& Quality Management
MTBF calculation according to established
only publicly available mechanical
MTBF calculation standard is
NSWC-11 (National Surface Warfare Center, Crane Division, 2011). Since
this special standard addresses only dedicated military shipboard
equipment, it has almost no importance for mechanical components in
For electronic equipment
however, the analyst can chose between the
list is ordered by recognition in Europe.
Worldwide, Mil-HDBK-217 is the most popular standard, followed by
Telcordia SR 332.
These two standards however are also globally the most common ones.
Each of these standards have unique advantages and disadvantages. The
failure rates on component level across standards can be terribly
different even for the same component type.
Sometimes the analyst has a real choice and can therefore identify the
best suitable standard from an engineering viewpoint.
In most cases however the analyst must use the standard mandated by the
customer, authoritiy, political interests and conventions of the
following statements generally apply:
- In comparison with other standards, Mil-HDBK-217 gives almost
the worst results, even with the use of ANSI/VITA 51.1
- However, using Mil-HDBK-217 is almost always safe.
- Telcordia Issue 4 and IEC-TR-62380 almost always gives the best