As pilots, we face a myriad of decisions and actions during flight. One of the most common questions I hear from IFR students is whether they should rely on autopilot or hand-fly during their check ride. The truth is, if your aircraft is equipped with an autopilot, you need to be proficient in using it while also being able to handle the same procedures manually. While it’s easy to say, "always hand-fly," or "never make mistakes with autopilot," the reality is that errors do occur. Let's explore the most common autopilot mistakes and how to avoid or rectify them.
Understanding Autopilot Basics
Autopilots come in various forms, and for this discussion, we’ll focus on the G1000 NXi. However, the principles can be applied to many other autopilot systems. The first and most critical tip comes from the commercial aviation sector: always set your heading bug to your current heading or to your new heading during a change. This simple action can prevent confusion and errors as you navigate.
Heading Bug Mismanagement
When flying a route using GPS, the autopilot tracks the GPS as indicated by the green GPS enunciation. For instance, if our current heading is 276 degrees and we are preparing to make a right turn to the next leg at 344 degrees, the heading bug must be adjusted accordingly. If we neglect to twist the heading bug to match our new desired track, confusion can arise.
Imagine needing to load an entire airway instead of just flying to the next waypoint. If the heading bug is left behind, activating heading mode (HDG) could cause the aircraft to turn left toward the previously set heading, leading to a deviation. Therefore, it's crucial to keep the heading bug synchronized with your current or intended heading.
Altitude Errors
Altitude errors are another common issue. When the autopilot is set to hold an altitude, say 2,000 feet, and ATC assigns a new altitude of 3,000 feet, the autopilot may enter altitude capture mode, locking in the previous altitude. If you attempt to change to the new altitude after entering capture mode, the aircraft will not climb as expected.
The solution? Always confirm the altitude being held or captured on the status bar. If no altitude is depicted in green and you’re still in FLC (Flight Level Change) mode, you can safely change your selected altitude, and the autopilot will register that change.
Approach Mode Arming Timing
Another frequent mistake involves when to arm approach mode (APR) on the autopilot. Many pilots mistakenly hit APR as soon as they receive their approach clearance. However, it's vital to understand what arming APR does. For example, in an LPV approach, arming APR will engage glide path capture mode, which means the aircraft will not descend until the glide path is intercepted.
Best practice dictates that you should only arm approach mode when you’re ready for the autopilot to manage both lateral and vertical guidance. If you still have heading or altitude changes to make, delay arming approach mode until you're prepared.
Best Practices for Autopilot Use
To avoid these common autopilot mistakes, here are some best practices to keep in mind:
Always set the heading bug:Â Adjust the heading bug to your current or new heading to avoid confusion.
Monitor altitude carefully:Â Confirm the altitude being held and adjust your altitude selector before entering altitude capture mode.
Arm approach mode wisely: Only arm APR when you’re ready for the autopilot to take over lateral and vertical guidance.
Practice regularly:Â Familiarity with your autopilot system will enhance your confidence and proficiency during flights.
Conclusion
Understanding and mastering your autopilot system, such as the G1000, is essential for any pilot, especially in IFR conditions. By recognizing common pitfalls and employing best practices, you can enhance your flying experience and safety. Remember, autopilot is a tool designed to assist you, but you must know how to use it effectively. If you're keen on improving your skills further, check out our Transition to Glass Cockpit course!