Numbers don't add up in 2007 Nall report?

[Jim Logajan]

The 2007 Nall Report is out:
http://download.aopa.org/epilot/2007/07nall.pdf

But I'm having a hard time believing the numbers presented in Figure 35 on
page 24 (which is explained in the first paragraph on page 25). I'm pretty
confident that there are more than 2,972 registered experimental aircraft
in 2005. (Unless they mean the total registered in just that year and not
the total of all active registrations. But I'm not sure the former number
is meaningful or useful in the context of their statistics.)

I'm also unable to figure out how the 9,037 and 206,628 numbers in the
"Totals" row were computed. Even if I total both columns I can't get
anywhere near the 206k number. And no obvious subset of the "Air Taxi"
column seems to yield 9,037. In that column the total seems too small.
(Doesn't seem to be due to a missing leading digit, either.)

If I'm not misreading their presentation and they indeed got those numbers
wrong, what other not-so-easily verified errors are there that may underlie
their other statistics? Kind of a disappointment, really.

(And while I'm on the subject of complaints - it seems more years than not
that some aspect of their PDF makes some or all of their document
unreadable with whatever version of Acrobat reader I have installed. And I
have been trying to keep up to date with the latest version.)

[Ron Wanttaja]

On Sat, 22 Dec 2007 00:06:46 -0000, Jim Logajan > wrote:

> The 2007 Nall Report is out:
> http://download.aopa.org/epilot/2007/07nall.pdf
>
> But I'm having a hard time believing the numbers presented in Figure 35 on
> page 24 (which is explained in the first paragraph on page 25). I'm pretty
> confident that there are more than 2,972 registered experimental aircraft
> in 2005. (Unless they mean the total registered in just that year and not
> the total of all active registrations. But I'm not sure the former number
> is meaningful or useful in the context of their statistics.)


I download the FAA Registration database every January. Here's the summary of
Experimental/Amateur-Built aircraft by date of download:

1/9/2004 26593
1/9/2005 27614
1/7/2006 28539
1/8/2007 29427

I suspect a digit got dropped on the Nall Report. The net increase in
homebuilts is about 1,000 per year, but the actual increase is closer to 1,300.

Ron Wanttaja

[Brad[_1_]]

On Dec 21, 7:06*pm, Jim Logajan > wrote:
> The 2007 Nall Report is out:http://download.aopa.org/epilot/2007/07nall.pdf
>
> But I'm having a hard time believing the numbers presented in Figure 35 on
> page 24 (which is explained in the first paragraph on page 25). I'm pretty
> confident that there are more than 2,972 registered experimental aircraft
> in 2005.

For that matter, why are there 752 experimentals (25% of all
experimentals) used for Air Taxi?