How Safe is Flying?
How safe is flying today?
How safe is flying? I used to get asked this a lot while I was training for my private pilots’ licence. My favourite response always used to be. “Well, the most dangerous part is the drive to the airport.”
Seriously though, it is a very good question. How safe is flying in those gigantic machines along with a few hundred other people coming along for the ride? Let’s face it, this isn’t a perfect world and things go wrong. When airliner accidents happen, they of course go spectacularly wrong. Larger aircraft, carrying more passengers flying faster. It seems a miracle any get through at all. But they do. In fact, travelling by air is one of the safest methods of transport available today.
As an example, in peak times there can be 5,000 commercial aircraft flying over the U.S.A. at any one time. Similar numbers are also over Europe and Asia. These flights all happen every day with little incident.
Air Crash Investigations
Air safety is no accident. Let’s turn that around. Ok, we know accidents happen, we see it on the news and of course those popular TV programs like Air Crash Investigation. It may seem like a lot of people taking a ghoulish interest in a tragic event.
The actuality is that accidents contribute more to air safety than almost anything else. When an accident happens, no matter how minor or major, investigators will examine the details until they are 100% sure of what the cause was. This can be a painstaking process and sometimes takes a year or more.
The reason for this painstaking process is prevention. By investigating and determining the cause of an accident, processes or new methods in construction can be put in place to prevent a similar accident from occurring in the future. In this way, no accident is ever without benefit for future fliers. These benefits will manifest themselves as new training procedures, new maintenance procedures, or new construction methods.
B Checks must be done in the aircraft hangar, whilst C and D checks must be done at a purpose-built aircraft maintenance centre.
Aircraft Maintenance
Aircraft maintenance is a key component to the safety of flying. Each aircraft has strict guidelines set down by the manufacturer on how the specific aircraft should be maintained. In addition, there are strict guidelines set down by aviation authorities such as the FAA (Federal Aviation Authority) in the U.S. or EASA (European Aviation Safety Agency) in Europe as well as other national aviation bodies in other countries. These bodies set the minimum standard of maintenance procedures for aircraft in that country as well as those flying into that country.
These procedures are constantly being updated with new findings from accidents, incidents or new technology that comes into the industry. All this is in place to ensure that when you and I get on a plane, we can count on doing so in full safety.
Aircraft maintenance service intervals can be broken into 4 categories or checks plus the daily pre-flight inspection. The timing of each of these checks is generally determined by the number of hours an aircraft has flown and/or the amount of flight cycles an aircraft has endured. A flight cycle is one take-off and one landing. Therefore a flight from Melbourne to London via Bangkok is 2 flight cycles.
How Safe is Flying is Determined By Aircraft Maintenance Checks
Daily Inspection
Prior to every day's first flight, a visual inspection of the aircraft is carried out. This inspection is a methodical walk-around performed by one of the pilots and is a check for any superficial damage or anomalies on the aircraft. The visual inspection looks for any outwardly obvious damage or inconsistencies that might render the airliner unsafe for flight that day.
The wings and skin are checked for damage caused by bird-strike or other foreign objects.
Moving parts such as flaps, ailerons and elevators are checked for any foreign objects that may impede their free movement.
Tyres and are checked for splits or excessive wear.
Brakes are checked for foreign objects or cracking
Air intake ports are checked for foreign objects
Pitot and Static air intake tubes are checked for any blockage
These checks are continued throughout the day before every flight. You can rest assured that the pilots want to have a safe aircraft every bit as much as you do. Nobody likes surprises once you are in the air.
Airlines very carefully schedule the various maintenance checks to coincide with their due date whilst minimising time out of service for aircraft.
As your car requires servicing according to the manufacturer's manual, aircraft also have a stringent schedule for mandatory checks and servicing. Airlines must have very detailed documented procedures for every step of aircraft maintenance which must be followed to the letter and signed off. As part of their certification to be allowed to fly into and out of various countries, airlines must be able to show their maintenance procedures and how they are followed to ensure passenger safety. In this way, the question of, how safe is flying? can be answered. As safe as we can possibly make it.
Airliner maintenance and safety checks can be broken down into 4 different levels. These are commonly known as the; A, B, C and D checks.
A Check
Other than the Daily Inspection, the A Check is the lightest check and is performed the most often. Depending on the aircraft type and the kind of use it gets, the A Check is performed every 300 – 600 flight hours or every 200 – 300 flight cycles. Remembering that a flight cycle equals one take-off and one landing. If the aircraft is used on short domestic flights, for example, it is more likely the cycles will be the determining factor as these will build up more quickly versus the flying hours.
The A Check itself is generally carried out overnight while the aircraft is not in service to minimise any loss of revenue. Around 20 – 50 man-hours are involved in this check and it can be carried out at the airport gate.
B Check
The B Check is a more intense check and needs to be performed in an aircraft hangar. The check is performed around every 6 months and depending on the aircraft type may require 120 – 150 man hours. A Checks can be incorporated into the B Check so that the aircraft’s removal from flying schedules is minimised.
C Check
The C Check is a much more intense check and requires a lot more space. For this reason, it must be carried out at a designated maintenance base. Depending on the aircraft type, this check is required to be carried out every 20 to 24 months which is also influenced by the number of flying hours. Around 6,000 man-hours will be required which may keep the aircraft out of service for 1 to 2 weeks. A much more in-depth check of the airframe is carried out while many components are removed for inspection or replacement.
This check is designed to capture any problems with corrosion and cracking before they become a problem, as well as replacing or servicing smaller components.
Early detection is the purpose of most of the checks performed during maintenance periods.
D Check
The D Check is by far the most intensive check performed on aircraft and is also known as the HMV (Heavy Maintenance Visit). This check is carried out around every 6 years and can take the aircraft out of service for 2 months. Like the C Check, the service must be carried out at a purpose-built maintenance base with the appropriate facilities. The work can involve around 50,000 man-hours and essentially is a total strip down of the aircraft. Often even the paint has to be removed to allow a detailed inspection of the aircraft skin, looking for cracking and corrosion.
Airlines will often use this opportunity to refresh or update the livery of the aircraft as well as refurbish and update the cabin interior.
The cost of performing a D Check is huge. Depending on the aircraft type, a ballpark figure of 1 million US dollars is not unusual. For this reason, the number of maintenance bases in places like the US is few. Many airlines will fly their aircraft to locations where labour costs are lower to perform this check. This doesn’t mean the work is inferior, as the same stringent documented work processes are in place and supervised.
As a rule of thumb, an airliner generally has 3 D Checks in its working life. After the third, the aircraft value has diminished to the point where it is likely to be worth less than the cost of doing the next scheduled D Check. At this point, the airline normally decides to retire the aircraft.
Air safety is no accident, but a painstaking very highly controlled process.
Conclusion
How safe is flying? When we look at the number of flights that are achieved without incident every day, we can see that the expectation of arriving at our destination in one piece is almost a given. Almost, because nothing in life is guaranteed. The same could be said for walking or driving down to our corner store. There is an element of risk in simply being alive.
The airline industry, and in this I include airlines, airliner manufacturers, and airport operators, takes safety extremely seriously. Their reason for their existence depends on the public being comfortable with the answer to, how safe is flying? Flight, for most people, is the only time in their lives that they will be in an environment that is totally hostile to their being. Too cold, not enough air to breathe, too far to fall, and too fast. Air travel has to be seen to be going the extra mile to provide a safe environment.
By learning from every accident that occurs and using that knowledge in maintenance procedures or flight training procedures, bit by bit accident likelihood is reduced.
Being on a commercial airliner is now one of the safest places to be.
I would love to hear your views or experiences regarding how safe is flying today. By all means, leave those comments below. Thank you for stopping by and reading about how safe is flying.
