Highly advanced cockpit automation, particularly full-function Flight Management System (FMS), can reduce pilot workload and increase the flight crew’s time available to manage all cockpit resources. Just program the FMS, twist the knobs and push the buttons on the flight guidance panel and you’re ready to go. After takeoff, clean up the aircraft, engage the autopilot, sit back, manage the automation and enjoy the trip. Just watch the airplane follow the magenta line on the Primary Flight Display (PFD) until you’re on final landing approach.
With advanced cockpit automation, everything on the flight deck seems so relaxed, so effortless, so controlled, so safe. It’s like you’re riding in an automated tram car, guided by virtual steel rails in the sky. Nothing can go wrong.
Is that reality? Or is it illusion? NTSB is already looking at the role over reliance on automation may have played in Asiana 214 Boeing 777 crash in San Francisco in early July 2014. The glideslope for the ILS Runway 28L, was out of service, thus the aircraft’s GPWS would not have provided an aural warning as the aircraft descended below the intended 3 degree glidepath. The 777’s autothrottle system is designed to provide automatic speed protection if the aircraft approaches stalling angle of attack, but it must be armed, if it isn’t engaged, and the aircraft must be above 100 feet radio altitude during approach. Was the crew using the autothrottle system?
General aviation and airline accidents and incident statistics clear up any ambiguity about the historical role that automation dependency has played in accidents. One such mishap occurred in April 2008 when the pilot of a Cessna Citation Mustang, who was flying from Lincoln, California., to Carlsbad McClellan-Palomar, California., suffered a landing mishap according to NTSB records. During the descent, the right side of the Primary Flight Display (PFD) started to flicker, then the autopilot disconnected. The pilot experienced heavy control forces and he found that the electric pitch trim was inoperative. During the approach the pilot hand-flew the aircraft through a 2400 feet thick cloud layer, then broke out at low altitude and continued the approach to Runway 24 at well over normal approach speed. The pilot told the NTSB, he was overwhelmed with the electrical failures and fatigued from maneuvering the airplane by hand for about 45 minutes.
He crossed the threshold about 15 knots faster than Vref and touched down halfway down the 4897 feet runway. He applied full brakes but realized he couldn’t stop by the end of the runway. He didn’t want to risk plunging down a steep embankment on the west end of the field, so he ground looped the aircraft before reaching the end. The aircraft careened off into an unpaved area south of the runway, collapsing the main landing gear and folding up the wing flaps. The occupants walked away, but the aircraft was seriously damaged.
This accident is emblematic of other mishaps that have occurred when pilots were unable to maintain control of their aircraft after the cockpit automation malfunctioned. But even if all the automation works flawlessly, there are instances when pilots were preoccupied with trying to reprogram it rather than fly the aircraft and resolve the problem in the simplest way. In doing so, they became overloaded with automation tasks and lost their situational awareness.
In the mid -1990s, American Airlines studied the role played by cockpit automation in aircraft accidents. Company flight safety specialists discovered that automation dependency was a factor in more than two-third of recent jetliner accidents. Many times automation dependency lulled flight crews into a false sense of security, luring them to fly considerably closer to the edges of the flight envelope that they might have otherwise. Once at the brink, they were compelled to extract maximum performance from the aircraft to avoid a serious excursion. More often than not in such jetliner incidents, cockpit automation was a significant distraction, but not the cause of the mishap. That was blamed on pilot error.
Simply put, flight crews became preoccupied with managing the automation rather than flying the aircraft. They almost seemed to believe that the airplane would somehow stop flying if they to degrade or disconnect automation systems, including the autopilot. They were unwilling or unable to say “I have the controls”, click off the autopilot and autothrottles, and hand-fly the aircraft. The Dallas-based air carrier became especially sensitive to FMS automation dependency after the NTSB and the Republic of Colombia issued their final reports on the crash of AA Flight 965, a Boeing 757-223 flying from Miami to Cali, Colombia, in December 1995. Accident investigators concluded that the flight crew became preoccupied with reprogramming the Flight Management Computer (FMC) instead of reverting to basic radio navigation. Notably the MFD’s, moving map display was relatively primitive by current standards, lacking EGPWS terrain imagery and other information layers that could have boosted situational awareness.
Preoccupation with the FMS, among other high-level automation devices, can blur the larger view of what needs to be done in a high workload situation to continue the flight safely, quickly, legally and comfortably. When tackling high priority tasks, less automation often yields more safety. There are three main levels of automation, according to AA. The lowest involves hand-flying the aircraft with the crew making heading, course, pitch, flight level change, speed and altitude inputs into the flight guidance panel, plus manually tuning navigation radios and then following computer generated lateral, vertical and speed cues that are displayed on the Primary Flight Display (PFD). When the autopilot is engaged and it responds to flight guidance panel and radio tuning inputs, the level of automation increases to intermediate. If the FMS is programmed and it’s providing leg-by-leg and point-by-point lateral and vertical guidance, the aircraft is using the highest level of automation.
Current generation of pilots have been taught that using the highest level of automation is preferable because it reduces cockpit workload and frees up time to manage all cockpit resources. But automation dependency has its perils.
Airlines are concerned that pilots will evolve into computer programmers, flying desk jockeys who’ve lost the ability to hand fly an aircraft with smoothness, precision and responsiveness.. AA advises pilots to click off the autopilot and autothrottles whenever it’s appropriate so that they can practice basic stick, rudder and energy management flying skills. Training captains note that the best automation system isn’t capable of avoiding a Controlled Flight into Terrain (CFIT) or midair collision accident, of executing a maximum wind-shear escape maneuver, or of recovering from a high altitude upset. With the exception of a few aircraft equipped with three-axis fly-by-wire (FBW) flight control systems, the automation systems of most aircraft cannot handle an engine failure after takeoff.
Deft programming of an FMS may provide you with a magenta line to guide you from takeoff to touchdown. But if the automation fails, it’s up to you to continue to fly the aircraft safely and successfully land it at the destination or an alternate airport.
Use the automation to off-load the crew. But when or if it disconnects, you need the skills to step up to it, says veteran Boeing test pilot Dale Ranz, an expert often cited by AA Flight Academy instructors. The message out there is we still need to teach pilots to keep the blue side up. How about if we shut down the FMC and ask pilots, “What are you going to do now? We need to train people to think. How fast can you change priorities in the right direction when things go wrong?”
AA Flight Academy training captains tell flight crews that they’re captains and pilots, not automation managers. They must keep themselves in the loop, mentally flying the aircraft even though they’re not touching the controls or power levers. Regardless of the level of automation, it’s up to the pilot flying (PF) to concentrate primarily on maintaining the desired lateral and vertical flight path. If the automation cannot perform that task, it’s up to the PF to disconnect it and exercise pilot-in-command authority.
Initial flight crew qualification usually involves handling single malfunctions or emergencies. During recurrent training, though, more than one malfunction may pop up at the same time. That’s when pilot’s workload ramps up and flight crews must reorder priorities creatively, quickly and correctly. If it’s all done by rote, then you can find yourself lost. “Everything you might encounter isn’t necessarily on page 3 of the Quick Reference Handbook (QRH)”, says Ranz. “What are you going to do now? You can find yourself on the short end of the stick if you haven’t thought through things in advance.”
If for example, an engine fails and then automation kicks off, pilot workload can increase exponentially. That’s the time for creative thinking in the cockpit. The autopilot and autothrottle systems, however capable, cannot recover the aircraft from a critical flight altitude. “It’s OK to split tasks,” says Ranz. “If you must hand-fly the aircraft consider assigning speed control to the pilot-not-flying while you handle the wheel and the rudder.”
The time to use the highest levels of automation is when you have all urgent pilot-in-command tasks under control and the aircraft’s flight path is stable. The pilot flying (PF) and pilot-not-flying (PNF) then need to agree on what is being programmed into the FMS, with one pilot making the inputs and the other pilot cross-checking the results. This requires the PF to split attention between head-up flying tasks and head-down automation management tasks. And it requires the PNF to split time between completing checklists and running radios along with programming the FMS.
Both crew members must know when to reduce the level of automation to adapt to a dynamic change in desired flight path if there is no time to reprogram the FMS. Today’s cockpit automation has great potential to reduce pilot workload. It’s a great substitute for having a third pilot in the cockpit. But it’s also the junior member of the flight crew, one far from being qualified to act as second-in-command, let alone pilot-in-command. As long as humans upfront know all of its capabilities, plus it’s limitations, they’ll be masters, not children of the magenta.
By courtesy: Automation Dependency by Fred George Business & Commercial Aviation Feb. 2014
Vref = Velocity reference speed you set as a bug on the Airspeed Indicator which also caters for unusual landing conditions such as headwind, gust etc. It is also used for flap configurations other than normal for the phase of flight by increasing the speed bug by knots for the degree of flaps not available..
ILS = Instrument Landing System; electronic guidance for landing provided in the cockpit from runway based transmitters
EGPWS = Enhanced Ground Proximity Warning System: warns of closure to terrain in an abnormal phase of flight