High-Altitude Upset Recovery
There is an interesting article in the Summer 12 edition of "focus" the magazine published by the UK Flight Safety Committee.
Radical revisions needed for pilot training, aircraft certification and simulator fidelity.
by Fred George
Investigators with the French Bureau d'Equetes et d'Analyses (BEA), the agency charged with investigating the crash of Air France Flight 447, now are focusing on a breakdown in situational awareness on the part of the flight crew and possible pilot error as contributing factors in the June 2009 mishap that killed 228 people when the Airbus A330 crashed into the South Atlantic. The latest findings broaden the scope of the inquiry well beyond a fly-by- wire flight control malfunction, possibly caused by iced-up pitot probes.
While the BEA is far from completing its investigation of the AF447 accident, its most recent progress report again focused the aviation community's attention on the perils of loss of control (LOC) incidents, especially at high attitude. This is a multifaceted challenge because improved stick-and-rudder skills are unlikely to eliminate the problem entirely.
"The Air France 447 crash was a seminal accident. We need to look at it from a systems approach, a human/technotogy system that has to work together. This involves aircraft design and certification, training and human factors. lf you look at the human factors alone, then you're missing half or two-thirds of the totaI system failure," says C. B. "Sully" Sullenberger, a 20,000-hour retired airline pilot and former fighter pilot.
Celebrated for his successful ditching of a powerless A320 in the Hudson River, Sullenberger is now a writer, aviation consultant and public speaker. He notes that there were 12 or 13 similar upset mishaps prior to AF447 in recent years, but that Air France 447 has attracted the most public interest. Sullenberger says that there needs to be a global safety reporting network that will enable the aviation industry to identify problems more quickly and find solutions.
Sullenberger says it's easy to blame the pilots in the AF447 crash while overlooking other contributing or causal factors. "l believe the transport airplane community, as a whole, would not expect the crew to lose all three speed indicators in the cockpit," he said. "That's like amputating the wrong limb in a hospital" because criticaI information was not available.
He also believes that accurate airspeed indications alone aren't the best data the crew needs to recover from an upset. That requires knowing the wing's criticaI angle of attack (AoA). "We have to infer angle of attack indirectly by referencing speed. That makes stall recognition and recovery that much more difficult. For more than half a century, we've had the capability to display AoA (in the cockpits of most jet transports), one of the most critical parameters, yet we have choose not to do it."
Training also needs improvement. "Currently, to my knowledge, air transport pilots practice approaches to stalls, never actually stalling the aircraft. These maneuvers are done at low altitude where they're taught to power out of the maneuver with minimum altitude loss." In some aircraft, they're taught to pull back on the stick, use maximum thrust and let the alpha floor (AoA) protection adjust nose attitude for optimum wing performance.
"They never get the chance to Practice recovery from a high-altitude upset," he continued. "At altitude, you cannot power out of a stall without losing altitude. "And depending upon the fly-by' wire flight control system's alpha floor protection isn't the best way to recover from stall at cruise attitude.
Maintaining situational awareness is another challenge in highly automated aircraft. "There are design issues in some aircraft that I've always wondered about," Sullenberger said. "For instance, I think the industry should ask questions about situationaI awareness and non-moving auto throttles. You lose that peripheral sense of where the thrust command is, especially in a big airplane where there is very little engine noise in the cockpit.
"ln some fly-by-wire airplanes, the cockpit flight controls don't move. That's also Part of the peripheraI perception that pilots have learned to pick up on. But in some airplanes that's missing and there is no control feel feedback," he said.