Using accident reports for test flight planning

When I was looking for a project, I did check out the NTSB Website for insight on accidents to see if there might be a design flaw, or just stupid pilot tricks.

As far as flight testing goes, I never bothered with the NTSB Website. Instead, I bought Vaughn Askue's book, "Flight Testing Homebuilt Aircraft." It gives a lot of detail on what to test for and how to correct problems as far as flight characteristics are concerned. It will take you from first taxi, through first flight up to envelope expansion and handling characteristics.

For the next step, I recommend "Understanding Performance Flight Testing: Kitplanes and Production Aircraft" by Hubert Smith. The price has really been jacked up on the new books, but the used prices seem reasonable.

Askue gets into a lot of detail about how an airplane reacts, he only glosses over performance. Smith glosses over the flight characteristics and gets into a lot of detail about performance. As a result, these two books complement each other.

Hi Jon,

Interesting article on your website/blog regarding your NTSB investigations. Seeing numbers like you have collected puts doubts into my mind about the flying qualities of the VP. But to answer that question would require a comparison of the VP to other homebuilts?

The Sport Aviation article from March 1972 "First and last flight" by George R. Gibson about his VP-1 accident also talks about the distinct flying qualities of the VP.

Other articles have also talked about how the speed of the VP only changes by attitude, not by throttle (this could have been from the book "Build and fly your own plane" by Robert Lowe?)

I will look forward to seeing your project and website evolve.

See you on the VP forum,

Steven in Winnipeg

Greetings Steven,

Most of the incidents that seemed to be related to the VP's flight characteristics were with higher time pilots having little or no time in type. It makes me think that the "I got this" attitude of a higher time pilot hopping in this dinky home-built is the main contributor to those accidents. For the most part, the rest seemed to be based firmly in the stupid pilot/builder tricks category.

Thanks for taking a look at the site!

Blue skies and tail winds.

~Jon

Greetings Andy,

Thanks for the book tips, I'll have to look into both of them.

My thought about using the NTSB data was to look for particular quirks with a given aircraft, using that to be forewarned about a pending hazard and then to examine that flight regimen more cautiously and throughly than you might otherwise.

Thanks again,

~Jon

The problem with that approach is that the sample size for all but the most-popular homebuilts is pretty low, and the NTSB reports usually don't go into fine enough detail.

For instance, my ten-year database of homebuilt accidents (1998-2007) includes only ten Volksplane accidents.  Two of them were first flights.  On one, the builder had installed a 1200 cc engine rather than the more-typical 1600 cc, and failed to abort the takeoff when the plane wouldn't climb (NYC04LA008).  The other was due to an incorrectly-adjusted propeller (DEN01LA020).

The detail part is a bit more subtle.  Say, for instance, the airplane has a very vicious stall and that causes a couple of first-flight accidents.   The NTSB reports are merely going to say, "Probable Cause:  Pilot's failure to maintain airspeed."  You don't really know if it's a training thing, or something wrong with the airplane.

Ideally, you might find that all the airplanes turned to a particular side as they stalled.  This might indicate a common rigging problem.  But, again, first-flight accidents are so rare as to minimize the number of cases you can examine.

I've attached my database's summary page for Volksplane accidents.  Six were VP-1s, four were VP-2s.  What catches my eye is the median hours in type...half of the Volksplane accidents happened to pilots with three hours or fewer in the airplane.   Note that it shows about 2/3rds of the VP accidents occuring on takeoff.  This is a bit deceptive; this only four of the ten accidents.  The percentage is of the number of the accidents where the NTSB Report included the phase of flight, and they did not on several of them.  Still, that's at least 40% of the total accidents, vs. ~25% for the overall fleet.

A lot of accidents are caused by just something stupid, which could have avoided if the pilot / builder had educated himself more. Asking questions and reading up on what you are planning to do is effective. As far as flight testing goes, I can recommend "Homebuilt aerodynamics and flight testing" (see http://www.caro-engineering.com). This book goes into details of why and how, and explains things in an easy to understand manner. If you understand what can go wrong, it is easy to avoid it.

 Greetings Ron,

The idea was to look for general general causees. I always take NTSB summary reports with a lot of grains of salt, and I agree completely that the report data is, in many cases, not close to "complete". 

What I was looking for was patterns, and yes you are right again as far as the sample goes. Volksplane does not have a decent sample. 

Unfortunately I couldn't view the PDF you included.

~Jon

Hi Ron,

Thanks for providing the additional insight on VP accidents. I  too wasn't able to open your attachment, hopefully  the website will resolve itself.

In your opinion, is  it valid to try to make a comparision of the "safeness" of one aircraft vs. another? Or are there so many other variables as to make such a comparision misleading/meaningless?

Regards,

Steven Smart

 Jonathan Wanzer wrote:

Well, poo.

 Here's a couple more shots at it:

http://www.wanttaja.com/vp.pdf 

 That's the same PDF stuck on my web page. 

Don't know why folks can't read it here...it opens fine for me.  However, I use an unusual page size to get it all in one piece, and that might be what is causing folks problems.  If the version on the web page doesn't open, that would probably be the explanation.

If so, I've also loaded it as an Excel spreadsheet:

http://www.wanttaja.com/vp.xls 

If you don't have Microsoft Excel, I highly recommend the OpenOffice suite:

http://www.openoffice.org/ 

OpenOffice is a fully-compatible package that is completely free.

In addition to the excellent ideas put foreward,I also suggest printing the FAA's Advisory Circular AC 90-89A. It was written for folks like us and it looks to me that it takes a lot of the mystery out of the process.

http://www.faa.gov/library/manuals/aircraft/media/ac90-89a.pdf

Bob

Greetings Ron,

Those links seem to be fine. 

Thanks,

~Jon

Where have the FAA accident reports gone? Cannot find em in the new format.

Thanks, Glen

Rather than trolling the NTSB site, I'll troll the pilots. 

Fortunately for me the 7/8th scale Nieuport 11 has a very open and vocal (if small) community that isn't afraid of pointing out the quirks of the type to expect.

It might sound weird, but I'd rather talk to the fellow that found a nasty habit of a plane and counteracted it without a wreck than the guy that couldn't figure out how to handle it and had to talk to the nice men with clipboards and cameras.

For example, there are very few accident reports for the Nieuport 11, with one being fatal (and on the first flight on take off).  There are loads and loads of incidents that don't show up, though, mostly due to the elevator having a lot of authority and the rudder not a whole lot under 25 MPH.  Bring the tail up too soon on takeoff and it's in auto turn with little recourse for the pilot other than to either hope to get the speed for it to bite before striking something and up in the air or chop throttle and get the tail down (a risky proposition).

The accidents that do show up beyond the one fatality (the pilot in that case pitched up steeply on takeoff and then went nose down into the pavement) are remarkable in that even minor injuries are rarely reported.  If the big fan stops, put it into a landing attitude and the tube and gusset construction will take the pain for the pilot, even if it flips.

Greetings Frank,

The Nieuport 11/17/24s are on my short list of aircraft I would like to build. I chose the VP mainly for cost considerations. My interests in A/C lean mostly to the WWI period. I would like to get plans for the Nieuports but most of the ones I have seen are for 7/8. Is there a reason the 7/8 are prevalent?

Also, I would like to start participating with the Nieuport community. What are the best resources?

Thank you for responding to the post, and I look forward to hearing from you.

~Jon