Author: comancheguytoo
Subject: CDI Needle Deflection Deadband Problem
Posted: 17 Jul 2015 at 2:34am
Has anyone noticed deadband or lag when turning the OBS on a CDI or HSI? Evidently PFDs have not seen this issue.
Subject: CDI Needle Deflection Deadband Problem
Posted: 17 Jul 2015 at 2:34am
Has anyone noticed deadband or lag when turning the OBS on a CDI or HSI? Evidently PFDs have not seen this issue.
I have a kcs-55a. Tuning a radial or a bearing in GPS/OBS mode, the needle takes 2 degree (one dot at a time) jumps. Effectively creating a 2-4 degree deadband on the indicator where the needle back and forths when you stop dialing. Would make finding cross radial bearings on a check ride kind of tough.:P
Sliding my 530 back in gives the predictable smooth movement, so for the moment I'm ruling out my HSI. The behavior in both VLOC and GPS mode rules out a VHF issue.
OBS calibration in config mode reads smoothly in 1/10th degree increments. Plus, the 'skips' are displayed graphically on the 540. So the HSI must be outputting what the 540 likes.
Flying from CA to KY yesterday I tested a number of VORs, all reception was good, more or less equal to my SL30. Also, CDI movement would continue smoothly through full deflection once the needle got out of this initial 'zone of confusion'.
Didn't have time to practice a VOR approach, was trying to beat sunset, but here are videos of the skips:
https://drive.google.com/folderview?id=0B-y2gabArdQ-QTVZY1diYzFBSVE&usp=sharing