What should be the indication when flying a 090 heading and rolling out on 360 at approximately 30 degrees latitude?

When flying a heading of 090 degrees and rolling out on a heading of 360 degrees at approximately 30 degrees latitude, the indication should reflect the magnetic variation of the region. At this latitude, due to the Earth's spherical shape and the influence of magnetic declination, the actual magnetic heading may not align perfectly with the true heading.

As the aircraft rolls out on a 360-degree heading, the compass will initially indicate a value that is influenced by the magnetic declination specific to that location. In many locations, when transitioning from a 090 to a 360 heading, the compass may lag or exhibit a less direct reading due to the gyroscopic precession and magnetic dip at that latitude.

Indicating 030 degrees would suggest that there is a significant back-swing or induced error experienced in the magnetic compass during the turn, which could be common when completing a turn from east to north. This scenario underlines the importance of understanding not only the heading system but also the magnetic influences that could alter the readings. Thus, the compass indication can often differ from the true navigation heading, leading to a reasonable expectation that the corrected heading would show 030 in this particular scenario.