In safe-life design products are designed to survive a specific design life with a chosen reserve.
Safe life is particularly relevant to metal aircraft, where airframe components are subjected to varying loads over the lifetime of the aircraft which makes them susceptible to metal fatigue. In certain areas such as in wing or tail components structural failure in flight would be catastrophic.
The safe-life design technique is employed in critical systems which are either very difficult to repair or may cause severe damage to life and property. These systems are designed to work for years without requirement of any repairs.
The drawback is that products designed with a safe-life approach are over-built or allocated more resources than they are expected to need, which may be uneconomical. In order to maintain the designed safety, they will have to be replaced after the design life has expired, while they may still have a considerable life ahead of them. To counter these drawbacks, alternative design philosophies like fail-safe design and fault-tolerant design were developed.
- Fault-tolerant design
- Safety engineering
- Damage tolerance
- 1945 Australian National Airways Stinson crash