REFLECTOR: 'Standardized' High Precautionary Approaches

[Bob Jackson]

In the Navy we used to fly High Precautionary Approaches (HPAs) for
emergency engine out landing practice.  We had published procedures -- for
example, starting over the intended landing point at 7000 feet altitude and
circling, in one 20-30 degrees angle of bank turn (180 KIAS) with the gear
down (no flaps), around for the landing (at approx. 130 KIAS).  This for a
jet with about a 11:1 (clean) glide ratio.

Now, we're getting close enough to completing our Velocity to be thinking
about HPA procedures for our plane during initial flight testing.  We
definitely don't plan on shutting down our engine, but since we have done
some major custom modifications to it, we are interested in the accumulated
experience of the flying Velocity community with (simulated) engine out
precautionary approaches.

I've been reading the Reflector now for over five years, and I don't
remember ever seeing any discussion, or even a mention of procedures for
Velocity precautionary approaches.  There is also not to my knowledge a
precautionary approach procedure that is published or 'standardized' by the
factory, although I know that basic engine out procedure practice is a
normal part of all Velocity transition training conducted by Nathan Rigaud.

Basic engine out procedure training, like the factory's, is typical of
general aviation.  But it's a little surprising to me that the experimental
aircraft community has not apparently created a more standardized procedure,
more similar to the old military HPAs, including recommended entry
altitudes, pattern configuration, speeds, descent rates, check-point
altitudes, etc..  Before GPS and moving map navigation, it was much harder
to estimate range to an intended emergency landing point, and this I believe
was the motivation for the creation of a circling high precautionary
approach by the military -- it gave you altitudes for an overhead or abeam
entry that could be used without the need for any estimate of range
(assuming you could get back overhead a strip).

Even today, given the likelihood that most of our own early flight testing
will be done almost directly overhead Sebastian field, knowing some 'pattern
numbers' for doing a circling HPA landing approach seems to make a lot of
sense for us.  One good way to develop and practice HPA procedures, and even
(I hope) to draw some initial pattern 'numbers' is with Microsoft Flight
Simulator 2004.  For less than $30, plus a joystick and a freely downloaded
plug-in software model for the Velocity XLRG, it's hard to hurt anything but
your pride in the simulator!  Using this simulator, I've created the
following HPA for the Velocity that seems to work well and to be easy to fly
with confidence during a 'dead stick' landing:

1.  Entry.  Start directly overhead the landing point, and on landing
heading, 1800 ft AGL, 100 KIAS glide  (100 sec to landing).
2.  Pattern.  One 20 deg. angle of bank circle -- 100 KIAS glide, gear down,
900 ft AGL abeam the landing point  (50 sec).
3.  Base Leg.  450 ft AGL, 100 KIAS, gear down with 90 degrees more to turn
onto final  (25 sec).
4.  Landing.  Slow below 100 KIAS only when you're sure the field is made.

Of course there are many variables that can affect an actual HPA,
particularly the wind.  But the pilot also has some variables he can
control, like angle of bank and when he puts down the gear.  On a short
field, it can be just as dangerous to land fast as it is to land slow (if
short!).

Based on the performance of the Velocity in FS2004 -- at 100 KIAS, 20
degrees angle of bank, and power at idle, the Velocity loses about 1800 feet
per 360 degree turn with a 1050 fpm descent rate, and the aircraft is about
5400 feet from the runway at the 180 'abeam' point.  In FS2004, the Velocity
has a gear up, 0 deg. angle of bank, 100 KIAS glide ratio of about 11:1,
however I've heard that in the real world it's closer to 12.5:1, even with
the gear down!

My questions for the guys flying the Velocity in 'real world' are:
a)  Do you have a HPA pattern and pattern 'numbers' that you trust?
b)  Have you flown the Velocity in FS2004 and do you trust it?
c)  Do you know an RPM and MAP that simulates engine out performance (zero
thrust, feathered drag)?  Has anyone used a 'feeler' gauge on their prop
flange to detect the zero thrust condition?
d)  Can someone with a GPS and the ability to log aircraft performance data
(like with the Blue Mtn EFIS) do some simulated power off, 80/100 KIAS, gear
up/down, 0/20 deg. angle of bank, glides to establish some real world glide
ratio data (selfishly, I would prefer data for the XLRG, but any data will
help, especially others in the community).

Sorry for the long post.
Bob Jackson
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.tvbf.org/mailman/private/reflector/attachments/20050124/588010f5/attachment.html