Flight Benefits of Using a Heading Indicator
The magnetic compass is the most common device found in the pilot’s cockpit; however, it is also known as the faultiest device. During times of turbulence, the compass can become increasingly difficult to read and be subject to incorrect acceleration and turning errors. Its inaccuracies can make it difficult for the pilot to fly by safely. To come to the rescue of frustrated pilots, the Heading Indicator (HI) is a gyroscopic instrument that maintains alignment with the magnetic compass. This tool makes for more accurate flight paths by eliminating severe acceleration or turning errors.
There are a few mechanical factors, mainly attributed to friction, that may cause the HI to drift off the original alignment with magnetic north. This is referred to as mechanical drift. The rotation of the earth can also affect the HI. If you imagine a line running north in space it will forever be changing because of Earth’s constant rotation. This is referred to as apparent drift.
However, these errors can be fixed with a simple solution. The HI is able to be realigned to the magnetic compass found in all aircrafts when corrections need to be made. The pilot should be sure to check the power source is active and that the correct turns are being indicated on the HI prior to entering air travel. Every HI has a “slaving knob” that enables the pilot to realign the HI, correcting for both the mechanical and apparent drift. This should be made a routine alignment by the pilot every 10-15 minutes.
Here are some tips to manually align the HI with the magnetic compass if these errors occur: First, choose a reference point directly ahead of the plane, aim on that point, and fly steady and straight. Maintain the plane’s heading toward this reference point and adjust the HI to match the magnetic compass readings. Ensure that the plane has remained steady and straight on its heading toward the reference to finish the realigning process.
With the use of these flight instruments in conjunction with one another, pilots should experience a more reliable tool to help them accurately navigate the sky.