older FCOM arrangement DSC-34-60-20-00006420.0005001 / 16 MAR 15 [MSN 271x to 471x]
The aircraft radio height is between 0 ft and 2 300 ft, and
(no mention of XPDR)
DSC-34-SURV-30-20-00020942.0004001 / 17 MAR 17 [oldest MSN 247x, the rest up to 691x]
the aircraft radio height is below 2 300 ft, and
(no mention of the XPDR)
DSC-34-SURV-30-20-00020942.0003001 / 17 MAR 17
WXR/PWS sw is in position 1 or 2 and the aircraft radio-height is below 1 800 ft, and
(no mention of the XPDR)
DSC-34-SURV-30-20-00020942.0001001 / 17 MAR 17 [newest MSN 319x, the rest down to 073x]
‐ The aircraft is below 2 300 ft AGL, and
‐ The ATC is switched to the ON, or AUTO
Confusing enough to me.
seem to remember that on the previous type PWS was only available on aircraft that came with Egpws from the factory, not the retrofitted ones around the time of the mandate. But could be imagining things.