Originally Posted by
Zeke
Depends on how Boeing want to portray their aircraft in their reports.
An equally valid way to portray the same data would have been to compare :
The entire 340 series to the entire 747 series.
The entire 320 series to the entire 737 series
As they all share the same TCDS.
Yes, you could do that, but you'd be missing some things that are important to the hull loss rate that the link report shows.
http://www.boeing.com/news/techissues/pdf/statsum.pdf
First, look at page 11. Note that the First Generation of jet transports (DC-8, 707 etc) had a high accident rate at initial introduction that dropped after inservice experience was gained, but has now increased to the initial rate or greater.
There are many reasons for these rates. An important one in the early years is that pilots transitioning from props to jets didn't have a full appreciation of the differences between the two types and there was a lot of learning and training required that wasn't there initially. Other reasons were that the existing certification regulations and pilot-to-airplane interfaces were not as well developed as they are today.
The climbing rate in the later years is due to airframe age and the relegation of these early airplanes to lower tier operators in less developed parts of the world.
Note that the second generation jet transports (727,737-100/200. BAC-111) show the same type of trends at both ends of their service life, albeit at lower accident rate levels.
The current generation of airplanes (A318/319/320/321, 737-300/400/500, 737NG, 757, 767, A330, A340, 744 and 777) began operation with low accident rates that have been continued over their careers.
Also consider that airplanes on the same TCDS do not necessarily share the same certification basis or the same design features. Certification regulations do advance and not all of them are "grandfathered" into new derivatives of older airplanes. Likewise, economic and customer demanded features also show up on the newer models. In many cases, these features also make the newer airplanes more operator "friendly" and safer.
Therefore, airplanes shown on the same TCDS can vary widely in their design philosophy and features.
For these reasons, the linked report does not lump the 737-100/200 with the 737-300/400/500 or the 747-100/200/300/SP with the 747-400. Likewise, the A300-B2/B4 is not included with the A300-600.
Assuming you want to discuss a design's merits relative to other airplanes, it would seem to be more consistent to argue those merits relative to its contemporaries rather than ancestors of those contemporaries that were developed 20 to 30 years earlier. After all, some of the reasons a 737-300 has a better hull loss rate than a 737-200 are same reasons an A300-600 has a better hull loss rate than an A300.