, pilot input such as using the rudder pedals to compensate for the lack of thrust and associated drag from inoperative engine is something that demands attention.
“If we were to suddenly have an engine fail,” Neville says calmly as he turns off the auto-throttles, “we’re just going to simulate that.” The right throttle lever is pulled back, the engine is reduced to idle and then it happens. Nothing. No need to stand on the left pedal to keep the airplane flying straight and no trim changes needed, either.
“You’re pretty much hands and feet off the controls,” Neville points out.
Technically, my hands are still on the yoke, but no control input is needed even though the airplane is now flying with almost half of its normal thrust. The rudder pedals do physically move, letting the pilot know what the computer has done to compensate. With the lack of thrust, we’re slowly decelerating, and I could push the nose down to descend and maintain our airspeed. But losing an engine during flight is a non-event. Neville says from a piloting point of view it’s basically the same during take-off and landing, though normally the auto-throttles would handle the still-working engine. Even with the automation turned off, according to the veteran test pilot, there isn’t much to flying on a single engine in the 787.
“Even manually flying, and manually controlling the throttles,” Neville says, “a single engine approach in this airplane is a no brainer. It’s so easy. It’s such a low workload.”
During single engine flight, the flight control laws in the fly-by-wire system compensate with the proper amount of control input to counteract the loss of thrust. The 777 has a version of thrust asymmetry compensation as well. But the version on the 787 does a better job of flying the airplane on one engine.
“It’s going to give you a minimum drag configuration,” Neville tells me, referring to the multi-axis control with the new software. “That’s the inherent flight controls, not the autopilot. It really reduces the pilot workload with what has typically been a pretty dynamic situation.”
Indeed, even for a total novice multi-engine, big jet pilot, the experience of flying and even making a few gentle turns on a single engine feels the same as flying with both engines operating. The only difference is the airspeed.
The new flight control laws – called “P-Beta” in the Dreamliner – like all parts of the 787 were tested thoroughly in a wide variety of conditions during develoment. Simulated engine failures were performed in just about every conceivable situation, including take-off roll, before nose rotation, during rotation, after rotation, during the climb, during the landing and during both compensating and aggravating crosswinds. The result is an airplane that is as boring as possible to fly, even in emergencies.
After making a few final turns, careful to let the Dreamliner hold altitude on its own, it’s time to relinquish the controls and give test pilot Mike Bryan his seat back. With the flight path marker lined up with the guidance circle on the heads up display, and trimmed to fly hands off at 36,000 feet, I voluntarily push the autopilot button on the panel and hand ZA003 back to its captain.
“The airplane is yours,” I say to Neville before climbing out the seat.
My flying experience is similar to what’s been given to pilots of customer – and potential customer – airlines during Boeing’s worldwide demonstration tour.
“It’s mostly letting them see the airplane, getting a feel for it, and doing some minor maneuvering,” according to Neville. “They’re mostly line pilots – they’re not in the test world. And on the demo flights we tend to have a lot of executives in the back.”
Back in the main cabin, there’s still plenty of time to explore the different seating options and check out the 787’s giant overhead bins. I peer through the oversized passenger windows, catching a glimpse of the Rockies while testing the dimming feature and watching the view lighten and darken with the press of a button.
Despite Boeing’s massive efforts to improve the passenger experience, for the final approach and landing I head back to the cockpit and again strap myself into the jump seat. The best seats are always in the front of the plane and it’s hard to imagine a better view as we touch down in Seattle.
All photos: Jason Paur/Wired