"Jay Honeck" wrote:
In the current issue of "Flying" magazine Richard Collins states that
flying on instruments is approximately twice as dangerous as flying
VFR. Twice as many deaths occur while flying under instrument flight
rules as they do in visual flight rules, per hour flown.

This statistic seems stunningly high.

Well... page 20 of the 2006 Nall Report provides stats on VMC vs. IMC (not
VFR vs. IFR, though). On one hand the report at
http://www.aopa.org/asf/publications/06nall.pdf states:

"Flights conducted at night and/or in adverse weather are
more challenging than daytime and/or VMC operations.
In spite of this, accidents are more likely to occur during
the day than at night (7.9 vs. 7.1 accidents per 100,000
hours), and are also more likely to occur in VMC than
IMC (8.0 vs. 5.0 accidents per 100,000 hours)."

But on the other hand, _fatal_ accidents are more likely to occur in IMC
than VMC (3.3 vs. 1.4 _fatal_ accidents per 100,000 hours). (From Fig. 29
on page 20 of that report.)

If one assumes IMC/VMC ratio is comparable to IFR/VFR then Collins'
assertion is probably correct. But since an unknown number will be flying
IFR in VMC (and almost none should be flying VFR in IMC!) then strictly
speaking IFR should show less than 3.3 fatals per 100,000 hours.