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ACRO E-mail Archive Thread: [IAC-L:1386] homebuilt aircraft safety

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ACRO E-mail Archive Thread: [IAC-L:1386] homebuilt aircraft safety



                


Thread: [IAC-L:1386] homebuilt aircraft safety

Message: [IAC-L:1386] homebuilt aircraft safety

Follow-Up To: ACRO Email list (for List Members only)

From: Peter Chapman <pchapman at octonline.com>

Date: Fri, 17 Oct 1997 05:26:07 UTC


Message:

 At 16:58 16/10/97 -0500, you wrote:
>>From the EAA site (www.eaa.org):
>
>HOW SAFE ARE AMATEUR-BUILT/CUSTOM-BUILT AIRCRAFT?
>Studies by FAA and the National Transportation Safety Board (NTSB) show 
>that Amateur-Built/Custom-Built aircraft have an accident rate less than 
>one percentage point higher than the general aviation fleet. In fact, 
>the accident rate for Amateur-Built/Custom-Built aircraft is dropping.  
>The total number of registered homebuilt aircraft is increasing by about 
>1,000 per year, while the total number of accidents has stayed virtually 
>the same. Another good barometer of safety is insurance rates.  

On the subject of homebuilt aircraft risk (though it is straying from purely
acro issues):
 
In the June issue of "Sport Aviation", Tom Poberezny reported improvements
in US homebuilt aircraft safety statistics over recent years. Despite a
registered fleet that grew about 25% from 1992 to 1996, the number of
accidents remained essentially constant, while fatal accidents and
fatalities dropped roughly 10 to 15%. In 1996, fatal accidents to homebuilts
in the USA numbered 56, out of a registered fleet of 18700. 

What wasn't noted in the article is the obvious conclusion that one in every
334 homebuilts is involved in a fatal accident each year. Which is not that
far from saying that if you are the pilot of a homebuilt aircraft, there is
a 1 in 334 chance of getting killed in it each year. Not quite so good sounding?

Naturally this ignores factors such as distinguishing passenger from pilot
fatalities, higher accident rates during initial test flights only (and
lower thereafter), the number of pilots flying each homebuilt, how an
accident involving two homebuilts is counted, and whether all registered
aircraft are actually flown. Still, the number should be a good ballpark
figure. Using the 1992 figures gives a more pessimistic 1 in 231. As
independent evidence, one report I saw in 1990 on the safety of different
sports and activities (US insurance company data) listed a 1 in 320 fatality
rate for homebuilts per participant, per year. 

To gain additional perspective, one can compare the numbers for homebuilts
to an aviation activity that has some reputation for high risk: skydiving.
US and international data on skydiving in recent years indicate a fatality
rate in the neighbourhood of 1 in 1000 participants per year, for
non-students. (Adding in students improves the rate by something like a
factor of four, as many make only one jump and so are exposed to little "per
participant" risk.) Conclusion: homebuilts are in some ways three times more
dangerous than skydiving. I didn't expect that when I first started looking
at the numbers. 

Peter Chapman           Toronto, Canada     
(250 jumps, and a 1/2 complete homebuilt in my dad's garage)



                


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