By The CTS Team on June 26, 2017
Category: In-flight safety

Preventing Loss of Control in Flight Part 2: Spatial disorientation

In order to prevent LOC-I, you must know what's happening to your aircraft at all times.

Last week, we began a four-part series on preventing loss of control inflight, or LOC-I, to go along with the FAA's #FlySafe campaign. In part two of our four-part series, we focus on LOC-I as a result of spatial disorientation, covering how to recognize common types of disorientation and combat them before they become dangerous.

Coming to your senses

Three sensory systems keep us oriented in space: the visual, the vestibular (motion and gravity, located in the inner ear), and the proprioceptive (skin, muscles). All three systems are prone to errors, with the visual being the most reliable. Trusting in an erroneous sensory system without cross-checking the others results in spatial disorientation.

Instruments will almost always provide what your senses cannot in terms of a reliable picture of aircraft orientation, but they are not infallible. Your senses and your instruments should work as cross-checks for one another. Even though instruments are the more reliable indicators, they can still malfunction, and your senses may be your first clue this has happened.

Spatial disorientation

Many of the most common types of disorientation are preventable if you are aware of their causes. For example, the leans can be avoided by refraining from very slow turns. Fluid within the inner ear moves with the head, sending signals to the brain about the head's orientation via tiny hairs. Entering a gentle banked turn causes the fluid to move too slowly for your brain to detect the motion, resulting in perception of straight and level flight. When you level off suddenly, the fluid moves back and your brain overcorrects to think you are in an opposite direction turn.

A similar form of disorientation occurs when you turn for long enough that the fluid in your ears stops moving, then level off, causing the coriolis illusion. If not recognized, you might try to overcorrect by returning to your original turn without adjusting for descent by adding back pressure. Once you recognize the descent, you'll erroneously assume you're in a wings-level descent, when you're actually banked. At this point, you might pull back on the yoke or increase power without leveling the wings, tightening into a graveyard spiral.

The rule of steady, deliberate control inputs remains the same for pitch and airspeed as it does for turns. Pitching up or down too quickly can give the inversion illusion of the aircraft tumbling backward or forward, causing the pilot to want to overcorrect. Sudden acceleration or deceleration without a visual reference can make the pilot feel they are pitching nose-up or nose-down, respectively, for a somatogravic illusion. Without visual references, you should always avoid control inputs that are very sudden or very subtle.

Corrective action

If you discover you have become disoriented during flight, do not panic. If not in a critical situation, take a moment to look inside the cockpit for several seconds to reorient yourself. Cross-check the gauges with one another and note any that provide conflicting information. Then, as necessary, take corrective action in the following order of priority:

As with most aspects of aviation, practice and good preparation are the keys to LOC-I prevention. Practice partial panel flying often and ensure you keep something in the cockpit (such as sticky notes) to cover any malfunctioning gauges. Use a simulator to practice recovery techniques in controlled conditions, and supplement this with an upset prevention and recovery course if possible. Regular practice will help ease the initial surprise of disorientation, enabling you to quickly recognize it and take appropriate action.

Part three of our LOC-I series continues next week, where we'll focus on good ADM and its role in preventing accidents.

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