We live in a world that is full of rules and regulations. This doesn't mean that we are all limited in to doing something that we want to do, rather than it is for us to play it safe and organized. In aviation, safety is a crucial and always become a priority in every aspect of flight. Besides safety, an organized sky will make flying more convenient and more economical. To not break the rules when flying, especially flying under iFR, we will list all the things that will result in a pilot deviation.
1) Failure To Reset Altimeter Settings
Forgetting to update your altimeter setting could leave you flying hundreds of feet above or below your assigned altitude, especially if you forget to reset while transitioning from the Flight Levels (29.92).
2) Descending Too Early On A STAR
Arrivals provide a scripted way to descend, and there are two ways to get down. Either ATC can manage your descent, or they can clear you to "descend via" the arrival which allows you to descend to each minimum altitude on the procedure. This also requires you to meet every altitude crossing restriction.
3) Descending Too Early On An Instrument Approach
Even if you've been cleared for the approach, you must be established on a published portion of the approach before descending further. Be careful to meet each step-down altitude and never descend below MDA until these three things happen.
What are the three things needed to go below DA/DH or MDA?
1. Continuous position to land on intended runway
2. Required flight visibility
3. Runway environment insight
4) Failure To Meet Climb Restrictions
Some SIDs require you to meet "at-or-above" crossing restrictions. Make sure you can meet these requirements before you depart.
5) Programming The Incorrect STAR Transition
Runway transitions usually direct aircraft to either side of an airport for separate downwind legs to parallel runways. Each runway transition will have its own set of fixes, and sometimes minimum altitudes. Let's take the TEJAS 4 Arrival for example. As you can see, there are separate downwind legs for various runways. This is shown both on the graphical depiction and in a textual description.
Flying an incorrect STAR transition is one of the most commonly reported deviations made by pilots. It almost always happens after a last-minute runway change as the crew is busy managing descent/arrival planning.
6) Failure To Level-Off
Avoid distractions as you approach your assigned altitude. If you deviate and separation is lost between IFR aircraft, you can expect a "possible pilot deviation" call over the radio.
7) Exceeding A Speed Limitation
While standard speed limitations apply for various types of airspace, ATC can limit you to certain airspeeds. If you deviate drastically, you may receive a pilot deviation.