Why homebuilts crash
An expert looks at the data behind experimental airplane crashes, determines the cause, and runs a comparision.

As this week's edition of the RV Builder's Hotline sadly shows, this was a tragic week for RVers. Coincidentally, a few weeks ago I saw that Ron Wanttaja was doing a presentation at EAA Chapter 26 in Seattle on the causes of accidents -- homebuilts and RVs -- and asked him to provide any data he could. He was kind enough to forward some details which make for excellent reading.

Here's his e-mail to me this week:

Hi, Bob, sorry to take so long to get back to you. The following data is based on my analysis of homebuilt aircraft accidents from 1998 through 2004, inclusive.

Attached is one of the key charts, showing the relative rates of accident causes for RVs vs. the overall homebuilt fleet. The causes of each accident come from my own assessment, not the NTSB "Probable Cause." Will be the same in most cases, but there are some instances where we differ. "SALA", by the way, stands for "Stupidity At Low Altitude," which incorporates buzzing as well as stuff like sudden pull-ups during low passes or flying up box canyons. "General Pilot Error" covers just those cases where the pilot loses control or incorrectly controls the aircraft...other "Pilot Error" categories (such as SALA, fuel exhaustion, etc.) are listed separately.

The overall annual rate of RV accidents is right about the same as those for the overall homebuilt fleet... about 0.95% of all RVs crash each year (a tad less than one in one hundred). However, this is based on the FAA registration database, and many of the homebuilts listed in the database are no longer flying. But since they're listed, they get included in the total fleet size when computing fleet accident rates. I suspect the number of inactive RVs is quite a bit less than some of the types that go into the statistics, and thus the annual rate is probably lower than the overall one.

One very bit of good news for RV'ers: During the period I looked at accidents, between 25% and 40% of all new homebuilts each year were RVs. Yet, only 4% of first-flight accidents involved RVs! Good testimony to the builder support network and those involved in checking out new RV pilots.

Ron Wanttaja