HSI Question
Posted: Sun Dec 09, 2012 1:54 am
I have a Century NSD360A HSI in the 170. It runs off the left side Venturi, has a regulator set to 5"/hg and is fed NAV info from the Garmin SL30. Over the last few weeks it's been behaving strangely in 2 ways:
1) Flying along straight and lever, pick a heading, say 180. The heading card reads 180 and the course needle is also set to 180. You execute a 180 degree turn and the heading card and the windshield strap mounted compass both match up at 360. The course needle will be anywhere from 10 - 20 degrees off. It won't stay at whatever heading you initially set it to. This happens consistently.
2) Flying along straight and level and the next thing you know is the heading card start’s spinning at an alarming rate. Vacuum gage reads about 6 to 6 1/2"hg so I know it’s getting the 5 of the regulator setting. It stops spinning in two ways - a) on its own or b) you push the heading selector knob in and re-set the card to the desired course. This doesn’t occur under identical conditions - sometimes it's during ground taxi and sometimes it's cruise flight and is also very intermittent.
Anyone ever experience this before?
Thanks,
Kyle T.
1) Flying along straight and lever, pick a heading, say 180. The heading card reads 180 and the course needle is also set to 180. You execute a 180 degree turn and the heading card and the windshield strap mounted compass both match up at 360. The course needle will be anywhere from 10 - 20 degrees off. It won't stay at whatever heading you initially set it to. This happens consistently.
2) Flying along straight and level and the next thing you know is the heading card start’s spinning at an alarming rate. Vacuum gage reads about 6 to 6 1/2"hg so I know it’s getting the 5 of the regulator setting. It stops spinning in two ways - a) on its own or b) you push the heading selector knob in and re-set the card to the desired course. This doesn’t occur under identical conditions - sometimes it's during ground taxi and sometimes it's cruise flight and is also very intermittent.
Anyone ever experience this before?
Thanks,
Kyle T.