Originally Posted by V1… Ooops
AirRabbit has explained that one can adjust seating appropriately by making three reference checks, and this makes a lot of sense, but does this fulfill the requirement for the 'fixed marker or other guide'?
In a word, Yes. The FAR requirement allows for either the “fixed marker” or “other guide.” The point is to allow the pilot to achieve the proper eye reference position in 3-dimensional space. Because most pilot seats do not have side-to-side adjustments except at the most aft position (for ingress/egress ease – and then the requirement is usually to have the seat in the forward “X” inches of travel – to prevent side-to-side errors), the only two adjustments that remain are “fore/aft” and “up/down." If you use the technique of sighting down the top of the glare shield, while being able to see the top of the annunciator lights above the flight instruments; AND are able to see the bottom of the EHSI, you will have achieved the necessary “fore/aft” and “up/down” positioning that would place your eye reference in the prescribed location.