When I checked the Adventure Light website, it stated a 5+ mile visibility.
Quite right - the
current main description says "it can be seen for over five miles" and the
current spec page I linked to in my post says "Over 3 miles (5 km) over land and over 6 miles air". Since the spec page seemed more detailed, I cited the low end number and provided the hyperlink.
In our tests, we were able to see the VIP survivor at a little over 6 miles from an aircraft.
That's good to know - you definitely have me thinking about upgrading from my current strobe. Was that with unaided vision? What altitude? How did that compare to your results with the other units?
It seems that USCG/SOLAS approved life jacket strobes are expected to be visible for at least ~2 nautical miles from the air: Table G-17 of the National SAR Supplement [1] and Table H-24 of the USCG addendum [2] both call out a 4.4 NM estimated visual sweep width when searching by helicopter for a 50,000 peak candlepower life jacket white strobe if time on task is < 1 hr, and 3.9 NM if time on task is > 1 hour. If I have it right, the visual sweep width is the track-track spacing of your search grid, which would imply the USCG expects to see such a strobe at a range of at least half the sweep width, or 3.9 miles/2 = ~2 miles.
The USCG tables also address much dimmer strobes - listing a 0.5 NM estimated sweep width for a 2,000 candlepower peak strobe at night - a pretty damning assessment, considering that they cite a 1.0 NM estimated sweep width for a "Cyalume personnel marker light" (glowstick). ( The cited references and lots more are available at this link:
USCG SAR Manuals and Documents Page ).
[1] United States National Search and Rescue Supplement
to the International Aeronautical and Maritime Search and Rescue Manual, May 2000. Available on the USCG web site at:
http://www.uscg.mil/hq/cg5/cg534/manuals/Natl_SAR_Supp.pdf[2] COMDTINST M16130.2E: U. S. COAST GUARD ADDENDUM TO THE UNITED STATES NATIONAL SEARCH AND RESCUE SUPPLEMENT (NSS) To The International Aeronautical and Maritime Search and Rescue Manual (IAMSAR) Sept. 2009. Available on the USCG web site at:
http://www.uscg.mil/directives/cim/16000-16999/CIM_16130_2E.pdf
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