Modern commercial aircraft with corresponding equipment are actually capable of following the guide beam of the instrument landing system and of landing automatically. The programming of the autopilot as well as lowering the landing gear and the operation of the landing flaps taking the traffic and weather conditions into consideration are still carried out by the crew. Even today, not by a long shot all aircraft and airports are equipped for a fully automatic landing. But even in the event of a fully automatic landing, the pilots control the electronic system and are ready to engage at all times. There are specified decision heights depending on the equipment of the aircraft and the airport. If the runway is not visible from this height or if the criteria for an automatic landing are not given, the aircraft must go around and if necessary, head for an alternative airport. However, in more than 95% of the cases, the landing is executed manually; that is why pilots must continuously have training in manual landings.
Contrary to military aircraft, commercial aircraft do not have an on-board radar, which indicates if there are other airplanes nearby. The radar screen in the cockpit is designed in a manner which allows weather patterns to be shown in advance, for instance thunderclouds or areas with heavy rainfall. So, it warns the crew of meteorological phenomena, which would be better to circle. The only possibility of getting an image of the traffic situation are the position reports from other airplanes via radio transmission. The only ones who can see on radar screens where which plane is, how fast it is, at which altitude it is and what course it is flying, are the air traffic controllers on the ground. The cockpit crew works with these specialists. However, the aircraft are also equipped with a device, which warns the pilots if two aircraft come too close to one another. This device does not work like a radar but is a computer, which regularly receives data such as position, altitude, course and speed from all aircraft in the vicinity and calculates possible conflict situations from this data.
In former times, there was still a navigator on board, who calculated the location from course, speed and wind on long-distance flights or who determined the position like on a ship with the sextant according to the stars. Of course, that is now a thing of the past. In principle, there are three methods to determine where you are above the clouds. One method works with special transmitters on the ground, so-called radio beacons, which mark the course of the airways. Not only the direction of where this so-called VOR is shown in the cockpit but also the exact distance. However, these precision radio beacons, which function in the VHF range, are not available worldwide; their range is very limited. Therefore, aircraft additionally have an inertial navigation system, which is based on laser gyroscopes. If the aircraft moves, deflecting forces effect these gyroscopes, which can be measured. Based on the geographical coordinates of the starting point, a computer can regularly calculate the current position from that data. Today’s commercial aircraft are of course equipped with a global positioning system (GPS), which enables navigation and positioning with an accuracy of merely a few metres.
Among other things, that is because of the previously described radio beacons. They are not only installed for one airway but form an intersection for several routes. Therefore, the path of a VOR to the next is always associated with small course corrections. Furthermore, the wind conditions at cruising altitude play a significant role. If the aircraft is confronted with heavy winds, a “jet stream”, with up to 300 km/h, the pilots try to avoid the wind field, to save flight time and fuel. On the other hand, if the wind blows in the direction of travel (i.e. from behind), it is specifically used as tailwind. That is why a flight path, which appears to be a detour on the map, is still the route with the shortest flight time.
In clouds or in the event of poor visibility, a pilot solely relies on his or her instruments. The most important one is the artificial horizon (attitude indicator), which reliably indicates the momentary orientation of the aircraft relative to Earth’s horizon.
Jet planes have cruising speeds between 700 and 900 km/h. When landing, the speed is between 200 and 300 km/h. Planes with propeller turbines have top speeds between 400 and 550 km/h and land with 130 to 220 km/h.
Of course, that depends on how large the aircraft is. A passenger version Boeing 747 for example uses approximately 13,000 litres of kerosene per hour with its four engines at a cruising speed of 900 km/h. That is around 88 tons or 109,000 litres on a flight from Frankfurt to the Caribbean (7,500 km). We know, that sounds like a lot. However, airplanes are actually a very economical means of transportation. If you convert the fuel consumption of the flight, it is approximately 1,500 litres for 100 km. Divided by 380 passengers, that amounts to a per capita consumption of 3.95 litres, less than an economical compact car. The about 20 tons of cargo – the payload of a whole truck – are not included in the calculation.
At the cruising altitude, 7,000m on short-haul flights and up to 12,000m on long- and medium-haul flights, the air is so cold that it only contains a small amount of water vapour. If it is heated in the airplane’s air conditioning system, the relative humidity is reduced even further. It is possible to do something about the dryness, however to do so, several tons of water would have to be taken along for this purpose on a long-distance flight. The cockpit’s electronic system even welcomes this “desert environment”.
Redundancy is one of the top priorities in aircraft construction. That means: There must be a multiple of all vitally important systems. That is why there are no single-engine commercial aircraft. Even if an engine fails in a twin-jet such as the Airbus A 320 or B 737 during take-off, the power of the other one is sufficient, to continue the climb. A twin-engine aircraft, which has a failed engine during cruise flight, must land at the next possible airport, for there is no redundancy left now. Statistically speaking, an engine failure occurs once every 8,000 to 10,000 flight hours. By the way, even if all engines failed, the plane would not drop from the sky like a rock. An Airbus would make it another 200 km gliding from a height of 10,000 km.
We can see on the weather radar how severe a thunderstorm is. It is better to avoid severe thunderstorms, like the ones which mainly occur in the tropics. However, less severe thunderstorms are also usually circled. Lightning is not the most dangerous factor in this scenario. The structure of an aircraft is made of metal and therefore a so-called Faraday cage, which protects the passengers in the same manner the body of a car does. On the other hand, the sensitive on-board electronic system is at risk. However, the most important reason to stay well clear of thunderclouds is the enormous turbulences inside them and the corresponding danger to passengers and the aircraft. In the case of minor thunderstorms, a detour is a compromise for the comfort of the passengers, in the case of severe thunderstorms however, it is a question of safety.
The outside temperature depends on the altitude. Normally, it gets 6 to 7 degrees colder per 1,000 metres. At an altitude of 12,000 metres, the temperature is 50 to 60 degrees below zero depending on the weather, the season and the latitude.
The higher you fly, the lower the air pressure. At an altitude of 5,000m it is only about half as high as it is at sea level; at 10,000m only a quarter. Commercial aircraft have a cabin pressure, which corresponds to an altitude of approximately 2,500m. During the landing phase, of course, it increases to the value of the outside air pressure again. The reason for the popping is the pressure equalisation of the inner ear. You can reduce it for example by swallowing more often during landing or by chewing gum.
Just like every passenger, the flight crew on long haul flights, which lead across several time zones, has problems with so-called jet lag. Scientific studies have shown that it takes several days for the “biological clock” to adjust. Basically, people who fly must deal with the same health problems as people, who work at different shifts. However, there are helpful hints in dealing with these problems. You should adjust your biological rhythm as quickly as possible after arrival. A good night’s sleep is particularly important after arriving. You can also prepare for a flight at home by beginning to adjust your body to the new time zone by going to bed later or earlier step by step. Moreover, you should also avoid anything that reduces your physical performance, such as the consumption of alcohol or heavy smoking for example.
Newspapers, TV and the radio report virtually every plane crash that takes place anywhere in the world. Of course, that type of reporting distorts the picture. If every car accident was reported, there would be no space left in newspapers for anything else. Cars, buses, trains and motorcycles, which everyone trusts without a doubt, are much more dangerous than airplanes. 100,000 people die every year worldwide as a result of car accidents; in the past 15 years an average of approximately 700 people perished in aircraft accidents per year. Although more and more aircraft are in operation, the number of fatal accidents, which were registered by the International Civil Aviation Organisation (ICAO), is virtually constant: 20 annually. In 2000, a fatal accident occurred every 2 million flight hours. Statistically speaking, a passenger would have to fly a distance of 4 billion kilometres before perishing in an airplane crash. That equals 100,000 flights around the world or 14 flights to the sun and back. The most dangerous situation is and continues to be getting to the airport.
The heaviest is the airplane itself including fuel. A Boeing 737 for example weighs approximately 26.8 tons empty, can fill up 16 tons of fuel and transport a maximum payload of 12 tons. The empty mass of an Airbus A 300 is about 85 tons and it can fuel 50 tons of kerosene. Its maximum payload is between 31 and 36 tons depending on the type. A jumbo jet Boeing 747-400 has a maximum take-off mass of 394.6 tons, more than ten large trucks. 45% of that mass consists of the empty mass (180 tons) and with full tanks the same percentage of fuel, so that approximately 42 tons remain for the payload at maximum range.
Some airline companies have pilots retiring at the age of 55 years. The statutory age limit is 65, however, under the condition that the pilot remains in good health. Every pilot must be examined by an aviation medical examiner once a year, in order to have his or her licence renewed. A severe health problem results in the loss of the job.
Twice a year, every cockpit crew member must verify that he or she is in command of everything to the very last detail. These so-called checks take place in a simulator. Emergency situations such as engine failure or on-board fire are also simulated under realistic conditions there. The crew not only has to verify that it is capable of flying, but that it would react appropriately in the case of an emergency. That means that it must constantly be up-to-date in matters pertaining to passenger safety. An additional check takes place on two normal flights, in which an instructor checks how the crew works. The professional career of a pilot depends on his or her passing all of these tests even under extreme stress without the possibility of excuses or apologies. As a basic principle, an examination by an aviation medical examiner must also take place once a year. This is not required for any other profession. Being a pilot means being subject to tests during your whole working life.
As in the case of many professions, there are also statutory maximum working hours for cockpit crews. Of course, these accommodate the special demands and burdens of a profession. For example, the physical stress caused by jet lag or by extremely long flights. For instance, a flight duty period can take up to 16 hours with all preparations and waiting periods – without taking delays into account. Apart from flight duty, there is also stand-by duty for pilots. Those are days on which they must be on stand-by for possible short notice duties. Preparation for simulator checks and further training also takes place during off-duty periods. Therefore, 80 hours of flight duty actually mean at least twice as many working hours. That equals approximately a 40-hours working week. A pilot is on flight duty somewhere in the world about 2/3 of each month regardless of Sundays or public holidays and only at home for approximately 1/3 of the time. That of course puts family life to the test time and again.
Contrary to the way things were once, today, flying is team work. Of course the captain is still the person in charge on board. He or she is responsible for everything that happens. In emergency situations everyone must follow his or her orders. However, the captain is not a dictator. Even the captain of a jumbo jet is – like any other person – not infallible. Therefore, his or her work is monitored by the other members of the crew – senior first officer and first officer (male as well as female!) – and advised by his or her colleagues when taking decisions. Who flies the aircraft or who speaks with the air traffic controllers is coordinated among the crew members. Sometimes the first officer (F/O) flies with the captain’s assistance and other times, it is done the other way around. The first officer is by no means a trainee in the cockpit, but a cockpit crew member with extensive training for his or her job.
That depends on the flight phase. Take off and a part of the ascent are always flown manually. There is no automatic system for these operations. When cruising, the crew uses the autopilot, which can take over a large part of the manual operations. It not only makes sure that the aircraft remains on the course and at the altitude, which were specified, it also autonomously flies the flight route, which was entered by the crew beforehand. This is of course a big help for the cockpit crew, because without it, the workload in modern commercial aircraft would be too great.
The work in a cockpit has changed drastically over the past 2 decades. The electronic systems have taken over a great deal of the work, but the profession on-board has not become any easier. After all, computers and human beings have very different work approaches and even the most state-of-the-art electronic system on board must be constantly programmed by the crew and appropriately applied. An error in this highly complex aircraft system, which occurs unexpectedly and is not immediately detected, can quickly lead to a critical situation. The more complex a system is, the greater the possibilities of error and the more difficult it is, to operate and monitor this system.
However, today’s captain is not only responsible for his or her aircraft to land safely at its destination. By selecting the ideal altitude, the appropriate speed, the most favourable ascent and descent, the crew ensures that fuel consumption and therefore, environmental pollution and costs are kept as low as possible.
Many think it is touching down softly! For pilots, there are other more important criteria: the length of the runway, its properties and condition, the weather conditions and the ground wind. Therefore, a landing, which feels harder, is often a better one for pilots!
Both phases of the flight demand the highest level of the crew’s concentration. However, stress during the landing phase is approximately 50% higher than during take-off. The take-off is also easier for the crew because in most cases they are well-rested and starting off their work day. On the other hand, the captain, senior first officer and first officer on long haul flights are often already on duty for twelve hours or longer when the aircraft finally lands at the destination airport. Take-off and landing are routines, which have been practiced thousands of times, which are carried out according to standardized procedures. However, at no time during a normal flight is the workload in the cockpit higher than it is now. Checklists need to be read, systems must be activated, the air traffic controllers give authorizations, instructions and information. All of this is accomplished according to a precisely defined distribution of tasks. Despite all experience, take-offs and landings require the highest level of concentration and precise, flawless work by the crew. No wonder, given that the aircraft is flying close to minimum speed and to ground level. Therefore, leeway to balance out unsteadiness is very minimal. For example, if an engine fails during take-off, which only happens very rarely, the crew must react immediately. It must either bring the aircraft to a halt on the remaining runway or take-off with the remaining engines, bring it to a safe altitude and then land again. This requires correct decisions in split seconds.