Wikipedia:
Most FDRs record approximately 17–25 hours worth of data in a continuous loop.
They are designed to emit an underwater locator beacon for up to 30 days and can operate immersed to a depth of up to 6,000 meters (20,000 ft).
An underwater locator beacon (ULB) or underwater acoustic beacon is a device fitted to aviation flight recorders such as the cockpit voice recorder (CVR) and flight data recorder (FDR).
A 37.5 kHz (160.5 dB re 1 μPa) pinger can be detectable 1–2 kilometres (0.62–1.24 mi) from the surface in normal conditions and 4–5 kilometres (2.5–3.1 mi) in good conditions. A 37.5 kHz (180 dB re 1 μPa) transponder pinger can be detected 4–5 kilometres (2.5–3.1 mi) in normal conditions and 6–7 kilometres (3.7–4.3 mi) in good conditions. Transponder 10 kHz (180 dB re 1 μPa) range is 7–9 kilometres (4.3–5.6 mi) in normal conditions and 17–22 kilometres (11–14 mi) in good conditions.
Some posts on this thread contradict the above.
So which part(s), if any, of the above quotes are incorrect to the extent that on-or-above sea surface searches with appropriate equipment won't locate the FDR when within the ranges stated?