PPRuNe Forums - View Single Post - AS332L2 Ditching off Shetland: 23rd August 2013
Old 19th Oct 2013, 16:47
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HeliComparator
 
Join Date: Aug 2004
Location: Aberdeen
Age: 67
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Hi john

Yes, I noticed a bit of a "disconnect" between the radalt and the derived vertical speed at the end. You have to remember that the L2 was designed in the late 80s and certified in the early 90s and as such, has limited "extra" parameters on the FDR and mostly at the minimum sample rates. I think the lat and long accelerations are only at 4Hz and might even be 2 Hz, therefore well below the Nyquist frequency for 1-per-rev vibration. Also I'm pretty sure that only the pilot's control positions are in the data frame, not the AFCS series actuator outputs. The low sample rate might also explain the radalt / vertical speed disconnect - maybe they hybridised their VS parameter with some integrated normal acceleration data - that parameter being the one with the highest sample rate.

Last edited by HeliComparator; 19th Oct 2013 at 16:49.
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