The design and development of a commercial airliner requires an unimaginable number of engineering man hours. The design process is heavily influenced by the strict regulations stipulated by various authorities, the main players being the Federal Aviation Administration in the US and the European Aviation Safety Agency in Europe. Although some countries have their own regulations they are often very similar. Aircraft design can be divided into two main areas; Airframe and Systems.
The airframe is the actual structure holding the aircraft together, and the goal is always to keep the weight to a minimum, for speed, climbing performance, fuel burn and payload reasons, all while maintaining maximal strength and durability. A challenging task indeed. When calculating the stress and strength of the airframe, regulated safety factors are applied to create the necessary margins. In some critical areas as much as factor five (5). In reality, this means that even if the specific area is designed and calculated to hold together for e.g. 100,000 flight hours, it’s only permitted to fly for 20,000 flight hours. Well, that’s real safety.
The aircraft systems constitute the actual equipment installed which make the whole aircraft function as one very sophisticated unit. Examples of such systems include landing gear, navigation systems, flight control systems and engines. All systems must be carefully integrated with each other and no interferences are allowed, which is why thorough testing is always a requirement.
When designing the aircraft systems, redundancy is the keyword. A critical system cannot be allowed to malfunction and hence these systems are doubled or even tripled to ensure safety. If a system fails, the back-up system automatically activates and in some cases there is even a third system just in case. Think about it, the probability that two very safe and reliable systems should fail at the same time is vanishingly small. And then a third system failing simultaneously is almost impossible. This is one of the reasons why flying is by far the safest way to travel.
A multi-engine commercial airliner is certified both to take-off and land with at least one failed engine. This means that you can afford to lose an engine and still be safe.
Another important factor in maintaining a high safety level is, of course, the maintenance programme. Every aircraft has a stipulated maintenance program which must be thoroughly followed. The programme is constantly being developed and optimised in order to achieve the best possible availability combined with reliability, safety and cost-efficiency. This is accomplished through an Industry Steering Committee, ISC, which is a workgroup consisting of the manufacturer, authorities, suppliers and airlines. Based on the outcome of real-life operations, the ISC proposes improvements to the Maintenance Review Board, MRB, and the official maintenance programme can be updated for the benefit of all involved.
The Saab 340 and the Saab 2000 are living proof that the system really works. The Saab 340 undertook its maiden flight back in 1984 and, during the 32 years since then, the aircraft has completed approximately 15.5 million flight hours, transported almost 300 million passengers and still remains one of the safest aircraft types in the world, with a very active community of operators and suppliers.
This week, from 16 to 20 May, Saab is hosting the biannual Saab 340 and Saab 2000 Global Operators Conference in Glasgow, Scotland, just as we have been doing since the mid 80’s. Around 250 participants from Saab operators, suppliers, authorities, to leasing companies and other interested parties get together, share experiences and build networks. We have a packed agenda for the week and, of course, we are taking the opportunity to host the ISC/MRB meeting in order to continue improving the safety and reliability of our flying platforms.
Odds of dying from (US statistics):
- Cardiovascular disease: 1 in 2
- Smoking (by/before age 35): 1 in 600
- Car trip, coast-to-coast: 1 in 14,000
- Bicycle accident: 1 in 88,000
- Tornado: 1 in 450,000
- Train, coast-to-coast: 1 in 1,000,000
- Lightning: 1 in 1.9 million
- Bee sting: 1 in 5.5 million
- U.S. commercial jet airline: 1 in 7 million
Sources: Natural History Museum of Los Angeles County, Massachusetts Institute of Technology, University of California at Berkeley