> When the pilot in an airliner refers to his Directional Gyro,
> he is really refering to a more modern and complex device
> called an HSI (horizontal situation indicator).

Maybe, maybe not.  Depends on the equipment fit.  Probably
true for large scheduled carriers flying large transports.
Now smaller feeder flying turboprops...

> This instrument shows you gyro heading alright, but it also
> shows you (with a needle) how much you are to the right or
> left of course, and the pilot may simply have calculated a
> 20 degree or more correction in order to get the needle to
> center.  Keeping the needle centered, he thinks he is just
> correcting for wind, while his actual heading is quite wrong.
> I am guessing that this is why he refered to the DG the way
> he did in the report. (yep, i'm a pilot, fly my own plane).

As long as the aircraft is flying the correct ground track,
it will have obstacle clearance.  The heading is immaterial.

For example, assume a news helicopter is tracking a parade on
an east-west road.  Parade is going east at 3 knots.  Wind is
out of the north at 30 knots.  Helicopter needs to fly at 30.1
knots airspeed on a heading of 006 to stay on a ground track
of 090.  That's 84 degrees of crab -- but the helicopter will
stay over the floats.  This is a exagerated example, but the
same thing works on a airway.

If the DG shows a value that's grossly at odds with the VOR
heading when corrected for expected/reasonable wind, then the
flight crew should suspect an equipment malfunction.  And use
all other available navigation gear (ADF, DME, GPS, and/or
Loran on board; radar track on ground [i.e. ask controller]) to
verify their location and pinpoint which instrument(s) failed.

                                                Lee Jones