REFLECTOR: Flying Magazine - 2009 Velocity accident

[Brett Ferrell]

Here is the note I intend to send to Mr. Garrison and the editor of Flying.
 The articles reference are on my website, and I will include them when I
contact them directly ([LINK: http://mailto:editorial@flyingmag.com]
editorial at flyingmag.com).
--
I'm writing to correct several inaccuracies in the Aftermath article in the
most recent (October 2012) edition of Flying magazine.  First, the title of
Mr. Garrison's article associates this accident with Deep Stall, which has
not been established by the [LINK:
http://dms.ntsb.gov/aviation/AccidentReports/ocmh5t451xyjp1iinsmxnret1/O10102012120000.pdf]
NTSB,  [LINK: http://velocityaircraft.com/] Velocity Inc., or any other
competent body.

At best deep stall would secondary to the actual cause, in-flight
separation of one blade of the three-bladed Vesta constant speed propeller.
 It's interesting that Velocity was mentioned in the article, but not
Vesta, but that is a side issue.  Second, the discussion of "three" deep
stall Velocity accidents is disingenuous at best.  One of these was by
factory test Pilot Carl Pascarell (former test pilot for Swearingen,
Continental Airlines Captain, USN jet pilot, and aerobatic show pilot, Note
1) while investigating how this situation (Note 2) might be created.  He
elected to stay with the airplane (though he was wearing a parachute),
which was repaired and flying again within the three weeks (Note 3).  In
the case of N141NH, the accident was caused by flight into the vortex of a
Boeing 727 (Note 4).  The third was caused by modifications by the builder
to decrease canard effectiveness (Note 5) None of these can be fairly
construed to reflect on aircraft's design as they were placed into
situations that no airplane should (flight outside of the W&B envelope,
into the wake vortex of a jumbo jet, and intentional reduction in canard
incidence angle in relation to the main wing).

Further, he states that the lack of injuries was "likely ... because their
airplanes fell into  water, and the rounded undersides of the fuselages
provided some shock absorption."  This is completely unsupported by fact.
To the contrary, in the aforementioned Sport Aviation article (Note 2), Mr.
Pascarell reported "the descent rate appeared to be very low, and there was
no discernible forward motion", which is why he elected not to bail out.
He instead rode the aircraft to the water and escaped uninjured, reporting
in Kitplanes (Note 6) that he was descending at less than 1,200 fpm.  This
calls into question, also, Mr. Garrison's assertion that the Houston crash
aircraft's on-board Garmin's reported "7,000 fpm" descent which, if true,
would then argue against this being an instance of Deep Stall at all.  Then
Mr. Garrison implies with his "At the time, it was widely believed that the
stable stall produced a very low rate of descent. This implied an
unexpectedly high, in fact unprecedented, drag coefficient, and novel,
semimagical vortices were posited to explain the new phenomenon; but ground
tests, conducted by Rutan with an airplane set up vertically on the back of
a truck, failed to produce them." that this low descent rate has never been
proved.  But an experienced test pilot with a functioning vertical speed
indicator and packed parachute is enough for me, particularly since Mr.
Garrison does not provide any reference to the testing that supposedly
demystified this, apparently irrational yet experiential, belief of Mr.
Pascarell's.

Next Garrison asserts that Burt Rutan did aerodynamic testing "with an
airplane setup vertically on the back of a truck".  Maybe, but the only
reference to this I can find is from Kitplanes (Note 7), where it states
Rutan did this with "a small scale model of the test aircraft" and a car,
but then goes on to show Danny Maher's full scale truck-based test bed,
designed in cooperation with Jim Paxton, Chief of Flight Operations at NASA
Langley (Note 3).  It does not mention any flat-plate testing that Danny
may have done with this test bed, but it would've been ideally suited to
it.

Finally, Mr. Garrison asserts that the vibration of propeller blade loss
might have been confused with flutter.  However, since this Velocity was
outside it's mandated 40 hour test period, and Mr. Garrison himself
indicates the accident pilot had flown it for "250 hours with a two-blade
fixed-pitch propeller", the accident pilot could hardly be expected to
suspect flutter at such a low airspeed.  The Velocity's Vne is 200 kias,
and is as such extremely docile and stable at a mere 128 kts.  It seems
that Mr. Garrison is not sufficiently familiar with the Velocity, and did
not chose to check his facts with the factory before publishing this highly
speculative and very flawed article.


Notes:
1) Carl Pascarell [LINK: http://www.airbum.com/Pitts/PittsParty.html]
http://www.airbum.com/Pitts/PittsParty.html, [LINK:
http://www.linkedin.com/pub/carl-pascarell/30/425/3b9]
http://www.linkedin.com/pub/carl-pascarell/30/425/3b9
2) Sport Aviation, July 1991, Velocity... Solving a Deep Stall Riddle, page
54
3) N81VA, probable cause MIA89LA117, [LINK:
http://dms.ntsb.gov/aviation/AccidentReports/yfe1djv2cjd3j3qahv1awf3b1/L10102012120000.pdf]
http://dms.ntsb.gov/aviation/AccidentReports/yfe1djv2cjd3j3qahv1awf3b1/L10102012120000.pdf
4) N141NH, probable cause MIA93LA011, [LINK:
http://dms.ntsb.gov/aviation/AccidentReports/cddyc255bkcba0mvfd2jqwyo1/T10102012120000.pdf]
http://dms.ntsb.gov/aviation/AccidentReports/cddyc255bkcba0mvfd2jqwyo1/T10102012120000.pdf
5) Sport Aviation November 1997, page 112, Canadian Council News, Deep
Stall
6) Kitplanes, November 1991, Testing on the Ground, page 75
7) Kitplanes, November 1991, Testing on the Ground,page 72
8) Sport Aviation, September 1991, Deep Stall Cont..., page 55
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