The photos taken in 2002 of the crashed aircraft are shocking and hopefully not
an indicator of the condition she was in at the time of the accident. But l
have to say that if the level of neglect extended to the systems, especially the
fuel system, the cause of the incident may easily have been a blocked filter.
According to a close friend of David, whom l spoke to yesterday at the Rally,
the accident occurred at full power in the climb out after refuelling. If
so the classic case of power starvation due to a blocked filer is a possible
cause. I note that the photos show the inline filter used is the standard glass
tube variety. Blockage of this type of inline filter has caused many incidents
and at least one written off Europa.
Analysing this filter shows it uses a 22 micron sized mesh. This is way smaller
than the 100 micron (largest) stipulated by Rotax. I had a stoppage due to
a blocked primary filter (same type) a few years ago, this led to a hasty decent
into Elstree using the reserve feed (thanks for the fire cover guys). The
filter was partially blocked with translucent material. It ran on the ground
but would not feed fuel to the goverened 5000 rpm of my AP332 controller.
Having thereafter spent a year in a constant state of fuel feed anxiety l
changed
them for Andair filters which have a 60 micron filter size. To date these
have proven extremely reliable (100%).
In 2012 l contacted Andy at Andair to ask if a version for 1/4in bore fuel lines
could be made. He said it was quite easy, just a CNC program change, the
filters
would then have a push-on nipple type end and not require screw fit unions
(as in my installation). Some discussion occurred with Andy Draper about the
mod.
Yesterday l checked with Andair, he had not got around to adapting the CNC code
and hence nothing had occurred at LAA Engineering.
If it turns out that the cause of the stoppage on GBXS was filter related (this
is speculative but informed on my part) we should support some action which will
lead to changes in the use of these standard glass tube filters. A possibility
for Europas could be a new filter, perhaps the Andair version.
I shall write to the LAA with my concerns over the continued use of the glass
tube,
22. Micron filters. If any Europa flyer, or other aircraft operator with
the same filter type, can supply information regarding the use of these filters
it may assist in deciding which way to go. Information such as frequency of
inspection, frequency of cleaning, stoppage or partial blockage info, leaks,
other issues will br gratefully received and treated in confidence. Likewise
any info showing satisfactory in service history is also welcome. Please post
info or email direct to me. John(dot)wighton@ultraflight.net
John Wighton
Chief of Stress
Pilatus Aircraft
--------
John Wighton
Europa XS trigear G-IPOD
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=407837#407837
|