View Full Version : someone know when is the 737NG "sink rate" warning be triggered?

7th Sep 2010, 18:30
today one of my friend had a SIM training(737-800), he had a "sink rate" aural warning when in low altitude(200ft AGL or less) and the rate was 850 ft/min.:confused::confused:(which i never experienced)
and i remember that there is a digram including a envelope when the sink rate warning would be triggered according to the altitude and the rate of decend. but i cann`t find it now~
someone tell me where to find this digram?

7th Sep 2010, 20:09
citizensun, see Operation - EGPWS - Honeywell Aerospace (http://www51.honeywell.com/aero/Products-Services/Avionics-Electronics/Egpws-Home3/operation.html?c=21) and download the appropriate pilots guide.
I donít know the exact part number applicable to your aircraft; I suspect that it will be the ĎMk V and Mk VIIí version.
Perhaps a 737 expert will provide information on the exact model.

My understanding is that mode 1 works at all altitudes; and donít forget that the alert depends on Vertical Rate against Rad Alt.
Also donít forget mode 3 after take off.

7th Sep 2010, 21:43
Rule of thumb at higher heights is that the rate of descent (ROD) must equal or exceed the height. i.e. at 2000' Rad Alt, the ROD triggers at 2000 fpm. (From Memory)