Ron

Tnx for the stats. Validated my gut feeling from seeing scattered
reports through the years.

Of benefit to those thinking about building , if you massaged your
figures to show which birds had the best safety rate, might help some
rethink their possible choice of home built? Of course your gross
figures would include stupidly on pilots part but total percentage
number would still be a good indicator. As chinese say, "Hot airplane
and stupid Pilot, accident make" G

Robert (Borovec) made Crater Lake, OR last night on their way to boat
in FL. They started east through the mountains and with the bad Wx
(ice and snow and cold temp) that came up think they rethought and
moved west to get in the 'Valley' to go south to LA and east into the
dessert and stay south rest of 'voyage' )

Big John


On Fri, 14 Nov 2003 16:04:17 GMT, Ron Wanttaja
wrote:

On Fri, 14 Nov 2003 13:57:03 GMT,
(Corky Scott) wrote:

Man those BD5's just don't seem like a good idea. Tiny, high stall
speed, tight engine compartment, and the pilot sits right on the
bottom of the fuselage.

The airplane has been discussed in this group previously and my
recollection is that it has a very high fatal accident rate. It's
first flight accident rate is also very high. Perhaps Ron Wanttaja
can step in with his always meticulous statistical analysis.

Damn, Corky, were you lurking in the back of the EAA Chapter 26 meeting
last night? I'm in the process of doing a detailed homebuilt accident
analysis, and presented my initial results.

Unfortunately, the year I chose for my in-depth analysis didn't include any
BD-5 crashes, so it's of no use for us in this case. Let's do a simpler
comparison. I ran the NTSB database for the accidents since January 1,
1990:

Total Amateur-Built Accidents: 2881
Total BD-5 Accidents: 22

BD-5s were involved in 0.8% of all homebuilt accidents, and in 1.1% of all
fatal homebuilt accidents. Due to the small size of the sample, this may
not be a significant difference (it's only three accidents extra over 13
years).

Looking at the FATALITY rate:

Total Amateur-Built Fatal Accidents: 837 (# of accidents, not fatalities)
Total BD-5 Fatal Accidents: 9

Homebuilt fatal accident rate: 837/2881, or 29.1%
BD-5 fatal accident rate: 9/22, or 40.1%

But what of the accident ratio in comparison to the size of the homebuilt
fleet? Let me "Back Out" some data that might let us make a comparative
analysis.

The January 2003 FAA database listed 25,886 aircraft as being in the
Experimental Amateur-Built category. The same database has listings for
237 BD-5s, of which 81 are listed as having Experimental Amateur-Built
certification.

Before I go on, allow me to explain the difference. Database listings
include a field for the category the aircraft is certified in. If the
field is blank, the usual process is to assume the airplane has received an
N-number but has not yet been approved for flight. My past analysis
indicates this is not necessarily the case; for instance, John Ammeter's
RV-6 (which flew something like ten years ago) STILL doesn't have an entry
in the Certification block, and, with Juan's help, I uncovered one BD-5
(not one of his, BTW) that made its first flight about five years after
being listed as certified.

Back when I did my first registration analysis, I found about 36,000
aircraft listings with "homebuilt-like" names, but only about 22,000 of
them (this was in 1997) were actually listed as certified. The FAA and EAA
only count those listed as certified, so the published figure is in the
20,000 range instead of in the 30,000s.

So...officially, we should only use the 81 BD-5s for analysis. Due to the
uncertainty, I'll list the figures for the full fleet as well. BTW, I used
"BD-5", "BD 5", "BD5", and "BEDE 5" (with appropriate wild cards) as my
search terms.

Anyway, to the stats:

Total homebuilts in 2003: 25886
Total certified BD-5s: 81
Total listed BD-5s: 237

Lets compare the number of accidents over the past 13 years with the
current number of homebuilts. We'll add the accident airplanes back into
the current fleet for a baseline.

This doesn't, in itself, produce a viable statistic. But it is useful in
comparing between aircraft types.

Total homebuilts plus accidents: 28767
Total certified BD-5s plus accidents: 103
Total listed BD-5s plus accidents: 259

(Note that the NTSB accident listings make no differentiation whether the
accident aircraft had a blank in the certification status field)

Percentages:

Total homebuilt accident rate: 10%
Total certified BD-5 rate: 21%
Total all-listing BD-5 rate: 8.5%

So whether the BD-5 is twice as bad as the main fleet or a little bit
better really depends on your interpretation of the certification data. By
the FAA and EAA's interpretation, the BD-5's accident rate is twice that of
the main homebuilt fleet.

Ron Wanttaja