Narrative:

We were departing ord in the afternoon; I was the pilot flying from the right seat in the caravan. We were given initial vectors for the climb to join the ord 5 departure. Once on the runway we verified the captain's side HSI; my dg; and the mag compass were all matching up; and were displaying runway heading. Everything looked fine at this point. In the climb; we were told to maintain a heading of 150. I turned to that heading as displayed on both my and the captain's dg. Departure advised us we were tracking closer to 210; and assigned us a heading of 240. Once rolling out on the heading of 240; we were again advised we were off by about 40 degrees. We checked against the mag compass and found that the captain's side dg had 'stuck' and was not slaved to the compass anymore. Since I am to set my dg to the captain's side dg; we ended up being off on heading by a margin of 40-60 degrees for a good 10 minutes. No traffic conflicts were given to us; nor did we get any conflicts on TCAS. The controller was helpful and did not seem to have an issue with what happened. We then reset both my dg and the captain's HSI to the compass manually; and it appeared to function normally from there all the way to destination. Due to not catching the stuck HSI on the captain's side we were off on heading by 40-60 degrees during a departure out of chicago's class B; and did so unintentionally. I have recommended that all crewmembers now verify the compass heading with the HSI and dg upon the initial rollout from the first vector/segment on departures.

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Original NASA ASRS Text

Title: C208 First Officer reports HSI/DG's 'sticking' during departure from ORD resulting in in a track deviation of 40 degrees initially.

Narrative: We were departing ORD in the afternoon; I was the pilot flying from the right seat in the Caravan. We were given initial vectors for the climb to join the ORD 5 departure. Once on the runway we verified the Captain's side HSI; my DG; and the Mag compass were all matching up; and were displaying runway heading. Everything looked fine at this point. In the climb; we were told to maintain a heading of 150. I turned to that heading as displayed on both my and the Captain's DG. Departure advised us we were tracking closer to 210; and assigned us a heading of 240. Once rolling out on the heading of 240; we were again advised we were off by about 40 degrees. We checked against the Mag compass and found that the Captain's side DG had 'stuck' and was not slaved to the compass anymore. Since I am to set my DG to the Captain's side DG; we ended up being off on heading by a margin of 40-60 degrees for a good 10 minutes. No traffic conflicts were given to us; nor did we get any conflicts on TCAS. The Controller was helpful and did not seem to have an issue with what happened. We then reset both my DG and the Captain's HSI to the compass manually; and it appeared to function normally from there all the way to destination. Due to not catching the stuck HSI on the Captain's side we were off on heading by 40-60 degrees during a departure out of Chicago's Class B; and did so unintentionally. I have recommended that all crewmembers now verify the compass heading with the HSI and DG upon the initial rollout from the first vector/segment on departures.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.