> >From my flying experience, I don't believe you are likely to
inadvertantly land
> a Europa with the flaps (and gear) up, the sight picture is different than
with
> them down.
Unfortunately it has been done, several times. I have personally witnessed
two incidents, and have heard of several others. The fist was after a bulked
landing and go around at a busy gliding site with lots of distractions. The
subsequent circuit was flown slow waiting for the runway to clear, so there
was no excess speed to bleed off. Gear extension was forgotten due to the
pilot being preoccupied by what was happening on the ground. The landing
was up hill, this together with needing more power than usual due to being a
bit low on final meant the picture looked normal and a perfect wheel up
landing was made.
The second incident followed a normal circuit and approach, but again to an
uphill landing with the wheel retracted. Again the picture on final looked
normal due to the speed being bled off early in the circuit, and an up hill
runway. I also know of at least one wheel up landing following a sideslip
approach. So it is possible to be fooled by the picture on final, under
certain circumstances.
Not wishing to join the list of 'Those that have', I decided to try to
design a foolproof gear up warning for the Europa. A switch working on the
throttle leaver in conjunction with one on the landing gear will work most
of the time, but there will always be the occasions when power is needed all
the way down the final approach and the throttle is not closed until the
last moment, to late for a warning unless your reactions are knife edge.
Airspeed and proximity to the ground are crucial factors on final, and a
system controlled by one or the other is the only way to get a reliable
warning. Using proximity involves expensive sophisticated equipment, so I
looked at airspeed. I am currently testing a very simple idea using a
pressure switch calibrated to work at 65-70 knots. in series with a micro
switch activated by the gear latch and in turn connected to a sounder.
Up to now it has performed 100% and as an added bonus it also acts as a 'low
speed warning' when flying flaps up, for that odd occasion when you might
just let your airspeed drop due to some distraction or problem.
Francis Donaldson at the PFA has shown an interest and mentioned it in his
recent letter regarding gear up and retractions on landing. There are two
many incidents, and insurance premiums will only keep going up if they are
not addressed.
When fully tested and approved by the PFA, I intend to make it available as
a club mod. thereby removing the requirement for individual approval for UK
builders. If there is enough interest I will offer it as a complete kit,
including all the necessary components pre-wired ready for simple
installation into a new build or as a retrofit. Anticipated price about 60 -
70 GBP
Jim Naylor
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