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Staying in practice

State-of-the-art doesn’t mean foolproof

In the airplane game, especially the turbine-powered world, there’s a term for airplanes more than, oh, say 20 years old. They’re not old airplanes, they’re “legacy” models. It’s a genteel, marketing-friendly way of saying “obsolete,” or on its way.

Turbine Intro

Time marches on, bringing technological advances with it. More and more new turboprops and jets are fitted out with full-authority digital engine control (FADEC), so you can set power precisely, stay within engine limitations, and prevent incinerating your engines in hot starts. Envelope protection keeps attitude and airspeed under control. Autothrottles let you dial in an airspeed. Fly-by-wire (FBW) control systems deliver digital precision, system integration, and unprecedented automation to the cockpit. Head-up display (HUD) technology and combined visual systems let you fly to lower minimums. And synthetic vision? That’s standard equipment on practically every new piston single these days. Legacy airplanes may have none of this exotic gear.

Pilots who fly late-model business jets and airliners can easily become overly reliant on automation. It’s easy to understand. The most modern avionics can fly more precisely than the pilots themselves, and the trend is toward systems sophisticated enough to eventually allow single-pilot—or even autonomous (uncrewed)—airline operations, according to some opinions.

This made me think of the Air France 447 crash en route from Rio de Janeiro to Paris in May 2009. The Airbus A330 was flying at FL350, at night, in turbulence, and near thunderstorms. Its pitot tubes iced up, causing miscompare warnings between its two independent pitot systems and a cascading sequence of events that led the FBW system to enter an alternate control law, the autopilot to disconnect, and the crew to allow the airplane to depart controlled flight and hit the Atlantic Ocean in a 10,000-fpm descent rate.

Pilots who fly late-model business jets and airliners can easily become overly reliant on automation.It can be very difficult to hand-fly when deep in the flight levels under these conditions, especially if you’re in an FBW airplane with degraded control laws. There’s less automation available in alternate law, false airspeed information owing to the pitot ice, and the cockpit that must have had every warning annunciator lit up. Indicated airspeed on the flight data recorder went from 275 to 60 knots, and the angle of attack at one point reached 40 degrees nose up.

The Air France 447 pilots’ only strategy was to fall back on stick-and-rudder skills. But startled, confused, and overcontrolling, the crew stalled the airplane. Based on pitch and bank indications on the primary flight displays, the pilots should have been able to keep the airplane level. But toward the end, the pilot flying was recorded as saying “I have no more displays,” and the pilot not flying said “we have no valid indications.” Their state-of-the-art automation had failed them, all because the ice-protection system couldn’t keep up with what was presumed to be an accumulation of especially dense ice crystals.

In its findings, the accident report mentioned “weaknesses of the two copilots in manual airplane handling.”

Automation is great, and FBW has plenty of redundancy. But things can quickly go wrong in the most sophisticated cockpits. France’s BEA (Bureau d’Enquêtes et d’Analyses—their NTSB) recommended “regular exercises dedicated to manual aircraft handling of approach to stall and stall recovery, including at high altitude” in its accident report.

That’s good advice for those flying any type of jet, even if it’s one of those old “legacy” models.

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Thomas A. Horne

Thomas A. Horne

AOPA Pilot Editor at Large
AOPA Pilot Editor at Large Tom Horne has worked at AOPA since the early 1980s. He began flying in 1975 and has an airline transport pilot and flight instructor certificates. He’s flown everything from ultralights to Gulfstreams and ferried numerous piston airplanes across the Atlantic.

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