Alan Carroll

Alan Carroll

Well Known Member
Since this topic has been getting a lot of attention I thought it would be interesting to see the actual numbers from which the FAA is drawing their conclusions. To get accidents per 100,000 hours requires combining two different data sets, the FAA Aircraft Activity Survey and the NTSB database. Both are readily available online. 2009 is the most recent year for which the survey data have been published online.

[URL="

The hours flown by RVs in this chart are my estimates, since this breakdown is not reported by the FAA. 6000 aircraft is approximately what the Van's Aircraft Hobbs meter indicated in Jan. 2009; the actual number of active RVs may have been different. Average hours flown by RVs is purely a guess. My sense is that RVs fly more than most homebuilts, but perhaps less than certified piston singles. If you accept these admittedly shaky numbers at face value it appears that RVs had more than twice as many fatal accidents per 100,000 hours as certified piston singles, but less than half the number experienced by EAB aircraft overall. Interestingly, the total accident rate for RVs was actually a bit less than that of certified singles.
 
Sorry Alan, but without hard and fast data on RV hours, your table above is not statistics but pure speculation on your part.
 
islandmonkey said:
Sorry Alan, but without hard and fast data on RV hours, your table above is not statistics but pure speculation on your part.
Click to expand...

Then survey the RV community and get actual hours for 2009. I will provide mine soon.

Put me down for 139 hours in 2009. That must be the first year (or second) where I dropped from my previous average of 250 hours/year.
 
Last edited:
poll will tell some things, not all

the EAB world and the RV world may be different, but in many ways similar to the rest of the Ga fleet.
again, the stats just aren't there to show us which GA flights are business, personal, etc.
...but it may be misleading to assume that every RV pilot is a keener who live on an airpark and flies every day at lunch.....we just wish we were.

put me down for 14 'flight' hours last year, actual 'air' time, 9.

so the 'average' of 75 may not wash.
 
Last year I put 0 hours on my RV.

This year I'm already put 20+ hours on it. The plane just went into the paint shop and with the cost of fuel, I'll be lucky to hit 100 hours this year.
 
Hours

Alan Carroll said:
Since this topic has been getting a lot of attention I thought it would be interesting to see the actual numbers from which the FAA is drawing their conclusions. To get accidents per 100,000 hours requires combining two different data sets, the FAA Aircraft Activity Survey and the NTSB database. Both are readily available online. 2009 is the most recent year for which the survey data have been published online.

[URL="

The hours flown by RVs in this chart are my estimates, since this breakdown is not reported by the FAA. 6000 aircraft is approximately what the Van's Aircraft Hobbs meter indicated in Jan. 2009; the actual number of active RVs may have been different. Average hours flown by RVs is purely a guess. My sense is that RVs fly more than most homebuilts, but perhaps less than certified piston singles. If you accept these admittedly shaky numbers at face value it appears that RVs had more than twice as many fatal accidents per 100,000 hours as certified piston singles, but less than half the number experienced by EAB aircraft overall. Interestingly, the total accident rate for RVs was actually a bit less than that of certified singles.
Click to expand...

I would challenge the notion that RV's fly less than certified. In fact I see hangars at almost every airport with spam cans that have not flown in years. Airplanes tied down that have not moved in years. Most RV's I see are going someplace every weekend. I don't see any RV's sitting around gathering dust like I see spam cans.

My 2 cents
 
The only spam cans doing more hours are those in training schools and I reckon most RV's average around 50-70. So an average of 75 is probably about right as a guess.

Ours has done 200/yr each year. Our Jabiru before that averaged 170 and it was less useful.

Alan, just for the sake of humouring me, what does the number look like when you take out the "typical GA prangs" like VFR into IMC and look at the two elements of accidents which are genuine ABE failures and the RV Cowboy antics.

I think it will show that the sensible folk have a better record equal to the certified fleet, and the cowboys are bring us down...literally :(
 
islandmonkey said:
Sorry Alan, but without hard and fast data on RV hours, your table above is not statistics but pure speculation on your part.
Click to expand...

You're absolutely correct with respect to RV hours flown. As pointed out I simply guessed at this. However, it turns out the guess isn't entirely without substantiation. There was a poll on this forum in 2007 that garnered 176 responses. The results of are reasonably consistent with what I guessed, although perhaps I was a bit low. On the other hand it could be that those who respond to polls are a bit more enthusiastic about flying than average.

http://www.vansairforce.com/community/poll.php?do=showresults&pollid=56

Everything else on the table is not speculation but comes directly from the FAA and NTSB. One can argue about the quality of the survey data, as EAA has appropriately done. However, these numbers do allow for some interesting comparisons to be made. For example, in order for RVs to have the same fatal accident rate as certified piston singles the RVs would have to fly about 190 hours per year on average.

The "% of Fleet" statistic doesn't use hours at all, only numbers of aircraft and numbers of accidents. Its not likely that this is very much in error. Interestingly, this measure seems to be roughly proportionate to the fatal accidents per 100,000 hours number.

I do not advocate using this stuff as an absolute indicator of what's happening; its an approximation at best. However, "poor data" is not necessarily the same thing as "no data".
 
Are the accident numbers quoted at the start of the thread for the US only? If so, we shouldn't use Van's Hobbs meter to get the total number of RVs for this comparison, as a significant proportion are outside the US.
 
Kevin Horton said:
Are the accident numbers quoted at the start of the thread for the US only? If so, we shouldn't use Van's Hobbs meter to get the total number of RVs for this comparison, as a significant proportion are outside the US.
Click to expand...

Good point. A few accidents outside the U.S. do show up in the NTSB database, but not all of them I'd guess. I just downloaded all the U.S. registered aircraft with "RV" somewhere in the model designation, and cleaned up those that weren't actually RVs. The resultant count is 6712 (give or take), compared to 7266 on Van's Hobbs meter.

Going back to Jan 2009 the Hobbs meter showed 6042, so if this number is corrected based on the present ratio of U.S. registered to Hobbs meter the number in my table should be 5581 U.S. RVs.
 
Is deaths/accidents per flying hours a valid way to compare these airplanes?

My thoughts are that A-B airplanes are in a significantly different environment from the certified aircraft, especially if you include multiengine airplanes. Sort of like comparing accident rate in NASCAR and the national rate (though I have no idea how they acctaully compare).
 
Philosophy

Chris Hill said:
My thoughts are that A-B airplanes are in a significantly different environment from the certified aircraft, especially if you include multiengine airplanes. Sort of like comparing accident rate in NASCAR and the national rate (though I have no idea how they acctaully compare).
Click to expand...

Just thinking out loud.
If accident/death rates for A-B airplanes were the same as certified airplanes, what would that say about the long certification process to pass Part 23? If experimentals are just as safe, why would we need certification?
I agree there is always room for safety improvements for all classes of aircraft but we need to make realistic goals and comparisons in our statistics. So what is an acceptable difference in safety between A-B and certified for the fact that A-B "DOES NOT COMPLY WITH THE FEDERAL SAFETY REGULATIONS FOR STANDARD ARCRAFT" per my required passenger warning placard.
 
Last edited:
Alan ...

What can I say? Your work is ALWAYS the best and most carefully though out, unbiased and meaningful on whatever challenge you take on. What else would I expect after meeting you in the 2005 AirVenture Cup and speaking with you on several occasions. Thanks for this - it needed to be done.

Bob Axsom
 
RV10inOz said:
Alan, just for the sake of humouring me, what does the number look like when you take out the "typical GA prangs" like VFR into IMC and look at the two elements of accidents which are genuine ABE failures and the RV Cowboy antics.

I think it will show that the sensible folk have a better record equal to the certified fleet, and the cowboys are bring us down...literally :(
Click to expand...

I haven't tried to do this yet because it requires interpreting the cause of accidents and thus is a bit more subjective. You're of course right that many of the RV accidents are similar "typical GA prangs" (great phrase!). On the other hand some RV accidents also occur while doing things that other GA aircraft generally don't do, like aerobatics, formation flight, etc.
 
RV vs RV

I don't have the numbers with me now, but I think I once did a comparison of RV9 accidents vs accidents for all RV's. I think I remember that the accident rate for RV9's was lower.

I don't suppose this is because RV9's are safer airplanes. Perhaps there is something about a non-aerobatic airplane that appeals to a more conservative pilot, and more conservative pilots are less likely to crash and add themselves to the accident statistics.
 
Hmmm

TThurston said:
I don't suppose this is because RV9's are safer airplanes. Perhaps there is something about a non-aerobatic airplane that appeals to a more conservative pilot, and more conservative pilots are less likely to crash and add themselves to the accident statistics.
Click to expand...

These numbers are corroborated by this article http://rvbuildershotline.com/articles/accidentrate.html .

I think this illustrates the point as well as anything. The average guy flying a 9 is not looking for thrills. Not saying he is or isn't a better stick - but he appears to have less accidents.

That more conservative attitude reflects the choice of planes and how it is built and how it is operated.

It's not a matter of forcing everyone to build a 9 and fly like a grandpa. It is a matter of how do we get the less conservative pilot the skills and judgement that he needs to survive his more adventuresome first 100 - 200 hours.

That is the question that Van has identified as important and see's as "low hanging fruit". I think we should all be able to get behind that effort.
 
Last edited:
You must log in or register to reply here.