I am currently training as a commercial pilot, following my childhood dream.
The aviation industry has always been at the forefront of engineering and technological innovation. It has developed alongside the computer revolution in the 20th century and aircraft manufacturers have been quick to take advantage of the increased reliability and accuracy of automated systems compared to those operated by humans.
Aviation has also benefitted from the research and development budgets afforded to military and space programmes, driven by two World Wars and the subsequent Cold War. Airframers and engine manufacturers to this day often work on civilian airliners alongside military projects, with crossover of technology between the two. In the last three decades automation in aeroplane cockpits has increased hugely whilst training of pilots has in general retained a more traditional emphasis on stick-and-rudder skills. Some recent incidents have highlighted that increased cockpit automation without appropriate training may in fact be increasing the risk of accidents, and airlines are starting to incorporate this factor into training programmes.
From the Wright Flyer to the Modern Jetliner
When aeroplanes were first conceived, early pioneers such as the Wright Brothers relied entirely on mechanical connections between cockpit controls and the moving parts of the aircraft, with a system of cables and pulleys connecting the yoke or stick and rudder pedals to the three primary control surfaces of the machine: ailerons, elevator and rudder. Basic piston engines with fixed-pitch propellers as fitted to early aircraft, as well as many light aircraft built and flown today, require only mechanical throttle, mixture and carburettor heat controls. Early aeroplanes could only fly low and slow, in visual conditions, so the workload on pilots was sufficiently low that they were able to manage the controls single-handedly. The main concern would have been mechanical failure of the structure or the engine, sadly commonplace in the first years of aviation.
As aircraft complexity grew and reliable computer systems became available, manufacturers incorporated increasing levels of automation into their designs. Automation in modern aircraft can be found virtually everywhere, from FADEC (Full Authority Digital Engine Control) systems controlling the engines, through fly-by-wire electronic movement of the aeroplane's control surfaces, to navigation and autopilot systems accurate enough to land over a hundred tons of metal flying at over 150 miles per hour on a narrow strip of tarmac with no pilot intervention other than to lower flaps and undercarriage. The role of the pilot clearly must be different in these ultra-modern aircraft, and indeed if it wasn't for those pesky flaps and gear the aeroplane could fly itself with no pilot at all. Military UAVs do just this; controlled by a pilot on the ground, all on-board systems are automatic. Most people feel happier having pilots in the pointy end, though, and there are currently no serious plans to remove humans from the cockpit of commercial airliners.
Evolution of the Boeing 747
The Boeing 747 was conceived in the early 1960s initially to serve the US military's cargo transport requirements. However, commercial jet travel quite literally took off around this time, and the company saw a niche in the market for a large passenger aircraft. The first variant, the 747-100, made its first flight in 1969 and entered service with Pan Am in 1970. As can be seen in the image above, the flight deck was full of traditional analogue-type instruments and gauges, and flying the aircraft required three crew members—the captain, the first officer and a flight engineer—who sat behind the pilots facing a huge instrument panel monitoring and controlling many aircraft systems.
The flight engineer was rendered obsolete with the advent of the 747-400 variant in 1989. The second picture shows the completely different layout of the cockpit, with large digital electronic displays in front of the pilots. Many functions that had to be performed manually were incorporated into automatic sequences activated by the push of a single button, reducing the number of dials, gauges and knobs in the cockpit from nearly 1000 to just 365.
In 2011 the latest 747-8 variant entered service with updated systems using technology developed for Boeing's all-new 787 airliner. The cockpit shown in the third photograph looks similar in terms of displays, hiding improved systems and use of fly-by-wire for some control surfaces.
The Fly-by-Wire System
Fly-by-wire is a system that replaces mechanical connections between the pilot's controls and the aircraft's control surfaces by an electronic interface which interprets the pilot's inputs and converts them to electronic signals which cause actuators to move the surfaces appropriately. Such systems can be used to improve flight stability, correcting automatically for disturbances from the desired flight state. This is used particularly in modern fighter jets which are highly manoeuvrable but inherently unstable and would be unflyable by a human if the flight control computers failed. Airliners do not behave in this way, but flight control computers can be programmed for flight envelope protection. This means that if a pilot's input demands a manoeuvre that would put the aircraft in a dangerous position or exceed structural limits, the computer will only allow the manoeuvre up to predetermined limits, whilst giving the pilot a cockpit warning.
Fly-by-wire has an impressive history, with Concorde the first production airliner to make use of it in its early analogue form, and the Space Shuttle the first aircraft to use a fully-digital system. Airbus was the first major civil airframer to adopt digital fly-by-wire technology, using it to a limited degree on the A310 and fully on the A320, introduced in 1988 and known colloquially as the "Electric Jet". After some initial resistance Boeing has subsequently adopted the technology and currently uses it on the 777, 787 and 747-8. Embraer uses fly-by-wire for its E-Jet series, and the Dassault Falcon 7X is the first business jet to use the system.
Air France Flight 447
On 1 June 2009, Air France Flight 447 from Rio de Janeiro to Paris crashed into the southern Atlantic Ocean. Initially the cause of the accident was a mystery as there had been no mayday call from the pilots and recovery of the flight data recorders from the seabed took two years.
Investigations focussed on suspected icing of instruments called pitot probes due to the weather conditions at the time. Normally pitot probes are heated to prevent ice formation, but if they become blocked the aeroplane's computers cannot accurately tell how fast it is travelling through the air. There is then a risk of flying too slowly, meaning there will not be enough air passing over the wings to maintain lift, and it will enter a stall and fall out of the sky. Discrepancies between readings from different pitot probes make it impossible to know which is the correct airspeed, and the autopilot which would have been flying the Airbus A330 at the time responded by disconnecting, meaning that the pilots were flying by hand. Critically, in this situation the flight control computers are programmed to degrade from "normal law" to "alternate law", in which condition flight envelope protection is not available and there is nothing to stop the aeroplane entering a stall, which is what happened in this case.
The mystery was why the crew were unable to recover from the stall. The standard stall recovery procedure for any aeroplane is to lower the nose to increase speed and allow the wings to generate lift again. Flying at over 35,000 feet there should have been plenty of time to recover, but it did not happen.
Recovery of the flight data and cockpit voice recorders revealed what happened, in chilling detail. It was clear from the pilots' dialogue that they had no idea what was happening until it was too late. Worse, one of the pilots was responding entirely inappropriately to the stalled condition by pulling back on the stick rather than pushing forward, despite stall warning indications in the cockpit. As with almost all aviation accidents the cause was multifactorial with contributions from the weather, the design of the pitot probes, and inappropriate pilot response to loss of automation.
Colgan Air Flight 3407
A few months earlier, on 12 February, a Bombardier Q400 crashed on approach to Buffalo, New York. The investigation revealed this aircraft had also stalled, albeit under different conditions. The autopilot was flying the aeroplane but the airspeed was falling rapidly as flaps and undercarriage were lowered, increasing drag. The crew failed to notice this until the stall warning system activated the stick-shaker. The appropriate response would have been to carry out a standard stall recovery, lowering the nose and applying power to increase speed. Instead the captain tried to pull the nose up. This activated the next stage of stall protection, the stick-pusher, which applies a strong nose-down force to the stick to recover the aircraft. However, the captain continued to pull back against this force, resulting in a full stall from which the aeroplane did not recover.
Accident Prevention Through Pilot Training for the Modern Cockpit
In both these cases deficits in training emerged as the investigations progressed. As a result of the Colgan crash it emerged that stall recovery as generally taught in the simulator emphasised recovery with minimum height loss, meaning that pilots were tending to move away from the stall recovery technique that they would have learnt early in their training in light aircraft, with a definite nose-down movement, and were tending to avoid height loss at all costs. This was thought to have contributed to the captain's inappropriate response to the stall warnings.
The Air France investigation discovered that the airline did not include any high-altitude stall recovery procedures in its training programme, and indeed no manual handling high-altitude training at all. This is likely to have resulted in the confusion shown by the pilots, their failure to follow appropriate checklists and their inappropriate responses.
These accidents have provoked much discussion in the aviation industry. In 2011 a report was presented at the Royal Aeronautical Society flight training conference suggesting that flight crew able to respond to unfamiliar situations often involving loss of automation were either military-trained or employed by an airline with more than the legal minimum recurrent training programme, suggesting that standard training is not providing modern pilots with the resilience required to manage modern cockpit challenges. It has been suggested that newly-trained pilots are relying too much on automation, unlike older pilots trained on less sophisticated systems who tend to question sources of information and be better prepared for malfunctions of any system.
There have been some immediate changes in training, notably in stall recovery where there has been a return to basic principles - nose down and increase airspeed as a priority. Some flight training organisations have introduced an upset recovery module into their basic training to increase situational awareness and instil correct recovery procedures at an early stage. There is a move towards competency-based training through the introduction of a new licence, the Multi-Crew Pilot Licence, which is designed to assess trainees based on actual performance in a range of situations rather than simply completing an arguably outdated syllabus.
It is unfortunate that sometimes accidents have to happen before problems are identified, but awareness of the different challenges to pilots operating highly automated aircraft is now at an all-time high, hopefully resulting in increased safety for all who fly.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
lobzang dorjay. on October 06, 2014:
if stall warning was alarming in the cockpit why didn't pilots took the measures to stabilize the plane and unstall. if there was ice on wings then the sensors should have alerted the pilot's about the icing. but no, crashed was bound to happen because of pilot's confusions and of terrifying situations which was occurring in the cockpit.
dkmayo on April 24, 2013:
Really liked the hub. I wonder if the pilot's instincts are to pull up when in fact the opposite should be the case? My father was a Navy pilot some years back and part of his training was to take a SNJ trainer aircraft up and put it into a stall and then recover.
Nalliah Thayabharan on August 06, 2012:
Beyond the reasoning and explanations there is still some eeriness about the crash, taking in consideration that Air France flight 447′s pilots just sat there in daze squeezing the control stick, barely being able to do more than commenting on how the airplane was falling out of the sky until crashing into the Atlantic Ocean, the arrival of the 58-year-old flight captain Marc Dubois in the cockpit not making much a difference either. The question might arise whether weren’t the pilots in a mentally incapacitating state of shock and disbelief? Whether do or can Air France test pilots of how well they can keep their mental stability under the duress of a catastrophic situation? None of it seems to be the fault of the Airbus A330, which needs only good, trained pilots to give superior performance for the good of the flying public. Very similarly 3 decades ago Captain Madan Kukar’s mistaken perception of the Air India Flight 855 situation resulted in causing the Boeing 747-237 to rapidly lose altitude and the airplane hit the Arabian Sea at 35 degree nose-down angle.
Practicing recovery from “Loss of Control” situations and improve flight crew training for high altitude stalls (simulator training usually has low altitude stalls which are significantly different due to energy status of the aircraft) should become the mandatory part of recurrent training.
The lack of academic understanding of aerodynamics by pilots, incomplete aero models in Full Flight Simulator, and in-appropriate use of Full Flight Simulator for upset training, and lack of realistic training environments for typical Loss of Control In-Flight events, cause these terrible Loss of Control In-Flight accidents which are the leading cause of death and loss of airplanes worldwide.
Nick Hanlon from Chiang Mai on August 04, 2012:
Nalliah Thayabharan on August 02, 2012:
Once the airplane is stalled, it will lose altitude about 150 feet per second. The pilots have to unstall to stop severe altitude loss by lowering the nose by manually reposition the All Flying Horizontal Stabilizer (Trimmable Horizontal Stabilizer - THS) nose down. If close to the ground, reducing altitude loss would be of up most importance during the recovery. A stall at high altitude would allow a generous degree of nose down pitch and altitude loss during the recovery. Air France and other airlines need a serious review of basic aerodynamic facts and amend their stall recovery procedure.
The crash of Air France flight 447 into the Atlantic Ocean, killing all 216 passengers was caused by the co-pilot induced stalled glide condition and the airplane - Airbus A330-203 remained in that condition until impact. To recover from stall is to set engine to idle to reduce nose up side effect and try full nose down input. If no success roll the aircraft to above 60° bank angle and rudder input to lower the nose in a steep engaged turn. Pilots lack of familiarity and training along with system malfunction contributed to this terrible accident. Also the following contributed to the accident
(1)the absence of proper immediate actions to correct the stalled glide
(2) Insufficient and inappropriate situation awareness disabling the co-pilots and the captain to become aware of what was happening regarding the performance and behaviour of the aircraft
(3)lack of effective communication between the co-pilots and the captain which limited the decision making processes, the ability to choose appropriate alternatives and establish priorities in the actions to counter the stalled glide
During most of its long descent into the Atlantic Ocean, Airbus A330-203 was in a stalled glide. Far from a deep stall, this seems to have been a conventional stall in which the Airbus A330 displayed exemplary behavior. The aircraft responded to roll inputs, maintained the commanded pitch attitude, and neither departed nor spun. The only thing the Airbus A330-203 failed to do well was to make clear to its cockpit crew what was going on.Its pitch attitude was about 15 degrees nose up and its flight path was around 25 degrees downward, giving an angle of attack of 35 degrees or more. Its vertical speed was about 100 knots, and its true airspeed was about 250 knots. It remained in this unusual attitude not because it could not recover, but because the co-pilots did not comprehend in darkness, the actual attitude of the aircraft. The co-pilots held the nose up. If the co-pilots had pushed the stick forward, held it there, and manually retrimmed the Trimmable Horizontal Stabilizer(THS), the airplane would have recovered from the stall and flown normally.
Air France complained that the copilots did not have enough time to analyze the situation. Gravitational stalled glide does not allow timeouts, to thoroughly discuss the situation to find out what went wrong. The co-pilots – 37 year old David Robert and 32 year old Pierre-Cédric Bonin missed the cardinal rule that first they must fly the airplane, and after start analyzing the situation, since a falling airplane is not going to wait for them. If they did not understand the instruments, then instead of pondering on it they should have come to the quick conclusion that they did not understand those instruments, and apply the unreliable airspeed procedure clearly prescribed for that situation, which is a blind, given thrust and pitch setting for the given configuration, and let the airplane fly itself, and only after get to analyzing what went wrong, and by the time they finished, the root-cause (pitot icing) would have probably cured itself. It was the safe solution to the problem, but not applied.
The Airbus A330 performed exactly as it was designed and described when the stall warning cut out at the end of valid values, except the co-pilots did not know it. Unfortunately, it happens too often with catastrophic results that pilots are not familiar with the systems of their own airplane, such as in the case of American Airlines 587 over Queens, which was clearly the airline’s fault.
Air France also argued that the stall warning system in the A330 is too “confusing”. Every modern airplane is quite a confusing piece of machinery. It is full of buttons, levers, all kinds of red, yellow, green lights with buzzers, and a host of other indicators and controls inside, which can look very confusing indeed, but it is the pilot’s duty to reign on them, or not to be pilot.
Airbus A330-203 is a new generation, highly automated piece of equipment with drastically simplified controls, displays, and instrumentation compared to older models. Still, pilots with the same human capabilities as the ones on Air France flight 447 could very well stay in full control in those planes, and many times acted heroically saving situations much graver than where the plight of Air France flight 447 started, such as United Airlines flight UA232 at Sioux City, or Air Canada flight AC143, the Gimli Glider. If those pilots could perform well in those older, much more complicated aircraft in tougher situations, then there is no excuse for the co-pilots of AF flight 447 to be confused in a generally much simpler and easier to fly aircraft.
The Airbus A320 is a digital fly-by-wire aircraft as the flight control surfaces are moved by electrical and hydraulic actuators controlled by a digital computer. The computer interprets pilot commands via input from a side-stick, making adjustments on its own to keep the plane stable and on course, which is particularly useful after engine failure by allowing the pilots to concentrate on engine restart and landing planning. Some say the Airbus A330 is a “video-game” airplane due to its side-stick control, which does not match up in real hard situations. But who can say that after the successful ditching of US Airways flight 1549 on the Hudson River? It was an Airbus A320 with the same side-stick control, and it matched up with the hardest situation very well with an experienced 57 year old Captain Chesley Sullenberger at the command. The Airbus A330 is not a video-game airplane, it is the airlines that make it a video-game by cutting corners, taking advantage of its superior automated capabilities thinking that it flies by itself, and no training and no knowledge of even the basics of the principles of flying is required in them for their pilots, as was demonstrated by the co-pilots of flight 447, who seemed to be incapable to react even on a basic level to the phenomenon of the aerodynamic stall. The co-pilots had not applied the unreliable airspeed procedure. The co-pilots apparently did not notice that the plane had reached its maximum permissible altitude. The co-pilots did not read out the available data like vertical velocity, altitude, etc. The stall warning sounded continuously for 54 seconds. The absence of any training, at high altitude, in manual airplane handling and in the procedure for ”Vol avec IAS douteuse” (Flight with questionable Indicated Airspeed) caused this terrible accident. Evidently, it might not be what Airbus had on its mind designing the aircraft. They might have meant the best of the both, an airplane with superior controls, matched with seasoned pilots with superior education in the principles of flying and the handling of hard situations, best of the best, as airlines are prone to boast of their flying personnel, to represent quality improvement in flying safety by this pairing. Now, if this piece of equipment falls in the hands of the airlines who use it as a video game to save training costs, telling only their pilots that “if the red light on the right side blinks, just pull the stick back as hard as you can, and let the system do the rest”, they can get away with it as long as everything is normal, the airplane is good enough for that, but in unforeseeable situations, such as the flight 447 en-route to Paris on that night, without any independent knowledge of flying in general, the video-gaming with the aircraft may ultimately come to a fatal end.
Beyond the reasoning and explanations there is
flyingvet (author) on July 27, 2012:
I am glad I added my info, Denise, and it's definitely provided motivation to write more. It's never too late to get your pilot's licence - I know someone who got his at the age of 72. Thanks so much for your positive comments.
Denise Handlon from North Carolina on July 26, 2012:
A hearty 'Congratulations' to you on your Hub of the Day recognition. Aren't you glad you added your info in the WTI! :) Nice work.
Hui (蕙) on July 24, 2012:
This is so professional and fantastic knowledge, which ordinary people like me need time to digest. Great colloquial words to explain, and vivid illustration pictures.
JP Carlos from Quezon CIty, Phlippines on July 24, 2012:
Although technology has provided us with many advancements especially in safety, pilot common sense and experience is still invaluable.
Sandra Busby from Tuscaloosa, Alabama, USA on July 24, 2012:
Great Hub. Congratulations on your award.
Urmila from Rancho Cucamonga,CA, USA on July 24, 2012:
Really an interesting and educational hub. Enjoyed reading the transformation of Boeing 747 over the years. Well deserved Hub of the day award. Keep it up!
Peter V from At the Beach in Florida on July 24, 2012:
What an interesting and entertaining hub to read! No wonder it got Hob of the Day! Congrats and great hub!
Mike Russo from Placentia California on July 24, 2012:
Our son flys 747-400 for Atlas Air Cargo. He flys virtually around the world. With two crews on board. The flights are usually 12 to 14 hours. One crew sleeps while the other one is at the controls. He has to go for flight simulator training every six months. He flew in Alasaka as an air taxi pilot out in the bush for 14 years. He also flew DC6's from Fairbanks to the North Slope for several years. I hope he has not lost any of those skills. Thanks for this great hub. Voting up, Interesting and Sharing.
flyingvet (author) on July 24, 2012:
Yes everyone learns initially in a light aircraft, but it's only between 100 and 250 hours depending on the route you take, so by the time you have several thousand hours on a big jet you may well have lost some of these skills, especially if you have to follow different procedures to pass a sim ride every 6 months for the jet. Not that those procedures are necessarily wrong, it's just possible to lose the flexibility to respond to unfamiliar situations appropriately.
Bill from Greensburg Pennsylvania on July 24, 2012:
Great Hub. Great Photo's and informative. Any way to prevent accidents is great.
Nick Hanlon from Chiang Mai on July 24, 2012:
Great hub.Love how you show the irrationality of totally trusting machines to do the job.I thought all pilots had to get a light aircraft licence before they could go onto the heavys.That way they can retain some stick and rudder instincts.
flyingvet (author) on July 24, 2012:
Thanks so much for all the positive comments, wasn't expecting that sort of response! Aviation really is fascinating, and I only just scratched the surface of the topics I covered in the hub. It's mind-boggling how well-engineered modern aircraft are. I think the human factors aspect is particularly interesting - the majority of accidents now have a significant human error component as mechanical failures are rare.
Your Cousins from Atlanta, GA on July 24, 2012:
I often worry about auto-pilot from the perspective that it will lull the pilot into over-complacency. However as you have shown, recent advances in the early warning signals can alert the pilot to the exact cause of the problem and, with the right training and skill, the pilot is equipped to handle the emergency. Thanks for the information.
Jenn-Anne on July 24, 2012:
Wonderful hub! I have always been fascinated by aviation and enjoy doing things like listening to ATC feeds and going to air shows. Loved all the interesting and useful information here!
deergha from ...... a place beyond now and beyond here !!! on July 24, 2012:
Awesome hub....very informative. Enjoyed reading about the accident prevention measures. Accompanying photos are superb as well.
Voted up and all.
Denise Handlon from North Carolina on July 23, 2012:
Excellent information and very interesting. So glad you snuck in there and added it to our list. Everyone has been concentrating on the ground instead of looking up-great choice.
Joseph A K Turner from West Yorkshire on July 23, 2012:
as do I, it can happen in anything, I wonder if in a few generations we will say the same thing about driving
RedElf from Canada on July 23, 2012:
Fascinating article - I certainly agree with what you have to say (in your comment above) about operator complacency. Thanks for the good read.
Simone Haruko Smith from San Francisco on July 23, 2012:
What a fantastic and fascinating peek you have offered into the world of flight! Absolutely love this Hub. Thanks for sharing all the fun facts and history!
flyingvet (author) on July 23, 2012:
Thanks, yes it's sad that it takes fatal accidents to discover design flaws. Unfortunately in aviation if the thing stops flying it's going to be pretty terminal unless you're very lucky/skilled (see the BA B777 that lost thrust on final approach to Heathrow, the US Airways A320 that landed in the Hudson River), so public awareness of faults tends to be higher than in other forms of transport. It's the most highly-regulated transport industry and the certification requirements for aircraft are, certainly in the West, incredibly high. Accident investigations are rigorous to identify any problems and regulatory bodies are quick to implement changes if necessary. I fully agree that automation makes aircraft more reliable and life much easier for pilots; the potential problems start when complacency sets in and people forget the basics so can't respond appropriately in an emergency.
Joseph A K Turner from West Yorkshire on July 23, 2012:
I have a few friends who did aviation at school, I watched a show a few weeks ago, about a particular style of plane that suffering from major icing problems, and twice, because the speed the plane was flying at it went down. Also the deicing system for the wings was complete crap. I think the whole story of aviation is marred with death. Definitely glad we have computers running the show, humans can be irrational. Nice hub, voted up